(I

Stereochemistry and Reactions ofPentacoordinate Organophosphorus
Compounds with Martin Ligands(?~1- '/ 1) j}',/ r~~T 6

5@21sL~t~ 1) '/1~%~mO)

fL 1*1~~ t JXJZ)

Thesis Submitted to Hiroshima University
for the Degree of Doctor of Science

Kazumasa Kajiyama
January, 1997

Contents.

Contents
Chapter 1. General Introduction
A.

General Introduction

1

B.

References

12

Chapter 2.

Syntheses and Characterization of Intra- and Intermolecular

Hydrogen Bonding Isomers of P-H (Apical) Phosphoranes Bearing a
Hydroxy Group.
A.

Introduction..........

16

B.

Results and Discussion..........

18

C.

Experimental Section..........

38

D.

References..........

55

Chapter 3.

First Characterization of 10-P-5 Spirophosphoranes with an

Apical Carbon-Equatorial Oxygen ring. Kinetic Studies on Pseudorotation.
A.

Introduction..........

57

B.

Results and Discussion. .........

60

C.

Experimental Section. . ........

75

D.

References. .........

99

Contents.

Chapter 4. Kinetic Studies of Thermal Cyclization Reactions of P-H (apical)
Phosphoranes Bearing a Hydroxy Group.
A.

Introduction..........

101

B.

Results and Discussion..........

104

C.

Experimental Section. .........

115

D.

References. .........

136

Acknowledgements

138

List of Publications

139

Chapter 1

General Introduction

Chapter 1.

A. General introduction

Phosphorus is required by all biological systems and holds an importantrole in biological processes in the form of phosphates. In living organisms,
phosphates are important parts of large molecules or molecular assemblies
such as DNA, RNA, and membranes, a carrier of substrates as shown inglucose phosphates and coenzymes, and transportation of chemical energy(A TP). 1) These phosphate esters easil y undergo hydrolysis and phosphoryltransfer in biological processes due to the ease of attaining thepentacoordinate state as a transition state or an intermediate.
The chemistry of pentacoordinate phosphorus has been developing overthe past decades. PPhs, the first organic phosphorane, was synthesised by
Wittig and Reiber in 1949,2) of which trigonal bipyramid (TBP) structure wasdetermined 15 years later by Wheatley,3) A large number of phosphoranes
have been synthesized and characterized in conjuction with the developementof the NMR technology.

Burgada and Setton have summarized attractive

fundamental aspects of the chemistry of pentacoordinate phosphorus
compounds into three items.4)

The first one is the discovery of theirstereochemical non-rigidity, that is, the exchange of substituents (ligands) at
the axial and equatorial positions in a TBP structure without bond cleavage.
This was interpreted by BerryS) based on Berry pseudorotation mechanism(stereomutation). The second one is the presence of equilibria between P (III)and P (V), P (IV) and P (V), and P (V) and P (VI), stemming from the easeof phosphorus to violate the Lewis octet rule 6 . A variety of experimental
observations have been reported since the first postulation was reported by
Fenton and Ingold 7 ) in 1929. The third one is the reports of Westheimer8)-1-Chapter 1.
that the rates of hydrolysis of five-membered cyclic phosphates weresignificantly faster than those of acyclic phosphates. He has postulated theexistence of pentacoordinate intermediates which are capable of undergoing
the stereomutations described by Berry.
The basic structure of pentacoordi nate phosphoranes are predicted to betrigonal bipyramid CTBP) structure (Fig. 1- 1), in which there are distinctive
sites, the apical and the equatorial positions, by fitting the axioms of thevalence shell electron pair repulsion (VSEPR) theory of Gillespie 9 ). Bothexperilnental results and theoretical calculations 9 , 10) show that the TBP
structure is more favorable than square pyramid (SP) structure (Figure 1-2).
In an ideal arrangement the three equatorial points would be in the sameplane, the angle formed with an arbittrary equatorial site, the center, andanother arbitrary equatorial site is 120 0 , while the length between the central
atom and the apical ligand is longer than the equatorial bond and the apicalbond comprising of the two sites positioned linearly with the center intersects
the equatorial plane perpendicularly. This inequivalence of sites causes anabrupt increase in the possible number of isomers. Assuming all five sites areoccupied by different substituents, up to 20 isomers are possible including
enantiomers as compared with only 2, a pair of enantiomers, for tetrahedral
molecules with four different substituents.
axial

F apic~l

I .",,'t F

equatorial

equatorial___

F - - - - -p .....

tb~~~..

,................. '~'F...1 ...........
equatorial
F apicalF

I .~a:al"'Ip \\\\

F/"F

basal

basal

Trigonal bipyramid(TBP)

Square pyramid(SP)

Figure 1-1

Figure 1-2-2-

Chapter 1.

In order to explain the electronic structure of the central atom and thevalidity of violation of the Octet rule, Pauling 11) has proposed theconventional explanation that the lowest lying d orbital would participate in
the hybridizaiton of orbitals to form a dsp3 type combination.

However,

Pimental 12) and Rundle 13 ) have proposed an alternative explanation based on
the concept of three-center four-electron (3c-4e) bond in 1951, in which theelectrons are delocalized into the apical substituents to relieve the electron
density upon the central atom. According to Musher's simplified bonding
scheme l4 ) for pentacoordinate species the three equatorial bonds is describedas involving Sp2 orbitals of the P atom, while the apical 3c-4e bonds can becomprised of the a and an bonds formed by the linear combination of theremaining p orbital on the central atom and one valence atomic orbital ofeach of the two apical atoms (Fig. 1-3).

Figure 1-3

DC)

CX3--tt- an~--tt-a

8

--7t*

888

/'B

F-P-F
<Apical Bond: 3-center 4-electron bond><allylic anion>

This concept is analogous to that of 7t electron conjugation as seen in theallylic anion. In order to alleviate the electron density upon the central atom,electron accepting substituents would be prefered in these apical positions,leading to the concept of apicophilicity. A large number of theoretical and-3-Chapter 1.
empirical studies on relative apicophilicity have been reported, 15) although not
all of them give the same results. It is probable that the apicophilicity of agroup must be attributed to the combined influences of many factors, such as
electronegati vi ty, p1t- d1t interaction, steric effects, stereoelectronic effects 16,17) and polarizability.

The fast permutation of pentacoordinate compounds as shown in PF5 or
as postulated by Westheimer can be accounted for by the Berrypseudorotation (BPR) process which is widely accepted over othermechanisms. 18 ) The mechanism assumes that the pair of apical substituents
bend away from a pivotal equatorial atom and the remaining two equatorial
substituents bend toward this pivotal atom to proceed via a transition state ofsquare pyramidal structure on to an isomer which has the apical atoms
exchanged with the two moving equatorial atoms (Fig. 1-4). According tothis mechanism when the five sites are unequally substituted the epimerizationof one isomer to the enantiomer needs at least five steps in which each
substituent is used once as the pivotal atom (Fig. 1-5). The permutation
processes by BPR has cleverly been summed up in a topological graph usuallyreferred to as the Desargues-Levi graph.19)

Figure 1-4.
1~I ~,,4:-------~...:."\'-----T~ ~~I - ... 1

e

I"::

'1'3

I":

:\

:::::==='1':::::3==~ ~.~,,'t\t\:,~-----i--" I

T~--'2
4 --.-

2~

TBP

5 ·-.-

1-----

SP

-4-

TBP

Chapter 1.

Figure 1-5. 5 Step Epimerization Process and the Desargues-Levi Graph
5

3-

2

1.. ., ,'\
"

I

\f' 1

~

1"2

1

1....,"'\

1 - .. '4

1"5'-I' 4~4-

31...," \2 \f' 2

....

~

1"3

1. . . , '\2 - .. '

5

1"1

3

5

4

23

15

34

1~ '-1'5
I

1

3_l/.
1" 5
,,,,,4

1

2

3_L. .",, 44,, ,, l_3
1"5 5/1
2

2

2

1"3
I

21

12
52

I . . .,\\\5

4 -P ····

52

53, , _ = - - - 32

2335'\.-== - - - 32

35

25

53

25

There are several guidelines for raising the permutation barrier which inprinciple is to differentiate the thermodynamic stability of topologically nonidentical configurations 20 ) ; (1) to fit in substituents in which the difference inelectronegati vity between the apical and equatorial substituents is as large as
possible; (2) to set bulky groups in the equatorial position; (3) to incoorporate
small rings (members of five or less) into the compound; (4) to fix the 1t
orbital of 1t donor equatorial substituents perpendicular to the apical bond and
1t orbital of 1t acceptor substituents parallel to the apical bond.

For example,

it has been suggested that, in the hydrolysis reaction of triesters of- 5-

Chapter 1.
phosphonoformic acid, 1t acceptor ligand in the equatorial position stabilize
the pentacoordinate intermediate by the charge transfer of an (apical P-O) to
1t*(C=O).17) Further modified compounds are polycyclic phosphoranes suchas phosphatranes 21 ), in which the ligands around phosphorus are fixed.
The inversion of spirophosphoranes bearing two carbon-oxygen fivemembered rings can be described with the seven step BPR and the DesarguesLevi graph is reduced to Fig. 1-6. 14,41,25, and 52 isomers can not exist at
all since the angle of apical O-P-C is 180°. Possible isomers 34, 43, 35, and53 are avoided because of their relatively higher energies due to thearrangement in which the five-membered ring is diequatorial and two
oxygens are in the equatorial positions. Among the remaining eight isomers
which can be grouped into four pairs of enantiomers, it is evident that themost stable isomers are enantiomers 12 and 21 bearing apical oxygenequatorial carbon five-membered rings, the second are 15 and 42 bearing anapical carbon-equatorial oxygen five membered ring, and the third are 54
and 45 bearing two oxygen in the equatorial positions from the concept ofapicophilicity.

The highest energy isomers of 23 and 13 bearing adiequatorial five-membered ring along with one apical oxygen should beeither intermediates or transition states of the inversion process ofenantiomers

12 and 21.

Thus, it appears possible to isolate

thermodynamically stable enantiomeric pairs of spirophosphoranes withasymmetry only at phosphorus by means of modifying the oxygen-carbon
five-membered ring.
Many examples of isolations of thermodynamically stable optically active
phosphoranes with chirality also in the backbone have been reported. 22 ) They
are all diastereomers which bear more than two chiral centers including
phosphorus.

We are aware of only one example of an optically active-6-

Chapter 1.
phosphorane with asymmetry only at phosphorus reported by Hellwinke1. 10b)
However this optically active species exhibited residual optical activity andcould not be stereochemically defined.

Figure 1-6. 7 Step Inversion Process of Spirophosphorane
Bearing Two Oxygen-Carbon Five-membered Rings
and the Desargues-Levi Graph~02 1

5~-~1<'
3

4

23

10~

'P4

(02

5

3

'Ps

'P)

5C~

~C4

15

42

13

H~J2

1°1

5C~
1 ..........

b~3-f<~: 51~)1-3 C:>!I-d4

1~ Y'I
3 - P.

2621······""01

C
1
5c/1
Ol

'+' 3 3 - P1 ·····"",C 4 4 "', .....
'+'3 I" P-3~
I"C5

4C~

20~

54

12

CC4
'-.1

...P - 3

20""""

1

~02

~C5

21

45
53

53
34

I

23

32

32

35

35

We have reported the preparation and characterization of the firstenantiomeric pairs of stereochemically definable 10-P-5 23 ) spirophosphoranes

I-Rp and I-Sp, and 2-Rp and 2-Rp (Figure 1-7).24) We have utilized Martin
ligand that is known to stabilize many hypervalent species. 25 ) The unique-7-

Chapter 1.
features of this ligand are that the trifluoromethyl groups raIse theelectronegativity of the oxygen atoms attached to the phosphorus, thebidentate and the phosphorus atom together form a five-membered ring, andthe trifluoromethyl groups exert Thorpe-Ingold effect 26 ) to favor theformation of the five-membered ring.

Figure 1-7
CF 3

F3 C

o

o
I

I
"""'... Io

I . . . . . ",R--P ..

.....P--R

"""CF

o
3

l-Rp;R=H
2-Rp; R = CH2CH20H

l-Sp;R=H
2-Sp; R = CH2CH20H

A large number of 10-P-5 monocyclic phosphoranes bearing a P-H bondhave been reported,27) most of which could only be observed in solution since
they usually exist in equilibrium with tricoordinate phosphorus species. The
large IJp_H coupling constants (650-800 Hz) usually observed indicate thepresence of an equatorial hydrogen. The only one example of a stable andisolable P-H phosphorane bearing an apical hydrogen has been reported by
M. R. Ross and J. C. Martin,28) where the IJp_H coupling constant (266 Hz) in

CDCh was much smaller than those of P-H (equatorial) phosphoranes.
In Chapter 2 the isolation and characterization of monocyclic P-H(apical) phosphoranes 6-8 bearing a hydroxy group are described (Scheme 1--8-

Chapter 1.
1). We have found that these P-H (apical) phosphoranes existed in solution as
equilibrating mixtures of intra- and intermolecular hydrogen bondingisomers which correspond to the structures determined by X-ray analysis andobserved 31p NMR chemical shifts in various solvents in order to support thestructure. The inversion of 6-8 turned out to be a combination of BPR andbond switching and kinetic behavior are described.

Scheme 1-1
e-exo
~

~

e-endof-endoF 3C'II,..

..,\\,CF301' ' '. . J~\

R/I ifi ..""
H

f_en:oonI~~:!~~~n!~ndO
F3C

CF3

"'~CF3solvent f-exo
0

F 3C"""e-exo

20. ;J.." " , ~, ' dtH I"R..

Hsolvent

6-Sp ; R = Me
7-Sp; R = n-Bu
8-Sp ; R = t-Bu

6-Rp; R = Me
7-Rp; R = n-Bu
8-Rp; R = t-Bu•

Switching of Hydrogen bond Partners

e-endo~•f-endo..,\\,CF301

F 3C'II" .

20~"""""'" "'p1*

F3 C

CF3
2Q
\
~
I

0
/

e-exo

f-exo

1

Ij
I
I
I

I
I

solvent

solvent-9-~*1p '". . "",,,,,~

Bond Switching,f-endo Inversion e-endo

R/I

H

~

I"R

H

Chapter 1.
It is well-known that phosphoranes bearing oxygen and carbon
substituents preferentially have oxygen atoms in the apical positions as themost stable stereoisomer according to the apicophilicity of the elements. 29 )However, no example of the isolation and characterization of phosphoranes
having an apical carbon-equatorial oxygen as the relatively less stablestereoisomers has been reported 24 , 2Sc) because of the low activation energy ofthe permutation of pentacoordinate compounds assuming TBP structures,
nonnally accounted for by BPR mechanism.
In chapter 3 the first isolation and characterization of both [TBPY-5-12]
spirophosphoranes 7-9 having an apical carbon-equatorial oxygen fivemembered ring along with their thermodynamically more stable apicaloxygen-equatorial carbon isomers 4-6 {[TBPY -5-11] spirophosphoranes}
formed from monocyclic P-H (apical) phosphoranes are described (Figure 1-8). The former correspond to 15 and 42 isomers, the latter to 12 and 21
isomers in Figure 1-6. Here, we describe their characterization and discuss
the relative thermal stability of 5 and 8 on the basis of kinetic studies.

F3 C

I~

.,,\CF 3

0~ "" ",·····P-R
I~~F34; R = Me
5; R = n-Bu
6; R = t-Bu

7-, R=Me8-, R = n-Bu
9', R = t-Bu

-10-

Chapter 1.
Monocyclic P-H (apical) phosphoranes 1-3 cyclized intramolecularly
with elimination of hydrogen to form the corresponding [TBP Y-5-11]
spirophosphoranes 4-6 predominantly in nondonor solvents and thecorresponding [TBPY-5-12] spirophosphoranes 8-10 predominantly in donor
solvents on heating. In order to gain an understanding of the mechanism andthe solvent effect of the thermal cyclization of 1-3, the kinetic studies of thethermal cyclization of 1-3 (Scheme 1-2) are described in Chapter 4. On thebasis of these results we propose mechanisms for formation of these
phosphoranes in both nondonor and donor solvent.

Scheme 1-2

donor
solventcc:

F3C

F3C"". CF3
I~
0

I ~

I
~ \\\\"\
I
1# 0#.....P-R.,,\,CF3.01~

111111

I"" 'P-R

F3CI/~'~?"F 3C

-::P'

I

~

8; R = Me
9-, R = n-Bu
10; R = t-Bu

4; R = Me
5;R=n-Bu
6;R=t-Bu-11-

Chapter 1.

B. References(1) Frausto da Silva, J. J. R.; Williams, R. J. P. "The Biological Chemistry of
the Elements. The Inorganic Chemistry of Life", Clarendon Press, Oxford,
1991 .
(2) Wittig, G.; Reiber, M. Justus Liebigs Ann. Chem. 1949,562, 147.
(3) Wheatly, P. J. J. Chern. Soc. 1964, 2206.
(4) Burgada, R.; Setton, Ralph. The Chemistry of Organophosphorus

COlnpounds, Vol 3, 185, Editated by Hartly F. R. John Wiley & Sons, 1994.
(5) Berry, R. S. 1. Chem. Phys. 1960,32, 933.
(6) (a) Lewis, G. N. J. Am. Chem. Soc. 1916,38, 762. (b) Langmuir, 1. 1.

Am. Chen1. Soc. 1919,41, 868.
(7) Fenton, G. W.; Ingold, C. K. 1. Chem. Soc. 1924, 2342.
(8) (a) Westheimer, F. H. Acc. Chem. Res. 1968, 1, 70. (b) Westheimer, F.
H. Pure Appl. Chem. 1977,49, 1059. (c) Grelt, J. A.; Westheimer, F. H.;
Sturtevant, J. M. 1. Bioi. Chem. 1975,250, 5059.
(9) Gillespie, R. J. Molecular Geometry, van Nostrand-Reinhold, 1972.

(10) (a) Muetterties, M. L.; Shum, R. A. Q. Rev. Chem. Soc. 1966,20, 245.
(b) Hellwinkel, D. Chem. Ber. 1966, 99, 3628.

(11) Pauling, L. The Nature of the Chemical Bond, 3rd ed., Cornell: Ithaca,
New York, 1960.
(12) Pimentel, G. C. J. Chem. Phys. 1951,19,446.

-12-

Chapter 1.
(13) Hach, R. J.; Rundle, R. E. 1. AJn. Chern. Soc. 1951, 73, 4321.

(14) Musher, J. I. Angew. Chern., Int. Ed. Engl. 1969,8, 54.
(15) (a) Stewart, A. P.; Trippett, S. 1. Chern. Soc., Chern. Commun. 1970,
1279. (b) Cram, R. K.; Trippett, S. 1. Chem. Soc., Perkin Trans. 1973,1,
1300. (c) Duff, E.; Trippett, S.; Whittle, P. J. 1. Chern. Soc., Perkin Trans.

1973, 1, 972. (d) Trippett, S.; Whittle, P. J. 1. Chem. Soc., Chern. Commun.
1973, 2302.
2203.

(e) Dickstein, J. I.; Trippett, S. Tetrahedron Lett. 1973,24,(f) Trippett, S. Pure Appl. Chern. 1974,40, 595. (g) Bone, S. A.;

Trippett, S.; White, M. W.; Whittle, P. J. Tetrahedron Lett. 1974,20, 1975.
(h) Bone, S. A.; Trippett, S.; White, M. W.; Whittle, P. J. 1. Chem. Soc.,

Perkin Trans. 1977, 1, 80.

(i) Brierly, J.; Trippett, S.; Whittle, P. J. 1.

CheJn. Soc., Perkin Trans. 1977, 1, 1977. (j) Trippett, S.; Waddling, R. E.
L. Tetrahedron Lett. 1979,2, 193. (k) Kay, P. B.; Trippett, S. 1. Chern.

Res. (s), 1986, 62. (1) Debruin, K. E.; Padilla, A. G.; Campbell, M. T. 1.
AnI. Chem. Soc. 1973,95,4681. (m) Emsley, J.; Hall, D. The Chemistry of
Phosphorus, Happer and Row, London, 1976.

(n) McDowell, R. S.;

Streitwieser, H.Jr. 1. Am. Chern. Soc. 1985,94, 3047.

(0) Buono, G.;

Llinas, J. R. 1. Arn. Chem. Soc. 1981,103, 4532. (p) Cavell, R. G.; Gibson,

J. A.; Gibson, K. I. 1. Am. Chern. Soc. 1977,99,7841.
(16) (a) Peake, S. C.; Schmutzler, R.I. Chern. Soc. A. 1970, 1049. (b)Landau, M. A.; Sheluchenko, V. V.; Drozd, G. I.; Dubov, S. S.; Ivin, S. Z.

Zh. Strukt . Khim. 1967,8, 1097. (c) Harris, J. J.; Rudner, B. 1. Org. Chern.
1968,33, 1392. (d) Harman, J. S.; Sharp, D. W. N. inorg. Chern. 1971,10,1538. (e) Muetterties, E. L.; Meakin, P.; Hoffmann, R.I. Am. Chern. Soc.

1972, 94, 5674.

-13-

Chapter 1.
(17) Gregory, R. 1.; Thatcher, E. S.; Krol, R.; Dale, R. 1. Chern. Soc., Perkin
Trans. 1994, 2, 683.

(18) (a) Ugi, I.; Marquarding, D.; Klusacek, H.; Gillespie, P. Acc. Chern.
Res. 1971,4, 288.

(b) Windus, T. L.; Gordon, M. S.; Burggraf, L. W.;

Davis, L. P. 1. AnI. Chen1. Soc. 1994, 116, 3568.

(19) Mislow, K. Acc. Chern. Res. 1970,3, 321.
(20) Holmes, R. R. 1. AnI. Chen!. Soc. 1978, 100, 433.
(21) (a) Tang, 1.; Dopke, 1.; Verkade, 1. G. 1. Arn. Chern. Soc. 1993,115,
5015. (b) Bosco, A. D'Sa.; Verkade, 1. G. 1. Org. Chern. 1996,61,2963.
(22) (a) McClure, C. K.; Grote, C. W.; Lockett, B. A. 1. Org. Chern. 1992,
57, 2963. (b) Moriarty, R. M.; Hiratake, 1.; Liu, K.; Wendler, A.; Awasthi,

A. K.; Gilardi, R.I. Arn. Chen1. Soc. 1991,113, 9374. (c) Acher, F.; luge,
S.; Wakselman, M. Tetrahedron 1987,43, 3721. (d) Klaebe, A.; Brazier, 1.

F.; Carrelhas, C.; Garrigues, B.; Marre, M. R. Tetrahedron 1982,38, 211l.
(e) Devillers, P. 1.; Garrigues, B.; Wolf, R. Acta Crystallogr. 1979, B35,

2153. (f) Contreras, R.; Brazier, 1. F.; Klaebe, A.; Wolf, R. Phosphorus,
1972,2,67. (g) Newton, M. G.; Collier, 1. E.; Wolf, R. 1. Arn. Chern. Soc.
1974, 96, 6888 and references cited therein.
(23) Perkins, C. W.; Martin, 1. C.; Arduengo, A. 1.; Lau, W.; Alegria, A.;
Kochi, 1. K. 1. Arn. Chern. Soc. 1980,102,7753.

(24) (a) Kojima, S.; Kajiyama, K.; Akiba, K.-y. Tetrahedron Lett. 1994,35,
7037. (b) Kojima, S.; Kajiyama, K.; Akiba, K.-y. Bull. Chern. Soc. lpn.
1995,68, 1785. (c) Kojima, S.; Nakamoto, M.; Kajiyama, K.; Akiba, K.-y.
Tetrahedron Lett. 1995,36, 22617.

-14-

Chapter 1.
(25) (a) Perozzi, E. F.; Martin, J. C. 1. Am. Chem. Soc. 1972,94, 5519. (b)Perozzi, E. F.; Michalak, R. S.; Figuly, G. D.; Stevenson, W. H., III; Dess,
D. B.; Ross, M. R.; Martin, J. C. 1. Org. Chem. 1981,46, 1049.

(c)Granoth, I.; Martin, J. C. 1. Am. Chem. Soc. 1979,101,4618,4623. (d)Stevenson, W. H., III; Wilson, S.; Martin, J. C.; Farnham, W. B. 1. Am.

Cheln. Soc. 1985, 107, 6340.

(26) (a) Beesley, R. M.; Ingold, C. K.; Thorpe, J. F. 1. Chem. Soc. 1915,
107, 1080. (b) Ingold, C. K. 1. Cheln. Soc. 1921,119, 305.

(27) (a) Malavaud, C.; Barrans, J. Tetrahedron Lett. 1975,35, 3077. (b)Boisdon, M. T.; Maravaud, C.; Mathis, F.; Barrans, J. Tetrahedron Lett.

1977, 39, 3501.

(c) Laurenco, C.; Burgada, R. Tetrahedron. 1976,32,

2253. (d) Lopez, L.; Fabas, C.; Barrans, J. Phosphorus Sulfur 1979, 7, 81.
(e) Tangom, B.; Malavaud, C.; Boisdon, M. T.; Barrans, J. Phosphorus

Sulfur 1988, 40, 33.

(28) Ross, M. R.; Martin, J. C. 1. Am. Chem. Soc. 1981, 103, 1234.
(29) (a) Holmes, R. R. Pentacoordinated Phosphorus-Structure andSpectroscopy; ACS Monograph 175, 176; American Chemical Society:
Washington, DC, 1980; Vols. I, II.

(b) Trippett, S. Phosphorus, Sulfur

Silicon Relat. Elem. 1976, 1, 89. (c) McDowell, R. S.; Streitwieser, A. 1.
Am. Chem. Soc. 1985,107,55. (d) Wang, P.; Zhang, Y.; Glaser, R.; Reed,
A. E.; Schleyer, P. v. R.; Streitwieser, A. 1. Am. Chem. Soc. 1991,113, 55.
(e) Thatcher, G. R. J.; Campbell, A. S. 1. Org. Chem. 1993,58, 2272. (f)Wasada, H.; Hirao, K. 1. Am. Chem. Soc. 1992, 114,16.

-15-

Chapter 2

Syntheses and Characterization of Intra- andIntermolecular Hydrogen Bonding Isomersof P-H (Apical) Phosphoranes Bearinga Hydroxy GroupChapter 2.

A. Introduction

Known examples of 10-P-5 1) phosphoranes bearing a P- H bond which
are mostly mono- or bicyclic phosphoranes containing some heteroatoms
bonded to phosphorus, which stabilize the hypervalent compounds. Althougha large number of monocyclic P- H phosphoranes have been reported,2) mostof them could only be observed in solution since they usually exist in theequilibrium with tricoordinate phosphorus species (eq. 1).

As forphosphoranes bearing monodentate oxygen or fluorine (Z = OR', F) ligands,
the lJp_H coupling constant in various solutions are 650- 800 Hz, whichindicates the presence of an equatorial p-H.2a-d, 3) The equatorial orientationof the hydrogen atom is probably due to its lower apicophilicity comparedwith oxygen and fluorine.

In the case of phosphorus bearing nitrogenmonodentates the IJp_H coupling constant comes in the range of 350-500 Hz
implying the existence of equilibrium between phosphoranes with apical H
and equatorial H.2e)

+HZ

(1)

The only one example of a stable and isolable P-H phosphorane bearing
an apical hydrogen has been reported by M. R. Ross and 1. C. Martin,4)
where the IJp_H coupling constant (266 Hz) in CDCl3 of the compound A wasmuch smaller than those of P-H (equatorial) phosphoranes.
-16-Chapter 2.

We have succeeded in the isolation of monocyclic P-H (apical)
phosphoranes 6-8 bearing a hydroxy group by the reaction of lO-P-5 P-H(equatorial) spirophosphorane 1 with 3 equivalents of RLi (R = Me, n-Bu, (Bu) in Et20 followed by careful treatment with 1 M Hel (Scheme 3-1). The
reactions involve the nucleophilic attack of RLi to the 10-P-4 phosphoranide
2 generated by incipient deprotonation of 1 to give ring opened dianionicspecies 3-5, which are diprotonated upon acidic workup.

Although we

obtained 6 and 7 as intramolecular hydrogen bonding isomers, in the case of8, both the intra- (8a) and intermolecular hydrogen bonding isomer (8b)
could be crystallized out as single compounds by changing the solvent.
Furthermore, we found that these P-H (apical) phosphoranes existed insolution as equilibrating mixtures of intra- and intermolecular hydrogenbonding isomers by their 31 P NMR chemical shifts in various solvents. The
inversion of 6-8 turn out to be a combination of Berry pseudorotation(BPR)5) and bond switching.

-17-

Chapter 2.

B. Results and Discussion

1. Preparation and the Structure of Monocyclic P-H (Apical)
Phosphoranes in Solution.

Scheme 2-1

RLiI

F C/, CF3

0

~

I

R"

RLi

... PGLi@· 13C~F3
U'OGLi@

3 ,. R=Me
4 ,. R = n-Bu
5 ; R = t-Bu

The preparation of monocyclic 10-P-5 P-H (apical) phosphoranes 6-8
was carried out as shown in Scheme 2-1.

The reaction of 10-P-5 P-H(equatorial) spirophosphorane 1 [8p (CDCb) = -45.8, IJp_H = 729 Hz]6) with
3 equivalents of alkyl lithium reagents in Et20 at -78°C followed by careful-18-

Chapter 2.
treatment with 1 M HCI gave stable phosphoranes 6 [yo 68%, 8p (CDCl)) =-51.9, IJp_H = 276 Hz], 7 [yo 90%, 8p (CDCl)) = -34.4, IJp_H = 273 Hz] and8a [8p (CDCl)) = -14.7, IJp_H = 273 Hz], Sb [8p (CDCI3) = -42.7, IJp_H =293 Hz] (combined y. 92%). However, in the case of MeLi and n-BuLi
when the reactions were performed in THF at -78°C, during the workup
the formation of cyclization products 9 and 10 or oxidation of 10-P-4
phosphoranide

2

generatinghydroxyphosphorane

12

occurredpredominantly. The reactions involve the nucleophilic attack of RLi to the
10-P-4 phosphoranide 2 [8 p (Et20) = 43.0] generated by incipient
deprotonation of 1 to give a ring opened dianionic species 3 [8p (Et20) =-33.5], 4 [8 p (Et20) = -23.1] and 5 [8 p (Et20)= -10.1], which is

diprotonated upon acidic workup. 10-P-5 [TBPY-5-11] spirophosphoranes
9 (R = Me) and 10 (R = n-Bu) were obtained as minor products in 22% and90/0 yields, respectively, whereas no 10-P-5 [TBPY-5-11] spirophosphorane

11 was obtained in the case of R = t-Bu. In the case of phosphorane 6 (R =Me) partial cyclization was found to occur even on PTLC (hexane-CH2CI2 =5 : 1). Upon slow recrystallization of phosphoranes 6 and 7 from hexaneCH2Cl2 slow cyclization occurred. These results indicate that the order ofstability of monocyclic phosphoranes towards cyclization is 6 < 7 < S.
Although intermediates could not be isolated, similar alkyl and aryl
spirophosphoranes have been obtained in nucleophilic reactions to a 10-Sb-4
stiboranide 7).

-19-

Chapter 2.

F3C11' CF3
~ I
0

C( I
~

.. P-Ph

Ph"'"

I

H

A

The IJp_H coupling constant (273- 293 Hz) of monocyclic phosphoranes

6-8 revealed the presence of an apical hydrogen in solution. As the only
known phosphorane bearing an apical hydrogen, J. C. Martin et al. hasreported that lJp_ H coupling constant of A (CDC13, 6p = -49.3) was 266
HZ.4) In contrast, lJp_H coupling constant of bicyclic phosphorane 1 (CDCl),

8p = -45.8) bearing an equatorial hydrogen was 729 Hz.6) This difference
can be understood as the difference in the bonding scheme about phosphorus.
The apical hydrogen is expected to bond with an essentially p-type
phosphorus orbital, while the equatorial hydrogen is attached to an
essentially Sp2 hybrid phosphorus orbital in trigonal bipyramid (TBP)
geometry8) .

2. Crystal Structure of Monocyclic P-H (Apical) Phosphoranes 6,7, 8a and 8b.
Single crystals of 6 and 7 could be obtained as prisms from hexaneC H 2C 12 .

Although isomers 8 a and 8 b

couldn't be separated bychromatography, they could each be crystallized out as single compounds bychanging the solvent, nondonor solvents (cyclohexane-CCI4) for the former
and donor solvents (CH3CN or EtOH) for the latter.

-20-

X-ray structural

Chapter 2.
analysis of phosphorane 6 (R = Me, Fig. 2-1), 7(R = n-Bu, Fig. 2-2), 8a (R= t-Bu, Fig. 2-3) and 8b (R = t-Bu, Fig. 2-4) showed the presence of anapical hydrogen in TBP geometry. As the drawings show the compounds
assume trigonal bipyramidal structures with an oxygen atom and a hydrogen
atom occupying the two apical positions and the three carbon atoms
occupying the three equatorial positions. The angles around the phosphorus
atom are nearly ideal as TBP with the apical O(l)-P(I)-H(I) angle being
172-176°, and the sum of the angles formed by the equatorial atoms andphosphorus being 359.4-360° implying coplanarity of the phosphorus atomand the three equatorial carbon atoms.

The structures of 6 and 7 were

essentially the same as 8a, differing only in the alkyl substituent.
Compounds 8a and 8b were found to differ only in the hydrogen bonding
partner of the hydroxy group, the former intramolecularly with the apicaloxygen of the bidentate and the latter intermolecularly with the nitrogen
atom of CH3 CN, a solvent molecule.

This is the first structuralcharacterization of hydrogen bonding isomers involving hypervalent
phosphorus. Although intramolecular hydrogen bond (01-H2) length of 6
[1.74 (4) A] and 7 [1.82 (5) A] was similar, that of 8a [1.4 (1) A] wassignificantly shorter because of the constraint imposed by the sterichindrance of t-Bu group. The PI-Ol (apical) bond was longer in 8a [1.922(5)] than in 8b [1.865 (2)].

This could be considered a consequence of

weakening of this polarizable bond by the intramolecular hydrogen bonding.
Additionally, the PI-02 (hydroxy) length of 8b [2.84 (4)] was shorter thanthat of 8a [3.131 (5)], thus we could expect the presence of stronger
intramolecular interaction of the hydroxy oxygen to phosphorus in donor
solvents.

- 2 1--

Chapter 2.

Table 2-1. Selected Bond Lengths and Angles for 6,7, 8a and 8b~CF3
I ~ O}~CF3
I ~ 01~CI/"'~~\-2
I,p-~CI/"'~1-2
IR~
H~. CF3
Cl9 HI 02 '//CF

R"""'"C19 HI

3

,p-

" CF3
?2 "'CF 3
H2,6; R=Me7·, R = n-Bu
8a·, R = t-Bu,

8b; R = t-Bu

Nl:::CCH 3

6

7

8a

8b

Bond length (A)
PI-OI
PI-HI
PI-CI
PI-CIOPI-CI9PI-02
01-H2

1.920 (3)1.38 (4)1.814 (4)1.842 (4)1.796 (6)3.100 (3)1.74 (4)1.952 (2)1.40 (4)1.805 (3)1.845 (3)1.812 (3)3.074 (2)1.82 (5)1.922 (5)1.47 (7)1.790 (7)1.881 (7)1.854 (9)3.131 (5)
1.4 (1)1.865 (2)1.33 (3)1.826 (2)1.855 (2)1.878 (3)2.84 (2)2.16 (4)(N1-H2)

Bond angle (deg)OI-P1-H1
01-PI-CI
CI-PI-Hl
OI-PI-CIO
CIO-PI-HI
OI-PI-CI9
C19-P1-H1
C1-PI-C10
C10-PI-CI9
CI9-PI-CI

176 (2)
83.5 (2)
92 (1)
88.1 (2)
95 (2)
90.6 (2)
90 (2)
117.0 (2)125.1 (2)117.4 (2)176 (1)
83.4 (1)
93 (2)
87.3 (1)93 (1)
91.0 (1)
92 (2)
116.5 (1)125.8 (1)117.1 (1)172 (3)83.6 (3)
89 (3)
90.9 (3)
90 (3)
95.0 (3)
91 (3)
111.4 (3)129.1 (4)119.5 (4)175 (1)
84.1 (1)93 (1)
87.75 (9)91 (1)
94.1 (1)90 (1)
131.2(1)111.5 (1)117.0 (1)0-22-Chapter 2.

Figure 2-1. ORTEP drawing of 6 showing thermal ellipsoids at the 30%
probability level.

C19

OHI

-23-

Chapter 2.

Figure 2-2. ORTEP drawing of 7 showing thermal ellipsoids at the 30%
probability level.

-

24 -

Chapter 2.

Figure 2-3. ORTEP drawing of 8a showing thermal ellipsoids at the 30%
probability level.

- 25 -

Chapter 2.

Figure 2-4. ORTEP drawing of 8b showing thermal ellipsoids at the 30%
probability level.

-

26 -

Chapter 2.
3. Solvent Effect
In order to gain further insight into structures in solution we examined
31P

NMR chemical shifts of monocyclic phosphoranes 6-8 in various

solvents at rt (Table 2-2). Phosphorane 6 was found to cyclize instantly
upon dissolving in MeCN, MeOH and pyridine and slowly in the othersolvents of lower donor ability.

In solvents of low donor ability thecompound was found to have a chemical shift of ca. -50.

However in

donative solvents a species of a higher chemical shift [bp (acetone) = -68.8,

Dp (THF) = -70.6] was observed. In the case of phosphorane 7 slow
cyclization occurred in the solvents of high donor ability (THF, CH3CN,
MeOH and pyridine). The emergence of a signal of high chemical shift at
ca. -52 was also observed as in the case of 6. Additionally, an equilibrium(Scheme 2-2) between intra- (lower chemical shift) and intermolecular(higher chemical shift) hydrogen bonding species could be observed in Et20,
acetone and CH 3CN.

No immediate cyclization was observed withphosphorane 8b. In contrast with 6 and 7 a signal of lower chemical shift
appeared upon dissolution of crystals containing 1 equivalent of solvent(EtOH) molecules in non-polar solvents (hexane, benzene and CHCl3).
Coupled with the X-ray structures these results suggest that all threecompounds exist as an equilibrating mixture of intermolecularly andintramolecularly hydrogen bonding species in solution and the ratio of thetwo is dependent on the solvent. In the case of 8, the bulky t-Bu groupsuppresses intramolecular hydrogen bonding by steric repulsion in theconformation required for it.

The general trend of the species (8b) ofintermolecular hydrogen bonding having a higher chemical shift than thoseof intramolecular interaction (8a) can be attributed to the shorter distance
between the phosphorus and the hydroxy oxygen in the intermolecular-27-

Chapter 2.
hydrogen bonding 8b (2.84 A) compared with that of 8a (3. 131 A) as
evident from the X-ray structures.

I

solvent

solvent

Table 2-2. 31 P NMR Chemical Shifts of Phosphoranes 6- 8 in Various
Solvents at RT.
7

solvent

6

8bhexane-53.0 b-35.5

-15.5 (8a) : -43.9 = 1 : 1benzene-52.6 b-34.2

-14.5 (8a) : -42.8 = 3 :2

CHCl3

-51.9 b-34.4

-14.7 (8a) : -43.0 = 2 : 1

Et20-53.4 b-35.0 : -52.3 = 3 : 1-42.2

acetone-68.8 b-31.3 : -51.4 = 1 : 3

-40.1

THF

-70.6 b-53.0 b

-41.2

CH3CN

a

-31.7: -51.4= 1: 1 b

-39.7

MeOH

a

-52.3 b-40.6

pyridinea-53.2 b-39.3
a Only the signal of the bicyclic compound was observed.
b The signal of the bicyclic compound was also observed.

-

28-

Chapter 2.
4. Kinetic Studies and Mechanism of Inversion of Configuration
at Phosphorus in Monocyclic lO-P-S P-H (Apical) Phosphoranes.

Scheme 2-3.

6-Sp; R = Me
7-Sp; R = n-Bu
8-Sp; R = t-Bu

6-Rp; R = Me
7-Rp; R = n-Bu
8-Rp; R = t-Bu

Although 19F NMR spectrum of monocyclic 10-P-5 P-H (apical)
phosphoranes 6 (R = Me) and 7 (R = n-Bu) in toluene-dg not only at low
temperature but also at rt showed four signals (a-d) for the four CF3groups, we could observe coalescence of peak band c at 327 and 363 K (Fig.
2-5 and 2-6), respectively. In the case of 8 (R = t-Bu) we could not observe

the coalescence of them. From 19F HOMO decoupling in CDCl3 at rt of 7
(Fig. 2-7), signals a (8 -72.9), b (8 -76.3), c (8 -76.8) and d (8 -77.0) were
found to be of CF3 groups of f-endo, e-exo, f-exo and e-endo in 7 -R p
(Scheme 2-3), respectively. Correlated exchange between e-exo and f-exo,and e-endo and f-endo takes place for the dynamical process. Thus theinversion of phosphoranes 6 and 7 should be explained with a combinationof BPR and bond switching.

-29-

Chapter 2.

Figure 2-5. 19 F NMR spectra of 6 in toluene-ds
T = 327 K

T = 223 K
. b

be

e
a

d
a

.; - ' -- ~-- ~ --.-.. -- :t - -.~-- - ...

; - ---~- - ., - ., - - ; ; -* Signals of cycliztion product 9 was also observed.

Figure 2-6. 19F NMR spectra of 7 in toluene-ds
T = 363 K

T = 233 K.. .....

-b~--------------be

e

a

d

I

I-----'

...

..

Jv

...

....

...

...

-

* Signals of cycliztion product 10 was also observed.

-30-.I• .a...

Chapter 2.

Figure 2-7. HOMO decouple of 19F NMR spectra of 7 in CDCl3

Irradiate signal a

Irradiate signal b

.

.

c

b

d

b
a

a

d

"
.I.

.10

.

-"

~

uU ..

c
~\

...

.10

Irradiate signal c

Ju

I

...

...

...

...

-

Irradiate signal dar.=;--

d

b c
a
~'.10

J..
.10

...

J~ V '-----;"
.lr

...

Two plausible mechanisms Path I and II for intramolecular exchange
are illustrated in Scheme 2-4 and 2-5, respectively. Path I involves trivalent
phosphine intermediate D by heterolysis 2, 4) of P-O and P-H bonds of C andE, while Path II involves sixcoordinate intermediate G in which exchange ofH2 occurs by concerted bond formation of P-02 and bond breaking of P-O I(Rp to Sp), that is, bond switching.

When an equivalent of CD30D wasadded to the solution of phosphorane 6 and 7 in toluene-ds at rt, themagnitude of integration of O-H proton decreased much more rapidly thanthat of P-H proton.

Furthermore, we could observe mono anionicderivatives 12-14 retaining the P- H bonding in Et20 by the treatment of thesolution of 6-8 in Et20 with excess amount of aqueous KOH. This implies-31-

Chapter 2.
that it is facile to attain the hexacoordinate state in P with compounds 6-8.
Therefore, we should believe Path II to be the case in which the exchange of
proton is not warranted for P-H but for O-H, probably due to the higher
acidity of the latter.

f=F 3
o

~

KG

~ :>f.'::'o X~::H

12; R = Me [~(Et20) = -153,1 Jp-H = 679 Hz]
13; R = n-Bu [8p (Et 20) = -130, IJp _H = 674 Hz] .
14; R = t-Bu [8p (Et20) = -117, IJp_H = 335 Hz]-32-

Chapter 2.

Scheme 2-4. <Path I>

e-exo
F 3C//

F3 C '

e-endo

10"

~r-HI
~02H2
F3C

CF 3

f-endo

f-exo

e-exo

e-endoF

llo/=
f-endof-exo

F3C'J:)'
20 CF~*I .. ", "'" I

H~O
F3~~'~'
I ~e-endo

e-exo

I

R- P"

"'H2

#

p_0 2 bond formation/ 2E
fp-O bond cleavage

D

-33-

Chapter 2.

Scheme 2-5. <Path II>

GH

The inversion of 6 and 7 in toluene could be monitored by 19F NMR
for the e-exo and f-exo CF 3 . Line shape analysis of the 19F NMR spectra [6(Fig. 2-8); temperature range of 313-335 K, 8v = 166 Hz, Tc = 327 K,~Gt327= 15.4 kcal mol- I: 7 (Fig. 2-9); temperature range of 353-373 K, 8v= 114 Hz, Tc = 363 K, ~Gt363 = 17.4 kcal mol- I] of one of the pairs ofsignals (b and c) gave the activation parameters (Table 2-3). Although thevalue of the activation entropy of 6 has little difference from that of 7, thebarrier of the inversion of 6 is lower than that of 7. Based on the fact thatthe solvent effect is insignificant (7 in v-dichlorobenzene; 8v = 106 Hz, Tc =363 K, i1Gt363 = 17.4 kcal mol- I), bond switching takes place rapidly and therate determining step exists in the BPR process.
-34-

Chapter 2.

Figure 2-8. Observed and Calculated line shape for CF) groups incompound 6 in toluene-dg_
Observed

T<K>
313

323

Calculated

k <sec- 1>

v
\...

190

...

315

325

347

327

389

329

432

331

482

333

524

335

584

- 35 -

Chapter 2.

Figure 2-9. Observed and Calculated line shape for CF3 groups incompound 7 in toluene-ds.
CalculatedObserved

T<K>
353

k <sec- I>

357

197

359

219

361

240

363

268

365

290

367

317

373

413

164

-36-

Chapter 2.

Table 2-3. Kinetic parameters of the inversion of 6 and 7 in toluene-ds

T c <K>k <sec- I>~G+ <kcal mol-I >Mi+<kcal mol- I>~S+ <eu>

6

327

268

15.3

10.0 ± 1.3- 16.2 ± 6.8

7

363

290

17.4

11.4±1.7-16.3 ± 4.9-37-Chapter 2.

c. Experimental Section

Melting points were measured with a Yanaco micro melting point
apparatus and are uncorrected.

lH NMR (400 MHz), I3C (100 MHz), 19F(376 MHz), 31p (162 MHz) spectra were recorded on a lEOL EX-400
spectrometer. 1H NMR chemical shifts (8) are given in ppm downfield frominternal Me4Si, determined by Me4Si or by residual chloroform-d (8 =7.26) , acetone-d6 (8 = 2.0) or toluene-d8 (CD3 group; of 8 = 2.31). 13C
NMR chemical shifts (8) are given in ppm downfield from internal Me4S i,
determined by Me4Si or by chloroform (8 = 77.0) or acetone (8 = 30.3).
19F NMR chemical shifts (8) are given in ppm downfield from external
CFCI3. 3I P NMR chemical shifts (8) are given in ppm downfield fromexternal 85 % H3P04.

Elemental analyses were performed on a Perkin-

Elmer 2400 CHN elemental analyzer.
All reactions were carried out under N 2. Et20 and THF were freshly
distilled from Na-benzophenone, and all other solvents were distilled from
CaH2.

Methyllithium, n-butyllithium and t-butyllithium were used asreceived. Preparative thin layer chromatography was carried out on platesof Merck silica gel 60 GF254.

Reaction of 1 with Methyllithium.
MeLi (c 1.14 M in Et20, 5.67 mL, 6.46 mmol) was added to a solutionof phosphorane 1 (460 mg, 0.891 mmol) in Et20 (10 mL) at -78 DC. Afterremoval of the cooling bath, the solution was stirred at room temperature(rt) for 50 min. The solution was quenched with 1 M HCI (3 mL), extracted-38-

Chapter 2.
with Et20 (3 x 30 nlL), dried with MgS0 4, and concentrated in vacuo.
Separation and purification of the residue was carried out on TLC (hexaneCH2Cl2 = 5 : 1) to give 6 (322 mg, 68 %) and 9 (105 mg, 22 %) as whitesolids. Recrystallization of 6 from hexane-CH2Cl2 gave crystals for X-ray
analysis:[T B P Y -5-15] -1-Hydro-l-methyl-l- {2-[2,2,2-trifluoro-l-hyd-r 0 x y -1- ( t r i fl U 0 rom e thy I ) e thy I ] ph e n y I }-3 ,3- b i s ( t r i fl U 0 rom e thy I ) [3H,2,1,A,5-benzoxaphosphoJe] (6): Mp 101°C; IH NMR (CDCl3) 88.86 (br s, IH), 8.10-7.90 (m, IH), 7.79 (br s, 4H), 7.55-7.20 (m, 3H), 6.37
(dq, IlH_P = 276 Hz, 31H_H = 3.9 Hz, IH), 2.44 (dd, 21 H_p = 14.7 Hz, 31H_H =3.9 Hz, 3H), IH NMR (toluene-dg) 89.26 (br s, IH), 8.04 (br s, 1H), 7.71
(br S, IH), 7.57-6,92 (m, 6H), 6.21 (br d, IlH_P = 274 Hz, IH), 2.44 (dd, 21H_
p = 14.6 Hz, 31H_H = 3.9 Hz, 3H);I3C NMR (CDCb) 8 136.7 (d, 21c _p = 11.0Hz), 134.8 (br s), 133.7 (d, 41c _p = 3.7 Hz), 133.5 (br s), 13l.4 (d, 31c _p =14.7 Hz), 13l.1 (br d, 21c _p = 12.9 Hz), 129.8 (br s), 129.6 (d, 11c _p = 123.2
Hz), 129.1 (br d, 31c _p = 14.7 Hz), 128.3 (d, 11c_p = 14l.3 Hz), 128.2 (d, 21c_

= 286.8 Hz), 124.8 (d, 31c _p = 14.7 Hz), 122.6(q, IJC_F = 284.8 Hz), 122.4 (q, IJC_F = 290.4 Hz), 122.2 (q, Ilc_F = 290.5
Hz), 79.0 (sept, 21c_F = 35.0 Hz), 78.9 (sept, 21c_F = 33.1 Hz), 22.4 (d, 11c_p =p = 25.7 Hz), 125.4 (q, 11c_F

99.3 Hz); 19F NMR (CDCb) 8 -72.9 (br S, 3F), -76.3 (br s, 3F), -76.9 (brs, 3F), -77.0 (br S, 3F), 19F NMR (toluene-dg, T = 223 K) 8 -7l.1 (br s,
3F), -75.0 (q, 21F _F = 8.5 Hz, 3F), -75.4 (q, 2JF_F = 7.9 Hz, 3F), -75 .5 (br s,
3F), 19F NMR (toluene-dg, T = 327 K) 8 -71.6 (br s, 3F), -75.2 (br s, 6F),

-75.6 (br s, 3F); 31p NMR (CDCl)) 8 -51.9; Anal. calcd for CI9H'3FI202P:
C, 42.88; H, 2.46. Found: C, 42.75; H, 2.37.

-39-

Chapter 2.
[ T B P Y - 5 -11 ] -1- Met h y 1- 3,3,3 t ,3 toot e t r a k i s ( t r i fl U 0 rom ethyl) -1,lt-spirobi[3H,2,1,;ts-benzoxaphosphole] (9): Mp 134°C; IH NMR(CDC1 3) 88.43-8.38 (m, 2H), 7.79- 7.69 (m, 6H), 2.11 (d, 21H _p = 16.6 Hz,3H); 13C NMR (CDCb) 8 136.8 (d, 31c _p = 9.1 Hz), 136.1 (d, 21c _p = 20.2
Hz), 133.7 (d, 41c _p = 3.7 Hz), 131.4 (d, 21c _p = 14.7 Hz), 130.6 (d, llc_p =176.5 Hz), 124.8 (d, 31c _p = 14.7 Hz), 122.6 (q, 11C_F = 285.0 Hz), 122.4 (q,11c _F = 288.6 Hz), 81.3 (sept, 21c _F = 31.2 Hz), 25.2 (d, llc _p = 125.0 Hz);

19F NMR (CDC13) 8 -75.1 (q, 41F_F = 9.5 Hz, 6F), -75.4 (q, 41F_F = 9.5 Hz,6F); 31p NMR (CDCI3) 8 -22.6; Anal. calcd for C19HI1F1202P: C, 43.04;
H, 2.09. Found: C, 42.83; H, l.86.

Reaction of 1 with Butyllithium.
n-BuLi (c 1.62 M in hexane, 2.00 mL, 3.24 mmol) was added to asolution of phosphorane 1 (500 mg, 0.969 mmol) in Et20 (10 mL) at -78°e. After removal of the cooling bath, the solution was stirred at rt for 60
min. The solution was quenched with 1 M HCI (10 mL), extracted with
Et20 (3 x 30 mL), dried with MgS0 4 , and concentrated in vacuo.
Purification of the residue was carried out on TLC (hexane-CH2CI2 = 5 : 1)
to give 7 (500 mg, 90 %) and 10 (47.2 mg, 9 %) as white solids.
Recrystallization of 7 from hexane-CH2Cl2 gave crystals for X-ray analysis:[T BP Y -5-15] -1-B utyI-l-hydro-l-{ 2-[2,2,2-trifluoro-l-hydr-

oxy-l-(trifluoromethyl)ethyl]phenyl }-3,3- bis(trifluoromethyl)[3H,2,I;ts-benzoxaphosphole] (7): Mp 119°C; IH NMR (CDCI 3) 89.13(br s, IH), 8.07-8.02 (m, IH), 7.89-7.85 (m, 1H), 7.80-7.72 (m, 3H), 7.55--40-

Chapter 2.
7.48 (m, 1H), 7.45- 7.41 (m, 1H), 7.36-7.32 (m, 1H), 6.16 (dd, IJH_P = 273
Hz, 3JH_H = 5.9 Hz, 1H), 3.21 - 3.06 (m, 1H), 2.69-2.52 (m, 1H), 1.65-1.46(m, 1H), 1.45- 1.36 (m, 2H), 1.35-1.22 (m, 1H), 0.88 (t, 3JH_H = 7.3 Hz, 3H),IH NMR (toluene-ds) 8 9.44 (br s, 1H), 8.06 (br s, IH), 7.73 (br s, 1H),
7.64-6.93 (m, 6H), 6.14 (dd, IJH_P = 279 Hz, 1H), 3.41-3.35 (m, IH), 2.842.79 (m, IH), 1.58-1.50 (m, lH), 1.39-1.28 (m, 3H), 0.92 (t, 3JH_H = 7.3 Hz,3H); 13C NMR (CDCl3) 8 136.6 (d, 2Jc_P = 12.8 Hz), 136.1 (d, IJC _p = 139.7
Hz), 134.7, 134.3 (d, 3Jc_p = 14.7 Hz), 134.1 (d, 3Jc_p = 14.7 Hz), 130.8 (d,2Jc _P= 16.5 Hz), 130.2, 129.8 (d, 1Jc_P = 139.7 Hz), 129.7, 129.1 (d, 2Jc_P =16.6 Hz), 127.0 (d, 3Jc_P = 12.9 Hz), 123.4 (g, 1JC_F = 290.4 Hz), 122.7 (g,= 286.8 Hz), 122.5 (g, IJC_F = 286.8 Hz), 122.3 (g, IJC _F = 288.6 Hz),78.9 (sept, 2JC_F = 31.2 Hz), 78.6 (sept, 2JC_F = 31.2 Hz), 34.7 (d, IJC_p =90.1 Hz), 27.7, 23.5 (d, 2JC_p = 23.9 Hz), 13.6; 19F NMR (CDCl3) 8 -72.9
IJC_F(br s, 3F), -76.3 (g, 4JF_F = 9.2 Hz, 3F), -76.8 (g, 4JF_F = 8.2 Hz, 3F), -77.0(gg, 4JF_F = 9.2 Hz, 9JF_F = 4.9 Hz, 3F), 19F NMR (toluene-d s , 233 K) 8

-71.2 (br s, 3F), -74.9 (g, 4JF_F = 8.6 Hz, 3F), -75.2 (g, 4JF_F = 8.7 Hz, 3F),
-75.5 (br s, 3F), 19F NMR (toluene-ds, 363 K) 8 -71.6 (br s, 3F), -74.9 (brs, 6F), -75.4 (br s, 3F);

31p NMR (CDC13) 8 -34.4;

Anal. calcd for

C22H19F1202P: C, 46.01; H, 3.33. Found: C, 46.09; H, 3.24.

[T B P Y -5-11]-1-Butyl-3,3,3',3' -tetrakis(trifluoromethyl)1,1'-spirobi[3H,2,1).,5-benzoxaphosphole] (10): Mp 109°C; IH NMR(CDCl)) 8 8.43-8.38 (m, 2H), 7.72-7.58 (m, 6H), 2.34 (ddt, 2JH_P = 28.3 Hz,
2JH_H = 12.2 Hz, 3JH_H = 4.9 Hz, 1H), 2.20 (ddt, 2JH_P = 12.2 Hz, 2JH_H = 12.2
Hz, 3JH_H = 4.4 Hz, 1H), 1.86-1.70 (m, 1H), 1.32-1.20 (m, 3H), 0.81 (t, 3JH_H== 7.3 Hz, 3H);

13C NMR (CDCl 3) 8 137.1 (d, 3Jc_p = 9.2 Hz), 136.2 (d, 2JC_p== 18.4 Hz), 133.6 (d, 4JC_p= 3.6 Hz), 131.3(d, 2JC _p = 14.7 Hz), 130.3 (d,-41-Chapter 2.
IJC_p = 160.0 Hz), 124.8 (d, 3Jc_P = 14.7 Hz), 122.7 (q, IJC_F = 286.8 Hz),122.5 (q, llc_F = 290.5 Hz), 81.3 (sept, 21c _F = 31.2 Hz), 39.2 (d, llc_p =115.8 Hz), 25.3 (d, 31c _p = 7.4 Hz), 23.6 (d, 21c _p = 23.9 Hz), 13.2; 19F
NMR (CDCI3) 8-75.1 (q, 41F_F = 9.3 Hz, 6F), -75.4 (q, 41F_F = 9.3 Hz, 6F);
31p NMR (CDCI3) 8 -18.8; Anal. calcd for C22H17F1202P: C, 46.17; H,
2.99. Found: C, 46.19; H, 2.84.

Reaction of 1 with t-Butyllithium.
t-BuLi (c 1.70 M in pentane, 3.60 mL, 6.12 mmol) was added to asolution of phosphorane 1 (1.00 g, 1.94 mmol) in Et20 (20 mL) at -78°C.
After removal of the cooling bath, the solution was stirred at rt for 30 min.
The solution was quenched with 1 M HCl (20 mL), extracted with Et20 (3 x50 mL), dried with MgS04, and concentrated in vacuo. Purification of theresidue was carried out on TLC (hexane-CH2C12 = 5 : 1) to give a mixture(1.01 g, 92 %) of 8a and 8b as white powder.

[T B P Y -5-15] -1-( 1, 1-Dimethyl)ethyl-1-hydro-1-{ 2- [2,2,2-tri-

fluoro-1-hydroxy-1-( trifluoromethyl)ethyl]phenyl }-3,3- bis( trifluoromethyl)-[3H,2,11l 5 -benzoxaphosphole] (8a): Mp 108°C; IH
NMR (CDC13) 8 8.58 (br s, IH), 8.00-7.89 (m, IH), 7.80-7.48 (m, 7H),
5.81 (d, IlH_P = 273Hz, IH), 1.30 (d, 31H_p = 23.4 Hz, 9H); 13C NMR(CDC13) 8 139.3 (d, llc_p = 139.7 Hz), 136.7 (d, llc_p = 132.4 Hz), 136.2 (d,lc-p = 16.6 Hz), 134.6 (d, lc-p = 12.9 Hz), 134.0, 131.3 (d, lc-p = 14.7 Hz),130.6 (d, lc-p = 14.7 Hz), 129.5, 129.2 (d, lc-p = 16.6 Hz), 129.0, 128.8 (d,lc-p = 3.6 Hz), 126.5 (d, lc-p = 16.6 Hz), 123.4 (d, 11C_F = 286.8 Hz), 123.1-42-Chapter 2.
(d, IJC_F = 290.4 Hz), 122.7 Cd, tJC_F = 288.6 Hz), 122.3 Cd, IJC_p = 288.6
Hz), 79.7 Cd, 2JC_F = 31.3 Hz), 78.4 (d, IJC_F = 31.3 Hz), 43.8 (d, IJC_p = 90.1
Hz), 15.1; 19F NMR (CDCl)) 8 -73.4 (q, 4JF_F = 9.5 Hz, 3F), -73.5 (q, 4Jp_F= 9.5 Hz, 3F), -74.6 (q, 4JF_F = 9.1 Hz, 3F), -76.1 (q, 4JF_F = 10.7 Hz, 3F);

31p NMR (CDCl3) 8 -14.7; Anal. calcd for C22H19F1202P: C, 46.01; H,
3.33. Found: C, 45.85; H, 3.23.

[ T B P Y - 5 -15 ] -1- ( 1 , 1-Dim e thy I) e thy 1- h Yd r 0 -1- {2 - [2,2,2 - t r i flu 0 r 0 - 1- h Yd r 0 x y -1- ( t r i fl U 0 rom e thy I) e thy I] ph e n y I} -3,3 -b i s ( t r i fl U oromethyI)-[3H ,2,IA,S-benzoxaphosphoIe](8b):

Mp 83-84 °C(containing EtOH); IH NMR (acetone-d6) 8 8.77-8.72 (m, IH), 7.87-7.82(m, IH), 7.75-7.63 (m, 4H), 7.63-7.54 (m, 2H), 7.48 (s, IH), 6.07 (d, IJH_P= 293 Hz, IH), 1.17 (d, 3JH_P = 19.5 Hz, 9H); 13C NMR (acetone-d6) 8 141.3
Cd, IJC_p = 141.3 Hz), 139.0 (d, 4JC_p = 5.5 Hz), 137.1 (d, 2JC_p = 14.7 Hz),136.1 (d, 2JC_p = 14.7 Hz), 135.1 (d, IJC_p = 139.7 Hz), 133.9, 132.7 (d, 2JC_p= 3.6 Hz), 131.3 (d, 2JC_p = 16.6 Hz), 130.7, 130.1 (d, 3JC_p = 12.9 Hz),

128.6 (d, 3Jc_P = 7.4 Hz), 125.9 (d, 3Jc_p = 12.9 Hz), 125.2 (q, IJC_F = 286.8
Hz), 124.7 (q, IJC_F = 288.6 Hz), 124.6 (q, IJC_F = 290.5 Hz), 124.5 (q, IJC_F= 288.7 Hz), 81.0 (sept, 2JC_p = 29.5 Hz), 80.0 (sept, 2JC_F = 29.4 Hz), 38.6
(d, IJC_p = 97.5 Hz), 19.4; 19F NMR (acetone-d6) 8 -73.3 (qq, 4Jp_p = 8.9

Hz, 9JF_F = 3.1 Hz, 3F), -73.6 (q, 4JF_F = 9.5 Hz, 3F), -74.3 (q, 4JF_F = 8.6
Hz, 3F), -75.5 (qq, 4JF_F = 9.2 Hz, 9Jp_p = 2.8 Hz, 3F); 31p NMR (acetoned 6) 8 -40.1; Anal. (containing EtOH) calcd for C24H2SF 1203P: C, 46.46; H,

4.06. Found: C, 46.26; H, 3.90.
NMR data was taken after removal of EtOH.

-43-

Chapter 2.
Crystallographic Studies.
Crystal Structure of 6, 7, 8a and 8b
Crystal data and numerical details of the structure determinations are
gi ven in Table 2-4 and 2-5.

Crystals suitable for X-ray structure

determination were mounted on a Mac Science MXC3 diffractometer andirradiated with graphite-monochromated Mo Ka radiation (A = 0.71073)(for 6) or graph ite- monochromated eu K a radiation (A = 1.54178) (for 7,

8a and 8b) for collection. Lattice parameters were determined by leastsquares fitting of 31 reflections for all compounds with 20° < 28 < 35°, 55°< 28 < 60°, 41 ° < 28 < 45° and 31 ° < 28 < 35° for 6, 7, 8a and 8b,

respectively.

Data were collected with the w scan mode. All data werecorrected for absorption 9 ) and extinction IO ). The structures were solved by adirect method with the Shelx 86 program 11). Refinement on F was carriedout by full-matrix least squares. All non-hydrogen atoms were refined withanisotropic thermal parameters. All hydrogen atoms in 6 and 8b, and thehydroxyl hydrogen atoms and apical hydrogen in 7 and 8a were locatedfrom a difference Fourier map calculated at the final stage of structural
analysis.

The other hydrogen atoms in 7 and 8a were included in therefinement on calculated positions (C-H = 1.0 A) riding on their carrier
atoms with isotropic thermal parameters.
carried out on a Titan-750 computer.

-44-

All the computations wereChapter 2.

Table 2-4. Details of the crystallographic data collection for 6 and 7
ComQoundFormulaMol wtCryst syst
Space group
Cryst dimens, mm
Color
Habit
a,A
b, A
C, A
a, deg/3, degY, degV, A3
Z
Dobs, Dcalc , g cm- 3
Abs coeff, cm- 1

6C]9 H 13 F 120 2P ]532.27
Triclinic
0.40 x 0.40 x 0.10
colorlessprIsm
9.214 (3)10.777 (4)11.518 (3)93.63 (2)92.26 (2)113.05 (2)1047.7 (6)2-, 1.69
1.96
532
Mo Ku, 0.71073
23±1
55.0
3

C22HI 9FI 20 2P1
574.40
Monoclinic
P2 1/n0.60 x 0.50 x 0.40
colorless
prIsm
16.653 (4)12.570 (3)11.523 (3)9092.72 (2)902409 (1)4-, 1.58
19.25
1160
Cu Ku, 1.54178
23±1
130
6

±h, ±k, -I
3925, 3686, 2330
(IFI > 1.56 () (IFI))
0.05
352
0.056, 0.051, 1.65
0.17
0.44

±h, -k, ±l
4518,4029,3594(IFI > 3.00 () (IFI))
0.01
350
0.057, 0.091, 3.40
0.43
0.91

P-1

0

0

0

0

F (000)

Radiation; A, A
Temp,oC
2e max, deg
Scan rate, deg/min
Linear decay, 0/0
Data collected
Total data collcd, unique, obsd
R int
No of params refined
R, R w , S
Max shift in final cycle
Final diff maE, max, e/A307Function minimized was sum [w(IFoI2 -IFcI2)2] which w = l.o/[(S~maIFoI2 + O.0007IFoI2].
R =sum[IIF01- IFcll)/sumIF01. Rw = [sumw(IF01 - IFcl)2/sumIF012] 1 2.

-45-

Chapter 2.

Table 2-5. Details of the crystallographic data collection for 8a and 8b
8a

ComQoundFormulaMol wtCryst syst
Space group
Cryst dimens, mm
Color
Habit
a,A
b, A
C, A
a, deg/3, degY, degV, A3
Z
Dobs, Dcal c , g cm- 3
Abs coeff, cm- 1

C22H19F1 20 2P1

C24H22F1 20 2P1N1

574.40615.40

Orthorhombic

Monoclinic
P2 1/n0.50 x 0.50 x 0.30
colorless
prIsm

P2121210.55 x 0.40 x 0.30
colorlessprIsm

014.027 (4)16.421 (4)10.704 (3)9090902465 (1)4-, 1.55
18.82
1160

0

0

0

F (000)

Radiation; A, A
Temp,oC
2() mruo deg
Scan rate, deg/min
Linear decay, %Data collected
Total data collcd, unique, obsd
R int
No of params refined
R, R w , S

Max shift in final cycle
Final diff maE, max, e/A3
08b

Cu Ko., 0.71073

23±1
130
3
10
-h, -k, ±l
2413,2350,1977(IFI > 3.00 (J (IFI))
0.00
350
0.068, 0.082, 2.72
1.00
0.44

15.748 (1)16.986 (2)11.016 (2)90.00 (1)110.257 (9)90.03 (1)2764.4 (5)4-, 1.48
17.23
1248
CuKo., 1.54178
23±1
130
5
+h, +k, +1
4492,4103,3632(IFI > 3.00 (J (IFI))
0.02
437
0.042, 0.068, 3.16
0.19
0.28

Function minimized was sum [wC1Fo12 -IFcI2)2] which w = 1.0/[CS~maIFoI2 + O.0007IFoI2].
R =sum[IIFol-IFcll)/sumIFol. Rw = [sumwCl F ol- 1Fcl)2/sumIFoI2]1 2.

-46-

Chapter 2.

Table 2-6. Positional parameters and equivalent isotropic temperaturefactors (Beq) for non-H atoms and H bonded to PI and 02

6
atom

x

y

z

B(eq)

PI
Fl
F2
F3
F4
F5
F6
F7
F8
F9
FlO
F 11
F 12
01
02
C1
C2
C3
C4
C5
C6
C7
C8
C9
C 10
C 11
C 12
C 13
C 14
C 15
C 16
C 17
C 18
C 19
HI
H2

-0.3696 (1)-0.3895 (3)-0.1382 (3)-0.2414 (3)-0.4181 (3)-0.2814 (4)-0.1668 (3)-0.9135 (3)-0.7078 (4)-0.9011 (4)-0.7908 (3)-0.9790 (3)-0.9122 (3)-0.3999 (3)-0.6923 (3)-0.1623 (4)-0.0440 (6)0.1122(6)0.1505 (6)0.0330 (5)-0.1224 (4)-0.2673 (4)-0.2606 (5)-0.2824 (6)-0.4552 (4)-0.3454 (5)-0.3712 (6)-0.5109 (6)-0.6235 (6)-0.5981 (4)-0.7343 (4)-0.8145 (6)-0.8553 (5)-0.4804 (6)-0.337 (4)-0.604 (6)- 0.2475 (1)-0.0577 (3)0.0491 (3)-0.1639 (3)0.1077 (3)0.1261 (3)0.2146 (2)-0.3224 (3)-0.3129 (4)-0.5036 (4)-0.4884 (3)-0.4579 (3)-0.6184 (3)-0.1301 (2)-0.2672 (3)-0.1389 (4)-0.1594 (5)-0.0740 (6)0.0302 (6)0.0519 (5)-0.0334 (4)-0.0282 (4)-0.0484 (5)0.1083 (4)-0.3878 (4)-0.4466 (4)-0.5506 (5)-0.6015 (5)-0.5493 (5)-0.4398 (4)-0.3936 (4)-0.3832 (6)-0.4901 (5)-0.1966 (6)-0.324 (4)-0.221 (5)0.1201 (1)0.4739 (2)0.4853 (2)0.4387 (2)0.3101 (3)0.1618 (2)0.3299 (2)0.3503 (2)0.4470 (2)3.88 (4)7.8 (1)
6.6 (1)
6.7 (1)7.4 (1)7.2 (1)
6.4 (1)7.8 (1)8.3 (1)9.2 (1)
6.8 (1)8.3 (1)7.7 (1)
3.68 (9)4.5 (1)
3.7 (1)5.1 (2)5.9 (2)
5.6 (2)4.6 (2)
3.5 (1)
3.4 (1)4.8 (2)4.8 (2)3.4 (1)4.7 (2)6.0 (2)5.8 (2)5.0 (2)
3.5 (1)
3.6 (1)
5.7 (2)5.0 (2)5.5 (2)
3.38 (0)4.68 (0)-47-004017 (3)0.0560 (2)0.1380 (3)0.1833 (3)0.2404 (2)0.2054 (3)0.1511 (4)0.0907 (4)0.1209 (5)0.2064 (5)0.2656 (4)0.2371 (3)0.2946 (3)0.4235 (4)0.2754 (4)0.2130 (3)0.2311 (4)0.3017 (5)0.3549 (5)0.3366 (4)0.2677 (3)0.2497 (3)0.3641 (5)0.1577 (4)0.0152 (4)0.033 (3)0.234 (4)Chapter 2.

Table 2-6. Continued (1)
7
atom
PI
Fl
F2
F3
F4
F5
F6
F7
F8
F9
FlO
F 11
F 12
01
02
C1
C2
C3
C4
C5
C6
C7
C8
C9
C 10
C 11
C 12
C 13
C 14
C 15
C 16
C 17
C 18
C 19
C 20
C 21
C 22
HI
H2

x
0.21788 (4)0.1442 (2)0.0512 (2)0.1742 (2)0.1376 (2)0.0917 (2)0.0164 (1)0.3578 (2)0.4389 (2)0.4802 (2)0.4415 (2)0.5184 (1)0.5021 (2)0.1980 (1)0.3449 (1)0.1115 (2)0.0722 (2)-0.0096 (2)-0.0506 (2)-0.0122 (2)0.0688 (2)0.1209 (2)0.1220 (2)0.0916 (2)0.2844 (2)0.2578 (2)0.2921 (2)0.3566 (2)0.3861 (2)0.3500 (2)0.3917 (2)0.4183 (2)0.4639 (2)0.2480 (2)0.2032 (2)0.2369 (6)0.219 (1)0.227 (2)0.302 (3)y
- 0.38258 (6)-0.2832 (2)- 0.1681 (3)-0.1207 (2)- 0.0383 (2)-0.1437 (2)- 0.0938 (2)- 0.1451 (2)- 0.0824 (2)-0.1951 (2)-0.3723 (2)- 0.3469 (2)-0.2241 (2)-0.2417 (2)-0.2067 (2)-0.4002 (2)-0.4942 (3)-0.5026 (3)-0.4197 (4)-0.3276 (3)-0.3172 (2)-0.2199 (2)-0.1969 (3)-0.1228 (3)-0.4071 (2)-0.4981 (2)-0.5325 (3)-0.4784 (3)-0.3906 (3)-0.3522 (2)-0.2579 (2)-0.1700 (3)-0.3010 (3)-0.3246 (3)-0.3737 (4)-0.3293 (4)-0.3616 (9)-0.486 (3)-0.201 (4)-48-z- 0.17388 (6)0.1092 (2)0.0866 (2)0.0812 (2)-0.1321 (2)- 0.2638 (2)-0.1316 (3)0.1008 (3)-0.0183 (3)0.1074 (2)- 0.1938 (2)-0.0425 (3)-0.1690 (3)- 0.1101 (2)-0.1383 (2)-0.1568 (2)-0.1900 (3)-0.1763 (3)-0.1283 (3)-0.0958 (3)-0.1105 (2)-0.0807 (3)0.0496 (3)-0.1521 (4)-0.0440 (2)0.0125 (3)0.1168(3)0.1658 (3)0.1101 (3)0.0064 (3)-0.0519 (3)0.0359 (4)-0.1153 (4)-0.3091 (3)-0.4136 (3)-0.5262 (4)-0.6218 (8)-0.216 (3)-0.119 (4)B(eq)
4.23 (9)8.0 (1)9.5 (1)8.2 (1)8.1 (1)7.7 (1)8.7 (1)8.7 (1)9.0 (1)8.0 (1)8.4 (1)8.6 (1)
9.6 (1)4.3 (1)5.2 (1)4.3 (1)5.3 (1)6.2 (1)
6.6 (1)5.8 (1)4.5 (1)4.4 (1)5.9 (1)
5.7 (1)4.2 (1)5.2 (1)6.0 (1)
6.4 (1)
5.7 (1)4.4 (1)4.7 (1)6.1 (1)
6.4 (1)5.3 (1)
6.4 (1)13.5 (3)25.8 (8)4.30 (0)5.31 (0)Chapter 2.

Table 2-6. Continued (2)

8a
atom
PI
Fl
F2
F3
F4
F5
F6
F7
F8
F9
F 10
F 11
F 12
01
02
C1
C2
C3
C4
C5
C6
C7
C8
C9
C 10
C 11
C 12
C 13
C 14
C 15
C 16
C 17
C 18
C 19
C 20
C 21
C 22
HI
H2

x

y

-0.0865 (1)0.1694 (4)0.2139 (4)0.2574 (4)0.0346 (5)0.1851 (6)0.1174(6)0.1435 (4)0.0897 (5)0.0760 (4)-0.1875 (4)-0.1153 (4)-0.0953 (5)0.0213 (4)-0.0405 (4)-0.0249 (6)-0.0626 (6)-0.0091 (8)0.0784 (8)0.1160 (6)0.0639 (5)0.0945 (6)0.1850 (6)0.1083 (9)-0.0488 (5)-0.0472 (6)-0.0170 (7)0.0090 (6)0.0048 (6)-0.0225 (5)-0.0229 (6)0.0724 (7)-0.1059 (6)-0.1753 (6)-0.1453 (7)-0.2588 (7)-0.2077 (7)-0.161 (5)0.003 (6)0.0384 (1)0.0158 (4)0.1393 (4)0.0494 (5)0.1696 (4)0.1534 (5)0.2324 (4)0.1295 (4)0.1273 (4)0.2329 (3)0.1187 (4)0.2227 (3)0.1120 (4)0.1105 (3)0.1742 (3)-0.0123 (4)-0.0826 (5)-0.1212 (6)-0.0945 (6)-0.0261 (6)0.0147 (4)0.0891 (5)0.0730 (8)0.1634 (6)-0.0016 (4)-0.0861 (4)-0.1360 (5)-0.1020 (5)-0.0181 (5)0.0336 (4)0.1235 (4)0.1532 (6)0.1452 (6)0.1184(5)0.2080 (6)0.l103 (7)0.0950 (6)-0.025 (5)0.141 (5)-49-z0.3271 (2)0.4005 (5)0.3777 (6)0.2479 (6)0.0747 (5)0.0790 (6)0.2117 (6)0.6164 (7)0.7990 (5)0.6924 (6)0.6720 (6)0.7349 (6)0.8279 (5)0.3226 (4)0.5234 (5)0.2030 (6)0.1448 (7)0.0538 (7)0.0228 (8)0.0780 (6)0.1686 (6)0.2398 (7)0.3184 (9)0.150(1)0.4842 (6)0.4745 (6)0.5691 (6)0.6823 (8)0.6940 (7)0.5976 (5)0.6278 (6)0.6859 (8)0.7168 (8)0.2895 (8)0.280(1)0.379 (1)0.1545 (9)0.321 (8)0.44 (1)B (eq)
4.26 (6)7.9 (2)9.4 (2)
10.2 (2)8.5 (2)10.5 (2)9.7 (2)
9.5 (2)9.4 (2)8.1 (2)8.4 (2)8.8 (2)
10.2 (2)4.4 (1)5.2 (2)4.3 (2)5.0 (2)6.2 (3)
6.6 (3)6.0 (2)4.4 (2)4.8 (2)
6.9 (3)7.2 (3)4.1 (2)4.9 (2)
5.6 (2)6.2 (2)5.7 (2)4.2 (2)4.6 (2)
5.6 (2)5.9 (3)5.2 (2)7.1 (3)7.8 (3)7.0(3)
4.30 (0)5.03 (0)Chapter 2.

Table 2-6. Continued (3)

8b
atom
PI
Fl
F2
F3
F4
F5
F6
F7
F8
F9
FlO
F 11
F 12
01
02
Nl
C1
C2
C3
C4
C5
C6
C7
C8
C9
C 10
C 11
C 12
C 13
C 14
C 15
C 16
C 17
C 18
C 19
C 20
C 21
C 22
C 23
C 24
HI
H2

x
-0.25727 (4)-0.2085 (1)-0.2461 (1)-0.1075 (1)-0.1247 (1)-0.0778 (1)-0.2159 (1)-0.2866 (2)-0.2307 (1)-0.3716 (1)-0.3342 (2)-0.4060 (1)-0.2664 (1)-0.2522 (1)-0.2205 (1)-0.0671 (2)-0.1355 (2)-0.0792 (2)0.0136 (2)0.0490 (2)-0.0066 (2)-0.0992 (2)-0.1712 (2)-0.1828 (2)-0.1472 (2)-0.3546 (1)-0.4221 (2)-0.5074 (2)-0.5279 (2)-0.4617 (2)-0.3749 (2)-0.3061 (2)-0.3004 (2)-0.3292 (2)-0.2958 (2)-0.3302 (4)-0.3704 (3)-0.2133 (3)0.l008 (3)0.0061 (2)-0.258 (2)-0.188 (3)y0.11027(4)0.3049 (1)0.3657 (1)0.3618 (1)0.1928 (1)0.3079 (1)0.2897 (1)0.2617 (1)0.1799 (1)0.1983 (2)-0.0069 (1)0.0470 (2)0.0243 (1)0.2020 (1)0.1238 (1)0.0869 (2)0.1255 (2)0.0720 (2)0.0866 (3)0.1526 (2)0.2064 (2)0.1916 (2)0.2421 (1)0.3194 (2)0.2583 (2)0.1542 (1)0.1844 (2)0.2037 (2)0.1948 (2)0.1693 (2)0.1495 (1)0.1278 (2)0.1919 (2)0.0479 (2)0.0470 (2)0.0891 (3)-0.0068 (3)-0.0033 (3)0.1149 (3)0.0990 (2)0.048 (2)0.115 (2)-50-

z-0.49748 (6)- 0.3854 (2)-0.5662 (2)-0.4413 (2)- 0.7173 (2)-0.6494 (2)- 0.7674 (2)-0.1587 (2)-0.0078 (2)-0.0795 (2)- 0.2586 (2)-0.1495 (2)-0.0627 (2)-0.5878 (2)-0.2271 (2)-0.0104 (3)-0.4209 (2)-0.3350 (3)-0.2860 (4)-0.3198 (3)-0.4036 (3)-0.4545 (2)-0.5502 (2)-0.4862 (3)-0.6719 (3)-0.4638 (2)-0.5738 (2)-0.5753 (3)-0.4653 (3)-0.3534 (3)-0.3497 (2)-0.2170 (2)-0.1158 (3)-0.1722 (3)-0.6465 (3)-0.7781 (4)-0.6357 (5)-0.6376 (5)0.1096 (6)0.0450 (3)-0.424 (3)-0.173 (4)B (eq)
4.0 (1)
6.3 (1)7.2 (1)8.1 (1)7.7 (1)8.6 (1)7.3 (1)8.7 (1)7.4 (1)
10.1 (1)
10.3 (1)9.9 (1)8.4 (1)4.1 (1)5.1 (1)
7.6 (2)4.3 (1)6.0 (1)7.0 (2)
6.6 (2)5.5 (1)4.1 (1)4.0 (1)5.0 (1)
5.5 (1)
3.7 (1)
4.6 (1)5.2 (1)5.4 (1)5.2 (1)4.0 (1)4.4 (1)5.8 (1)
6.3 (2)5.9 (1)8.6 (2)8.7 (2)9.7 (2)9.7 (2)6.1 (2)4.02 (0)5.61 (0)Chapter 2.
31p

NMR chemical shifts of 6-8 in various solvents at r.t.
31p

NMR spectra were measured on a lEOL EX-400 (162 MHz)

spectrometer at 22 ± 1°C. Samples of 6, 7, and 8 including EtOH (8b)were dissolved in distilled solvents. The concentration of the solution was ca
0.016-0.018 M.

Dynamic NMR Measurement and Line Shape Analysis
Samples of 6,7 and 8 (ca. 15 mg) dissolved in freshly distilled solvents(0.5-0.6 mL) were sealed in NMR tubes under N2.

19F NMR spectra were

measured on a lEOL EX-400 (376 MHz) in a variable temperature mode,and the specified temperatures were maintained throughout each set ofmeasurements (error within ± 1°C).

The observed temperatures were

calibrated with the I H NMR chemical shift difference of signals of neat 1,3propanediol (high temperature region) and MeOH (low temperature region).
The rates and activation free energies at the coalessence point were
calculated using the following equations derived from the Gutowsky-Holmappoximation of k = 7t ~ v/2- 112 .I 1)~G*= 19.14 Tc {9.97 + log (Tc/8v)}/4.184<kcal mol-I>

L\G* = {23.76 - In (kID} RT
The line shape analysis was performed in a narrow temperature range
around the coalescence point according to the classical Gutowsky- Holmmethod neglecting 4iF_F coupling since the condition il ~ v«

1 is met. The

activation enthalpies and entropies were calculated according to the transition
state theory of Eyring 12) using the following equations by linear regression.

-51-

Chapter 2.

In (kiD = i1HtIRT + i1st + In (kBlh)
The systematic error associated with the simulated rates was estimatedto be 10% and calculated with the following equation since the proportional
error for i1Ht and i1st are the same as for Ea 11).

-52-

Chapter 2.

Table 2-7. Rate Constants of Inversion at the Phosphorus Atom in 6 and 7.
6 in toluene-dg
T<K>

k <sec- I>~Gt <kcal mol- I>

313

190

15.1

323

315

15.3

325

347

15.3

327

389

329

Mit <kcal mol- I>~St <eu>

15.3

10.0 ± 1.3-16.2 ± 6.8

432

15.4

(± 0.1)*(± 0.3)*

331

482

15.4

333

524

15.4

335

584

15.4

* Statistical error in parenthesis

In (kIT)0.6

Y = 15.605 - 5044.6x RI\2 = 0.999

0.4
0.2
0.0
-0.2
-0.4
-0.6 4----T"'""----r--r-----.,.---....,.-----1
0.00290.00300.00310.0032 lIT </K>

-53-

Chapter 2.

Table 2-7. Continued (1)7 in toluene-d s
T<K>

k <sec- I>~G t <kcal mol- I>

353

164

17.2

357

197

17.3

359

219

17.3

361

240

363

M-/t <kcal mol- I>~st <eu>

17.3

11.4 ± 1.7-16.3 ± 4.9

268

17.4

(± 0.1)*(± 0.3)*

365

290

17.4

367

317

17.4

373

413

17.5

* Statistical error in parenthesis

In (kff)
0.2

y= 15.542 - 5757.1x RI\2 = 0.999

0.0
-0.2
-0.4
-0.6
-0.8 -I---.....,.----,.-----r----y----,.----t0.00260.00270.00280.0029 lIT </K>

-54-

Chapter 2.

D. References(1) For designation: Perkins, C. W.; Martin, J. C.; Arduengo, A. J.; Lau, W.;
Alegria, A.; Kochi, J. K. 1. Am. Chem. Soc. 1980, 102,7753.

(2) (a) Malavaud, C.; Barrans, J. Tetrahedron Lett. 1975,35, 3077. (b)Boisdon, M. T.; Maravaud, C.; Mathis, F.; Barrans, J. Tetrahedron Lett.

1977,39, 3501.

(c) Laurenco, C.; Burgada, R. Tetrahedron. 1976,32,

2253. (d) Lopez, L.; Fabas, C.; Barrans, J. Phosphorus Sulfur 1979,7,81.
(e) Tangom, B.; Malavaud, C.; Boisdon, M. T.; Barrans, J. Phosphorus

Sulfur 1988, 40, 33.
(3) Brazier, J. F.; Houalla, D.; Loenig, M.; Wolf, R. Top. Phosphorus.

Cheln. 1976,8, 99.
(4) Ross, M. R.; Martin, J. C. 1. Am. Chem. Soc. 1981,103, 1234.

(5) Berry, R. S. 1. Chem. Phys. 1960,32, 933.
(6) (a) Granoth, I.; Martin, J. C. 1. Am. Chem. Soc. 1979,101, 4623. (b)Kojima, S.; Kajiyama, K.; Akiba, K.-y. Tetrahedron Lett. 1994,35, 7037.
(c) Kojima, S.; Kajiyama, K.; Akiba, K.-y. Bull. Chem. Soc. lpn. 1995,68,
1785.
(7) Akiba, K.-y.; Nakata, H.; Yamamoto, Y.; Kojima, S. Chem. Lett. 1992,
1559.
(8) Musher, J. I. Angew. Chem., Int. Ed. Engl. 1969,8, 54.
(9) Furusaki, A. Acta. Crystallogr. 1979, A35, 220.

-55-

Chapter 2.
(10) Katayama, C. Acta. Crystallogr. 1986, A42, 19.
(11) Jackman, L. M.; Cotton, F. A. "Dynamic Nuclear Magnetic Resonance
Spectroscopy", Academic Press, New York 1975.

(12) Wynne-Jones, W. F. K.; Eyring, H. 1. Chern. Phys. 1935,3, 492.

-56-

Chapter 3

First Characterizationof lO-P-5 Spirophosphoranes

with an Apical Carbon-Equatorial Oxygen ring.

Kinetic Studies on Pseudorotationof StereoisounersChapter 3.

A. Introduction

Most pentacoordinate phosphorus compounds usually assume trigonal
bipyramidal (TBP) structures in the ground state, in which there are two
distinctive sites, the apical and the equatorial positions.

As described in

Chapter 1 the apical bond consisting of three atoms (two apical and thephosphorus atoms) could be regarded as a three-center four-electron (3c-4e)
bond 1) similar to the delocalized 1t electron conjugation as seen in the allylic
anion.

The stable phosphoranes would naturally prefer to have electron

negative substituents in these apical positions, leading to the concept ofapicophilicity.

It is well-known that phosphoranes bearing oxygen andcarbon substituents preferentially have oxygen atoms in the apical positions as
the most stable stereoisomer according to the apicophilicity of the elements. 2 )However, no example of the isolation and characterization of the relatively
less stable stereoisomers has been reported 3) because of the low activationenergy of the permutation of pentacoordinate compounds assuming TBP
structures, normally accounted for by the Berry pseudorotation (BPR)
mechanism. 4)

,

R

o

II""

I

"'p - O

0/1
o

CI

~

Cl

CI

A; R = Ph, Et-57-

Chapter 3.
As for phosphoranes that violate the element electronegativity rule,
recently, phosphorane A bearing an apical carbon and three equatorial
oxygen substituents has been reported by Holmes, R. R. et al. However, astereoisomer having an apical oxygen in the eight-membered ring could not
be observed because of the steric effect of aryl groups bearing t-Bu groups.5)
The kawashima-Okazaki group has reported that pentacoordinate 1,2oxaphosphetanes Band C had an apical oxygen-equatorial carbon fourmembered ring, and the equatorial oxygen-apical carbon stereoisomers D
and E could not be observed. 6 ) However, recently, on dissolution of 1,2azaphosphetidine F (Dr -29.9), in which the oxygen has been exchanged witha nitrogen substituent, in toluene-d8 at rt they observed another signal which
was assigned to the pseudorotamer G (Dp -50.9) with the nitrogen being
equatorial (eq 1).7) However, the isomer G could not be isolated. In both ofthese examples the unusual phosphoranes obtained or observed are due tothermodynamic stabilization of these configuration relative to the ordinarily
expected phosphoranes.

D ,' Rl = H
E ; Rl = C02MeF C .,\CF3~
0."CF 30~IpPh""--~==lPh

#

1111,

#

1111,

I •• •

Ph/

I

""P _

/

Ph

N

Ph""-- L1('h
Ph

Ph

G

F
-58-

(1)

Chapter 3.
We have succeeded in the first isolation and characterization of both[TBPY-5-12] spirophosphoranes 7-9 having an apical carbon-equatorial

oxygen five-membered ring along with their thermodynamically more stableapicaloxygen-equatorial

carbonIsomers

4-6{[TBPY -5-11]

spirophosphoranes} . Here, we report on their characterization and discuss
the relative thermal stability of 5 and 8 on the basis of kinetic studies.

-

59 -

Chapter 3.

B. Results and Discussion

1.

Preparation

and

the

Structureof[T B P Y -5-12]

P-R

Spi rophosphoranes.

When the recrystallization of monocyclic 10-P-5 P-H (apical)
phosphorane 8) 2 (R = n-Bu) was being carried out from CH3CN standing atroom temperature for a week, the author could obtain as the first crystals
what were later found by X-ray crystal analysis (vide infra) to be unexpected[TBPY-5-12] P-Il-Bu spirophosphorane 8, having C(apical)-O(equatorial)configuration.

Subsequent crystallizations of the remaining substance insolution yielded the [TBPY-5-11] P-n-Bu spirophosphorane 5, bearingC( equatorial)-O( apical) configuration. In order to examine the chemistry ofthis novel type of phosphoranes, reaction conditions for obtaining them were
optimized.

F3C/""

Scheme 3-1#11111",

R~ I

#

\~CF3

I~CF3

"'p

C( I
I~

F3 C .",CF 3
~
0HO

~

~

CF3
0

nondonative solvents

•

#

~

I~

... P-R +H2\\\\",.. I
0

F3C

H

4; R = Me
5; R = n-Bu
6; R = t-Bu

1; R = Me
2; R = n-Bu
3; R = t-Bu

-60-

Chapter 3.

Scheme 3-2
F3C//,.

CCI
I~

F3 C
~

~

=O

."CF3
0
H0

lIllI,

I

" 'p

R",

I

CF3

0

,;:::;
CF.. P-R.,' 3,\'\\'+ 4 5 +HF 3 2 equiv pyridine F C O ,
2
..

~

~.#

THF. t.

3".

F 3C'"

H

7; R = Me
8;R=n-Bu
9; R = t-Bu

1; R = Me
2·, R = n-Bu
3; R = t-Bu

Thermal reactions of monocyclic 10-P-S P-H (apical) phosphoranes 1(R = Me), 2 (R = n-Bu) and 3 (R = t-Bu) in nondonative solvents led to the
exclusive formation of [TBPY-S-11] spirophosphoranes 4 [mp 134°C, 8p(CDCI 3) = -22.6], 5 [mp 109°C, 8p (CDCh) = -18.8] and 6 [mp 128°C, 8p(CDC13) = -9.8], respectively (Scheme 3-1). However, when phosphorane 2
was treated with 2 equiv of pyridine in THF at 60°C for 20 min, the new
species [TBPY-S-12] spirophosphorane 8 [yo 71 %, mp lIS DC, 8p (CDCI3) =-3.S] was obtained along with 5 (y. 29%) after separation by PTLC (hexane-

CH 2 Cl 2 = 2 : 1) (Scheme 3-2). [TBPY-S-12] spirophosphorane 9 [R = t-Bu,

y. 7S%, mp 138°C, Dp (CDCh) = 7.7] was also obtained under the same
conditions except for the reaction time (36 h) along with some recovery (y.

180/0) of the starting material. [TBPY-S-12] spirophosphorane 7 [R = Me, y.
460/0, mp ,8p (CDCh) = -6.3] could be obtained along with 4 (y. S2%) byheating a solution of 1 in THF at 40°C for 1h. In this case pyridine was not
used because of the rapid cyclization of 1 to [TBPY-S-11] spirophosphorane-61-

Chapter 3.
4, probably due to the fast permutation of spirophosphorane 7 to 4 in its
presence.
Initially, ] Hand 19F NMR spectra (CDCI3) of 7-9 at rt lead us toanticipate

C2 symmetrical structure as in 4-6.

However, at low

temperatures, NMR spectra appeared much more complex as expected for
those of 4-6 (vide infra).

In order to determine the structures of the

spirophosphoranes, X-ray crystal structure analysis was carried out on the
spirophosphoranes of which crystals were prism shaped.

The ORTEP

structures of 5, 8 and 9 are shown in Fig. 3-1, 3-2 and 3-3, respectively,
along with selected structural parameters in Table 3-1.
X- ray structural analysis of 5 (Fig. 3-1) and 8 (Fig. 3-2) revealed thatthese compounds were stereoisomers with TBP structures. As the drawing
shows the compound 5 assumes a trigonal bipyramidal (TBP) structure withthe two oxygen atoms occupying the two apical positions and the three carbon
atoms occupying the three equatorial positions. In TBP structures of 8 and 9(Fig. 3-3) a carbon and an oxygen atoms occupy the two apical positions, andtwo carbon and an oxygen atoms occupy the three equatorial positions. It isclearly shown that the apical bonds of 8 and 9 are longer than thecorresponding equatorial bonds [i.e., 8; PI-OI (ap) 1.768> PI-02 (eq)1.659 A and PI-CIa (ap) 1.863 > PI-CI (eq) 1.813 A: 9; PI-Ol (ap)l.770> PI-02 (eq) 1.651 A and PI-CI0 (ap) 1.889 > PI-CI (eq) 1.831 A].
On the other hand, the pairs of bonds of 5 are almost equal [i .e., P-O (ap)l.753, 1.765 A and P-C (aryt eq) 1.818, 1.820 A].

-62-

Chapter 3.

Figure 3-1. ORTEP drawing of 5 showing thermal ellipsoids at the 30%
probability level.

- 63 -

Chapter 3.

Figure 3-2. ORTEP drawing of 8 showing thermal ellipsoids at the 30%
probability level.

- 64 -

Chapter 3.

Figure 3-3. ORTEP drawing of 9 showing thermal ellipsoids at the 30%
probability level.

- 65 -

Chapter 3.

Table 3-1. Selected Bond Lengths and Angles for 5, 8 and 9

8·, R = n-Bu

9;R=t-Bu5

8

9

Bond length (A)Bond length (A)PI-Ol

1.765 (2)PI-01

1.768 (3)1.770 (2)PI-02

1.753 (2)PI-02

1.659 (2)1.651 (2)PI-Cl

1.818(2)PI-Cl

1.813 (4)1.831 (3)PI-CI01.820 (2)PI-CIO

1.863 (4)1.889 (3)PI-CI91.818 (2)PI-CI91.835 (5)1.878 (3)Bond angle (deg)Bond angle (deg)01-PI-02

175.79 (6)OI-PI-CIO

170.6 (1)

169.3 (1)01-PI-Cl

87.32 (8)OI-PI-CI87.1 (2)85.5 (I)

02-PI-CI087.30 (8)02-PI-CI087.8 (1)87.4 (1)

CI-P1-CI0

126.84 (8)02-P1-Cl

119.9(2)120.4 (1)CI0-PI-CI9

116.6 (1)

CI-PI-C19

114.8 (2)121.7(2)

C19-P1-C1

116.6 (1)

C19-PI-02

124.0 (2)116.4 (2)-66-

Chapter 3.

2.

Kinetic

Studyof Inversion

of[T B P Y -5-12]

P-n - B u

Spirophosphorane 8.

Scheme 3-3
a-endo

a-exo

F3C
~

.'

b-exo
F 3C 1'1,"CF 3

I,.

0

~

0

I
I
,
\
\
:
:
:
,
.
.
';P-n-Bu ::::::;"';::=:=====.~n-Bu-P.
· ··\.-9 111II

0
F3C"'tr,.

b-endotoluene-d 8'0
a-endo..,\\\CF3

F3 C
b-exo

a-exo

8-Sp

19F NMR spectra of compound 8 at rt showed only a pair of quartets[19F NMR (toluene-d8, 293 K) 8 -74.7 (q, 4JF_F = 8.5 Hz, 6F), -75.9 (q, 4JF_F= 8.5 Hz, 6F)] for the four anisochronous CF3 groups. This initially lead us

to anticipate C2 symmetrical structure for this compound. However, at low
temperatures, the CF3 groups decoalesced into four signals [I9F NMR(toluene-d8, 193 K) 8 -74.3 (br s, 3F), -74.5 (br s, 3F), -75 .5 (br s, 3F),76.0 (br s, 3F)], whereas only a sole 31p signal [31P NMR (toluene-d8, 219 K)

8 -3.6] could be observed for the compound throughout the temperature
range.

This dynamic behavior could only be rationalized as due tointerconversion between enantiomers 8-Rp and 8-S p (Scheme 3-3), in which
exchange between fluorines, a-endo and b-endo, and a-exo and b-exo, occurs,
respectively, by a single-step pseudorotation with the n-Bu group as the pivot.
Line shape analysis (Fig. 3-4) of the 19F NMR spectra (temperature range of
223-243 K; 8v = 209 Hz; Tc = 235 K; ~G* = 10.8 kcal mol- I) of one of the-67-Chapter 3.
pairs of signals (higher field chemical shift) gave the activation parameters

t1Hi = 10.0 ± 0.7 kcal mol-I and t1Si = -3.4 ± 3.0 eu.

19F NMR spectra of[TBPY-5-12] P-t-Bu spirophosphorane 9 showed only a pair of quartets evenat 193 K in toluene-dg probably due either to the faster pseudorotation or
smaller peak separation of the coalescing signals.

-68-Chapter 3.

Figure 3-4. Observed and calculated line shape for CF3 groups incompound in toluene-d s .

Observed

Calculated

T<K>

k <sec- I>

223

150

228

243

231

341

233

415

235

505

237

600

239

705

241

870

243

1030

- 69 -

Chapter 3.

3.

Kinetic

Studyof

Pseudorotationof[T B P Y - 5 - 12]

Spirophosphoranes to [T B P Y -5-11] Spirophosphoranes.

Scheme 3-4
F3C /",.

CF3

CC
I~

F3 C

0

I~

I
.. P-R

#

~

-:P

I

·cr:"',-R

0\\\\\'F3 C
F 3 C"""

0
1IIIt,

1#

1

F C\\\'

~

3

0

CF

3

5·, R = n-Bu
6; R = t-Bu

8; R = n-Bu
9; R = t-Bu

Rates of pseudorotation of [TBPY-5-12] spirophosphorane 8 (R = n-Bu)
to [TBPY-5-11] spirophosphorane 5, an apparently irreversible process, were
measured by monitoring 19F NMR in toluene (temperature range of 302-328K), pyridine (temperature range of 308-323 K) and EtOH (temperature
range of 313-328 K) and were found to obey first-order kinetics.

The

activation parameters were derived from the Eyring plot of the rates (Table

3-2).

-70-

Chapter 3.

Table 3-2. Kinetic Parameters of Pseudorotation of 8 to 5
k <sec- I>~G t <kcal mol- I>(323 K)(323 K)

toluene-dg(1.29 ± 0.01) x 1Q-4

pyridine*
EtOH

Solvent

M-/t <kcal mol- I>~st <eu>

24.7

21.8 ± 0.4- 9.0 ± 1.2(1.26 ± 0.02) x lQ-4

24.7

20.3 ± 0.5-13.8 ± 1.7(1.16 ± 0.0 1) x 10-4

24.8

23.1 ± 0.5-5.3 ± 1.5* Rates determined from the consecutive reaction of P-H (apical)

phosphorane 2 (see Chapter 5).

The rates [ca. 1.16-1.29 x 10-4 S-1 (323 K)] were almost identical in all
solvents, thus it can be concluded that a P-O (ap) bond cleavage, whichshould proceed through a very polar transition state or an intermediate, does
not take place at all. For pyridine, since the rate measured with isolated 8 to

5 [(4.24 ± 0.09) x 10-5 sec- 1 at 313 K] was within experimental error of rate
determined from the consecutive reaction of P-H (apical) phosphorane 2[(4.36 ± 0.11) x 10-5 sec- l at 313 K], the parameters derived from the lattermeasurements are shown.
Rates of pseudorotation of [TBPY-5-12] spirophosphorane 9 (R = t-Bu)
to [TBPY-5-11] spirophosphorane 6 were also measured by monitoring 19F
NMR in t-butyltoluene (temperature range of 403-463 K) and were found toobey first-order kinetics. The Eyring plot of the rates gave the activation
parameters, i.e., I1Ht = 27.2 ± 0.8 kcal mol- 1 and I1St = -13.1 ± 1.8 eu. The
higher activation enthalpy is presumably due to steric hindrance of the t-Bugroup.

-71-

Chapter 3.
3. Kinetic Study of Inversion of Diastereomer [T B P Y - 5 -11]
Spirophospboranes 10.

Scheme 3-5
CH

F3 C
1

~
#

o * -::P

* 0
11111

c&
1#

F 3C'\\'

I ,.,,\\\\ ~

I*

I,..

,-n-BU1. . n-BU-,:p'
-::P

oq

0

o

CF 3

F3 C

lO-exo

~I

"IICF

3

lO-endo

The pseudorotation between enantiomers 5-Rp and 5-Sp was found to be
too slow to measure by NMR techniques such as saturation transfer.
Therefore, diastereomers 10-exo [3Ip NMR (CDCI 3) 8 -22.2; 19F NMR(CDCI 3) 8 -75.4 (m, 6F), -79.7 (s, 3F)] and 10-endo [31P NMR (CDCh) 8-22.7; 19F NMR (CDCh) 8 -74.9 (q, 4JF_F = 9.3 Hz, 3F), -75.4 (q, 4JF_F =9.3 Hz, 3F), -80.1 (s, 3F)], differing from 5 only by having a CH3 group in
the place of one of the CF3 groups (Scheme 3-5) were examined.
The pseudorotation between the diastereomers was examined bymonitoring the singlet signals of 19F NMR in 4-t-butyltoluene (temperature
range of 442-463 K). The averaged activation parameters obtained for thelO-exo to 10-endo and 10-endo to 10-exo processes were ~Hf = 33.7 ±0.9 kcal mol- 1 and ~Sf = -8.8 ± 1.9 eu.
Phosphorane 10 should be only slightly less stable than 5, and therefore
the activation enthalpy obtained for pseudorotation between 10-exo and 10-72-

Chapter 3.
endo should differ from that between 5-Rp and 5-Sp by only a very small

amount. Hence, it is reasonable to use the values to evaluate the activationenergy of the permutation process of 5. Thus, 8 is concluded to be less stable
than 5 by at least ca. 12 (34 - 22) kcal mol- I.

4. Energy Diagram for Berry Pseudorotation of 5, 8 and 10.
The shortest series of Berry pseudorotation processes of lowest energy
for the inversion of 5 is shown as Scheme 3-6. The isomer of highest energy
must be I which has an equatorial five membered ring, and the next highest
must be H which has two equatorial oxgens.
In order to determine the validity of the assumption that 5 and 8
undergo stereomutation via the same transition state and that the value (ca. 12
kcal mol-I) given above is the difference between 5 and 8, the relative
stability of analogous [TBPY-5-12] spirophosphorane J and [TBPY-5-11]
spirophosphorane K was calculated at the HF/3-21G level using the Gaussian
94 program. J was found to be less stable than K by 14.7 kcal mol-I, a value
very close to the experimental value of 12 kcal mol-I.

r~I

C1

11111 I,,.P-MeF~\\\\\'
",
",
F

~

" 'P-Me

~~

K

J

-73-

I

~

-..l

F)C"

7 4
~ 1

~
2
~

5

~

-

F)C4 CF~3
~

•

ill

F)C'I:

H-Rp

I

5-S p

lO-e.ro...._-_... -- - ----------- -- -----

I

I

,,

,

t

(observed)

22 kcal mol- 1

I-Rp

I

P-n-Bu

I

8-R p

~I

7

>12 kcal mol- 1•

1 .• \CF J
";;:
CF)

8-S p

1~

5 3

p'

I .\,~

20 4 7 1------ II-BU~-~o\fI 5J
FJC'R)CF

\fI 4
__

8-R p

"

8-S p

(observed),

10 kcal mol-I,'

F)C'"

I-Sp

5

2 II-Bu

o~ I

-

\

\

~

/IO

'CFJ

2., CF)

H-Sp

1 ";;:

5 4

.

CF
.')
CF)

~

J

n-Bu-P.

1

\

\

\

I

5-Rp

lO-endo5-RpF)C "CFJ

34 kcal mol- 1(observed)

\

:;i'

5 20 4 ~ 1

I- - n-BU-p:ro.

F)C. CF10
7)0 ...!!..
1.10
~

~

----------------------cil~~
FJCo.J.. 4~"'~li0 +•-----------------------------------------------------------------FJCF)CI~'
2 4 5/.:11-";;:3 0 1

6t0:;;

F c .,CF3•, ----------------- ------- ------ --- -~--...."

,

I

,

34 kcal mol- 1(observed)---------------------

5-S p

CF)

>34 kcal mol- 1

F)C~

.-B"
5

I"
0
A
TJ
FJC" 0 I J'1', 'I ~ 4 PI",' 3
CFJ :;;;:::. . : 1,_. I\fI 5 F)C
,p-n-BU - 1' 0 ""CFJI";;:I-- • ":: p- .-Bu:;;;::: ....: 4 02 5

Of
cg:

F C "CF)
1 ";;: 3 0 I

Scheme 3-6

~

~

..,

~.....

~;::-

Chapter 3.

c. Experimental Section

Melting points were measured with a Yanaco mIcro melting point
apparatus and are uncorrected. IH NMR (400 MHz), 13C (100 MHz), 19F(376 MHz), 31p (162 MHz) spectra were recorded on a JEOL EX-400
spectrometer. 1H NMR chemical shifts (8) are given in ppm downfield frominternal Me4Si, or from residual chloroform-d (8 = 7.26). 13C NMR
chemical shifts (8) are given in ppm downfield from internal Me4Si, or fromchloroform-d (8 = 77.0). 19F NMR chemical shifts (8) are given in ppm
downfield from external CFCI3. 31 P NMR chemical shifts (8) are given inppm downfield from external 85 % H3P04.

Elemental analyses were

performed on a Perkin-Elmer 2400 CHN elemental analyzer.
Preparative thin layer chromatography was carried out on plates of
Merck silica gel 60 GF254. Butyllithium and t-BuOK were used as received.

[T B P Y - 5 -12] -1- M e th y 1- 3,3,3 ' ,3 ' - t e t r ak is ( t r i fl U 0 rom e thy I) -1 , 1 '-spirobi[3H ,2,1,A.-5-benzoxaphosphole] (7):A solution of P-H (apical) phosphorane 1 (50 mg, 9.4 x 10-2 mmol) in

THF (0.5 mL) was heated at 40°C for 1 h. The solution was concentrated invacuo. Purification of the residue was carried out on TLC (hexane-CH2CI2 =2 : 1) to give 7 (Rf = 0.8, 23 mg, 46%) and 4 (Rf = 0.9, 26 mg, 52%) as
white solids. 7: Mp 127°C; IH NMR (CDCh) 87.80-7 .31 (m, 8H), 2.28
(d, 21H _p = 10.2 Hz, 3H); l3C NMR (CDCh) 8136.8 (d, lc-p = 9.1 Hz), 136.1(d, lc-p = 20.2 Hz), 133.8 (d, lc-p = 3.7 Hz), 132.3 (br s), 132.0 (br s), 131.4(d, lc-p = 14.7 Hz), 130.3 (d, lc-p = 11.1 Hz), 125.6 (d, lc-p = 9.1 Hz), 124.8-75-

Chapter 3.
(d, lc-p = 14.7 Hz), 122.6 (q, llc_F = 285.0 Hz), 122.4 (q, llc_F = 288.6 Hz),122.3 (q, Ilc_F = 285.9 Hz), 121.9 (q, llc_F = 285.8 Hz), 79.8 (sept, 21c_F =31.3 Hz), 26.2 (d, llc_p = 129.5 Hz); 19F NMR (CDCI3) 8 -75.6 (q, 4IF _F =9.2 Hz, 6F), -76.4 (q, 4IF_F = 8.6 Hz, 6F); 31p NMR (CDCh) 8 -6.3; Anal.
calcd for C19HllF1202P: C, 43.04; H, 2.09. Found: C, 43.34; H, 1.99.

[T BPY -5-12]-1-Butyl-3,3,3',3' -tetrakis(trifluoromethyl)-l,l'-spirobi[3H ,2,1,A,S-benzoxaphosphole] (8):P-H (apical) phosphorane 2 (200 mg, 0.348 mmol) was treated withpyridine (0.07 mL, 0.8 mmol) in THF (5 ml) at 60°C for 20 min. The
solution was then poured into a separatory funnel containing Et20 (50 mL)
and washed with 1 M HCI (50 mL), aqueus CUS04 (50 mL), water (50 mL)
and brine (50 mL), dried with MgS04, and concentrated in vacuo.
Purification of the residue was carried out on TLC (hexane-CH2CI2 = 2 : 1)
to give 8 (Rf = 0.7, 141 mg, 71 %) and 5 (Rf = 0.'/1, 58.2 mg, 29%) as whiteI

solids. 8: Mp 115°C; IH NMR (CDCI3) 87.75-7.69 (m, 2H), 7.65-7.61(m, 2H), 7.59-7.56 (m, 4H), 2.48 (dt, 21H _p = 17.1 Hz, 3IH _H = 6.8 Hz, 2H),

1.67-1.54 (m, 2H), 1.39-1.29 (m, 2H), 0.83 (t, 3IH _H = 7.3 Hz, 3H); 13C
NMR (CDCI3) 8 135.9 (br d, llc_p = 88.3 Hz), 134.2 (d, 2lc _p = 16.5 Hz),132.2,132.0 (d, 3lc _p = 11.1 Hz), 130.3 (d, 2lc _p = 11.1 Hz), 125.5 (d, 3lc _p =11.0 Hz), 122.5 (d, 3lc _p = 7.4 Hz), 122.5(q, llc_F = 286.8 Hz), 122.0 (q, llc_F= 288.8 Hz), 79.9 (sept, 21c-F = 31.3 Hz), 40.2 (d, llc_p = 114.0 Hz), 24.7 (d,3lc _p = 7.4 Hz), 24.0 (d, 2lc _p = 20.2 Hz), 13.3; 19F NMR (CDCh) 8 -74.9(q, 4IF_F = 8.5 Hz, 6F), -76.2 (q, 4IF_F = 8.5 Hz, 6F); 31p NMR (CDCI3) 8-3.5; Anal. calcd for C22H17F1202P: C, 46.17; H, 2.99. Found: C, 46.17; H,
2.72.

-76-

Chapter 3.
[T B P Y - 5 - 11 ] - 1- ( 1 , 1- Dim e thy I) e thy 1- 3 ,3,3 ' ,3 ' -t e t r a k i s ( t r i fl U 0 r 0 -methyl)-I,I' -spirobi[3H ,2,1,A,S-benzoxaphosphole] (6).
A solution of P- H (apical) phosphorane 3 (150 mg, 0.261 mmol) in 0 dichlorobenzene (10 mL) and CH3CN (2 mL) was heated at 150°C for 4 d.
The solution was concentrated in vacuo.

Purification of the residue wascarried out on TLC (hexane) to give 6 (Rf = 0.8, 224 mg, 80%) as a whitesolids. Recrystallization of 6 fron1 hexane gave an X-ray sample. Mp 128°C; IH NMR (CDCh) 88.42-8 .38 (m, 2H), 7.66-7 .64 (m, 6H), 1.13 (d, 3JH _P= 20.0 Hz, 9H); l3C NMR (CDCh) 8 137.2 (d, 3Jc _p = 9.2 Hz), 136.4 (d, 2le _p = 16.6 Hz) , 132.9 (d, 4Jc _P= 3.7 Hz), 132.5 (d, 1Jc_P = 160.0 Hz), 130.9 (d,2lc _p = 12.8 Hz), 124.1 (q, 3lc _p = 14.7 Hz), 122.7 (q, IJe _F = 286.7 Hz),122.4 (q, IJe _F = 288.6 Hz), 81.5 (sept, 2JC _F = 31.3 Hz), 40.5 (d, lle_p =103.0 Hz), 28.2; 19F NMR (CDCI3) 8 -72.4 (q, 4lF _F = 10.1 Hz, 6F), -74.5(q, 4JF_F = 10.1 Hz, 6F);

31p NMR (CDCI3) 8 -9.8;

Anal. calcd for

C22HI7F1202P: C, 46.17; H, 2.99. Found: C, 46.04; H, 2.73.

[T B P Y -5 -12] -1- (1, I-Dimethyl)ethyl-3,3,3',3' -tetrakis(trifluoro-

methyl)-I,1 '-spirobi [3H ,2,1,A,S-benzoxaphosphole] (9).
P-H (apical) phosphorane 3 (300 mg, 0.523 mmol) was treated withpyridine (4.0 mL, 0.8 mmol) in THF (20 ml) at 60°C for 36 h. The solution
was then poured into a separatory funnel containing Et20 (50 mL) andwashed with 1 M HCl (50 mL), aqueus CUS04 (50 mL), water (50 mL) andbrine (50 mL), dried with MgS04, and concentrated in vacuo. Purificationof the residue was carried out on TLC (hexane-CH 2C I2 = 3 : 1) to give 9 (Rr== 0.6,224 mg, 75%) and 3 (Rr = 0.4, 53.7 mg, 18% recovered) as whitesolids. Recrystallization of 9 from EtOH gave an X-ray sample. 9: Mp 138-77-

Chapter 3.
°C; IH NMR (CDC13) 87.91 - 7.88 (m, 2H), 7.73-7.71 (m, 2H), 7.62- 7.52
(m , 4H), 1.21 (d, 3JH _P = 21.0 Hz, 9H); l3C NMR (CDCI3) 8 136.3 (d, IJC _p=77.2 Hz), 134.1 (d, 2JC _p = 14.7 Hz), 133.8 (d, 2JC _p = 12.9 Hz), 131.7, 129.4(d, 3JC _p = 9.2 Hz), 125.4 (d, 3JC _p = 9.2 Hz), 122.64 (q, IJC _F = 286.8 Hz),122.57 (q, IJC _F = 286.8 Hz), 122.0 (q, IJC_F = 288.6 Hz), 79.6 (sept, 2JC_F =31.2 Hz), 44.4 (d, IJC _p = 112.1 Hz), 29.6; 19F NMR (CDCh) 8-73.7 (q, 4JF_
F

= 9.2 Hz, 6F), -75.9 (q, 4JF _F = 9.5 Hz, 6F); 31p NMR (CDCI3) 8 7.7;

Anal. calcd for C22H17F1 202P: C, 46.17; H, 2.99. Found: C, 46 .32; H, 3.27.

-

78 -

Chapter 3.
Crystallographic Studies.
Crystal Structure of 5, 6, 8 and 9
Crystal data and numerical details of the structure determinations are
given in Tables 3-3. Crystals suitable for X-ray structure determination were
mounted on a Mac Science MXC3 diffractometer and irradiated withgraphite-monochromated Cu Ka radiation (A = 1.54178 A) for collection.
Lattice parameters were determined by least-squares fitting of 31 reflections
for all compounds with 53° < 28 < 60°, 55° < 28 < 60°, 52° < 28 < 60° and
31 ° < 28 < 35° for 5, 6, 8 and 9, respectively. Data were collected with the(0scan mode.

All data were corrected for absorption 9 ) and extinction 10).

The structures were solved by a direct method with the Shelx 86 program.
Refinement on F was carried out by full-matrix least squares.

All non-hydrogen atoms were refined with anisotropic thermal parameters.

Allhydrogen atoms in 8 were located from a difference Fourier map calculated
at the final stage of structural analysis. All hydrogen atoms in 5 and 6 were
included in the refinement on calculated positions (C-H = 1.0 A) riding on
their carrier atoms with isotropic thermal parameters.
were carried out on a Titan-750 computer.

-79-

All the computations

Chapter 3.

Table 3-3. Details of the crystallographic data collection for 5 and 6
5Com.e ound
Formula8

9

C 22H' 7F' 20 2P)
572.3

C 22 H) 7F )20 2P )Mol wtC22H '7F 120 2P I
572.3

Cryst syst

Monoclinic

Monoclinic

Monoclinic

Space group

P21/a

P2/n

P2/c

Cryst dimens, mm

0.70 x 0.60 x 0.50

0.50 x 0.50 x 0.25

0.60 x 0.50 x 0.15

Color

colorlesscolorlesscolorless

Habit

pnsm

pnsm

pnsm

a,A
b,A
c,A

19.522 (4)12.041 (2)14.463 (2)11.819(2)16.936 (3)36.842 (6)10.596 (2)11.401 (2)8.973 (1)a, deg90

90

90(3, deg

103.50 (2)96.05 (1)96.67 (1)Y, deg

90

90

90

V, A3

2377.4 (8)2311.9 (6)4749 (1)

Z

4

4

8

Dobs, Deale, g cm-3-, 1.60-, 1.66-, 1.61

Abs coeff, cm-)

19.51

20.26

19.54

F (000)

1152

1152

2304

Radiation; A, A

Cu Ka, 0.71073

Cu Ku, 1.54178

Cu Ku, 1.54178

Temp,oC

23±1

23±1

23±1

28 max' deg

130

130

130

Scan rate, deg/min

4

3

5

574.3010Linear decay, %Data collected±h, +k, ±l±h, +k, ±l+h, -k, ±l

Total data coIled,

4508, 3993, 3767

4264, 3861, 3016

8526, 7942, 6890

unique, obsd

(IFI > 3.00 (J (IFI))(IFI > 5.00 (J (IFI))(IFI > 3.00 (j (IFI))

R int

0.02

0.03

0.04

No of params refined

395

344

677

R,Rw,S

0.045, 0.081, 2.70

0.066, 0.093, 2.67

0.073, 0.112, 2.06

Max shift in final cycle

0.37

0.47

0.14

Final diff map, max, e/ A3 0.41

0.92

0.75

Function minimized was sum [w(IFoI2 -IFcI2)2] which w = 1.0/[(sigmaIFoI2 + 0.0007IFoI2].
R = sum[IIFol-IFcll)/sumIFol. Rw = [sumw(IFol-IFcl)2/sumIFoI2]1I2.

-80-

Chapter 3.

Table 3-4. Positional parameters and equivalent isotropic temperaturefactors (Beq) for non-H atoms.

5
atom

x

PI
Fl
F2
F3
F4
F5
F6
F7
F8
F9
F 10
F 11
F12
01
02
Cl
C2
C3
C4
C5
C6
C7
C8
C9
C 10
C 11
C 12
C 13
C 14
C 15
C 16
C 17
C 18
C 19
C 20
C 21
C 22

- 0.11399 (2)- 0.30577 (8)- 0.3370 (1)-0.3065 (1)-0.1304 (1)-0.2022 (2)-0.2363 (2)-0.14673 (8)-0.0878 (1)-0.0406 (1)0.02815 (9)0.06110 (8)0.0192 (1)-0.17287 (8)-0.06090 (7)-0.1484 (1)-0.1281 (1)-0.1580 (1)-0.2066 (1)-0.2270 (2)-0.1979 (1)-0.2142 (1)-0.2921 (1)-0.1957 (2)-0.1479 (1)-0.1983 (1)-0.2162 (2)-0.1846 (2)-0.1337 (2)-0.1160 (1)-0.0622 (1)-0.0837 (1)0.0125 (1)-0.0386 (1)-0.0351 (2)0.0281 (2)0.0335 (4)y- 0.14888 (4)- 0.1364 (2)- 0.0214 (2)- 0.1900 (2)0.0070 (2)-0.1128 (2)0.0543 (2)-0.1294 (1)-0.2532 (2)-0.0955 (2)-0.3259 (2)-0.1992 (2)-0.3545 (2)-0.1590 (1)-0.1384 (1)-0.0074 (2)0.0680 (2)0.1745 (2)0.2070 (2)0.1336 (2)0.0264 (2)-0.0661 (2)-0.1035 (2)-0.0293 (3)-0.2804 (2)-0.3501 (2)-0.4503 (2)-0.4809 (2)-0.4131 (2)-0.3122 (2)-0.2259 (2)-0.1760 (2)-0.2765 (2)-0.1605 (2)-0.2717 (2)-0.2796 (4)-0.3908 (5)-81-z0.27026 (4)0.2167 (2)0.3472 (3)0.4072 (2)0.5610 (2)0.6060 (2)0.5500 (2)- 0.0850 (2)-0.1596 (2)- 0.0869 (2)0.2125 (2)0.0976 (2)0.0112(2)0.3734 (1)0.1582 (2)0.2290 (2)0.1433 (2)0.1272 (3)0.1956 (3)0.2808 (3)0.2961 (2)0.3836 (2)0.3394 (3)0.5271 (3)0.1902 (2)0.2222 (2)0.1556 (2)0.0574 (2)0.0254 (2)0.0921 (2)0.0712 (2)-0.0675 (2)0.0972 (3)0.4078 (2)0.4804 (3)0.5925 (4)0.6635 (5)B (eq)
3.48 (4)6.85 (6)9.84 (9)8.33 (7)9.31 (8)9.45 (9)10.8 (1)
6.15 (6)
7.98 (7)7.76 (6)7.88 (7)8.23 (7)9.10(8)4.05 (5)4.40 (5)3.67 (6)4.39 (6)5.30 (7)5.70 (8)5.31 (8)4.11(6)4.50 (6)5.94 (8)6.8 (1)
3.58 (6)4.41 (6)5.24 (7)5.50 (8)5.13 (7)4.05 (6)4.35 (6)5.21 (7)5.94 (8)4.84 (7)5.98 (8)8.3 (1)
10.8 (2)Chapter 3.

Table 3-4. Continued (1)
8

atom

x

y

z

PI
FI
F2
F3
F4
F5
F6
F7
F8
F9
F 10
F 11
F 12
01
02
Cl
C2
C3
C4
C5
C6
C7
C8
C9
C 10
C 11
C 12
C 13
C 14
C 15
C 16
C 17
C 18
C 19
C 20
C 21
C 22

0.22201 (8)0.1929 (2)0.0776 (2)0.2406 (2)0.2601 (3)0.2732 (3)0.1155 (2)0.2696 (3)0.1701 (3)0.1015 (3)-0.0175 (2)- 0.0627 (2)-0.0017 (2)0.1613 (2)0.1302 (2)0.3538 (3)0.4563 (3)0.5505 (3)0.5417 (4)0.4398 (4)0.3460 (3)0.2277 (3)0.1843 (4)0.2190 (4)0.2667 (3)0.3416 (4)0.3609 (4)0.3068 (4)0.2307 (4)0.2122 (3)0.1322 (3)0.1664 (4)0.0098 (4)0.1892 (5)0.0734 (6)0.0516 (7)0.0549 (7)0.19316 (6)- 0.0076 (2)0.0148 (2)- 0.0293 (2)0.2109 (2)0.0952 (2)0.1434 (2)0.0327 (2)0.0339 (2)- 0.0086 (2)0.2196 (2)0.1000 (2)0.1403 (2)0.1520 (2)0.1355 (2)0.1526 (2)0.1593 (3)0.1252 (3)0.0846 (3)0.0760 (3)0.1101 (2)0.1052 (2)0.0200 (3)0.1394 (4)0.2286 (2)0.2895 (2)0.3084 (3)0.2688 (3)0.2090 (3)0.1907 (2)0.1299 (2)0.0464 (3)0.1473 (3)0.2917 (3)0.3131 (4)0.3951 (4)0.3916 (4)- 0.1 0 183 (8)- 0.0198 (2)0.1070 (3)0.1625 (3)0.2307 (3)0.3059 (2)0.2488 (2)- 0.2778 (3)- 0.4443 (2)- 0.2919 (3)- 0.3313 (3)-0.3135 (3)- 0.4717 (2)0.0189 (2)- 0.1795 (2)- 0.0372 (3)-0.0814 (4)- 0.0207 (4)0.0829 (4)0.1261 (4)0.0656 (3)0.0972 (3)0.0877 (4)0.2214 (4)-0.2443 (3)-0.2646 (4)-0.3790 (4)-0.4729 (4)- 0.4557 (4)- 0.3408 (3)-0.3025 (3)-0.3298 (4)-0.3547 (4)-0.0482 (5)-0.0703 (6)-0.0123 (7)0.1145 (6)-82-

B (eq)
3.5 (3)6.0 (3)7.1 (3)
6.8 (3)7.7 (3)8.0 (3)8.0 (3)7.0 (3)7.7 (3)7.5 (3)6.4 (3)7.6 (3)7.0(3)
3.9 (3)3.6 (3)3.4 (3)4.3 (3)4.8 (3)5.1 (3)4.4 (3)3.6 (3)3.8 (3)4.8 (3)5.4 (3)3.6 (3)4.5 (3)5.0 (3)4.9 (3)4.5 (3)3.5 (3)3.6 (3)5.1 (3)4.7 (3)
6.5 (3)7.8 (3)10.2(4)9.5 (4)

Chapter 3.

Table 3-4. Continued (2)
9
atom
PI
P2
Fl
F2
F3
F4
F5
F6
F7
F8
F9
F 10
F 11
F 12
F 13
F 14
F 15
F 16
F 17
F 18
F 19
F 20
F 21
F 22
F 23
F 24
01
02
03
04
Cl
C2
C3
C4
C5
C6
C7
C8
C9
C 10
C 11
C 12
C 13
C 14

x
-0.26485 (5)0.22229 (5)-0.3716 (2)-0.5032 (2)-0.4207 (2)-0.3790 (2)-0.4288 (2)-0.5070 (2)-0.2032 (2)-0.1924 (2)-0.3250 (2)-0.3245 (3)-0.4015 (2)-0.2771 (2)0.2381 (2)0.0921 (2)0.1735 (3)0.0600 (2)0.0735 (2)-0.0114 (2)0.3954 (2)0.4385 (3)0.3179 (3)0.2109 (3)0.2066 (2)0.3263 (3)-0.3703 (1)-0.3124 (1)0.1346 (1)0.2292 (2)-0.2078 (2)-0.1119(2)-0.0810 (3)-0.1412 (4)-0.2360 (3)-0.2681 (2)-0.3682 (2)-0.4166 (3)-0.4216 (3)-0.1573 (2)-0.0749 (3)-0.0042 (3)-0.0166 (3)-0 .0976 (3)y0.12665 (2)0.12121 (2)0.13744 (8)0.1537 (1)0.19056 (8)0.22024 (9)0.23683 (7)0.20013 (8)0.09318 (7)0.03530 (8)0.06066 (7)0.0276 (1)0.02871 (7)-0.00195 (7)0.1606 (1)0.1645 (1)0.21200 (9)0.20492 (8)0.23639 (7)0.18930 (8)0.1215 (1)0.0681 (1)0.0929 (1)0.02304 (9)0.03862 (9)0.0115 (1)0.14861 (6)0.09253 (5)0.14432 (6)0.09641 (6)0.16373 (8)0.1698 (1)0.1986 (1)0.2207 (1)0.2150 (1)0.18676 (9)0.17693 (8)0.1645 (1)0.2089 (1)0.09758 (9)0.1040 (1)0.0784 (1)0.0458 (1)0.0383 (1)-83-z-0.21990 (8)0.4] 435 (9)0.1139 (3)0.0056 (4)0.1470 (4)-0.2831 (4)-0.0791 (5)-0.2252 (4)0.1291 (2)0.1385 (4)0.1413 (3)-0.2944 (4)-0.1092 (4)-0.0985 (6)0.7790 (3)0.7803 (3)0.7851 (4)0.3475 (4)0.5441 (4)0.5300 (5)0.7041 (4)0.7821 (4)0.8567 (3)0.5187 (7)0.7453 (5)0.6812 (6)-0.1914 (2)-0.1368 (2)0.5017 (3)0.5689 (2)-0.1086 (4)-0.0741 (5)0.0156 (7)0.0785 (8)0.0490 (6)-0.0449 (5)-0.0901 (4)0.0451 (4)-0.1677 (6)-0.2205 (4)-0.2834 (5)-0.2713 (6)-0.2031 (6)-0.1409 (6)B (eq)
4.90 (4)4.77 (4)8.97 (9)10.0(1)
10.3 (1)
11.2 (1)
10.8 (1)9.4 (1)7.40 (8)10.0 (1)8.47 (8)11.9(1)9.4 (1)12.0 (2)9.8 (1)
10.7 (1)11.0 (1)9.8 (1)
10.3 (1)
10.3 (1)9.8 (1)
14.1 (2)12.1 (2)13.2 (2)12.6(1)15.8 (2)5.19 (7)5.14 (7)5.25 (7)5.42 (7)5.22 (8)6.5 (1)8.3 (2)9.8 (2)8.6 (2)6.0 (1)5.40 (9)6.8 (1)7.4 (1)
5.46 (9)6.6 (1)7.7 (1)8.4 (2)
7.3(1)

Chapter 3.

Table 3-4. Continued (3)
9

atom
C 15
C 16
C 17
C 18
C 19
C 20
C 21
C 22
C 23
C 24
C 25
C 26
C 27
C 28
C 29
C 30
C 31
C 32
C 33
C 34
C 35
C 36
C 37
C 38
C 39
C 40
C 41
C 42
C 43
C 44

x
- 0.1667 (2)- 0.2593 (2)- 0.2446 (3)- 0.3158 (3)-0.2956 (3)-0.2505 (4)-0.4016 (3)-0.2617 (5)0.2802 (2)0.3615 (3)0.3980 (3)0.3562 (3)0.2764 (3)0.2389 (2)0.1521 (2)0.1640 (3)0.0679 (3)0.3230 (2)0.3669 (3)0.4413 (3)0.4759 (3)0.4346 (2)0.3582 (2)0.3043 (2)0.3653 (4)0.2619 (4)0.1320 (3)0.1334 (4)0.0335 (3)0.1521 (4)y0.06468 (9)0.06175 (9)0.0626 (1)0.0288 (1)0.1305 (1)0.1648 (2)0.1327 (2)0.0980 (2)0.16546 (8)0.1742 (1)0.2087 (1)0.2350 (1)0.2269 (1)0.19238 (8)0.17909 (9)0.1793 (1)0.2026 (1)0.09414 (9)0.0949 (1)0.0726 (1)0.0498 (1)0.0482 (1)0.07044 (9)0.0725 (1)0.0893 (2)0.0360 (2)0.1068 (1)0.1352 (2)0.1057 (2)0.0696 (2)-84-z- 0.1520 (4)- 0.0909 (4)0.0825 (4)- 0.1473 (6)- 0.4284 (4)-0.4800 (6)-0.4749 (5)- 0.5128 (6)0.4135 (4)0.3520 (5)0.3683 (6)0.4460 (6)0.5104 (5)0.4925 (4)0.5534 (4)0.7253 (5)0.4949 (6)0.3583 (4)0.2266 (4)0.2107 (4)0.3255 (5)0.4551 (5)0.4687 (4)0.6035 (4)0.7382 (5)0.6366 (9)0.2578 (4)0.1333 (6)0.3041 (7)0.1944 (8)B (eq)
5.74 (9)5.54 (9)6.5 (1)
7.6(1)
6.7(1)
9.8 (2)8.4 (2)11.0 (2)5.18 (8)6.5 (1)8.1 (1)8.2 (2)7.1 (1)
5.66 (9)5.45 (9)7.1 (1)7.3 (1)
5.15 (8)6.1 (1)
6.5 (1)
6.6 (1)
6.5 (1)5.40 (9)6.2 (1)9.0 (2)10.5 (2)
6.4 (1)9.3 (2)9.8 (2)9.7 (2)

Chapter 3.
Dynamic NMR Measurement and Line Shape Analysis
Samples of 8 (ca. 15 mg in 0.5- 0 .6 mL of solvent unless noted
otherwise) dissolved in freshly distilled toluene-dg were sealed in NMR tubes
under N2.

19F NMR spectra were measured on a JEOL EX-400 (376 MHz)in a variable temperature mode, and the specified temperatures weremaintained throughout each set of measurements (error within ± 1°C). The
observed temperatures were calibrated with the IH NMR chemical shiftdifference of signals of neat 1,3-propanediol (high temperature region) andMeOH (low temperature region). The rates and activation free energies atthe coalescence point were calculated using the following equations derived
from the Gutowsky-Holm appoximation of k = It ~ vI2- 1/2.ll)~G*= 19.14 Tc {9.97 + log (Tc/8y)}/4.184~G*= {23.76 - In (kiD} RT<kcal mol- I>

The line shape analysis was performed in a narrow temperature range
around the coalescence point according to the classical Gutowsky-Holmmethod neglecting 4ip_p coupling since the condition il ~ v«

1 is met. The

activation enthalpies and entropies were calculated according to the transition
state theory of Eyring 12) using the following equations by linear regression.

In (kiD = ~HtIRT + ~st + In (kBlh)
The systematic error associated with the simulated rates was estimated tobe 10% and calculated with the following equation since the proportional
error for ~t and ~st are the same as for Ea. 11)-85-

Chapter 3.

Table 3-5. Kinetic Parameters of Inversion at Phosphorus Atom in 8 intoluene-d8

T<K>

k <sec- I>~G:j: <kcal mol- I>

223

150

10.7

228

243

10.7

231

341

10.7

233

415

10.7

235

505

237

~:j: <kcal mol- I>~S:j: <eu>

10.7

10.0 ± 0.7-3.4 ± 3.0

600

10.8

(± 0.1)*(± 0.4)*

239

705

10.8

241

870

10.8

243

1030

10.8

* Statistical error in parenthesis
Eyring Ploty = 22.068 - 5010.4x RI\2 = 0.999,-.2----------------.
~
~

'-'

-=

1

o

-1+-~~~--~~--~--~~--~

0.00410.00420.00430.00440.0045liT </K>-86-

Chapter 3.
Kinetic Measurements of the Pseudorotation of 8 and 9.
Samples of 8 and 9 (ca. 15 mg in 0.5- 0.6 mL of solvent) dissolved in
freshly distilled solvents were sealed in NMR tubes under N2. For theobservation of the permutation of 8 19F NMR spectra were measured on alEOL EX-400 in a variable temperature mode, and the specified
temperatures were maintained throughout each set of measurements (error
within ± 1°C). The observed temperatures were calibrated with the IH NMR
chemical shift difference of signals of neat 1,3-propanediol (high temperature
region) and MeOH (low temperature region).

For the observation of thepseudorotation of 9, 19F NMR spectra were measured on a lEOL EX-400 at
rt after heating samples at maintained temperatures for arbitrary periods oftime, and the specified temperatures were maintained with a silicon oil bath(error within ± 2°C).
The ratio of [TBPY-5-12] phosphoranes (8,9) and [TBPY-5-11]
phosphoranes (5,6) was monitored by integration of 19F NMR signals. The
data were analysed by assuming irreversible first-order kinetics using theequation In (colc) = k T, in which Co = concentration of [TBPY-5-12]
phosphoranes (8, 9) at t = 0, c = concentration of [TBPY-5-12] phosphoranes(8, 9) at arbitrary intervals. Plots are showed in Fig. 3-5.
The activation enthalpies and entropies were calculated according to thetransition state theory of Eyring using the following equation.
In (kiD = I1HtlRT + I1st + In (kBlh)
Plots are showed in Fig. 3-6. Kinetic parameters are listed in Table 3-6.

-87-

Chapter 3.

Figure 3-5. Plot of In (colc) vs . time. [co = concentration of [TBPY-5-12]
phosphoranes (8, 9) at t = 0, C = concentration of [TBPY-5-12] phosphoranes(8 , 9) at arbitrary intervals].

8 in toluene-d 8
•
C

A
b.

In (CO/C)o

T = 302 K
T = 308 K
T=313K
T=318KT = 323 K
T = 328 K

1.0 - . - - - - - r - - - - - - - , - - - - - - , - - - - - - - ,

0 .8

0 .6

0.4

0 .2

0 .0 ~-=--__r---__r__--_r___--__f

o

10000

-88-

20000 time <sec>Chapter 3.

Figure 3-5. Continued (1)8 in pyridine

In (CO/C)•

T = 313 K y = 1.4830e-2 + 4.2406e-5x R"2 = 0.998

0.8 - r - - - - - - - - - - - - - - - - - .

0.6

0.4

0.2

0.0 ___--~---_r__---...._--~
o
10000
20000 time <sec>

8 in EtOH• T=313K
o T=318K• T = 323 K
0
T = 328 K

In (CO/C)

2-r-----~--~------

o

o

10000

20000

-89-

30000 time <sec>Chapter 3.

Figure 3-5. Continued (2)9 in 4-t-butyltoluene

In (CO/C)•[]

T = 403 K
T = 423 K•

T = 443 K
T = 463 Ko2~----~--------------------~

o~----~------~----~------~o100000-90-200000 time <sec>Chapter 3.

Figure 3-6. Eyring plot.

8 in toluene-ds

In (kff)y= 19.208 - 1.0957e+4x R"2 = 0.999

-14

-15

-16

-17

-18 +--..---""'---r--"'---~--.----.--~
0.00300.00310.00320.00330.0034 liT </K>

8 in EtOH.

In (kff)

y = 21.091 - 1.1610e+4x R"2 = 0.999

-14

-15

-16

-17
0.00300.0031-91-

0.0032 liT </K>

Chapter 3.

Figure 3-6. Continued (1)9 in 4-t-butyltoluene

In (kff)

y = 17.188 - 1.3678e+4xR"2 = 0.998-12 ~~---------------,

-13

-14

-15

-16

-17 -+----r------.----.----r--r-----.----..----lI

0.00210.00220.00230.0024-92-

0.0025 lIT </K>

Chapter 3.

Table 3-6. Kinetic Parameters

8 in toluene-d8
~Gt

T
<K>

k
<sec- I>

<kcal mol- I>

302( 1. 18 ± 0.0 1) x 10- 5

24.5

308

(2.45 ± 0.04) x 10- 5

24.5

313

(4.03 ± 0.07) x 10- 5

24.6

318

(7.61 ± 0.12) x 10-5

24.6

323

(1.29 ± 0.01) x 10- 4

24.7

328

(2.31 ± 0.01) x 10- 4

24.7

Mit
<kcal mol- I><eu>

21.8 ± 0.4-9.0 ± 1.2

Mit<kcal mol- I>

~S:f:

<eu>

23.1 ± 0.5-5.3 ± 1.5~st

8 in EtOH
~Gt

<K>

k
<sec- I>

<kcal mol- I>

313(3.44 ± 0.03) x 10-5

24.7

318

(6.56 ± 0.05) x 10-5

24.7

323

(1.16 ± 0.03) x 10- 4

24.8

328

(1.97 ± 0.02) x 10- 4

24.8

T

-93-

Chapter 3.

Table 3-6. Continued (1)9 in 4-t-butyltoluene
T

k

~Gt

<K>

<sec- I>

<kcal mol- I>

403(6.73 ± 0.10) x 10- 6

33.4

423

(3.89 ± 0.02) x 10- 5

33.5

443

(2.15 ± 0.04) x 10- 4

33.7

463

(7.62 ± 0.02) x 10- 4

34.1

-94-

Mit
<kcal mol- I><eu>

27.2 ± 0.8-13.1 ± 1.8~stChapter 3.
Kinetic Measurements of the Pseudorotation of 10-exo and 10endo.

Samples of 10-exo or 10-endo (ca. 20 mg) dissolved in freshly distilled
solvents (0.5- 0.6 mL) were sealed in NMR tubes under N 2 . For theobservation of the pseudorotation between 10-exo and 10-endo 19F NMR
spectra were measured on a lEOL EX-400 at rt after heating samples atmaintained temperatures for arbitrary periods of time.

The specified

temperatures were maintained with a silicon oil bath (error within ± 2°C).
The change in the diastereomers was monitored by integration of 19F NMR
signals. The data were analyzed by assuming reversible first-order kinetics
using the equation In [(xe - XO)/(xe - x)] = k (K + 1) t, in which Xe = ratio at
equilibrium , Xo = ratio observed at t = 0, x = ratio observed at arbitrary
intervals , k = rate constant to be determined (k+; 10-exo to 1O-e ndo: k_;
10-endo to 10-exo), and K = equilibrium ratio.

The equilibrium ratios

were determined after heating the measured samples in a silicon oil bath at
the specified temperature (± 2°C) for at least 5 lifetimes.

-95-

Chapter 3.

Figure 3-7. Plot of In [(xe - xo) / (xe - x)] vs. time.

(xe = ratio at

equilibrium, Xo = ratio observed at t = 0, x = observed ratio at arbitrary
intervals) .

10 in 4-t-butyltoluene~

1.2 - r - - - - - : - - . . . , , - - - - . , - - - - - - - - ,T = 442 K• T = 448 K
o T = 453 K• T = 458 K
o T = 463 K

~

6.

~ 1.0
"-'

..."'"~ 0.8-c: 0.4
0.2
0.0 <'F--~--""T'""""""-__r_--r___---r--___t
o
40000
80000
120000 t <sec>-96-Chapter 3.

Figure 3-8. Eyring plot.

10 in 4-t-butyltoluene

-..

E-c

?2
""-'

• In (k-ff)
o In (k+ff)= 19.316 - 1.6862e+4x R"2 = 0.998
Y = 19.355 - 1.6991e+4x R"2 = 0.998

y-17 ~~---------------,

-18

-19

-20 -+---r--"T"'"""'"-"T"'"""'"-~-~---'r----4 lIT </K>
0.002220.00226
0.002140.00218-97-

Chapter 3.

Table 3-7. Kinetic Parameters

lO-endo to lO -exo

T<K>

k <sec- I>~Gt <kcal mol- I>

442(3.02 ± 0.03) x 10- 6

37.4

448

(4.74 ± 0.07) x 10- 6

37.5

453

(7.52 ± 0.16) x 10- 6

37.5

458

(1.18 ± 0.01) x 10- 5

37.5

463

(1.74 ± 0.02) x 10- 5

37.6

Mit <kcal mol- I>~S:j: <eu>33.5 ± 0.9- 8.8 ± 1.9

Mi:j: <kcal mol- I>~S:j: <eu>33.8 ± 0.9-8.7 ± 1.9

lO-exo to lO-endo

T<K>

k <sec-I>~G:j: <kcal mol- I>

442(2.34 ± 0.03) x 10-6

37.6

448

(3.68 ± 0.06) x 10-6

37.7

453

(5.83 ± 0.12) x 10-6

37.7

458

(9.18 ± 0.09) x 10-6

37.8

463

(1.35 ± 0.02) x 10-5

37.8

-98-

Chapter 3.

D. References(1) (a) Pimentel, G. C. 1. Chern. Phys. 1951,19,446.

(b) Hach, R. J.;

Rundle, R. E. 1. Ant. Chent. Soc. 1951, 73, 4321.
(2) (a) Holmes, R. R. Pentacoordinate Phosphorus-Structure andSpectroscopy; ACS Monograph 175, 176; American Chemical Society:

Washington, DC, 1980; Vols. I, II.

(b) Trippett, S. Phosphorus, Sulfur

Silicon Relat. Elern. 1976, 1, 89. (c) McDowell, R. S.; Streitwieser, A. 1.
A1n. Chen!. Soc. 1985,107, 55. (d) Wang, P.; Zhang, Y.; Glaser, R.; Reed,

A. E.; Schleyer, P. v. R.; Streitwieser, A. 1. Am. Chern. Soc. 1991, 113, 55.
(e) Thatcher, G. R. J.; Campbell, A. S. 1. Org. Chern. 1993,58, 2272. (f)Wasada, H.; Hirao, K. 1. Am. Chern. Soc. 1992,114,16.
(3) (a) Granoth, I.; Martin, J. C. 1. Am. Chern. Soc. 1979,101,4618. (b)Granoth, I.; Martin, J. C. 1. Am. Chern. Soc. 1979,101, 4623. (c) Kojima,S.; Kajiyama, K.; Akiba, K.-y. Tetrahedron Lett. 1994,35,7037. Kojima,S.; Kajiyama, K.; Akiba, K.-y. Bull. Chern. Soc. lpn. 1995,68, 1785.
Kojima, S.; Nakamoto, M.; Kajiyama, K.; Akiba, K.-y. Tetrahedron Lett.
1995, 36, 22617.

(4) Berry, R. S. 1. Chern. Phys. 1960,32, 933.
(5) (a) Timosheva, N. V.; Prakasha, T. K.; Chandrasekaran, A.; Day, R. 0.;
Holmes, R. R. Inorg. Chern. 1995,34, 4525.

(b) Timosheva, N. V.;

Chandrasekaran, A.; Prakasha, T. K.; Day, R. 0.; Holmes, R. R. Inorg.
Chern. 1996,35, 6552.

-99-

Chapter 3.
(6) (a) Kawashima, T.; Kato, K.; Okazaki, R.I. Am. Chern. Soc. 1992, 114,4008.

(b) Kawashima, T.; Kato, K.; Okazaki, R. Angew Chern., Int. Ed.

Engl. 1993,32, 869.
(7) Kawashima, T.; Soda, T.; Kato, K.; Okazaki, R. Phosphorus, Sulfur

Silicon Relat. Elern. 1996, Vols. 109-110,489.

(8) Kajiyama, K.; Kojima, S.; Akiba, K.-y. Tetrahedron Lett. 1996,37,

8409.
(9) Furusaki, A. Acta. Crystallogr. 1979, A35, 220.

(10) Katayama, C. Acta. Crystallogr. 1986, A42, 19.
(11) Jackman, L. M.; Cotton, F. A. "Dynamic Nuclear Magnetic Resonance
Spectroscopy", Academic Press, New York 1975.
(12) Wynne-Jones, W. F. K.; Eyring, H. 1. Chern. Phys. 1935,3, 492.

-1 00 -

Chapter 4

Kinetic Studiesof Thermal Cyclization Reactionsof P-H (apical) Phosphoranes

Bearing a Hydroxy GroupChapter 4.

A. Introduction

The heterolysis of element-carbon or element-hydrogen bonds which
gives compounds bearing new element-heteroatom bonds with elimination ofhydrocarbon or H2 has been implicated to involve species of higher
coordination number during the reaction. 1) As part of our continuous studies
on hypervalent organic compounds, we have found that in the intramolecularcyclization reaction of a series of acyclic 8-Si-42) o-silylbenzyl alcohols (weakacids) A to 8-Si-4 cyclic alkoxysilanes B with elimination of hydrocarbons(eq 1), the selectivity of the eliminating hydrocarbon is highly dependent on
the relative stabilities of isomeric 10-Si-5 transition states) ) We havesuggested that the reaction proceeded via transition states involving
pentacoordinate species with a concerted four-membered ring formed byintramolecular coordination of the hydroxy oxygen to Si that the structural
stability of the pentacoordinate species has a significant bearing on theselectivity of elimination. This showed the importance of participation of thehypervalent bond in the transition state besides acidity of the eliminatinghydrocarbons. 4 )

(1)

A

-101-

Chapter 4.
In analogous transformation of mono cyclic 10-Bi-5 alcohols to bicyclic
10-Bi-5 bismuthanes the intermediacy of hexacoordinate 12-Bi-6 species
could be verified. S) We have also observed selectivity that does not parallel
the acidities in hydrocarbon elimination from monocyclic 12-Sb-6 atecomplexes upon hydrolysis. 6 ) In the case of phosphorus compounds thisphenomenon is not usually seen for neutral ordinary valent compounds.
Especially for hypervalent phosphorus compounds bearing P-H bonds weknow of only a few examples. Hexacoordinate P-H phosphate C cyclizedwith elimination of hydrogen gas to give tricyclic hexacoordinate phosphate
D (eq 2).7) Monocyclic P-H phosphorane F was observed upon reacting E

with cathecol, and F gradually transformed to G (eq 3).8) However since
hypervalent phosphorus compounds are usually very susceptible to moisture
it has been rather difficult to carry out kinetic studies of this interestingprocess of dihydrogen elimination and there is no report that we are aware

of.

(2)

c
8p (MeCN) = -99(IJp_H = 802Hz)-102-

Chapter 4.

(3)

As described in Chapter 3, monocyclic P-H (apical) phosphoranes 1-3
cyclized intramolecularly with elimination of hydrogen to form thecoresponding [TBPY-5-11] spirophosphoranes 4-6 predominantly innondonor solvents and the coresponding [TBPY-5-12] spirophosphoranes 810 predominantly in donor solvents on heating.

In order to gain anunderstanding of the mechanism and the solvent effect of the thermal
cyclization of 1-3, we have carried out the kinetic studies on it. On the basisof these results we propose the mechanisms for the process for both innondonor and donor solvents .

-103-

Chapter 4.

B. Results and Discussion

1. Kinetic Studies of Thermal Cyclization Reaction of P-H(Apical) Phosphoranes 2 and 3 Bearing a Hydroxyl Group in
Nondonor Solvents.

F3CIIII.

cc:\\\.. I.
,~I#

nondonor solvents

CF3
0,.. P-R

~

';;7

+ H2

0

F3 C

4; R = Me
5; R = n-Bu
6; R = t-Bu
7; R=HIn nondonor solvents such as toluene, p-xylene, o-dichlorobenzene,
monocyclic P-H (apical) phosphoranes 1-3 cyclized intramolecularly withelimination of hydrogen to form [TBPY-5-11] spirophosphoranes 4-6 onheating (Scheme 4-1). The cyclization of 1 (R = Me) to 4 was too fast to
monitor. The rates of cyclization of 2 (R = n-Bu) to 5 were measured intoluene- d 8 (343-373 K) and o-dichlorobenzene (343-373 K) by monitoring
19F NMR.

In the case of cyclization of 3 to 6, the rates in p-xylene (393-423K) and o-dichlorobenzene (393-423K) were measured by monitoring 3lp
NMR because of the complexity of the 19F NMR spectra. In the case of thecyclization of 3 in o-dichlorobenzene, [TBPY -5-11] P-H (equatorial)-104-

Chapter 4.
spirophosphorane 7 [38 % (423 K)] also formed along with 6 [62 % (423 K)].
The cyclization of 3 to 7 could also be observed in p-xylene. However, in therange of 403-423 K 7 could only be detected in trace amounts compared with
6. All the processes followed first-order kinetics quite satisfactorily. The
Eyring plot of the rates also turned out to be linear thus implying theexistence of only a single process for the cyclization. Representative rates andactivation parameters of the cyclization of 2 and 3 are shown in Table 4-1
and 4-2, respectively.

,'

Table 4-1. Kinetic Parameters of the Cyclization of 2

solvent

toluene-ds

a-dichlorobenzene

product

5

5k <sec-I> (373 K)(1.46 ± 0.03) x 10-5

(5.55 ± 0.05) x 10-5

~Gt <kcal mol-I> (373 K)

30.3

29.3

Mit <kcal mol-I>

17.3 ± 0.6

14.0 ± 0.2~st <kcal mol-I>-34.7 ± 1.7-41.0 ± 0.6-105-Chapter 4.

Table 4-2. Kinetic Parameters of the Cyclization of 3

solventp-xylene

product

6

7

k <sec- I> (393 K)(1.14 ± 0.02) x 10- 6(8.10 ± 0.21) x 10- 7~Gt <kcal mol- I> (393 K)

33.9

34.2

j)Jft <kcal mol-I>

32.2 ± 1.1-~st <kcal mol-I >-4.29 ± 2.6-

solvent

a-dichlorobenzene

product

6

7

k <sec-I> (393 K)(2.06 ± 0.01) x 10-6

(1.81 ± 0.02) x 10-6

~Gt <kcal mol-I> (393 K)

33.4

33.5

j)Jft <kcal mol-I>

29.5 ± 0.7

25.0 ± 1.0~st <kcal mol- I>-9.9 ± 1.8-21.8 ± 2.6

In nondonor solvents, the cyclization rates of phosphoranes 2 and 3 to
[TBPY-5-11] spirophosphoranes 5,6 and 7 in a-dichlorobenzene (ET N =0.225) as the polar solvent [2 to 5~ k = (5.55 ± 0.05) x 10- 5 sec- 1 (373 K), 3
to 6~ k = (2.06 ± 0.01) x 10- 6 sec- 1 (393 K), 3 to 7~ k = (1.81 ± 0.02) x 10-6
sec- I (393 K)] were faster than those in toluene-d8 (ETN = 0.099) and p-xylene(ETN = 0.074) as the nonpolar solvents [2 to 5~ k = (1.46 ± 0.03) x 10- 5 sec- 1(373 K), 3 to 6~ k = (1.14 ± 0.02) x 10- 6 sec- 1 (393 K), 3 to 7; k = (8.10 ±-106-

Chapter 4.
0.21) X 10-7 sec- I (393 K)]. The activation enthalpies in the polar solvent (2;= 14.0 ± 0.2 kcal mol- I, 3; ~H+ = 29.5 ± 0.7 kcal mol- I) were ca. 3 kcal
mol-I smaller than those in nonpolar solvents (2; ~H+ = 17.3 ± 0.6 kcal mol-~HtI, 3; ~Ht = 32.2 ± 1.1 kcal mol- I), while the difference in barriers between 2
and 3 was ca. 15 kcallmol (= 32 - 17). The activation entropies of 2 werelarge negative values and those of 3 were negative but the magnitude wasmuch smaller.
The fact that a solvent effect in terms of solvent polarity existed but thedegree was small suggests that the intramolecular cyclization reactions ofphosphoranes 1-3 with elimination of hydrogen gas proceed via slightly
polarized, concerted four-membered transition states 3 , 4) (TS-A), with the
involvement of hexacoordinate phosphorus species which is considerably
more congested than the pentacoordinate ground state to afford [TBPY-5-11]
spirophosphoranes 4-6 as depicted in Scheme 4-2. TS-A and TS-B will
result from pseudorotation and successive approach of the hydroxy oxygen to
the lowest 0-* orbital; that of the P-O bond. Among nondonor solvents, themore polar solvent (o-dichlorobenzene) stabilizes the polarized transition
state so that the rate of the intramolecular cyclization may be accelerated.
The large difference in activation enthalpy between 2 and 3 probably reflects
the reluctance for 3 to cyclize due to much larger steric hindrance. The large
negative activation entropies values of 2 is in accord with the hinderedenviropment about phosphorus upon assuming hexacoordination from
pentacoordination in the transition state. 9 ) In the case of 3 to 6, the groundstate is probably already highly motion ally hindered due to the back strain of
the t- Bu group. That the magnitude of activation entropy of the formation of
7 is larger than that of 6 is probably because the t-butyl group itself
participates in the bond transformation in the transition state (TS-B).

-107-

Chapter 4.

,\\\CF3

I~
#

0

I

111111"" "P_R

I~
(&

1

0

F3 C\\'\' CF 3

4', R=Me5·, R = n-Bu
6; R = t-Bu
-108-

Chapter 4.
2.

Kinetic Studies of Thermal Cyclization Reaction of P-H

Phosphoranes 2 and 3 Bearing a Hydroxyl Group in Pyridine asDonor Solvent.

Scheme 4-3

8', R=Me9', R = n-Bu
10', R = t-Bu

Upon thermal cyclization of monocyclic P- H (apical) phosphoranes 1-3
in pyridine as donor solvent we could observe the formation of [TBPY-5-12]
spirophosphoranes 8-10 (Scheme 4-3). Although the hydrogen bonding witha solvent molecule exists in donor solvents (Chapter 2), these reactions could
be considered to be the intramolecular cyclization with elimination ofhydrogen like in nondonor solvent since the cyclization rates of monoanionicderivatives 11-13 [8p (Et20) = -117 amount of aqueous KOH were much slower.

-109--153] generated with an excess

Chapter 4.

11; R = Me [~ (Et20) = -153, IJp_H = 679 Hz]
12; R = n-Bu [8p (Et20) = -130, IJp _H = 674 Hz]
13; R = t-Bu [8p (Et2 0) = -117, 1J p- H = 335 Hz]

The cyclization of 1 (R = Me) to 8 was too fast to monitor. The rates ofcyclization of 2 (R = n-Bu) to 9 (308-323 K) and 3 (R = t-Bu) to 10 (333-363 K) were measured by monitoring 19F NMR. In the case of 1 (R = Me)and 2 (R = n-Bu) the formation of [TBPY-5-11] spirophosphoranes 4 and 5,
respectively, was also observed even in the early reaction period.

Asmentioned in Chapter 3, since the pseudorotation of 9 to 5 occurred in thistemperature range, the reaction of 2 in pyridine was assumed to involve a
combination of competitive and consecutive reactions, and follow irreversible
first-order kinetics (Scheme 4-4).

The analysis was carried out by curve

fitting (Fig. 4-1; T = 323 K) of the data to the following set of equations.
[2] = [2]0 exp {-(kl + k3) t}(1)[9] = K [2]0 exp {-(kl + k3) t} - K [2]0 exp (-k2 t)(2)[5] = [2]0 - (1 + K) [2]0 exp {-(k 1 + k3) t} + K [2]0 exp (-k2 t)

-110-

(3)

Chapter 4.
In which [2]0 = concentration of . P- H (apical) phosphorane 2 at t = 0
normalized to 100, [2] = concentration of P- H (apical) phosphorane 2 atarbitrary intervals, [9] = concentration of [TBPY-5- 12] spirophosphorane 5at arbitrary intervals, [5] = concentration of [TBPY-5- 11] spirophosphorane
5 at arbitrary intervals, k I, k2, k3 = rate constants to be determined. In order
to attain maximum accuracy, equation (1), which corresponds to a first-order
reaction was solved separately and kl + k3 derived from this equation wasused in the subsequent equations.

Representative rates and activation

parameters of the cyclization and pseudorotation of 2 are shown in Table 4-3.

Figure 4-1. Curve fitting (T = 323 K)

1\ 1000; [2]~vc0; [9]
6; [5]

o

:=
~

80

.....
1-1

C

Q)

u

C

ou 60

40

20

o

2

4

8

6

x10

3

-111-

10

12

time <sec>Chapter 4.

Scheme 4-4
F3C~",.

I ~0 HO "CF 3

n-Bu

I

I ~

~,,9

H

CF3

F3CIII,. CF 3I ~0~ ,\\"".. I

0 ,\"'.

F3C","

F3C\\:

~
r

0

I

I #'

0

~

2 9 5

t

I

k3

Table 4-3. Kinetic Parameters of the Cyclization and Pseudorotation of 2 inpyridine .

k <sec- I>~G:j: <kcal mol-I >(T = 323 K)(T = 323K)

2 to 9(4.52 ± 0.20) x 10-4

2 to 59 to 5

Mi:j: <kcal mol- I>~S:j: <eu>23.917.1±0.3- 21.0±1.1(6.64 ± 0.43) x 10- 4

23.7

23.9 ± 1.3

0.8 ± 4.2

(1.26 ± 0.20) x 10-4

24.7

20.3 ± 0.5- 13.8 ± 1.7

On the other hand, the formation of [TBPY-5- 11] spirophosphorane 6
could not be observed in pyridine in this temperarure range, thus, the analysis
of cyclization process of 3 to give 10 followed simple first-order kinetics
quite satisfactorily. The Eyring plot of the rates also turned out to be linear
thus implying the existence of only a single process for the cyclization and

-

112-

Chapter 4.
gave the activation parameters I1Hi = 22.3 ± O.6kcal mol- J and I1Si = -12.7 ±1.8 eu ..
We suggest that the intramolecular cyclization reactions of phosphoranes

1-3 with elimination of the hydrogen gas to [TBPY-5-12] spirophosphoranes
8-10 in pyridine proceed via polarized, concerted four-memberedintramolecular transition

statesT S -C, with the involvement ofhexacoordinate phosphorus species as depicted in Scheme 4-5. TS-C may
result from the approach of the hydroxy oxygen which is more nucleophilic,due to hydrogen bonding, to phosphorus and has the advantage of retaining
the structure of the ground state, thus allowing the formation of [TBPY-5-12J
spirophosphoranes 8-10 in pyridine (donor solvent).

The fact that theactivation enthalpy was larger in pyridine than in toluene for the formation of
5 implies that solvation of 2 is stronger in pyridine leading to larger
stabilization of the ground state.

That the activation entropy of thecyclization of 2 to 5 was ca. 0 eu may be because the intermolecularhydrogen bonding with a solvent molecule in the ground state is lost in thetransition state.

The large negative value of entropy in the case of thecyclization of 2 to 9 could be an indication of a tighter transition state for
product formation due to the higher lying a*p-c compared with a*p-o.

-113-

Chapter 4.

Scheme 4-5

endo,,~CF3

02
\ -

>

~ e

R'" I';1
J. Iltl" ,•••"'.p .'1/

I

H,

CenFd30"""IICF3
exo'H~ ~ ~pyridine

TS-C

~-H2

I ~

~ 1111"3..'\"CF1

0

I"···P-R

20"F3 Cltl", ..
F3 C

8; R = Me
9; R = n-Bu
10; R = l-Bu
-114-

Chapter 4.

c. Experimental Section
19F (376 MHz), 31p (162 MHz) spectra were recorded on a JEOL EX400 spectrometer.

19F NMR chemical shifts (8) are given in ppm downfieldfrom external CFCI3. 31 P NMR chemical shifts (8) are given in ppm
downfield from external 85 % H3P04.

Kinetic

Measurements of the

Cyclization Reaction of 2 inNondonative Solvents and 3 in Nondonative Solvents and Pyridine(Donative Solvent).
Samples of 2 and 3 (ca. 15 mg) dissolved in freshly distilled solvents(0.5-0.6 mL) were sealed in NMR tubes under N2. Especially in the case of
3, the sample was throughly dried in vacuo to remove the solvent molecule.
Kinetic measurements were carried out on a JEOL EX -400 in a variabletemperature mode, and the specified temperatures were maintained
throughout each set of measurements (error within ± 1°C). The observed
temperatures were calibrated with the 1H NMR chemical shift difference of
signals of neat 1,3-propanediol (high temperature region) and MeOH (lowtemperature region).
In the cyclization reactions of 2 (R = n-Bu) in nondonor solvents and 3(R = t-Bu) in pyridine, the ratio of P-H (apical) phosphoranes (2, 3) and thecyclization products (5, 10) was monitored by integration of 19F NMR
signals. In the cyclization reactions of 3 in nondonor solvents, the ratio of 3
and the cyclization products (6, 7) was monitored by integration of 31 P NMR
signals in a proton bond decoupled mode. That the integrals of 31 P NMR are-115-

Chapter 4.
proportional to the compound was comfirmed by I9F NMR. The data wereanalysed by assuming irreversible first-order kinetics using the equation In(colc) = k T, in which Co = concentration of P-H (apical) phosphoranes at t =0, c = concentration of P-H (apical) phosphoranes at arbitrary intervals.
Their graph are showed in Fig. 4-2.
The activation enthalpies and entropies were calculated according to thetransition state theory of Eyring I 0) by linear regression of the rate data using
the following equation. II)
In (kiT) = ~HtIRT + ~st + In (kBlh)
Plot of the measurements are showed in Fig. 4-3.
listed in Table 4-4.

-116-

Kinetic psrameters areChapter 4.

Figure 4-2. Plot of In (colc) vs time (co = concentration of P- H (apical)
phosphoranes at t = 0, c = concentration of P- H (apical) phosphoranes atarbitrary intervals)
2 in toluene-d s ; Product is 5.
•

T = 343 K
T = 353 K• T = 363 K
0
T = 373 K
In (CO/C)
0.15 , - - - - - - . , - - - - - - - - , - - - - - - - ,
o

0.10

0.05

0.00
10000

0

20000

30000 t <sec>

2 in a-dichlorobenzene; Product is 5.

• T = 343 K
0•0

In (CO/C)
0.12

T = 353 K
T = 363 K
T = 373 K

0.10
0.08
0.06
0.04
0.02
0.00
0

2000

4000

6000

-117-

8000 t <sec>Chapter 4.

Figure 4-2. Continued (1)3 in p-xylene; Product is 6 .

• T = 393 K

CJ•
In (CO/C)

0

T = 403 K
T = 413 K
T = 423 K

0.10
0.08
0.06
0.04
0.02
0.00
0

10000

20000

30000 t <sec>

3 in p-xylene; Product is 7 .

In (CO/C)•

T = 393 K

y = - 3.S303e-4 + 8.0980e-7x

RI\2 = 0.998

0 .02 - - - - - - - - - - - - - - - -0 .01

0 .00 -III£----r--_r----y----r---r---~
30000 t
20000
10000
o

-118-

<sec>

Chapter 4.

Figure 4-2. Continued (2)3 in o-dichlorobenzene; Product is 6.
• T = 393 K[] T = 403 K• T=413K
0
T = 423 K

In (CO/C)

0.12 - y - - - - , . . . - - r - - - - - - - y o - - - - - - - - ,
0.10
0.08
0.06
0.04
0.02
0.00

~-

o

__---.-_---.---......._-or____
10000
20000
30000
40000t <sec>-~

3 in o-dichlorobenzene; Product is 7.
• T = 393 K[] T = 403 K• T=413K
0
T = 423 K

In (CO/C)

0.08

0.06

0.04

0.02

0.00

o

10000

20000

30000

-119-

40000 t <sec>Chapter 4.

Figure 4-2. Continued (3)3 in pyridine; Product is 10.
•

T = 333 K
o T = 343 K• T = 353 K
0
T = 363 K

In (CO/C)

2~~--~------------------~

o~--~~--~--~~--~--~~

o

10000

20000

30000

-120-

40000t <sec>Chapter 4.

Figure 4-3.

Eyring plot of the cyclization reaction of P-H (apical)

phosphorane.
2 in toluene-dg; Product is 5.
In (kff)y= 6.3092 - 8699.9x RA2 = 0.998-17~------------------------~

-18

-19

-20+---~~--~--~~--~--~~

0.00260.00270.00280.00290.0030 lIT </K>

2 in o-dichlorobenzene; Product is 5.
In (kff)
y = 3.1299 - 7026.0x RA2 = 1.000-15 -y-------------------,

-16

-17

-18 4---.,..--,----,----r---r---~-~---t
0.00260.00270.00280.00290.0030 lIT </K>

-121-

Chapter 4.

Figure 4-3. Continued (1)3 in p-xylene; Product is 6.
In (kIT)-16~~------------------------~

-17

-18

-19

-20 -+---~----~----r-------...----....,.---l"'---~
0.00230.00240.00250.0026 liT </K>

3 in a-dichlorobenzene; Product is 6.
In (kIT)-16----------------------------~

-17

-18

-19

-20
0.00230 .00240.0025-122-

0.0026 liT </K>

Chapter 4.

Figure 4-3. Continued (2)3 in o-dichlorobenzene; Product is 7.
In (kff)

y = 12.805 - 1.2592e+4x R"2 = 0.997-16 ~-------------..

-17

-18

-19

-20 -+---~------r---r---~-~----I
0.00230.00240.00250.0026 lIT </K>

3 in pyridine; Product is 10.
In (kff)-13~-----------------------~

-14

-15

-16

-17~--~~--~--~~---r--~~0.00270.00280.00290.0030-123-

0.0031 lIT </K>

Chapter 4.

Table 4-4. Kinetic Parameters

2 in toluene-d g; Product is 5.

T
<K>

k
<sec- I>

L1Gt
<kcal mol- I>

343(1.76 ± 0.05) x 10-6

29.2

353

(3.95 ± 0.08) x 10-6

29.5

363

(8. 15 ± O. 12) x 10- 6

29.8

373

(1.46 ± 0.03) x 10-5

30.3

L1Ht
<kcal mol- I>

L1st
<eu>

17.3±0.6-34.7 ± 1.7

L1Ht<kcal mol- I>

L1st
<eu>

14.0 ± 0.2-41.0 ± 0.6

2 in a-dichlorobenzene; Product is 5.

T
<K>

k
<sec- I>

L1Gt
<kcal mol- I>

343(9.87 ± 0.23) x 10-6

28.0

353

(1.84 ± 0.07) x 10-5

28 .4

363

(3.32 ± 0.02) x 10-5

28.8

373

(5.55 ± 0.05) x 10-5

29.3

-124-

Chapter 4.

Table 4-4. Continued (1)3 in p-xylene; Product is 6.

,--

~Gt

T
<K>

k
<sec- I>

<kcal mol- I>

393(1.14 ± 0.02) x 10-6

33.9

403

(3.66 ± 0.07) x 10-6

33.9

413

(9.58 ± 0.01) x 10-5

33.9

423

(2.30 ± 0.04) x 10-5

34.0

~st

Mit
<kcal mol- 1><eu>

32.2 ± 1.1-4.2 ± 2.6

Mit<kcal mol-I>

~st

<eu>

29.5 ± 0.7-9.9 ± 1.8

3 in o-dichlorobenzene; Product is 6.
~Gt

T
<K>

k
<sec-I><kcal mol- I>

393(2.06 ± 0.01) x 10-6

33.4

403

(5.73 ± 0.10) x 10-6

33.5

413

(1.45 ± 0.04) x 10-5

33.6

423

(3.22 ± 0.07) x 10-5

33.7

-125-

Chapter 4.

Table 4-4. Continued (2)3 in a-dichlorobenzene; Product is 7.
~Gt

T
<K>

k
<sec- I>

<kcal mol- 1>393(1.81 ± 0.02) x 10- 6

33.5

403

(3.84 ± 0.08) x 10--6

33.8

413

(8.06 ± 0.09) x 10--6

34.1

423

(1.92 ± 0.03) x 10--5

34.2

M-It
<kcal mol- I><eu>

25.0 ± 1.0-21.8 ± 2.6

M-I*<kcal mol-I>

~s*

<eu>

22.3 ± 0.6-12.7 ± 1.8~st

3 in pyridine; Product is 10.
~G*

T
<K>

k
<sec-I><kcal mol-I>

333(2.75 ± 0.03) x 10--5

26.5

343

(8.43 ± 0.11) x 10--5

26.6

353

(2.04 ± 0.03) x 10-- 4

26.7

363

(4.93 ± 0.08) x 10--4

26.9

-126-

Chapter 4.
Kinetic

Measurements of the

Cyclization Reaction of 2 inPyridine (Donative Solvent)
Samples of 2 (ca. 15 mg) dissolved in freshly distilled solvents (0.5-0.6mL) were sealed in NMR tubes under N2.

19F NMR spectra were measured

on a JEOL EX -400 in a variable temperature mode, and the specified
temperatures were maintained throughout each set of measurements (error
within ± 1°C). The observed temperatures were calibrated with the IH NMR
chemical shift difference of signals of neat 1,3-propanediol (high temperature
region) and MeOH (low temperature region).
The ratio of 2 and the cyclization products (5, 8) was monitored byintegration of 19F NMR signals. The reaction was assumed to involve a
combination of competitive and consequtive reactions and follow irreversible
first-order kinetics. The analysis was carried out curve fitting of the data to
the following set of equations.
[2] = [2]0 exp {-(k 1 + k2) t}(1)[5] = K [2]0 exp {-(k 1 + k 2) t} - K [2]0 exp (-k2 t)(2)[8] = [2]0 - (1 + K) [2]0 exp {-(kl + k 2) t} + K [2]0 exp (-k2 t)(3)

in which [2]0 = concentration of P-H (apical) phosphorane 2 at t = 0
normalized to 100, [2] = concentration of P-H (apical) phosphorane 2 at= concentration of [TBPY-5-12] (a-cis)spirophosphorane 5 at arbitrary intervals, [8] = concentration of [TBPY-5-

arbitrary intervals,[5]11] (a-trans) spirophosphorane 8 at arbitrary intervals, kl' k2, k3 = rate

-127-

Chapter 4.
constants to be determined. In order to attain maximum accurary, equation(1) , which corresponds to a first-order (Fig. 4-4).
The activation enthalpies and entropies were calculated according to thetransition state theory of Eyring using the following equation. Plot of themeasurements are showed in Fig. 4-5.

In (kiD = I1HtlRT + I1St + In (kBlh)
The kinetic parameters are listed in Table 4-5.

-

128 -

Chapter 4.

Figure 4-4. Curve fit

T= 308 K

0; [2]" 1 00~v

0; [9]. 6; [5]

c:
o

~

...
..~

80 ;

c:
c:
~

C,J

8 60 •
40 .

20

~

o

.

10

20

30

x10

3

40

50

time <sec>[2] = 100 exp (-2.2010 x 10-4 t)[9] = -60.091 exp (-2.2010 x 1Q-4 t) + 60.091 exp (-2.6314 x 10-5 t)[5] = 100 - 39.909 exp (-2.2010 x 10-4 t) -60.091 exp (-2.6314 x 10-5 t)
kl + k3 = (2.2010 ± 0.07) x 10-4

K [2]0 = kI [2]0/{ k2 - (k 1 + k3)} = -60.091 ± 1.14
k2 = (2.6314 ± 0.08) x 10-5-129-

Chapter 4.

Figure 4-4. Continued (1)T = 313 K

0; [2]
0; [9]
6; [5]

20

o

30

20
x10

3

40

time <sec>[2] = 100 exp (-3.5748 x 10-4 t)[9] = -58.898 exp (-3.5748 x 10-4 t) + 58.898 exp (-4.3611 x 10-5 t)[5] = 100 - 41.102 exp (-3.5748 x 10-4 t) -58.898 exp (-4.3611 x 10-5 t)
kl + k3 = (3.5748 ± 0.04) x 10-4

K [2]0 = kl [2]01 {k2 - (kJ + k3)} = -58.898 ± 0.76
k 2 = (4.3611 ± O. 11) x 10- 5-130-Chapter 4.

Figure 4-4. Continued (2)T = 318 K
100

0; [2]=o80 :0; [9]
6; [5]

"

~

v

:c
~

........

~
==
u

o==

u

60 ;

40 '

20 :.

o

............ .
o

10

5

x10

15

3

20

time <sec>[2] = 100 exp (-6.1475 x 10-4 t)[9] = -52.485 exp (-6.1475 x 10-4 t) + 52.485 exp (-7.8271 x 10-5 t)[5] = 100 - 47.515 exp (-6.1475 x 10-4 t) -52.485 exp (-7.8271 x 10-5 t)
kl + k3 = (6.1475 ± 0.15) x 10-4

K [2] 0 = k 1 [2] 01 {k2 - (k 1 + k3)} = -52.485 ± 3.05
k2 = (7.8271 ± 0.38) x 10- 5-131-Chapter 4.

Figure 4-4. Continued (3)T = 323 K"~

0; [2]

100v

0; [9]~; [5]c.-.....
o~.....S-c
C

~
~

C

o

~

40

o

2

4

6
x10

8
3

10

12

time <sec>[2] = 100 exp (-1.1153 x 10- 3 t)
[9] = -45.646 exp (-1.1153 x 10-3 t) + 45.646 exp (-1.2589 x 10-4 t)[5] = 100 - 54.354 exp (-1.1153 x 10- 3 t) -45.646 exp (-1.2589 x 10-4 t)
kl + k3 = (1.1153 ± 0.02) x 10- 3

K [2]0 = kl [2]01 {k2 - (k 1 + k3)} = -45.646 ± 0.80
k2 = (1.2589 ± 0.04) x 10- 4-132-Chapter 4.

Figure 4-5. Eyring plot

•
c
o

•
...-..

In {(k1 +k3)rr}
In(k1ff)
In(k2ff)
In(k3ff)

y = 19.713 - 1.0441e+4x R"2 = 0.996

Y = 13.204 - 8623.9x R"2 = 0.999
Y = 16.807 - 1.0192e+4x R"2 = 0.999
Y = 24.159 - 1.204ge+4x R"2 = 0.994-12~........
~

----

-=

-13

-14

-15

-16

-17 +------r------,r------r---~--_____,--___I

0 .0030

0.0031

0 .0032

0 .0033lIT </K>-133-

Chapter 4.

Table 4-5. Kinetic Paranleters of the Cyclization Reaction or 2 in Pyridine
T
<K>

kl
<sec- I>

~Gtl

~Htl

~Stl

<kcal mol- I><kcal n101- 1>

<eu>

308

(1.17±0.07) x 10- 4

23.6

313

(1.83 ± 0.05) x 10- 4

23.7

17.1 ± 0.3-21.0 ± 1.1

318(2.82 ± 0.26) x 10- 4

23.8

323

(4.52 ± 0.20) x 10- 4

23.9

T
<K>

k2
<sec- I>

~Gt2

~t2

~St2

<kcal mol- I><kcal mol- I>

<eu>

308

(2.63 ± 0.08) x 10- 5

24.5

313

(4.36 ± 0.11) x 10- 5

24.6

20.3 ± 0.5-13.8 ± 1.7(4.24 ± 0.09) x 10-5 *

24.6

318

(7.83 ± 0.38) x 10-5

24.6

323

(1.26 ± 0.04) x 10- 4

24.7* The rate was measured from 9 by monItoring 19F NMR.

-134-

Chapter 4.

T
<K>

k3
<sec-I>

L\ Gt 3<kcal mol- I>

308(1.04 ± 0.14) x 10- 4

23.7

313

(1.74 ± 0.09) x 10- 4

23.7

318

(3.33 ± 0.41) x 10-4

23.7

323

(6.64 ± 0.43) x 10- 4

23.7

-135-

Mit 3
<kcal mol- I>

L\St3
<eu>

23.9 ± 1.3+0.79 ± 4.2

Chapter 4.

D. References(1) For example: Abraham, M. H.; Grellier, P. L. In the Chemistry of theMetal-Carbon Bond; Hartley, F.; Patai, S., Eds. John Wiley and Sons: New

York, 1985; Vol. 2, Chapter 2.
(1) For designation: Perkins, C. W.; Martin, J. C.; Arduengo, A. J.; Lau, W.;

Alegria, A.; Kochi, J. K. 1. Afn. Cheln. Soc. 1980,102, 7753.
(3) Yamamoto, Y.; Takeda, Y.; Akiba, K.-y. Tetrahedron Lett. 1989,30,725.
(4) (a) Depuy, C.H.; Bierbaum, L.W.; Damrauer, R. 1. AI1L Chern. Soc.

1984,106,4051. (b) Depuy, C.H.; Damrauer, R.; Bowie, J. H.; Sheldon, J.

C. Acc. Chern. Res. 1987,20, 127.

(c) Davis, L.P.; Burggraf, L.W.;

Gordon, M.S. 1. Arn. Chern. Soc. 1988, 110, 3056.

(d) Taylor, W. S.;

Babcock, L. M. 1. Am. Chern. Soc. 1995, 117, 6497.
(5) Yamamoto, Y.; Ohdoi, K.; Chen, X.; Kitano, M.; Akiba, K.-y.

Organometallics 1993,12,3297.
(6) Yamamoto, Y.; Fujikawa, H.; Fujishima, H.; Akiba, K.-y. 1. Am. Chern.

Soc. 1989,111,2276.

(7) Lopez, L.; Boisdon, M. T.; Barrans, J. Acad. Sci., Ser. C, 1972,275,
295.
(8) Malavaud, C.; Barrans, J. Tetrahedron Lett. 1975,35, 3077.
(9) (a) Rothwell, L. I. Acc. Chern. Res. 1988,21, 153. (b) Li, L.; Hung, M.;
Xue, Z. 1. Am. Chern. Soc. 1995, 117, 12746.

-136-

Chapter 4.
(10) Wynne-Jones, W. F. K.; Eyring, H. 1. Chern. Phys. 1935,3,492.
(11) Jackman, L. M.; Cotton, F. A. "Dynamic Nuclear Magnetic Resonance
Spectroscopy", Academic Press, New York 1975.

-

137 -

Acknowledgment.

Acknowledgment

The author expresses his sincere gratitude to Professor Kin-ya Akiba ofHiroshima University for his relevant guidance, advice, encouragement, andfull support of this work.
The author is especially grateful to Research Associate Satoshi Kojima of
Hiroshima University for his relevant guidance, discussion, encouragement,
and full support of this work.
The author is grateful to Professor Katsuo Ohkata, Associate Professor
Yamamoto Y ohsuke, and Research Associate Mao Minoura of Hiroshima
University for their advice, discussion and encouragement.
The author appreciates Mr Masaaki Nakamoto for his assistance anddiscussion, Miss N atsuko Shimizu for the theoretical calculations, and all themembers of Professor K.-y. Akiba's Laboratory and fellows for their help.
Last but not least, the author is deeply grateful to his family for theirsupport and encouragement all through his graduate study.

-138-

List of Publications.

List of Publications(1) Characterization of an Optically Active Pentacoordinate Phosphoranewith Asymmetry Only at Phosphorus.
Kojima, S.; Kajiyama, K.; Akiba, K.-y. Tetrahedron Lett. 1994,35, 7037
-7040.
(2) Non-dissociative Permutation of a Stable Hydrophosphorane andRetention of Stereochemistry of the Electrophilic Reaction of Its Conjugate
Phosphoranide Base.
Kojima, S.; Nakamoto, M.; Kajiyama, K.; Akiba, K.-y. Tetrahedron Lett.

1995, 36, 2261-2264.
(3) Characterization of Enantiomeric Pairs of Optically Active 10-P-5
Phosphoranes with Asymmetry Only at Phosphorus.
Kojima, S.; Kajiyama, K.; Akiba, K.-y. Bull. Chern. Soc. Jpn. 1995, 68,
1785-1797.
*(4) Synthesis and Characterization of Intra- and Intermolecular Hydrogen
Bonding Isomers of P-H (apical) Phosphoranes Bearing a Hydroxyl Groupand Their Thermal Cyclization.
Kajiyama, K.; Kojima, S.; Akiba, K.-y. Tetrahedron Lett. 1996,37, 8409
-8412.

-139-

List of Publications.

*(5) First Characterization of a 10-P-5 Spirophosphorane with an Apical
Carbon-Equatorial Oxygen Ring. Kinetic Studies on Pseudorotation of
S tereoisomers.
Kojima, S.; Kajiyama, K.; Nakamoto, M.; Akiba, K.-y. 1. A rn. Chern. Soc.

1996, 118, 12866-12867.

* ~ n G ~i I~ffiJX 0) £1Jl t tj ~ t:. JJ¥( ~~ffiJx --r: cb 6
No.1, 2, 3 'i~~~ffiJx--r: cb 6 0

-

140 -

0