Chiral unsymmetric diphosphine compound and transition metal complex containing the same as ligand

A novel chiral unsymmetric diphosphine compound of formula (I): ##STR1## wherein Ar.sup.1 and Ar.sup.2, which are different from each other, each represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a pyridyl group, a quinolyl group, an isoquinolyl group, a furfuryl group, a benzofurfuryl group, a thienyl group, or a benzothienyl group, and a transition metal complex containing the diphosphine compound as a ligand. The complex catalyzes various asymmetric synthesis reactions, e.g., asymmetric hydrogenation or asymmetric hydrosilylation, exhibiting excellent performance in selectivity, conversion and catalytic activity, to provide a product of desired absolute configuration at high optical purity and in high yield.

FIELD OF THE INVENTION 
This invention relates to a novel chiral unsymmetric diphosphine compound, 
an intermediate therefor, a process for preparing the intermediate and the 
diphosphine compound, and a transition metal complex containing the 
diphosphine compound as a ligand. 
BACKGROUND OF THE INVENTION 
Many transition metal complexes have been used as a catalyst for asymmetric 
synthesis, such as asymmetric hydrogenation, asymmetric isomerization, and 
asymmetric hydrosilylation, and a good number of reports have been made on 
such transition metal complex catalysts. 
Many complexes exhibiting excellent performance in catalytic asymmetric 
synthesis are found among those comprising a transition metal, e.g., 
rhodium, ruthenium, iridium, palladium or nickel, and an optically active 
tertiary phosphine compound as a ligand. To further improve the 
performance of these catalysts, various phosphine compounds having a 
unique structure have been developed to date as disclosed, e.g., in Nippon 
Kagakukai (ed.), KAGAKU SOSETSU, Vol. 32, pp. 237-238, "YUKI KINZOKU 
SAKUTAI NO KAGAKU" (1982) and Ryoji Noyori, Asymmetric Catalysis in 
Organic Synthesis, A Wiley-Interscience Publication. 
In particular, 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (hereinafter 
abbreviated as BINAP) is one of excellent phosphine ligands, and a rhodium 
complex and a ruthenium complex using BINAP as a ligand have been reported 
in JP-A-55-61937 and JP-A-61-63690 (the term "JP-A" as used herein means 
an "unexamined published Japanese patent application"). JP-A-60-199898 and 
JP-A-61-63690 report that a rhodium or ruthenium complex using 
2,2'-bisdi(p-tolyl)phosphino!-1,1'-binaphthyl as a ligand brings 
satisfactory reaction results in asymmetric hydrogenation and asymmetric 
isomerization. JP-A-3-255090 declares that a ruthenium complex having 
2,2'-bisdi(3,5-dialkylphenyl)phosphino!-1,1'-binaphthyl gives good 
results in asymmetric hydrogenation of .beta.-keto esters. 
The above-mentioned phosphine compounds can be prepared by, for example, a 
process comprising bromination of a racemic binaphthol compound with 
triphenylphosphine dibromide at a high temperature (e.g., 240.degree. to 
320.degree. C.), forming a Grignard reagent and condensation of the 
Grignard reagent with a diarylphosphinyl chloride to obtain a phosphine 
dioxide compound, optically resolving the phosphine dioxide compound, and 
reducing the resulting optically active compound with a reducing agent, 
e.g., trichlorosilane to obtain a tertiary phosphine compound (BINAP 
derivative) (see J. Org. Chem., Vol. 51, p. 629 (1986)). BINAP can also be 
synthesized by preparing 
2,2'-bis(trifluoromethanesulfonyloxy)-1,1'-binaphthyl from optically 
active binaphthol and reacting the compound with diphenyl phosphine in the 
presence of a nickel-phosphine complex as described in J. Org. Chem., Vol. 
59, pp. 7180-7181 (1994). 
In recent years, a ligand having a binaphthyl skeleton and yet having an 
unsymmetric structure with no C.sub.2 chirality due to the different 
substituents on the 2- and 2'-positions has been synthesized, and 
transition metal complexes using this ligand have been reported (see J. 
Am. Chem. Soc., Vol. 115, p. 7033 (1993) and JP-A-6-263776). For example, 
2-(diphenylphosphino)-1,1'-binaphthalen-2'-yl-(1,1'-binaphthalen-2,2'-yl)p 
hosphite was found to exhibit excellent performance in asymmetric 
hydroformylation of olefins. 
However, compounds having an optically pure binaphthyl skeleton generally 
meet difficulty in modifying with a functional group as compared with 
those derived from optically pure tartaric acid or amino acid. There are 
only a few reports on synthesis of that kind of derivatives or ligands 
having an unsymmetric structure. 
When used in asymmetric synthesis, a transition metal complex having, as a 
ligand, a known symmetric phosphine compound, such as BINAP, is often 
unsatisfactory in selectivity (chemoselectivity and enantioselectivity), 
conversion, catalytic activity, and optical purity for some reactions or 
some reaction substrates. Therefore, it has been keenly demanded in the 
art to develop an optically active phosphine compound capable of a new 
catalytic asymmetric synthesis reaction or different asymmetric 
recognition for the sake of utility of chiral compounds and also to 
develop unsymmetric phosphine ligands that could be expected to be 
different from conventional phosphine compounds in selectivity 
(chemoselectivity and enantioselectivity), conversion, catalytic activity, 
and optical purity. 
SUMMARY OF THE INVENTION 
An object of the invention is to provide a novel unsymmetric diphosphine 
compound meeting the above demand. 
Another object of the invention is to provide a novel unsymmetric 
diphosphine monoxide compound which is an intermediate for preparing the 
above-described unsymmetric diphosphine compound. 
A further object of the invention is to provide a process for preparing the 
above-described unsymmetric diphosphine compound and its intermediate, 
unsymmetric diphosphine monoxide compound. 
A still further object of the invention is to provide a novel transition 
metal-unsymmetric diphosphine complex comprising a transition metal, e.g., 
ruthenium, rhodium, iridium, palladium or nickel, and the above-described 
unsymmetric diphosphine compound as a ligand, which complex is a promising 
catalyst for various asymmetric synthesis reactions. 
In the course of study on a ligand capable of catalytic asymmetric 
reactions, the inventors have succeeded in synthesis of a novel 
unsymmetric diphosphine compound having a binaphthyl skeleton and yet 
having no C.sub.2 chirality and found the compound capable of forming a 
complex with a transition metal. Based on this finding and as a result of 
further study, the inventors have reached the present invention. 
The invention relates, in its first aspect, to an unsymmetric diphosphine 
compound represented by formula (I): 
##STR2## 
wherein Ar.sup.1 and Ar.sup.2, which are different from each other, each 
represent a phenyl group, a phenyl group substituted with 1 to 5 groups 
arbitrarily selected from the group consisting of a halogen atom, a lower 
alkyl group, a lower alkoxy group, a di(lower alkyl)amino group, a 
halogenated lower alkyl group, and a phenyl group, a naphthyl group, a 
naphthyl group substituted with a lower alkyl group or a lower alkoxy 
group, a pyridyl group, a quinolyl group, an isoquinolyl group, a furfuryl 
group, a benzofurfuryl group, a thienyl group, or a benzothienyl group. 
The invention relates, in its second aspect, to an unsymmetric diphosphine 
monoxide compound represented by formula (II): 
##STR3## 
wherein Ar.sup.1 and Ar.sup.2, which are different from each other, have 
the same meaning as defined above, which is an intermediate for preparing 
the unsymmetric diphosphine compound (I). 
The invention relates, in its third aspect, to a process for preparing the 
unsymmetric diphosphine compound (I) comprising reacting a 2-disubstituted 
phosphino-2'-trifluoromethanesulfonyloxy-1,1'-binaphthyl represented by 
formula (III): 
##STR4## 
wherein Ar.sup.1 is as defined above; and Tf represents a 
trifluoromethanesulfonyl group, with a disubstituted phosphine oxide 
represented by formula (IV): 
##STR5## 
wherein Ar.sup.2 is as defined above, provided that it is different from 
Ar.sup.1, in the presence of a transition metal-phosphine complex to form 
an unsymmetric diphosphine monoxide compound (II), and reducing the 
compound (II). 
The invention relates, in its fourth aspect, to a transition 
metal-unsymmetric diphosphine complex, in which the transition metal is 
selected from rhodium, ruthenium, iridium, palladium, and nickel, and the 
unsymmetric diphosphine is the unsymmetric diphosphine compound (I). 
Both the unsymmetric diphosphine compound (I) and the unsymmetric 
diphosphine monoxide compound (II) embrace the (-)-form and the (+)-form, 
and all these isomers are included under the scope of the invention. 
DETAILED DESCRIPTION OF THE INVENTION 
The unsymmetric diphosphine compound (I) and the unsymmetric diphosphine 
monoxide compound (II) are both novel compounds. 
In formulae (I) and (II), Ar.sup.1 and Ar.sup.2 each represent a 
substituted or unsubstituted phenyl group, a substituted or unsubstituted 
naphthyl group, a pyridyl group, a quinolyl group, an isoquinolyl group, a 
furfuryl group, a benzofurfuryl group, a thienyl group, or a benzothienyl 
group. Specific examples of the substituted phenyl group are p-tolyl, 
p-methoxyphenyl, p-trifluoromethylphenyl, p-fluorophenyl, 
p-dimethylaminophenyl, p-t-butylphenyl, 3,5-dimethylphenyl, 
3,5-di-t-butylphenyl, 3,4,5-trimethoxyphenyl, 
3,5-dimethyl-4-methoxyphenyl, 3,5-ditrifluoromethylphenyl, 
3,5-dichlorophenyl, pentafluorophenyl, and biphenyl. The substituted or 
unsubstituted naphthyl group includes .alpha.-naphthyl, .beta.-naphthyl, 
6-methoxy-.alpha.-naphthyl, and 6-methoxy-.beta.-naphthyl. The pyridyl 
group includes 2-pyridyl, 3-pyridyl, and 4-pyridyl. The quinolyl group 
includes 2-quinolyl, 3-quinolyl, and 4-quinolyl. The isoquinolyl group 
includes 1-isoquinolyl, 3-isoquinolyl, and 4-isoquinolyl. The furfuryl 
group includes 2-furfuryl and 3-furfuryl. The benzofurfuryl group includes 
2-benzofurfuryl and 3-benzofurfuryl. The thienyl group includes 2-thienyl 
and 3-thienyl. The benzothienyl group includes 2-benzothienyl and 
3-benzothienyl. The substituents Ar.sup.1 and Ar.sup.2 are arbitrarily 
combined with no particular limitation as far as they are different from 
each other. 
Unless otherwise specified, the term "lower alkyl group" is intended to 
include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, 
and t-butyl groups; the term "lower alkoxy group" is intended to include 
methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, 
and t-butoxy groups; the term "halogen atom" includes fluorine, chlorine 
and bromine; the term "halogenated lower alkyl group" includes 
trifluoromethyl and trichloromethyl groups; and the term "di(lower 
alkyl)amino group" includes a dimethylamino group. That is, the "lower" 
alkyl or alkoxy means alkyl or alkoxy having 1 to 4 carbon atoms. 
The 2-disubstituted 
phosphino-2'-trifluoromethanesulfonyloxy-1,1'-binaphthyl (III), which is a 
starting material used in the invention, can easily be synthesized from a 
known compound, 1,1'-bi-2-naphthol, in accordance with the following 
reaction scheme A. 
##STR6## 
wherein Ar.sup.1, Ar.sup.2, and Tf are as defined above. 
In the above scheme, Ac represents an acetyl group; Ph represents a phenyl 
group; Me represents a methyl group; DPPP represents 
1,3-bisphenylphosphinopropane; and DMSO stands for dimethyl sulfoxide 
(hereinafter the same). 
That is, optically active 1,1'-bi-2-naphthol (IV) is reacted with 
trifluoromethanesulfonic acid anhydride (Tf.sub.2 O) to obtain 
2,2'-bis(trifluoromethanesulfonyloxy)-1,1'-binaphthyl (V) in accordance 
with the method described in Tetrahedron Letters, Vol. 31, pp. 985-988 & 
1945-1948 (1990). The resulting compound (V) is reacted with a 
disubstituted phosphine oxide in the presence of palladium acetate, 
1,3-bisdiphenylphosphinopropane (DPPP), and N,N-diisopropylethylamine to 
obtain a 2-disubstituted 
phosphinyl-2'-trifluoromethanesulfonyloxy-1,1'-binaphthyl (VI) in 
accordance with the method described in J. Org. Chem., Vol. 58, pp. 
1945-1948 (1993). The compound (VI) is then reduced with, e.g., 
trichlorosilane to give a 2-disubstituted 
phosphino-2'-trifluoromethanesulfonyloxy-1,1'-binaphthyl (III). 
Commercially available optically active 1,1'-bi-2-naphthol can be made use 
of as a starting compound (IV). Alternatively, it may be prepared with 
ease at high optical purity and in high yield by a known process 
disclosed, e.g., in J. Org. Chem., Vol. 53, p. 3607 (1988) and 
JP-A-64-13063, which comprises reacting optically active 
O,O'-dimethyl-N,N'-tetramethyltartaric acid amide obtainable from natural 
or unnatural tartaric acid with racemic binaphthol to form a complex 
between the acid amide and one of the optically active compounds of the 
racemic binaphthol, and resolving the complex. 
The unsymmetric diphosphine compound (I) and the unsymmetric diphosphine 
monoxide compound (II) can be synthesized in accordance with, for example, 
the following reaction scheme B. 
##STR7## 
wherein Ni(dppe)Cl.sub.2 represents 
1,2-bis(diphenylphosphino)ethane!nickel dichloride; DABCO represents 
diazabicyclo2,2,2!octane; and other symbols are as defined above. 
A 2-disubstituted phosphino-2'-trifluoromethanesulfonyloxy-1,1'-binaphthyl 
(III) is reacted with a disubstituted phosphine oxide in the presence of a 
catalytic amount of a transition metal-phosphine complex to obtain a 
2-disubstituted phosphino-2'-disubstituted phosphinyl-1,1'-binaphthyl (II) 
(unsymmetric diphosphine oxide compound). 
The unsymmetric diphosphine oxide compound (II) is then reduced with a 
reducing agent, such as trichlorosilane, to obtain a 
2,2'-bis(disubstituted phosphino)-1,1'-binaphthyl (I) (unsymmetric 
diphosphine compound). 
The transition metal-phosphine complex which can be used in the preparation 
of the unsymmetric diphosphine compound (I) and unsymmetric diphosphine 
monoxide compound (II) includes those comprising cobalt or nickel as a 
transition metal. The phosphine ligand in the complex is not particularly 
limited and includes triphenylphosphine, tri-o-tolylphosphine, 
tri-p-tolylphosphine, tri-m-tolylphosphine, 
1,2-bisdiphenylphosphinoethane, 1,3-bisdiphenylphosphinopropane, 
1,4-bisdiphenylphosphinobutane, 1,5-bisdiphenylphosphinopentane, and 
1,6-bisdiphenylphosphinohexane. While the reducing agent to be used in the 
preparation of the unsymmetric diphosphine compound (I) is not 
particularly limited, a silane compound is usually used. Suitable silane 
compounds include trichlorosilane, dichlorosilane, chlorosilane, 
methyldichlorosilane, dimethylchlorosilane, phenyldichlorosilane, 
phenylmethylchlorosilane, and diphenylchlorosilane. 
The thus prepared novel unsymmetric diphosphine compound (I) serves as a 
ligand to provide a complex with a transition metal. The transition metals 
capable of forming a complex with the compound (I) include rhodium, 
ruthenium, iridium, palladium, and nickel. 
The transition metal-unsymmetric diphosphine complex of the invention can 
be prepared by known processes as described below. In what follows, the 
symbols "L", "cod", and "nbd" stand for a diphosphine compound (I), 
1,5-cyclooctadiene, and norbornadiene, respectively. 
(1) Rhodium Complex 
A rhodium complex can be prepared by reacting a 2,2'-bis(disubstituted 
phosphino)-1,1'-binaphthyl (I) with bis(cycloocta-1,5-diene)rhodium (I) 
tetrafluoroborate in accordance with the method described in The Chemical 
Society of Japan (ed.), Dai 4-han Jikken Kagaku Koza, Vol. 18, "Yuki 
Kinzoku Sakutai", pp. 339-344 published by Maruzen Co. (1991). Examples of 
rhodium complexes thus prepared are Rh(L)Cl, Rh(L)Br, Rh(L)I, 
Rh(cod)(L)!BF.sub.4, Rh(cod)(L)!ClO.sub.4, Rh(cod)(L)!PF.sub.6, 
Rh(cod)(L)!BPh.sub.4, Rh(nbd)(L)!BF.sub.4, Rh(nbd)(L)!ClO.sub.4, 
Rh(nbd)(L)!PF.sub.6, and Rh(nbd)(L)!BPh.sub.4, (wherein L represents a 
diphosphine compound (I) (hereinafter the same)). 
(2) Ruthenium Complex 
A ruthenium complex can be prepared by reacting a 2,2'-bis(disubstituted 
phosphino)-1,1'-binaphthyl (I) with Ru(cod)Cl.sub.2 !, under reflux by 
heating in toluene solvent in the presence of triethylamine in accordance 
with the method described in J. Chem. Soc. Chem. Commun., p. 922 (1988). 
It can also be prepared by heating a 2,2'-bis(disubstituted 
phosphino)-1,1'-binaphthyl (I) and Ru(p-cymene)I.sub.2 !.sub.2 in 
methylene chloride and ethanol while stirring by heating in accordance 
with the method described in J. Chem. Soc., Chem. Commun., p. 1208 (1989). 
Examples of ruthenium complexes thus prepared are Ru(OAc).sub.2 (L), 
Ru.sub.2 Cl.sub.4 (L).sub.2 N(C.sub.2 H.sub.5).sub.3, 
RuCl(benzene)(L)!Cl, RuBr(benzene)(L)!Br, RuI(benzene)(L)!I, 
RuCl(p-cymene)(L)!Cl, RuBr(p-cymene)(L)!Br, RuI(p-cymene)(L)!I, 
Ru(L)!(BF.sub.4).sub.2, Ru(L)!(ClO.sub.4).sub.2, 
Ru(L)!(PF.sub.6).sub.2, and Ru(L)!(BPh.sub.4).sub.2. 
(3) Iridium Complex 
An iridium complex can be prepared by reacting a 2,2'-bis(disubstituted 
phosphino)-1,1'-binaphthyl (I) and Ir(cod)(CH.sub.3 CN).sub.2 !BF.sub.4 
under stirring in tetrahydrofuran in accordance with the method of J. 
Organomet. Chem., Vol. 428, p. 213 (1992). Examples of the iridium 
complexes thus prepared are Ir(L)Cl, Ir(L)Br, Ir(L)I, 
Ir(cod)(L)!BF.sub.4, Ir(cod)(L)!ClO.sub.4, Ir(cod)(L)!PF.sub.6, 
Ir(cod)(L)!BPh.sub.4, Ir(nbd)(L)!BF.sub.4, Ir(nbd)(L)!ClO.sub.4, 
Ir(nbd)(L)!PF.sub.6, and Ir(nbd)(L)!BPh.sub.4. 
(4) Palladium Complex 
A palladium complex can be prepared by reacting a 2,2'-bis(disubstituted 
phosphino)-1,1'-binaphthyl (I) and a .pi.-allylpalladium chloride in 
accordance with the method described in J. Am. Chem. Soc., Vol. 113, p. 
9887 (1991). Examples of palladium complexes thus prepared are PdCl.sub.2 
(L), (.pi.-allyl)Pd(L), Pd(L)!BF.sub.4, Pd(L)!ClO.sub.4, 
Pd(L)!PF.sub.6, and Pd(L)!BPh.sub.4. 
(5) Nickel Complex 
A nickel complex can be prepared by dissolving a 2,2'-bis(disubstituted 
phosphino)-1,1'-binaphthyl (I) and nickel chloride in a mixed solvent of 
isopropyl alcohol and methanol and heating the solution with stirring in 
accordance with the method described in The Chemical Society of Japan 
(ed.), Dai 4-han Jikken Kagaku Koza, Vol. 18, "Yuki Kinzoku Sakutai", p. 
376, published by Maruzen Co. (1991). Examples of nickel catalysts thus 
prepared are NiCl.sub.2 (L), NiBr.sub.2 (L), NiI.sub.2 (L), 
Ni(L)!(BF.sub.4).sub.2, Ni(L)!(ClO.sub.4).sub.2, 
Ni(L)!(PF.sub.6).sub.2, and Ni(L)!(BPh.sub.4).sub.2. 
The transition metal-unsymmetric diphosphine compound complexes thus 
prepared can be used as a catalyst for asymmetric synthesis, for example, 
asymmetric hydrogenation and asymmetric hydrosilylation, to give a product 
of desired absolute configuration with a high optical purity. 
For example, asymmetric hydrogenation of a ketone in the presence of a 
combination of the unsymmetric diphosphine compound (I) and a complex 
precursor, i.e., a metal complex before addition of a ligand (e.g., 
Ru(p-cymene)I.sub.2 !.sub.2 for a ruthenium complex, Ir(cod)(CH.sub.3 
CN).sub.2 !BF.sub.4 for an iridium complex, (.pi.-allyl)PdCl!.sub.2 for a 
palladium complex, or NiCl.sub.2 for a nickel complex), or in the presence 
of the transition metal complex of the invention gives a corresponding 
optically active alcohol. This reaction is carried out by dissolving the 
substrate ketone in an appropriate solvent, such as methanol, 
tetrahydrofuran, methylene chloride, benzene or a mixture thereof, adding 
the complex of the invention in an amount of 1/1000 to 1/10 mol per mole 
of the substrate, and keeping the reaction system at 10.degree. to 
50.degree. C. at a hydrogen pressure of 2 to 100 kg/cm.sup.2. 
Thus, the invention provides a novel unsymmetric diphosphine compound, 
2,2'-bis(disubstituted phosphino)-1,1'-binaphthyl compound. The 
unsymmetric diphosphine compound of the invention is capable of forming a 
complex with a transition metal, such as rhodium, ruthenium, iridium, 
palladium or nickel. The resulting transition metal complex catalyzes 
various asymmetric synthesis reactions, such as asymmetric hydrogenation 
and asymmetric hydrosilylation, exhibiting excellent performance in 
selectivity, conversions, and catalytic activity, to provide a product of 
desired absolute configuration at high optical purity and in high yield. 
The present invention will now be illustrated in greater detail with 
reference to Examples, but it should be understood that the invention is 
not deemed to be limited thereto. (Unless otherwise indicated, all the 
percents are by weight.) 
Equipment and instruments used for measuring physical properties of the 
products prepared are as follows. 
NMR: Model AM-400 (manufactured by Bruker Inc.) .sup.1 H-NMR: 400 MHz, 
tetramethylsilane (internal standard) .sup.31 P-NMR: 162 MHz, 85% 
phosphoric acid (outer standard) Melting Point: Model MP-500D 
(manufactured by Yanaco Co.) Optical Rotation: Model DIP-4 (manufactured 
by JASCO Inc.) GLC: Model 5890-II (manufactured by Hewlett Packard) HPLC: 
LC10AT, SPD10A (manufactured by Shimadzu Corp.) Mass Spectrum: M-80B 
(manufactured by Hitachi, Ltd.)

EXAMPLE 1 
(1) Synthesis of (S)-2,2'-Bis(trifluoromethanesulfonyloxy)-1,1'-binaphthyl 
(V) 
In 181 ml of methylene chloride were dissolved 36.2 g (127 mmol) of 
(S)-1,1'-bi-2-naphthol and 25.2 g (319 mmol) of pyridine, and the solution 
was cooled to 0.degree. C. To the solution was added dropwise 76.5 ml (271 
mmol) of trifluoromethanesulfonic acid anhydride, followed by stirring at 
room temperature for 18 hours. The reaction mixture was washed with 200 ml 
of a 2N hydrochloric acid aqueous solution. The organic layer was washed 
with water and then with a sodium chloride aqueous solution, and the 
solvent was removed by evaporation to give 69.3 g of a crude product. 
Recrystallization from 280 ml of hexane gave 64.1 g (yield: 92%) of the 
title compound. 
.sup.1 H-NMR (CDCl.sub.3) .delta. ppm: 7.25-8.15 (m, aromatic proton) 
(2) Synthesis of 
(S)-2-Di(2-naphthyl)phosphinyl-2'-(trifluoromethanesulfonyloxy)-1,1'-binap 
hthyl (VI) 
In 45 ml of dimethyl sulfoxide (DMSO) were dissolved 9.1 g (16.5 mmol) of 
(S)-2,2'-bis(trifluoromethanesulfonyloxy)-1,1'-binaphthyl, 0.372 g (1.65 
mmol) of palladium acetate, 0.683 g (1.65 mmol) of 
1,3-bis(diphenylphosphino)propane, and 0.113 g (1.65 mmol) of sodium 
formate, and the solution was stirred at room temperature for 1.5 hours. 
To the solution was added a solution of 6.00 g (19.8 mmol) of 
di(2-naphthyl)phosphine oxide and 5.8 ml (33 mmol) of 
N,N'-diisopropylethylamine in 55 ml of DMSO, followed by stirring at 
100.degree. C. for 4 hours. The reaction mixture was cooled to room 
temperature, and 75 ml of methylene chloride was added thereto. The 
solution was cooled on an ice bath, and 100 ml of a 2N hydrochloric acid 
aqueous solution was slowly added thereto dropwise. After stirring at room 
temperature for 30 minutes, the mixture was allowed to stand for 
liquid-liquid separation. The aqueous layer was extracted with methylene 
chloride. The combined organic layer was washed with water and dried over 
magnesium sulfate. The solvent was removed by concentration, and the 
residue was purified by silica gel column chromatography (hexane:ethyl 
acetate=4:1 to 1:4 by volume) to obtain 8.45 g (75.3%) of the title 
compound as yellowish white crystals. 
Melting point: 122.degree.-123.degree. C. Optical rotation: 
.alpha.!.sub.D.sup.24 -66.8.degree. (c=1.00, toluene) .sup.1 H-NMR 
(CDCl.sub.3) .delta. ppm: 6.99-8.05 (m, aromatic proton) .sup.31 P-NMR 
(CDCl.sub.3) .delta. ppm: 29.03 Mass spectrum (m/z): 703 (M+H).sup.+ ! 
(3) Synthesis of 
(S)-2-Di(2-naphthyl)phosphino-2'-(trifluoromethanesulfonyloxy)-1,1'-binaph 
thyl (III) 
Trichlorosilane (3.7 ml, 37 mmol) was added to a mixture of 8.59 g (12.2 
mmol) of 
(S)-2-di(2-naphthyl)phosphinyl-2'-(trifluoromethanesulfonyloxy)-1,1'-binap 
hthyl, 170 ml of toluene, and 4.6 ml (36 mmol) of dimethylaniline, and the 
mixture was stirred at 90.degree. C. for 1 hours and then under reflux for 
22 hours. The reaction mixture was cooled, and 150 ml of a 1N sodium 
hydroxide aqueous solution was slowly added thereto dropwise. The aqueous 
layer was extracted with 50 ml of toluene. The combined organic layer was 
washed successively with 150 ml of water, 150 ml of a 1N hydrochloric acid 
aqueous solution, and two 150 ml portions of water. The organic layer was 
concentrated, and the residue was purified by silica gel column 
chromatography (hexane:ethyl acetate=1:0 to 9:1 by volume) to obtain 7.00 
g (83.9%) of the title compound as a yellow solid. 
Melting point: 113.degree.-115.degree. C. Optical rotation: 
.alpha.!.sub.D.sup.24 +3.9.degree. (c=1.00, ethanol) .sup.1 H-NMR 
(CDCl.sub.3) .delta. ppm: 6.86-8.07 (m, aromatic proton) .sup.31 P-NMR 
(CDCl.sub.3) .delta. ppm: -10.95 Mass spectrum (m/z): 686 (M.sup.+) 
(4) Synthesis of 
(S)-2-Di(2-naphthyl)phosphino-2'-diphenylphosphinyl-1,1-binaphthyl (II) 
In 4 ml of dimethylformamide (DMF) were dissolved 1.00 g (1.46 mmol) of 
(S)-2-di(2-naphthyl)phosphino-2'-(trifluoromethanesulfonyloxy)-1,1'-binaph 
thyl, 0.327 g (2.91 mmol) of diazabicyclo2,2,2!octane (DABCO), and 76.9 mg 
(0.146 mmol) of 1,2-bis(diphenylphosphino)ethane!nickel dichloride 
(Ni(dppe)Cl.sub.2), and the solution was stirred at room temperature for 1 
hour. To the solution was added a solution of 0.357 g (1.77 mmol) of 
diphenylphosphine oxide in 2.4 ml of DMF. The mixture was stirred at 
100.degree. C. for 16 hours, followed by concentration. To the residue was 
added 10 ml of methylene chloride, and the solution was washed 
successively with 10 ml of water and 10 ml of a 1N hydrochloric acid 
aqueous solution. The solution was concentrated, and the residue was 
purified by silica gel column chromatography (hexane:ethyl acetate=1:0 to 
0:1 by volume) to give 0.59 g (56.2%) of the title compound as a yellowish 
white solid. 
Melting point: 242.degree.-245.degree. C. Optical rotation: 
.alpha.!.sub.D.sup.26 -80.4.degree. (c=1.00, chloroform) .sup.31 P-NMR 
(CDCl.sub.3) .delta. ppm: -13.09, +28.21 Mass spectrum (m/z): 738 
(M.sup.+) 
(5) Synthesis of 
(S)-2-Di(2'-naphthyl)phosphino-2'-diphenylphosphino-1,1'-binaphthyl (I) 
Trichlorosilane (0.3 ml, 3.6 mmol) was added to a mixture of 0.535 g (0.723 
mmol) of 
(S)-2-di(2-naphthyl)phosphino-2'-diphenylphosphinyl-1,1'-binaphthyl, 0.46 
ml (3.6 mmol) of dimethylaniline, and 11 ml of toluene, and the mixture 
was stirred at 90.degree. C. for 1 hour and then under reflux for 24 
hours. The reaction mixture was cooled on an ice bath, and 21 ml of a 1N 
sodium hydroxide aqueous solution was added thereto. The aqueous layer was 
extracted with toluene, and the organic layer was washed successively with 
10 ml of water, 21 ml of a 1N hydrochloric acid aqueous solution, and two 
10 ml portions of water. The solution was concentrated, and the residue 
was purified by silica gel column chromatography (hexane:ethyl acetate=1:0 
to 1:1 by volume) to afford 0.426 g (81.2%) of the title compound as a 
white solid. 
Melting point: 140.degree.-143.degree. C. Optical rotation: 
.alpha.!.sub.D.sup.26 -190.41.degree. (c=0.50, toluene) .sup.31 P-NMR 
(CDCl.sub.3) .delta. ppm: -14.73 (d, J=10.5 Hz), -13.43 (d, J=10.5 Hz) 
Mass spectrum (m/z): 722 (M.sup.+) 
EXAMPLE 2 
(1) Synthesis of 
(R)-2-Diphenylphosphinyl-2'-(trifluoromethanesulfonyloxy)-1,1'-binaphthyl 
(VI) 
In 100 ml of DMSO were dissolved 11 g (20 mmol) of 
(R)-2,2'-bis(trifluoromethanesulfonyloxy)-1,1'-binaphthyl, 0.255 g (50 mol 
%) of palladium acetate, and 0.43 g (50 mol %) of 
1,4-bis(diphenylphosphino)propane, and the solution was stirred at room 
temperature for 1.5 hours. To the solution was added a solution of 8.08 g 
(40 mmol) of diphenylphosphine oxide and 20 ml of 
N,N'-diisopropylethylamine in 100 ml of DMSO, followed by stirring at 
100.degree. C. for 12 hours. The reaction mixture was cooled to room 
temperature, and 75 ml of methylene chloride was added thereto. The 
solution was cooled on an ice bath, and 100 ml of a 2N hydrochloric acid 
aqueous solution was slowly added thereto dropwise. After stirring at room 
temperature for 30 minutes, the mixture was allowed to stand for 
liquid-liquid separation. The aqueous layer was extracted with methylene 
chloride. The combined organic layer was washed with water and dried over 
magnesium sulfate. The solvent was removed by concentration, and the 
residue was purified by silica gel column chromatography (hexane:ethyl 
acetate=4:1 to 1:4 by volume) to obtain 11.5 q (96%) of the title compound 
as yellowish white crystals. 
Optical rotation: .alpha.!.sub.D.sup.24 +44.45.degree. (c=0.50, 
chloroform) .sup.1 H-NMR (CDCl.sub.3) .delta. ppm: 7.00-8.01 (d, m, 
aromatic proton) .sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 28.73 
(2) Synthesis of 
(R)-2-Diphenylphosphino-2'-(trifluoromethanesulfonyloxy)-1,1'-binaphthyl 
(III) 
Trichlorosilane (2.5 ml, 25 mmol) was added to a mixture of 11.5 g (19.2 
mmol) of 
(R)-2-diphenylphosphinyl-2'-(trifluoromethanesulfonyloxy)-1,1'-binaphthyl, 
170 ml of toluene, and 3.1 ml (24 mmol) of dimethylaniline, and the 
mixture was stirred at 90.degree. C. for 1 hour and then under reflux for 
7 hours. The reaction mixture was cooled, and 150 ml of a 1N sodium 
hydroxide aqueous solution was slowly added thereto dropwise. The aqueous 
layer was extracted with 50 ml of toluene, and the combined organic layer 
was washed successively with 150 ml of water, 150 ml of a 1N hydrochloric 
acid aqueous solution, and two 150 ml portions of water. The organic layer 
was concentrated, and the residue was purified by silica gel column 
chromatography (hexane:ethyl acetate=1:0 to 9:1 by volume) to afford 9.03 
g (80%) of the title compound as a yellow solid. 
Melting point: 55.degree.-58.degree. C. Optical rotation: 
.alpha.!.sub.D.sup.24 -110.6.degree. (c=0.85, methylene chloride) .sup.1 
H-NMR (CDCl.sub.3) .delta. ppm: 6.63-8.20 (m, aromatic proton) .sup.31 
P-NMR (CDCl.sub.3) .delta. ppm: +30.80 
(3) Synthesis of 
(R)-2-Diphenylphosphino-2'-di(p-trifluoromethylphenyl)phosphino-1,1'-binap 
hthyl (I) 
A mixture of 0.99 g (1.63 mmol) of 
(R)-2-diphenylphosphino-2'-(trifluoromethanesulfonyloxy)-1,1'-binaphthyl, 
179.4 mg (0.340 mmol) of 1,2-bis(diphenylphosphino)ethane!nickel 
dichloride, 875.0 mg (7.02 mmol) of DABCO, and 4 ml of DMF was stirred at 
room temperature for 1 hour in a nitrogen stream. A solution of 2.18 g 
(6.45 mmol) of di(p-trifluoromethylphenyl)phosphine oxide in 14 ml of DMF 
was added thereto, followed by stirring at 100.degree. C. for 25 hours. 
The solvent was removed by evaporation under reduced pressure, and the 
residue was dissolved in 50 ml of dichloromethane. The organic layer was 
washed successively with 20 ml of water and 20 ml of a 1N hydrochloric 
acid aqueous solution, and dried over anhydrous sodium sulfate. The 
solvent was removed by evaporation under reduced pressure, and the residue 
was purified by silica gel column chromatography (hexane:ethyl 
acetate=15:1 by volume) to yield 0.49 g (37%) of the title compound. 
Melting point: 110.degree.-112.degree. C. Optical rotation: 
.alpha.!.sub.D.sup.24 +69.1.degree. (c=0.50, chloroform) .sup.1 H-NMR 
(CDCl.sub.3) .delta. ppm: 6.77-7.93 (m) .sup.31 P-NMR (CDCl.sub.3) .delta. 
ppm: -14.5, -14.7 Mass spectrum (m/z): 759 (M.sup.+) 
EXAMPLES 3 TO 6 
Unsymmetric diphosphine monoxide compounds (II) shown in Table 1 below were 
prepared in the same manner as in Examples 1 and 2. 
TABLE 1 
______________________________________ 
Ex- 
ample 
No. Ar.sup.1 Ar.sup.2 Physical Properties 
______________________________________ 
3 phenyl p-tolyl m.p. 143-150.degree. C. 
.alpha.!.sub.D .sup.24 +32.4.degree. (c = 0.500, 
CHCl.sub.3) 
.sup.31 P-NMR (CDCl.sub.3) .delta.: +27.9, -14.6 
Mass spectrum: 667 (M.sup.+) 
4 phenyl biphenyl m.p. 245-250.degree. C. 
.alpha.!.sub.D .sup.24 +2.40.degree. (c = 0.500, 
CHCl.sub.3) 
.sup.31 P-NMR (CDCl.sub.3) .delta.: +27.7, -14.7 
Mass spectrum: 791 (M.sup.+) 
5 phenyl p-fluoro- 
m.p. 130-135.degree. C. 
phenyl .alpha.!.sub.D .sup.24 +66.2.degree. (c = 0.501, 
CHCl.sub.3) 
.sup.31 P-NMR (CDCl.sub.3) .delta.: +26.5, -14.6 
Mass spectrum: 675 (M.sup.+) 
6 phenyl 2-thienyl 
m.p. 249-252.degree. C. 
.alpha.!.sub.D .sup.24 +0.59.degree. (c = 1.01, 
CHCl.sub.3) 
.sup.31 P-NMR (CDCl.sub.3) .delta.: +13.6, -14.7 
Mass spectrum: 650 (M.sup.+) 
______________________________________ 
EXAMPLES 7 TO 10 
Unsymmetric diphosphine compounds (I) shown in Table 2 below were prepared 
in the same manner as in Examples 1 and 2. 
TABLE 2 
______________________________________ 
Ex- 
ample 
No. Ar.sup.1 Ar.sup.2 Physical Properties 
______________________________________ 
7 phenyl p-tolyl m.p. 207-209.degree. C. 
.alpha.!.sub.D .sup.24 +86.36.degree. (c = 
0.506, CHCl.sub.3) 
.sup.31 P-NMR (CDCl.sub.3) .delta.: -16.4, -14.8 
Mass spectrum: 651 (M.sup.+) 
8 phenyl biphenyl m.p. 278-281.degree. C. 
.alpha.!.sub.D .sup.24 +12.49.degree. (c = 
0.512, CHCl.sub.3) 
.sup.31 P-NMR (CDCl.sub.3) .delta.: -15.8, -14.7 
Mass spectrum: 775 (M.sup.+) 
9 phenyl p-fluoro- 
m.p. 271-272.degree. C. 
phenyl .alpha.!.sub.D .sup.24 +1.99.degree. (c = 0.502, 
CHCl.sub.3) 
.sup.31 P-NMR (CDCl.sub.3) .delta.: -16.9, -14.6 
Mass spectrum: 659 (M.sup.+) 
10 phenyl 2-thienyl 
m.p. 185-188.degree. C. 
.alpha.!.sub.D .sup.24 +170.74.degree. (c = 
1.08, CHCl.sub.3) 
.sup.31 P-NMR (CDCl.sub.3) .delta.: -41.0, -14.4 
Mass spectrum: 634 (M.sup.+) 
______________________________________ 
EXAMPLES 11 TO 16 
Ruthenium complexes and rhodium complexes were prepared by using the 
unsymmetric diphosphine compounds (I) obtained in Examples 1, 2, and 7 to 
10 as ligands. The NMR data of the resulting complexes are shown in Table 
3 below. 
(1) Synthesis of Ruthenium Complex 
In a mixed solvent of 6 ml of methylene chloride and 3 ml of ethanol were 
dissolved 48.9 mg (0.05 mmol) of Ru(p-cymene)I.sub.2 !.sub.2 and 0.1 mmol 
of the unsymmetric diphosphine compound (I). The solution was stirred at 
50.degree. C. for 3 hours and then concentrated to obtain a ruthenium 
complex. 
(2) Synthesis of Rhodium Complex 
In a mixed solvent of 5 ml of tetrahydrofuran and 5 ml of methylene 
chloride were dissolved 40.5 mg (0.1 mmol) of Rh(cod).sub.2 !BF.sub.4 and 
0.1 mmol of the unsymmetric diphosphine compound (I). The solution was 
stirred at room temperature for 2 hours and then concentrated to obtain a 
rhodium complex. 
TABLE 3 
__________________________________________________________________________ 
Example 
No. Ligand Ruthenium Complex 
Rhodium Complex 
__________________________________________________________________________ 
11 Compound of 
RuI(p-cymeme) (L*)!I; 
Rh(cod)(L)!BF.sub.4 ; 
Example 1 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 25.1 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 24.8 
(dd, 
J = 60), 41.8 (d) 
J = 147.8, 31.8Hz), 28.3 (dd, J = 
144.2, 31.8Hz) 
12 Compound of 
RuI(p-cymene)(L)!I; 
Rh(cod)(L)!BF.sub.4 ; 
Example 2 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 42.0 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 24.0 
(dd, 
J = 59), 40.8 (d, J = 60), 26.4 (d, 
J = 143.8, 21.9Hz), 28.6 (dd, J = 
J = 61), 24.1 (d, J = 60) 
146.2, 21.9Hz) 
13 Compound of 
RuI(p-cymene)(L)!I; 
Rh(cod)(L)!BF.sub.4 ; 
Example 7 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 41.6 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 23.9 
(dd, 
J = 70), 39.7 (d, J = 53), 24.9 (d, 
J = 145.5, 32.3Hz), 26.9 (dd, J = 
J = 76), 23.2 (d, J = 60) 
146.1, 32.4Hz) 
14 Compound of 
RuI(p-cymene)(L)!I; 
Rh(cod)(L)!BF.sub.4 ; 
Example 8 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 41.7 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 25.3 
(dd, 
J = 58), 40.2 (d, J = 60), 24.8 (d, 
J = 146.0, 32.3Hz), 25.9 (dd, J = 
J = 48), 23.3 (d, J = 59) 
146.3, 32.3Hz) 
15 Compound of 
RuI(p-cymene)(L)!I; 
Rh(cod)(L)!BF.sub.4 ; 
Example 9 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 41.5 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 23.9 
(dd, 
J = 60), 39.5 (d, J = 60), 24.5 (d, 
J = 147.8, 32.5Hz), 25.6 (dd, J = 
J = 60), 23.7 (d, J = 62) 
146.0, 32.8Hz) 
16 Compound of 
RuI(p-cymene)(L)!I; 
Rh(cod)(L)!BF.sub.4 ; 
Example 10 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 4.5 
.sup.31 P-NMR (CDCl.sub.3) .delta. ppm: 4.2 
(dd, 
J = 66), 12.2 (d, J = 63), 24.2 (d, 
J = 147.5, 31.5Hz), 23.9 (dd, J = 
J = 52.8), 42.4 (d, J = 65) 
145.7, 31.5Hz) 
__________________________________________________________________________ 
*"L" represents a diphosphine compound represented by formula (I). 
APPLICATION EXAMPLE 
Hydrogenation of Ketopantolactone 
A mixture of 86 mg (0.11 mmol) of 
(S)-2-di(2-naphthyl)phosphino-2'-diphenylphosphino-1,1'-binaphthyl, 28 mg 
(0.1 mmol) of Ru(cod)Cl.sub.2 !.sub.n, 3 ml of toluene, and 0.05 ml (0.4 
mmol) of triethylamine was heated under reflux for 16 hours in a nitrogen 
stream. The solvent was removed by evaporation, and the residue was dried 
to solid under reduced pressure. 
In a stainless steel-made autoclave were charged 9.5 mg (0.01 mmol) of the 
resulting catalyst Ru.sub.2 
Cl.sub.4.{(S)-di(2-naphthyl)phosphino-2'-diphenylphosphino-1,1'-binaphthyl 
}.sub.2.triethylamine, 250 mg (2 mmol) of Ketopantolactone 
(dihydro-4,4-dimethyl-2,3-furandione, produced by Aldrich Co.), 2.5 ml of 
isopropyl alcohol, and 6.5 mg (0.1 mmol) of potassium hydroxide, and the 
mixture was stirred at 50.degree. C. and 50 atm for 16 hours. The reaction 
mixture was concentrated, and the residue was purified by silica gel 
column chromatography (hexane:ethyl acetate=3:1 to 1:1 by volume). 
The resulting hydrogenation product (25 mg) was stirred with 150 mg of 
(S)-.alpha.-methoxy-.alpha.-trifluoromethylphenylacetyl chloride and 0.5 
ml of pyridine to be converted to an 
(S)-.alpha.-methoxy-.alpha.-trifluoromethylphenylacetate, which was then 
analyzed by HPLC under the following conditions. As a result, the optical 
purity of the product was found to be 50% ee. 
HPLC Column: Inertsil (produced by GL Science) SIL 5 .mu.m, 4.6.times.250 
mm Eluent: hexane:tetrahydrofuran=95:5 by volume Flow rate: 1 ml/min 
Detection: UV (254 nm) 
While the invention has been described in detail and with reference to 
specific examples thereof, it will be apparent to one skilled in the art 
that various changes and modifications can be made therein without 
departing from the spirit and scope thereof.