Chiral compounds of the beta-binaphthyl type, their preparation and their use

New chiral compounds of the formula ##STR1## a process for their preparation and their use for the preparation of optically active compounds.

The present invention relates to new chiral compounds of the 
.beta.-binaphthyl type of the formula (I) 
##STR2## 
in which Me represents B, Al, CR.sup.4, SiR.sup.4, Sn(IV)R.sup.4, P or P=O 
where R.sup.4 is hydrogen, C.sub.1 -C.sub.6 -alkyl, halogen, phenyl or 
O--C.sub.1 -C.sub.6 -alkyl, 
X represents O, S or NR.sup.5 where R.sup.5 is hydrogen, C.sub.1 -C.sub.6 
-alkyl or phenyl, 
R.sup.1 represents hydrogen, C.sub.1 -C.sub.6 -alkyl, tri-C.sub.1 -C.sub.4 
-alkyl-silyl or substituted or unsubstituted, phenyl, 
R.sup.2 and R.sup.3 can be identical or different and each represent 
hydrogen, C.sub.1 -C.sub.6 -alkyl, substituted or unsubstituted phenyl, 
tri-C.sub.1 -C.sub.4 -alkylsilyl, halogen or O--C.sub.1 -C.sub.6 --alkyl. 
If R.sup.2, R.sup.3 and R.sup.4 denote halogen, fluorine, chlorine and 
bromine, in particular fluorine and chlorine, are preferred. If R.sup.1, 
R.sup.2 and R.sup.3 denote substituted or unsubstituted phenyl, examples 
of suitable substituents are C.sub.1 -C.sub.6 -alkyl, halogen or 
O--C.sub.1 -C.sub.6 -alkyl radicals. 
Preference is given to compounds of the formula (I) in which 
Me represents B, Al, CR.sup.4 or P, 
X represents O or S, 
R.sup.1 represents hydrogen, C.sub.1 -C.sub.4 -alkyl, tri-C.sub.1 -C.sub.2 
-alkyl-silyl or phenyl and 
R.sup.2 and R.sup.3 represent hydrogen. 
Particular preference is given to the compound of the formula (I) in which 
Me represents B, X represents O and R.sup.1 to R.sup.3 represent hydrogen. 
Further examples of suitable individual compounds of the formula (I) are 
those in which X is O, R.sup.2 is hydrogen and R.sup.3 is hydrogen and 
which have the following further substituents: 
______________________________________ 
Me R.sup.1 R.sup.4 
______________________________________ 
B CH.sub.3 -- 
C.sub.2 H.sub.5 
C.sub.3 H.sub.7 
C.sub.6 H.sub.5 
Al H -- 
CR.sup.4 H H 
CH.sub.3 
C.sub.2 H.sub.5 
C.sub.6 H.sub.5 
F 
Cl 
OCH.sub.3 
OC.sub.2 H.sub.5 
SiR.sup.4 H H 
CH.sub.3 
C.sub.2 H.sub.5 
C.sub.6 H.sub.5 
F 
Cl 
OCH.sub.3 
OC.sub.2 H.sub.5 
SnR.sup.4 H H 
CH.sub.3 
C.sub.2 H.sub.5 
C.sub.6 H.sub.5 
F 
Cl 
OCH.sub.3 
OC.sub.2 H.sub.5 
P H -- 
P = O H -- 
______________________________________ 
The present invention also relates to a process for the preparation of 
chiral compounds of the .beta.-binaphthyl type of the formula (I), which 
is characterized in that a .beta.-binaphthyl compound of the formula (II) 
##STR3## 
in which X, R.sup.1, and R.sup.3 have the meaning mentioned in formula (I) 
and 
R.sup.6 represents hydrogen, C.sub.1 -C.sub.6 -alkyl or tri-C.sub.1 
-C.sub.4 -alkyl-silyl with a compound of the formula (III) 
EQU Me Y.sup.1 Y.sup.2 Y.sup.3 (III), 
in which 
Me has the meaning mentioned in formula (I) and 
Y.sup.1, Y.sup.2 and Y.sup.3 are identical or different and each represent 
hydrogen, fluorine, chlorine, bromine, iodine, NH.sub.2, mono-C.sub.1 
-C.sub.6 -alkyl-amino di-C.sub.1 -C.sub.6 -alkyl-amino, C.sub.6 -C.sub.10 
-aryl-C.sub.1 -C.sub.6 -alkyl-amino, di-C.sub.6 -C.sub.10 -aryl-amino, OH, 
C.sub.1 -C.sub.6 -alkoxy, C.sub.6 -C.sub.10 -aryloxy, tri-C.sub.1 -C.sub.4 
-alkyl-siloxy, C.sub.1 -C.sub.6 -thioalkoxy, C.sub.6 -C.sub.10 
-thioaryloxy, C.sub.1 -C.sub.6 -alkyl or C.sub.6 -C.sub.10 -aryl. 
If appropriate, the compounds of the formula (III) can be used in the form 
of adducts, for example boron compounds as etherates or thioetherates, 
such as BF.sub.3 x O(C.sub.2 H.sub.5).sub.2, BH.sub.3 x tetrahydrofuran, 
H.sub.2 B Cl x O(C.sub.2 H.sub.5).sub.2 or H.sub.2 BBr x 
S(CH.sub.3).sub.2. 
Inasfar as in formulae (II) and (III) symbols are used which are identical 
to those of formula (I), in formulae (II) and (III) those meanings which 
have been mentioned as preferred in formula (I) are also preferred. In 
formula (II), R.sup.6 preferably represents hydrogen or trimethylsilyl; in 
formula (III), Y.sup.1, Y.sup.2 and Y.sup.3, independently of one another, 
preferably represent hydrogen, chlorine, bromine, OH, methoxy and/or 
ethoxy. 
Particularly preferred compounds of the formula (II) are .beta.-binaphthol, 
.beta.-thiobinaphthol, 2,2'-diamino-1,1'-binaphthyl and derivatives 
thereof which are substituted in the 3- and 3'-position by hydrogen, 
methyl, ethyl, propyl or phenyl. 
Particularly preferred compounds of the formula (III) are boron trifluoride 
diethyl etherate, boron trichloride, BH.sub.3 x tetrahydrofuran, 
chlorodihydroborane diethyl etherate and bromodihydroborane dimethyl 
sulfide. 
The compounds of the formula (II) and (III) are either known or accessible 
in a manner analogous to that of the known compounds. 
In a particular embodiment of the process according to the invention, the 
reaction is carried out in the presence of acid acceptors. Suitable acid 
acceptors are, for example, basic nitrogen compounds such as 
trialkylamines, dialkylcycloalkylamines, dialkylaralkylamines and 
dialkylarylamines. Preference is given to triethylamine, tripropylamine, 
tributylamine, dimethylcyclopentylamine, dimethylcyclohexylamine, 
diethylcyclopentylamine, diethylcyclohexylamine, 
dimethylbenzylamine,diethylbenzylamine and dimethylaniline. 
If the reaction is to be carried out in the presence of acid acceptors, 
these can be used, for example, in amounts of 1 to 10 mol, relative to 1 
mol of the compound of the formula (III). 
The process according to the invention can be carried out in the presence 
or absence of diluents. Suitable diluents are inert or largely inert 
organic solvents which are liquid under the reaction conditions used in 
each case. Examples of these are aliphatic and aromatic hydrocarbons, 
halogenated hydrocarbons, ethers, ketones, esters, nitriles, amides, 
dimethyl sulfoxide and tetramethylene sulfone. Individual compounds are: 
pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane, 
petroleum ether, benzine, ligroin, benzene, toluene, xylene, tetralin, 
methylene chloride, ethylene chloride, trichloroethylene, chloroform, 
carbon tetrachloride, chlorobenzene, dichlorobenzene, diethyl ether, 
dipropyl ether, diisopropyl ether, dibutyl ether, methyl tert.-butyl 
ether, glycol dimethyl ether, diglycol dimethyl ether, tetrahydrofuran, 
dioxane, acetone, methyl ethyl ketone, diethyl ketone, methyl isopropyl 
ketone, methyl isobutyl ketone, methyl tert.-butyl ketone, methyl acetate, 
ethyl acetate, propyl acetate, butyl acetate, amyl acetate, dimethyl 
phthalate, diethyl phthalate, acetonitrile, propionitrile, 
dimethylformamide, dimethyl acetamide and N-methylpyrrolidone. Methylene 
chloride, chloroform, chlorobenzene and dichlorobenzene are particularly 
preferred. 
Suitable reaction temperatures for the process according to the invention 
are, for example, those between -100.degree. and +250.degree. C. 
Preferably, the process is carried out at -40.degree. to +150.degree. C. 
For example, 0.6 to 7 mol of a compound of the formula (III) can be used, 
relative to 1 mol of a compound of the formula (II). Preferably, this 
ratio is 1:0.7 to 2.0, in particular 1:0.8 to 1.2. 
In general, the reaction is carried out at atmospheric pressure. However, 
it is also possible to carry it out at reduced pressure or elevated 
pressure and use, for example, pressures in the range of 0.1 to 10 bar. It 
is often advantageous to work under an inert gas atmosphere, for example 
nitrogen. 
In a particular embodiment of the process according to the invention, a 
solution of the compound of the formula (III) is added dropwise to a 
solution of the compound of the formula (II), and the reaction mixture is 
then stirred, for example, for 1 to 5 hours. 
The work up of the reaction mixture is often very simple. For example, all 
volatile components can be removed in vacuo, which then gives a compound 
of the formula (I) as a solid residue which, if necessary, can be 
recrystallized, for example, from methylene chloride. 
It is often possible to obtain the compounds of the formula (I) in the 
manner described above in yields of more than 90% of theory. 
By means of the process according to the invention, the preparation of 
compounds of the formula (I) can be achieved in a simple manner, in a 
one-step process and in good to very good yields. 
The present invention furthermore relates to the use of compounds of the 
formula (I) for the preparation of optically active compounds in 
concentrated or pure form. Examples of reactions in which by means of the 
compounds of the formula (I) as catalyst optically active compounds can be 
obtained in concentrated or pure form are asymmetric cycloaddition 
reactions, such as Diels-Alder reactions, asymmetric photo reactions, 
asymmetric catalytic hydrogenations (in this case the compounds of the 
formula (I) serve as ligands for catalytically active transition metal 
complexes) and asymmetric epoxidations. Examples of reactions in which by 
means of molar amounts of the compounds of the formula (I) optically 
active compounds can be obtained in concentrated or pure form are 
asymmetric ring openings of epoxides, asymmetric reductions of carbonyl 
and heterocarbonyl compounds, asymmetric hydrometalations, and asymmetric 
protonations. 
In these reactions, it is a particular advantage that the compound of the 
formula (I) or (II) used can be recovered almost quantitatively after 
these catalytic reactions, for example by hydrolysis, without racemisation 
taking place.