Optically active diphosphines, preparation thereof according to

Details Optically active diphosphines, preparation thereof according to Optically active diphosphines, preparation thereof according to

1996-10-04

1998-07-21

Rotman, Alan L.

Organic compounds -- part of the class 532-570 series

Organic compounds

Phosphorus containing

556 20, 556 21, 556 23, C07F 9547

Patent

active

057837384

DESCRIPTION:

BRIEF SUMMARY
This application is a 371 of PCT/FR95/01716, filed Dec. 22, 1995 now WO 96/20202.
The present invention relates to optically active diphosphines. It is also targeted at their preparation according to a process for the resolution of the racemic mixture of the said phosphines to optically active isomers.
More precisely, the subject of the invention is new optically active process for the resolution of the racemic
The invention also relates to new optically active metal complexes comprising the said phosphines and to their use in a process for the preparation of optically active carboxylic acids and/or derivatives according to a process for the hydrogenation of .alpha.,.beta.-unsaturated carboxylic acids and/or derivatives.
The preparation of a mixture of been described by F. Mathey et al. in Bull. Soc. Chim. Fr., 129, pp. 1-8 (1992).
The starting material in the synthesis of the latter is 1-phenyl-3,4-dimethylphosphole (II) described by F. Mathey et al. in Synthesis, 1983, pp. 983.
The starting point is the preparation of 3,3',4,4'-tetramethyl-1,1'-diphosphole (IV). To this end, 1-phenyl-3,4-dimethylphosphole (II) is reacted in TEF with lithium metal according to the following reaction: ##STR1##
At the end of the reaction, aluminium chloride is introduced in order to trap the phenyllithium produced during the reaction.
In a following stage, (III) is dimerized by the action of diiodine I.sub.2 in THF. For more details on the preparation of (IV), reference may be made to the article by F. Mathey et al., Organometallics, 1983, 2, 1234. ##STR2##
On heating to approximately 140.degree. C., the compound (IV) rearranges to (V), which reacts with diphenylacetylene according to the Diels-Alder ##STR3##
A practical embodiment is given on page 6 of the publication by F. Mathey et al. in Bull. Soc. Chim. Fr., 129, pp. 1-8 (1992).
However, the writers obtained, as mentioned on page 3, right-hand column, lines 7 and 8, a mixture of two diastereoisomers subsequently identified by the Applicant Company as being a meso (I m)- RS,SR--and a racemate (I r)- RR,SS--called (13b) and (13a) respectively in the article.
The publication mentions the separation of the two diastereoisomers by formation of a palladium(II) chelate. To do this, a description is given of the separation of the mixture of diastereoisomers obtained by reaction with PdCl.sub.2 (PhCN).sub.2 in dichloroethane, resulting in (VI m) and (VI r), and the separation by chromatography on silica gel, followed by elution and then by a decomplexation carried out by NaCN.
The two diastereoisomers, on the one hand the meso (I m) and, on the other hand, the racemate (I r), are thus recovered separately.
The document of the state of the art does not describe the separation of the enantiomers.
The problem of resolving two enantiomers is difficult to solve when the chirality is carried by the phosphorus.
An object of the present invention is to provide new, bidentate, optically active disphosphines which are chiral on the phosphorus and which cannot be racemized.
Another object of the present invention is to make available a process which makes it possible to obtain them according to a process for resolving the racemic
Finally, another object of the invention is to have available a process for the preparation of optically active carboxylic acids and/or derivatives according to a process for the hydrogenation of .alpha.,.beta.-unsaturated carboxylic acids and derivatives which makes use of metal complexes using the optically active diphospine as ligand.
According to a first subject of the present invention, new optically active been found which correspond to the following formulae: ##STR4##
According to another subject of the invention, the racemic according to a process which comprises reacting it with a palladium and/or platinum complex as chiral auxiliary in an organic solvent, thus forming diastereoisomer complexes, and then resolving the said optically pure complexes.
In accordance with the process of the invention, a palladium complex is used. This type of chiral auxiliary

REFERENCES:
CA:121:57572-abstract of "The equilibrium between 1H and 2H phopholes", Laporte, Bull Soc. Fr. 139(6), pp. 843-850, 1993.
CA:117:48704-abstract of "Mechanism of the thermal tetramerization of phospholes" Bevierre<Bull Soc Chim Fr.,129(1) pp. 1-8, 1992.

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