A PROCESS FOR THE STEREOSELECTIVE REDUCTION OF ALPHA , BETA -UNSATURATED KETONES

A process for the preparation of alpha,beta-unsaturated alcohols of general formula (I),whereinR means an alkyl group of 1-4 carbon atoms, or benzoyloxy group optionally substituted with a phenyl group;R1 means a hydrogen atom or an alkyl group of 1-4 carbon atoms,R2 means a hydrogen atom or an alkyl group of 1-4 carbon atoms;R3 means an alkyl group of 1-6 carbon atoms optionally substituted by phenyl group or cycloalkyl group of 5-7 carbon atoms; or a phenoxy group optionally substituted by a halogen atom, or a cycloalkyl group of 5-7 carbon atoms;R4 means a hydrogen atom or a halogen atomwhereby at alpha,beta-unsaturated ketones of general formula (II) wherein themeanings of R, R1, R2, R3, and R4 are as given above-is diastereoselectively reduced with a borohydride type compound in an aprotic solvent, in the presence of an inorganic substance dissolublein the reaction mixture and having particle size from 0.01 micrometer to 10000 micrometer and optionally from the resulting mixture of epimeric alpha,beta-unsaturated alcohols of general formula (I) and (III)meanings of R, R1, R2, R3, and R4 are as given above-the alpha,beta-unsaturated alcohol of general formula (I) is separated by methods known.