Patent ID: 7368568

Claim:
A process for producing an optically active compound of the following formula (III) wherein the configuration at the C-atom of the secondary alcohol is S: in which R 1 stands for an alcohol protective group, and Y stands for a group —NA1A2, where A1 and A2, independently of one another, stand for C 1 -C 6 alkyl, aryl, aralkyl, —OH, —OMe, or —O-benzyl, or Y is and, where the dashed line bonds indicate the point of attachment, which process comprises: enantioselectively saponifying, by means of enzymatic reaction, a racemic ester of formula VI in which R 1 and Y have the above-mentioned meanings, and R3 is a C 1 -C 6 alkyl group or an allyl, phenyl or benzyl group.