Patent ID: 8304252

Claim:
A method for preparing a compound of formula I: wherein C 3 has an (S) configuration; R 1 is hydrogen, (C 1-6 ) alkyl or phenyl; and R 2 is (C 1 -C 8 ) alkyl, (C 2 -C 8 ) alkenyl, (C 3 -C 8 ) cycloalkyl, —O(C 1 -C 6 ) alkyl, —CH 2 —CH 2 —O—C 1 -C 6 )alkyl, (C 1 -C 6 )alkyl-OH, -phenyl-(C 1 -C 6 )alkyl-OH, -phenyl-O—(C 1 -C 6 )alkyl, phenyl or substituted phenyl; with the proviso that when R 2 is methyl, R 1 is hydrogen, (C 1 —C 6 ) alkyl or phenyl, comprising the steps of: (a) contacting a compound of formula II: with an enzyme catalyst, in which said catalyst is a nitrilase from Arabidopsis thaliana in a reaction medium; and (b) recovering the (3S) isomer of the compound of formula I from the reaction medium; and, optionally, recovering unchanged (3R) isomer of the compound of formula II.