Abstract
The asymmetric epoxidation of (±)-methyl (2Z, 4E)-1', 4'-dihydroxy-α-ionylideneacetates is described for the preparation of chiral abscisic acid. A conventional Sharpless kinetic resolution of (±)-1', 4'-cis-dihydroxyacetate with diethyl L-tartarate and then two simple steps of conversion gave (S)-abscisic acid, which was also obtained by the combination of (±)-1', 4'-trans-dihydroxyacetate with diethyl D-tartarate. Finally, (S)-abscisic acid was obtained in a 25% overall yield from the racemic mixture.
