KATSUKI-SHARPLESS ASYMMETRIC EPOXIDATION OF ALLYLIC-HOMOALLYLIC ALCOHOLS SHARING THE CENTRAL OLEFINIC BOND

Katsuki-Sharpless asymmetric epoxidation of four isomeric chiral allylic-homoallylic diols sharing the central olefinic bond has been examined. Among these, three heptenediols having (3E,2R,6R), (3E,2R,6S), and (3Z,2R,6R) configurations underwent diastereospecific epoxidation to give the corresponding epoxides each as a single epimer in the presence of L-DIPT, but the diol having (3Z,2R,6S) configuration did not show high diastereoselection in the presence of either L- or D-DIPT. Interestingly, (3Z,2R,6R)-diol afforded the same epoxide irrespective of the chirality of DIPT used.