Total Asymmetric Synthesis of Taxol by Dehydration Condensation between 7-TES Baccatin III and Protected N-Benzoylphenylisoserines Prepared by Enantioselective Aldol Reaction

Total asymmetric synthesis of Taxol was completed by dehydration condensation between a protected N-benzoylphenylisoserine 4 or 9 and 7-TES baccatin III which was prepared from 8-membered ring enone. Taxol side chains 4, 7, 9 and 11, optically active protected N-benzoylphenylisoserines, were successfully synthesized by enantioselective aldol reaction from two achiral starting materials, benzaldehyde and an enol silyl ether derived from S-ethyl benzyloxyethanethioate.