The stereoselective total synthesis of (+)-epi-cytoxazone was performed satisfactorily in 8 steps, in 17% overall yield, via a novel route from 2,3-O-(3-pentylidene)-(R)-glyceraldehyde. The bulky group alkene-ketal allowed intramolecular control of the target molecule's asymmetric centers in the dihydroxylation step by promoting the approach of OsO4 to the face opposite to that of the ketal group.
Keywords:
cytoxazone; epi-cytoxazone; 2,3-O-(3-pentylidene)-(R)-glyceraldehyde; Wittig olefination; stereoselective dihydroxylation