New Approach for the Stereoselective Synthesis of (+)-epi-Cytoxazone

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