Enantioselective synthesis of the C5-C23 segment of biselyngbyaside

Stereo and enantioselective synthesis of C5-C23 fragment of cytotoxic marine natural product biselyngbyaside is achieved using E-selective methyl lithium addition onto enyne, Crimmin's acetate aldol reaction, Sharpless asymmetric epoxidation, and Julia-Kocienski olefination as the key steps.