Total Synthesis of Aplysiasecosterols A and B, Two Marine 9,11-Secosteroids.

The total synthesis of aplysiasecosterols A and B has been accomplished. Key features of the synthesis include the Suzuki-Miyaura coupling of each AB-ring segment and common D-ring segment. The AB-ring segment of aplysiasecosterol B was synthesized by Shi asymmetric epoxidation as a key reaction. The common D-ring segment was constructed by stereoselective hydrogenation and Sharpless asymmetric dihydroxylation as key reactions. This late-stage convergent synthesis, which has rarely been reported in secosteroid synthesis, can be adapted to many 9,11-secosteroids.