Enantioselective Total Synthesis of (−)‐Cephalotanin B

Abstract

Cephalotaxus diterpenoids are attractive natural products with intriguing molecular frameworks and promising biological features. As a structurally unusual member, (–)‐cephalotanin B possesses an extraordinarily congested heptacyclic skeleton, three lactone units, and nine consecutive stereocenters. Herein, we report an enantioselective total synthesis of (–)‐cephalotanin B based on crucial transformations including a divergent asymmetric Michael addition reaction, a novel Pauson–Khand/deacyloxylation process discovered in the development of the second‐generation of stereoselective Pauson–Khand reaction protocol, and the developed epoxide‐opening/elimination/dual lactonization cascade to achieve the challenging propeller shaped A‐B‐C ring system.