Development of Biomimetic Synthesis of Propindilactone G†

This is the authors' abstract. We don't add key points for this paper.

Summary of main observation and conclusion The natural product propindilactone G is a complex Schisandra nortriterpenoid with a unique 5/5/7/6/5 pentacyclic framework. This full paper describes the development of concise biomimetic synthesis of propindilactone G from a known steroid lactone. The key C19‐OH intermediate was synthesized via Breslow and Suárez radical remote C—H functionalizations. Wagner‐Meerwein rearrangement was subsequently utilized for the expansion of the B ring. To invert the configuration of the C10 tertiary alcohol, an intramolecular peroxide cyclization catalyzed by BF3·Et2O was devised. The 5/5 fused lactone system was then assembled in a biomimetic transesterification/oxa‐Michael addition sequence. Our work should provide experimental support for the proposed biosynthetic pathway and facilitate investigation of the biological activities of propindilactone G.