Bioinspired Synthesis Of Nortriterpenoid Propindilactone G

A concise bioinspired synthesis of Schisandra nortriterpenoid propindilactone G has been accomplished from a readily accessible steroidal lactone. Key transformations include a Breslow remote functionalization, a Suarez remote radical functionalization, a ring expansion enabled by a Wagner-Meerwein rearrangement, a stereoinversion of a tertiary alcohol, and a biomimetic transesterification/oxa-Michael addition cascade. This work also provides experimental evidence of the putative propindilactone G biosynthesis pathway.