Total synthesis of (–)-deglycocadambine†

Abstract

The first total synthesis of the monoterpene indole alkaloid (–)-deglycocadambine is achieved in 12 steps with (+)-genipin as the chiral starting material. The reported synthetic approach is characterized by an orchestrated cascade annulation between tryptamine and the highly functionalized dialdehyde precursor, rapidly introducing the unique 6/5/6/7/6-fused pentacyclic skeleton and the ketone functional group at C19 in a convergent manner. The successful implementation of transannular oxidative cyclization at C3 for bridged oxazolidine formation in the late-stage synthetic campaign ensured the final total synthesis of this molecule.