Diastereoselective Total Synthesis of (+)-Raputindole A: An Iridium- Catalyzed Cyclization Approach

This work describes the total synthesis of Raputindole A (1) through a convergent approach which features: 1) an iridium-catalyzed cyclization to assembly the tricyclic core of the northern part, 2) enzymatic resolution to secure the preparation of enantiomerically pure benzylic alcohol, 3) installation of the butenyl substituent via methallylation of the corresponding benzylic carbocation and coupling of the northern and southern parts via Heck reaction. (+)-Raputindole A (1) was prepared in 10 steps (LLS) and 10% overall yield.