Synthesis of (±)-Cycloclavine and (±)-5-epi-Cycloclavine

Significance

Cycloclavine is an indole alkaloid isolated from the African morning glory (Ipomea hildebrandtii) and possesses three contiguous stereocenters, including one which is part of a ­cyclopropane ring. This is the second total synthesis of (±)-cycloclavine, the first was completed by Incze et al. in 2008 in 14 steps with 0.2% overall yield (Tetrahedron 2008, 64, 2924). This synthesis revolves around an intramolecular Diels-­Alder cycloaddition of a furan to close the indole ring; methodology previously published by the Wipf group (Chem. Commun. 2009, 104).