Abstract
We describe the first total syntheses of tabernanthine and ibogaline. Entry to these iboga alkaloid natural products is enabled by a thermal coupling of indoles and aziridines to furnish the requisite nosyl tryptamine starting materials. This route features a Friedel-Crafts type alkylation to form the key indole-isoquinuclidine C-C bond. Finally, a regio- and diastereoselective hydroboration-oxidation enables C-N bond formation to close the isoquinuclidine ring system and deliver tabernanthine and ibogaline in 10 and 14% yield respectively. Both syntheses were completed in eight steps.