Total Synthesis of Tabernanthine and Ibogaline: Rapid Access to Nosyl Tryptamines

Abstract

We describe the first total synthesis 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.