Development and Scope of the Arene-Fused Domino Michael/Mannich Reaction: Application to the Total Syntheses of Aspidosperma Alkaloids (-)-Aspidospermidine, (-)-Tabersonine, and (-)-Vincadifformine.

The development and application of the arene-fused domino Michael/Mannich route to the tetrahydrocarbazole (ABE) core of Aspidosperma alkaloids is described. The scope of this novel transformation was studied in terms of the nucleophilic component (i.e., N-sulfinyl metallodienamine) and the electrophilic component (i.e., Michael acceptor). The successful application of this methodology toward the concise total syntheses of classical indole alkaloids (-)-aspidospermidine, (-)-tabersonine, and (-)-vincadifformine in 10-11 steps, respectively, is also discussed.