Revisiting a Classic Approach to the Aspidosperma Alkaloids: An Intramolecular Schmidt Reaction-Mediated Synthesis of (+)-Aspidospermidine

摘要

A total synthesis of (+)-aspidospermidine (>1) is described. The key reactions used in the synthesis of this pentacyclic Aspidosperma alkaloid were a deracemizing imine alkylation/Robinson annulation sequence, a selective “redox ketalization” and an intramolecular Schmidt reaction. A Fischer indolization step carried out on a tricyclic ketone mirrored the sequence reported by Stork and Dolfini in their classic aspidospermine synthesis.