Concise approach to pyrrolizino[1,2-b]indoles from indole-derived donor–acceptor cyclopropanes

Abstract

Developed here is a direct three-step approach to a previously unexplored pyrrolizino[1,2-b]indole system based on a sequence of three synthetic steps: (a) one-pot azide ion promoted ring opening of the indole-derived donor–acceptor cyclopropane and Krapcho dealkoxycarbonylation; (b) Vilsmeier–Haack formylation; (c) tandem Staudinger/intramolecular aza-Wittig reaction and reductive cyclization realized in a one pot fashion.