A new indole synthesis via [3 + 3] annulation of 2-(benzotriazol-1-ylmethyl)pyrroles with α,β-unsaturated aldehydes and ketones

Abstract

Poly-substituted indoles are readily accessible from substituted 2-(benzotriazol-1-ylmethyl)pyrroles by lithiation, reaction with α,β-unsaturated aldehydes and ketones, and subsequent facile dehydrobenzotriazolylation-cyclodehydration. The substituted 2-(benzotriazol-1-ylmethyl)pyrrole precursors are obtained by reacting α-bromoketones with terminally lithiated propargylbenzotriazole, and treating the resulting epoxide with a primary amine.