Diastereoselective synthesis of pyrroloindolines using α,β-unsaturated N-aryl ketonitrones and activated alkynes

A synthetic method has been developed for diastereoselective de nova synthesis of pyrroloindolines using readily available alpha,beta-unsaturated N-aryl ketonitrones and amino acid derived activated alkynes. The reaction likely proceeded by initial formation of C3-quaternary indolenines followed by N-cyclization of the pendent nitrogen atom to give the complex heterocyclic system from simple starting materials in one step. Pyrroloindolines with substituents that may be difficult to introduce via other approaches have been prepared using this method. (C) 2015 Elsevier Ltd. All rights reserved.