Synthesis of N-Functionalized/NH-Multisubstituted Indoles, Thienopyrroles, Pyrroloindoles, and Pyrazolopyrroles via Sequential One-Pot Base-Mediated and Copper-Catalyzed Inter- and Intramolecular Amination of 2-[2-Bromo(het)aryl]-3-(het)aryl-3-(methylthio)acrylonitriles

Abstract

A novel, efficient route to substituted 1-N-(het)aryl/NH-2-(het)aryl-3-cyanoindoles and related pyrrolo-fused heterocycles such as thienopyrroles, pyrroloindoles, and pyrazolopyrroles has been reported. The overall protocol involves sequential cycloamination of readily available 2-[2-bromo(het)aryl]-3-(het)aryl-3-(methylthio)acrylonitrile precursors with primary amines or amides via two key C-N bond-forming processes, one base-mediated intermolecular and the other Cu-catalyzed intramolecular arylamination leading to N(1)-C(2) and N(1)-C(7a) bond formation, respectively, in a two-step one-pot procedure.