Efficient Synthesis of Aminomethylated Pyrroloindoles and Dipyrrolopyridines via Controlled Copper-Catalyzed Domino Multicomponent Coupling and Bis-cyclization

Efficient methods for the synthesis of pyrrole-fused indole derivatives via domino copper-catalyzed multicomponent coupling and bis-cyclization have been developed. The mono- or bis-aminomethylated pyrroloindoles and dipyrrolopyridines were selectively obtained in moderate to excellent yields by a controlled Mannich-type reaction-cyclization of 4,6-diethynyl-1,3-phenylenediamine or its pyridine congener with paraformaldehyde and a secondary amine. The high-yielding bis-cyclization of terminal alkynes without using Mannich-type reactions is also presented.