Synthesis of Tetrasubstituted Pyrroles via DBU-Mediated Cyclization of Unactivated Propargyl Tertiary Amines.

Abstract

Compared with the well-developed cyclization of functionalized propargylamines, the use of unactivated tertiary propargylamines to access pyrroles remains challenging. Herein, we report an efficient method for constructing tetrasubstituted pyrroles via a DBU-mediated intramolecular cycloaddition of N-alkyl propargylamines. This reaction employs cyclization to access dihydropyrrole intermediates, followed by oxidation to produce pyrroles in the presence of 2,3-dichloro-5,6-dicyano-p-benzoquinone. In addition, a broad substrate scope, high atom economy, high selectivity, and simple operation are also advantages of this protocol.