An efficient method for the synthesis of unsymmetrical 2,2′-bis(pyrrolyl)alkanes

Abstract

A new strategy for the preparation of unsymmetrical 2,2′-bis(pyrrolyl)alkanes has been developed. It involved the condensation of pyrrole derivatives onto N-benzylhydroxylamines in the presence of HCl. This two-step procedure provided access to a wide variety of 2,2′-dipyrromethanes (3a–m). It has also been extended to the synthesis of tripyrromethanes 4a–d and of N-confused dipyrromethanes 6a–d.