Copper‐catalyzed Clauson–Kass pyrroles synthesis in aqueous media

Abstract

An efficient and convenient copper‐catalyzed Clauson–Kass reaction of 2,5‐dimethoxytetrahydrofuran with amines in aqueous media has been developed, providing a wide range of N ‐substituted pyrroles in good yields. It is noteworthy that the Clauson–Kass reaction of 2,5‐dimethoxytetrahydrofuran with p ‐phenylenediamine or m ‐phenylenediamine proceeds smoothly to afford the corresponding monopyrroles and bispyrroles with high selectivity in impressive yields. A plausible mechanism for the formation of N ‐substituted pyrroles has been proposed. Copyright © 2012 John Wiley & Sons, Ltd.