A Powerful New Strategy for Diversity-Oriented Synthesis of Pyrroles from Donor−Acceptor Cyclopropanes and Nitriles

Abstract

Lewis acid activated donor-acceptor cyclopropanes react with aliphatic, aromatic, and alpha,beta-unsaturated nitriles in a novel cascade [3 + 2] dipolar cycloaddition, dehydration, and tautomerization sequence to afford pyrroles in moderate to excellent overall yield. This cost-effective and regiospecific method is ideally suited for the preparation of combinatorial libraries. [reaction: see text]