Synthesis of 2-chromanone-fused [3.2.0] bicycles through a phosphine-mediated tandem [3 + 2] cyclization/intramolecular Wittig reaction

Abstract

A phosphine-mediated tandem [3 + 2] cyclization/intramolecular Wittig reaction of 3-aroylcoumarin with alkynone is described. The high efficiency of the tandem process allows the synthesis of 2-chromanone-fused bicyclo[3.2.0]heptenones in moderate to high yields with remarkably high regio- and diastereoselectivities under mild reaction conditions, which represents an extremely simple, economical and straightforward synthetic method to construct complex cyclic building blocks with potential biological applications.