DABCO catalyzed unusual formal [4 + 2] cycloaddition of 3-acyl(or alkoxycarbonyl)-1,4-enediones with 2,3-butadienoates: effective access to highly functionalized pyrans

Abstract

A convenient and efficient DABCO-catalyzed formal [4 + 2] cycloaddition of 3-acyl(or alkoxycarbonyl)-1,4-enediones with 2,3-butadienoates is presented. This transformation takes advantage of mild conditions, wide substrate scope and significant functional group tolerance as well as excellent regioselectivity, which makes this method powerful for one-pot synthesis of highly functionalized pyrans in moderate to excellent yields.