Catalyst-controlled cycloisomerization/[4 + 3] cycloaddition sequence to construct 2,3-furan-fused dihydroazepines and 2,3-pyrrole-fused dihydrooxepines

Abstract

A novel catalyst-controlled cycloisomerization/[4 + 3]cycloaddition sequence of readily available acyclic enyne-amides and crotonate-derived sulfur ylides is reported. This strategy enables the rapid and efficient construction of a series of bicyclic 2,3-furan-fused dihydroazepines and 2,3-pyrrole-fused dihydrooxepines with diverse substituents in generally good yield.