Copper-catalyzed stereodefined synthesis of halogenated spirodihydrofurans

Abstract

A copper-catalyzed decarboxylative cyclization of cyclic ethynylethylene carbonates (EECs) with anthranils in the presence of halide salts under aerobic conditions is reported. This transformation proceeds via unique alkylidene ketenimine intermediates, followed by I₂-mediated intramolecular nucleophilic α-addition, affording a diverse range of halogenated spirodihydrofurans in good yields with high regio- and stereoselectivities.