Catalytic oxidative cyclization of α-carbonyl-γ-alkynyl sulfoxonium ylides for stereospecific synthesis of (1Z,3Z)-1,3-bismethyleneisobenzofurans

Abstract

A new copper(II)-catalyzed annulation-enabled radical addition cascade of α-carbonyl-γ-alkynyl sulfoxonium ylides with sulfonyl hydrazides in the presence of tert-butyl hydroperoxide (TBHP) is reported, enabling a completely regio- and stereoselective strategy to access (1Z,3Z)-1,3-bismethyleneisobenzofurans in moderate-to-good yields. The protocol features a good substrate scope and functional group tolerance and proceeds through regioselective 5-exo-dig oxo-cyclization followed by stereoselective radical addition reaction.