Visible-Light-Catalyzed Tandem Radical Addition/1,5-Hydrogen Atom Transfer/Cyclization of 2-Alkynylarylethers with Sulfonyl Chlorides.

A novel visible-light-catalyzed tandem radical addition/1,5-hydrogen atom transfer/cyclization cascade of 2-alkynylarylethers with sulfonyl chlorides in 2-methyltetrahydrofuran was developed under photocatalyst- and additive-free conditions. This reaction relies on unique energy transfer and solvent-radical relay strategies to generate sulfonyl radicals for the preparation of a series of sulfonyl-functionalized dihydrobenzofurans in moderate to high yields catalyzed by visible light or solar radiation.