Visible Light-Promoted Cascade Cyclization/Allylation of 2-Allyloxyaryl Sulfonium Salts with Morita-Baylis-Hillman Acetates

A photoinduced radical cascade cyclization/allylation of 2-allyloxyaryl sulfonium salts and Morita-Baylis-Hillman acetates has been developed. The method employs Eosin Y as an organophotocatalyst at room temperature under metal- and oxidant-free conditions, affords a one-step and effective route to produce a wide range of allylated 2,3-dihydrobenzofurans in moderate to good yield, and displays high selectivity, broad substrate scope, and good functional group tolerance.