Divergent synthesis of 2,3-dihydrobenzofuran selenides via visible light-mediated cascade cyclization/selenylation of 2-allyloxyaryl sulfonium salts with diselenides.

A visible light-mediated divergent synthesis of 2,3-dihydrobenzofuran selenides via cascade cyclization/selenylation of 2-allyloxyaryl sulfonium salts with diselenides is reported. The protocol offers a safer alternative to toxic PhSeCl for constructing biologically selenylated heterocycles in moderate to excellent yields. This method exhibits broad substrate scope, good functional group tolerance, and practical scalability. Mechanistic studies support a radical cascade pathway involving 5-exo-trig cyclization.