Facile synthesis of benzo[b]thiophenes via metal-free radical-triggered intramolecular C–S bond formation

Abstract

A facile method for the synthesis of benzo[b]thiophenes with good to excellent yields via metal-free intramolecular C–S bond formation has been developed by utilizing I₂ as a catalyst and O₂ from air as an oxidant (20 examples). Its notable features such as catalytic I₂, intramolecular C–S bond formation, short reaction times, and broad functional group tolerance make this strategy highly attractive. The purification of products only needs washing with solvents, thereby avoiding traditional chromatography and recrystallization, which belongs to group-assisted purification (GAP) chemistry.