Photo-induced intramolecular alkyl/aryl group transfer and SO2 insertion: a new strategy for the synthesis of 3-(alkyl/arylsulfonyl)benzothiophenes

Abstract

A new and efficient strategy for the synthesis of 3-(alkyl/arylsulfonyl)benzothiophenes and benzoselenophenes via a photo-induced tandem cyclization of 2-alkynylthioanisoles or -selenoanisoles with DABSO through intramolecular alkyl/aryl group transfer and SO₂ insertion was developed. The reaction proceeded smoothly under visible-light irradiation without any external photocatalyst, and generated the desired products in excellent yields with good functional-group tolerance.