Photoinduced Radical Cyclization of 2-Alkynylthioanisoles with Disulfides without an External Photocatalyst.

An efficient strategy for the synthesis of 3-arylthiobenzo[ b ]thiophenes via a photodriven radical cyclization of 2-alkynylthioanisoles with disulfide was developed. The reaction proceeded smoothly under visible-light irradiation without any external photocatalyst and generated the desired products in high yields with good functional group tolerance.