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

Abstract

An efficient strategy for the synthesis of 3-arylthiobenzo[b]thiophenes via a photodriven radical cyclization of 2alkynylthioanisoles 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.

Sustainable Synthesis through Catalyst‐Free Photoinduced Cascaded Bond Formation

“…A similar photocatalyst-free strategy was reported by Li and co-workers for synthesis of 3-arylthiobenzo [b]thiophenes via radical mediated cyclization of 2-alkynylthioanisoles with disulfides. [65] Many discussions on photoinduced sulfonylation and selenylation under transition metal-free conditions have been previously covered (vide supra). In this context, Chen and coworkers showcased a multicomponent cascade synthesis of βsulfonylvinylselanes from alkynes 31 a, diselenides 31 b, and DABSO under blue LED irradiation (Scheme 31).…”