Photoinduced intramolecular S-α-C(sp3)–H functionalization enabled by an electron donor–acceptor complex-Mediated radical relay

Abstract

We describe a consecutive reaction of 2-alkynylthioanisoles and 4-cyanopyridine enabled by EDA complex photoactivation, which facilitates the sequential S-α-C(sp³)–H bond activation, cyclization and radical coupling under mild conditions. A variety of 3-(4-pyridylbenzyl)benzothiophenes and benzoselenophenes were synthesized via a single-step process. Mechanistic investigations indicate that EDA complexes between thioethers and 4-cyanopyridines are crucial to this process.