Visible-Light-Induced Organophotocatalytic Difunctionallization:Open-Air Hydroxysulfurization of Aryl Alkenes with Aryl Thiols

Abstract

Herein, we report a regioselective visible-light-induced organophotoredox catalytic difunctionalization methodto prepare beta-hydroxysulfides using aryl alkenes and aryl thiols assubstrates. The reaction provides a wide substrate scope of arylalkenes (from simple styrene to complex bioactive compounds)and aryl thiols (from diverse heteroaromatic thiols to nonhetero-aromatic thiols) (total 45 examples, up to 88% yield). Based on the combined experimental and computational studies, we demon-strate thatin situgenerated hydroperoxyl radicals from O2in airreact with benzylic radicals, which restrains the reaction betweenbenzylic radicals and the acidic form of thiols in a classical thiol-ene radical reaction. We show that difunctionalization is possibledue to the choice of bases, diluted substrate concentrations, increment in catalyst loading, and selection of suitable aryl thiols underaerobic conditions. Considering the biological importance of heteroaromatic thiols and the lack of methods to install them, ourapproach offers a platform to derive various beta-hydroxysulfides that contain aromatic elements.