Dual-Role Catalysis by Thiobenzoic Acid in Cα-H Arylation under Photoirradiation

Thiobenzoic acid (TBA) can serve as a single-electron reducing agent under photoirradiation from a blue light-emitting diode, in the presence of appropriate electron acceptors, and the resulting sulfur-centered radical species undergoes hydrogen atom abstraction. This dual-role catalysis by TBA enables regioselectivie C alpha-H arylation of benzylamines, benzyl alcohols, and ethers, as well as dihydroimidazoles, with cyano(hetero)arenes in good yield, without the need for a transition-metal photocatalyst and/or synthetically elaborated organic dyes.

Automated summary

Thiobenzoic acid (TBA) can act as a single-electron reducing agent under blue light irradiation, enabling regioselective C alpha-H arylation of benzylamines, benzyl alcohols, ethers, and dihydroimidazoles through dual-role catalysis.