CO‐Boosted Protocol for the Photocatalytic C−H Thiolation of Aldehydes Using Phenylthiobenzenesulfonate

Abstract The formyl C−H thiolation of aldehydes using thiosulfonates and the decatungstate anion as a photocatalyst is reported. Using this photocatalytic protocol together with a CO atmosphere, both aromatic and aliphatic thioesters can be synthesized in good yields. The transformation consists of a cascade of double S H 2 reactions, HAT and an ArS group transfer. CO atmosphere effectively limits the extent of decarbonylation of acyl radicals that are generated in the reaction.