Photocatalytic C(sp 3 )-H thiolation by a double S H 2 strategy using thiosulfonates.

Site-selective C(sp 3 )-H thiolation using thiosulfonates has been achieved using the decatungstate anion as a photocatalyst. Using the protocol, a variety of thiolated compounds were synthesized in good yields. The transformation consists of a cascade of double S H 2 reactions, HAT and ArS group transfer, and PCET (proton-coupled electron transfer) of the leaving arylsulfonyl radical to arylsulfinic acid thus allowing the catalyst, W 10 O 32 4- , to be recovered.