Photocatalytic α-Trifluoromethylthiolation of N-Acyl Amines

A photocatalytic approach for the C(sp3)–H trifluoromethylthiolation of amides under mild reaction conditions is reported. We have developed a protocol that tolerates a large range of functional groups and allows the functionalization of aromatic and aliphatic amides in high yields (26 examples, up to 83% yield) by using a low catalytic loading of an organophotocatalyst. With this approach, the synthesis of original fluorinated acyclic thioaminals is successfully achieved. Detailed mechanistic studies are conducted and enable deciphering an oxidative quenching catalytic cycle via a proton-coupled electron transfer (PCET), allowing the formation of a primary radical at the α-position of the nitrogen.