Palladium-Catalyzed Late-Stage C-H Deuteration of Arenes

We describe a palladium catalyzed non-directed late-stage deuteration of arenes. Key aspects include the use of D2O as a convenient and easily available deuterium source and the discovery of highly active N,N-bidentate ligands containing an N-acyl sulfonamide group. The reported protocol enables high degrees of deuterium incorporation via a reversible C-H activation step and features an extraordinary functional group tolerance, allowing for the deuteration of complex substrates. This is exemplified by the late-stage isotopic labelling of various pharmaceutically relevant motifs and related scaffolds. We expect that this method, amongst other applications, will prove useful as a tool in drug development processes and for mechanistic studies.