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

[Image: see text] We describe a palladium-catalyzed nondirected late-stage deuteration of arenes. Key aspects include the use of D(2)O as a convenient and easily available deuterium source and the discovery of highly active N,N-bidentate ligands containing an N-acylsulfonamide group. The reported protocol enables high degrees of deuterium incorporation via a reversible C–H activation step and features extraordinary functional group tolerance, allowing for the deuteration of complex substrates. This is exemplified by the late-stage isotopic labeling of various pharmaceutically relevant motifs and related scaffolds. We expect that this method, among other applications, will prove useful as a tool in drug development processes and for mechanistic studies.