Selective Copper- or Silver-Catalyzed Decarboxylative Deuteration of Aromatic Carboxylic Acids

The practical utility of decarboxylative transformations in organic synthesis is discussed, and the decarboxylative deuteration of (hetero)aromatic carboxylic acids is disclosed as a further example. Various monodeuterated arenes were synthesized under mild conditions, in a single step from easily accessible aromatic carboxylic acids and deuterium oxide. Copper catalysts were found to have the widest scope, but silver catalysts are superior for some ortho-substituted benzoates. A few substrates, e.g. quinoline-2-carboxylic acid, decarboxylate even in the absence of a metal catalyst.