Manganese-pyridone-catalyzed site-selective hydrogen isotope exchange of 2-arylpyridines using D2O.

We report a manganese-catalyzed protocol for the selective ortho-deuteration of 2-arylpyridines using D2O as a readily available deuterium source. Enabled by Mn(CO)5Br and 2-pyridone, the reaction delivers deuterated products in good isolated yields with high deuterium incorporation across a broad range of electronically and sterically diverse substrates. Gram-scale synthesis and late-stage derivatization highlight the utility of this method for accessing deuterated pharmaceutically relevant molecules.