Multideuteration of Nitroaromatics by Silver-Catalyzed Hydrogen-Isotope Exchange

A silver-catalyzed deuteration of nitroaromatics had been achieved employing D2O as deuterium source. Distinct from the well-established directing group guided hydrogen-isotope exchange, the protocol showed an interesting deuteration pattern, where considerable deuterium accumulation was observed around the aromatic ring. Control experiment indicated the deuteration was initiated by a silver-promoted C-H activation, and a tentative two-stage deuteration mechanism involving aryl-silver species was proposed to explain the deuteration on meta- and para-sites.