Multideuteration of Nitroaromatics by Silver-Catalyzed Hydrogen-Isotope Exchange

Silver-catalyzed deuteration of nitroaromatics has been achieved using D₂O as the deuterium source. Distinct from the well-established directing group-guided hydrogen-isotope exchange, this protocol showed an interesting deuteration pattern, where considerable deuterium accumulation was observed around the aromatic rings. Controlling experiments suggested that the deuteration was initiated by a silver-promoted C-H activation. Therefore, a tentative two-stage deuteration mechanism involving aryl-silver species was proposed to explain the deuteration on meta- and para-positions.