Nitrile Oxidation at a Ruthenium Complex leading to Intermolecular Imido Group Transfer.

The oxidation of an acetonitrile ligand coordinated to ruthenium is explored in deuterated dimethylsulfoxide by H NMR spectroscopy. When oxidized with an iodosoarene oxygen atom transfer (OAT) reagent, kinetic studies demonstrate that the nitrile ligand does not dissociate before reacting. Instead, OAT to the central nitrile carbon is implicated (nitrile oxidation), and is further supported by the product of the reaction, -acyl-dimethylsulfoximine. The -acyl-dimethylsulfoximine likely formed by an imido group transfer reaction from ruthenium to the NMR solvent, and the product was synthesized independently to verify its identity in the reaction. This reaction represents the first time that a nitrile oxidation reaction has resulted in intermolecular imido group transfer to a substrate, presumably through a reactive ruthenium(IV)imido intermediate. This suggests that nitrile oxidation is a plausible route into reactive metal-imido intermediates for amination and aziridination reactions.