Selective Oxidation of Primary Amines to Nitriles Catalyzed by the Ru‐Doped Hexagonal Perovskite SrMnO ₃

The selective oxidation of primary amines to generate nitriles provides a cost‐effective and atom‐economical synthetic approach that avoids the formation of harmful byproducts. However, achieving high yields under mild conditions remains challenging, due to the difficulty in efficiently activating the α ‐CH bonds of amines and the multiple competing pathways that reduce selectivity. The present study employed Ru‐substituted hexagonal perovskite nanoparticles (SrMn 1−x Ru x O 3 ) as a highly effective heterogeneous catalyst for the aerobic oxidation of benzylamine at 40°C in air and without additives, affording benzonitrile in quantitative yields. The selectivity of this reaction for nitriles or dimeric secondary imines could be switched simply by changing the solvent. The catalyst exhibited excellent reusability without any significant loss of catalytic performance and was found to be applicable to a broad range of aromatic and aliphatic primary amines, yielding the corresponding nitriles. Mechanistic studies suggest that this reaction proceeds through the Mars–van Krevelen mechanism, in which scission of the α ‐CH bond of a strongly adsorbed amine is the rate‐determining step. The incorporation of Ru in the catalyst evidently enhanced the reactivity of surface metal‐oxygen species, thereby facilitating α ‐CH bond scission and enabling efficient nitrile synthesis under remarkably mild conditions.