Unraveling the Metal–Ligand Cooperativity in a Phosphine-Free Mn(II)-Catalyzed Transfer Hydrogenation of Nitriles to Primary Amines and Dehydrogenation of Dimethylamine Borane

Selective synthesis of primary amines from nitriles is challenging in synthetic chemistry owing to the possible en route formation of various amines and imines. Herein, we report a well-defined phosphine-free Mn(II)-pincer complex-catalyzed transfer hydrogenation of nitriles to the corresponding primary amines with a relatively unexplored hydrogen source (dimethylamine borane). The protocol proceeds under relatively mild conditions with a broad substrate scope involving metal–ligand cooperation. Various control studies have been performed to understand the mechanism of the present strategy. The gas chromatography analysis of the reaction mixture revealed the evolution of the H2 gas through the dehydrogenation of dimethylamine borane. Detailed computational calculations were undertaken to shed light on the possible intermediates and transition states involved during the present protocol.