Electrohydrogenation of Nitriles with Amines by Cobalt Catalysis

Catalytic hydrogenation of nitriles represents an efficient and sustainable one-step synthesis of valuable bulk and fine chemicals. We report herein a molecular cobalt electrocatalyst for selective hydrogenative coupling of nitriles with amines using protons as the hydrogen source. The key to success for this reductive reaction is the use of an electrocatalytic approach for efficient cobalt-hydride generation through a sequence of cathodic reduction and protonation. As only electrons (e-) and protons (H+) as the redox equivalent and hydrogen source, this general electrohydrogenation protocol is showcased by highly selective and straightforward synthesis of various functionalized and structurally diverse amines, as well as deuterium isotope labeling applications. Mechanistic studies reveal that the electrogenerated cobalt-hydride transfer to nitrile process is the rate-determining step. Reported herein is a mild and efficient electrocatalytic method for earth-abundant cobalt hydride generation through a sequence of cathodic reduction and protonation. The application of this molecular cobalt catalyst allows for electroreductive amination of nitriles to produce various secondary and tertiary amines, as well as deuterium isotope labeling applications from readily available deuterium source.image