Electrochemical aldehyde hydrogenation: probing the inner-sphere strategy with nickel-bipyridine complexes†

Developing electrohydrogenation routes for organics is crucial in synthesis electrification. Herein, we examine the electrocatalytic hydrogenation of aldehydes through an inner-sphere mechanism at a nickel-bipyridine complex. An (electro)reduction triggers the coordination of the aldehyde into a key nickeloxirane species, which affords hydrogenation products by stoichiometric protonations. Turnover yet remains challenging with acids suitable for electrocatalytic conditions due to sluggish proton transfers, which we probed by combined reactivity and computational studies.