Recent advances in nickel-catalyzed asymmetric hydrofunctionalization of alkenes

Nickel-catalyzed reactions have attracted more and more attention. A variety of transformations of organic compounds have been achieved through single-electron or two-electron transfer processes catalyzed by nickel. In these transformations, asymmetric hydrofunctionalization of alkenes, in which a hydrogen atom and a functional group are enantioselectively added across to C–C double bonds of alkenes, allows the construction of value-added optically active molecules from readily available raw materials. These reactions fulfill the growing demands for highly efficient, atom-economical, and green synthesis. This review overviews recent developments in the nickel-catalyzed intermolecular asymmetric hydrofunctionalization of alkenes under reductive and redox-neutral conditions. Nickel-catalyzed asymmetric hydrofunctionalization reactions of alkenes provide an atom- and step-economical method for synthesizing optically active molecules and attracts increasing attention in recent years. These reactions are initiated by Ni-H species, so finding an eligible hydrogen source to form Ni-H species is crucial for the success of the reactions. Efficient chiral ligands are another key to control enantioselectivity. This review summarizes recent advances in the nickel-catalyzed intermolecular asymmetric hydrofunctionalization of alkenes via an Ni-H intermediate under reductive or redox-neutral conditions. Perhaps, the most ideal nickel-catalyzed asymmetric hydrofunctionalization of alkenes go through the direct addition of H-X (X = C, N, P, O, S, etc.) with nickel to form Ni-H species without the use of stochiometric reductants. Thus, we hope that this review will encourage future research toward redox-neutral nickel-catalyzed asymmetric hydrofunctionalization of alkenes. Due to the growing demands for environmentally friendly and sustainable processes in recent organic synthesis, it becomes important to use earth-abundant metals as catalysts to transfer available raw materials to valuable products via efficient and atom-economical reactions. Nickel-catalyzed hydrofunctionalization reactions of alkenes undoubtedly fulfill the demands for highly efficient, atom-economical, and green synthesis. This review summarizes recent advances in the nickel-catalyzed intermolecular asymmetric hydrofunctionalization reactions of alkenes and forecasts the future direction of this field.