Copper Catalysts Unleashing the Potential for Hydrogenation of Carbon−Oxygen Bonds

Abstract The catalytic hydrogenation of carbon−oxygen bonds by copper‐based catalysts has made significant progress in the past decade. Broad carbonyl compounds, such as aldehydes, ketones, carboxylic acids and their derivatives, and CO 2 have been subjected to heterogeneous and homogeneous catalytic systems. Although heterogeneous copper catalysts have been used in established industrial hydrogenation processes, recent catalyst design focusing on (i) novel supports, (ii) controlled nanostructure of copper species, and (iii) bimetallic active site in combination with copper have improved the productivity of the desired reduction products. With regard to homogeneous catalysts, phosphine‐coordinated copper complexes have been utilized in chemo‐ and enantioselective hydrogenation. In addition to the phosphorus ligand effect, several sp 2 ‐nitrogen bases have recently been explored as beneficial promoters of CO 2 hydrogenation.