Transfer Hydrogenation: Advances in Manganese and Nickel Metal Catalysis

Transfer hydrogenation (TH) of ketones, catalyzed by transition–metal complexes, produces alcohols, which are important building blocks in the pharmaceutical and fine chemical industries. For a long time, catalysts based on noble metals such as ruthenium, rhodium, and iridium have dominated the TH of ketones. However, due to limited availability, high price, and toxicity of these noble metals, there has been a push for their replacement with abundant, nonprecious, and biocompatible metals. In this respect, the reactions catalyzed by first‐row transition metals, which are more abundant and benign, have attracted more and more attention. Thus, in this review, we provide a comprehensive overview of the advances made in the last decade, in the application of the first‐row transition metals, manganese and nickel, in the hydrogenation of ketones. Special focus is given to ligand design and reaction conditions in influencing the catalytic activity, yield, and the nature of the product.