Abstract

This article presents a data-driven study of homogeneous metal-based catalytic transfer hydrogenation (CTH) reactions. These reactions have gained considerable interest over the past decade as they provide non-pressurized hydrogen-based alternatives for diverse chemical processes. CTH enables the selective reduction of functional groups such as carbonyls and unsaturated bonds, often under mild conditions. In this work, we analyze data trends to elucidate the influence of solvents, metals, and reaction parameters, while also exploring clustering patterns that emerge across reported systems. Although ruthenium-based catalysts remain the most widely applied, there is increasing attention to non-precious transition metals, particularly cobalt and nickel. Alcohols, including isopropanol, ethanol, and methanol, are frequently employed as both hydrogen donors and solvents, with isopropanol prevailing in Co- and Ni-mediated reactions, and ethanol predominant in Cu-based systems. While a wide variety of substrates has been explored, often incorporating nitrogen heteroatoms, the most frequently reported transformations involve the reductions of acetophenone, cyclohexanone, benzaldehyde, and furfural. Overall, these data-driven insights help clarify solvent-catalyst-substrate relationships and provide practical guidance for pre-laboratory planning of CTH reactions.