Recent advances in homogeneous catalysts for the acceptorless dehydrogenation of alcohols to ketones and aldehydes

Oxidant-free oxidation, also known as acceptorless dehydrogenation, has emerged as a powerful strategy for the oxidation of alcohols. Besides yielding carbonyl compounds, the method produces hydrogen gas- a promising green fuel with water as the only by-product. The elimination of toxic and stoichiometric oxidants or hydrogen acceptors makes this approach attractive from the standpoint of green and sustainable chemistry. Consequently, several transition metals-based catalytic methods have been developed to synthesise ketones and aldehydes through this green method. In this review, we would like to summarise the recent development of homogeneous catalysts for the acceptorless dehydrogenation of primary and secondary alcohols to yield aldehydes and ketones, respectively. Also, we delve into the specific roles played by various ligands, including bi-functional ligands, in fine-tuning the stereo-electronic properties of the metal catalyst and delineate their impact on reaction outcomes.