Methanol for Hydrogenation and Methylation of Carbonyls: Advances and Challenges in Homogeneous Catalysis

Abstract The catalytic dehydrogenation of methanol to give formaldehyde or formic acid, followed transfer hydrogenation and/or tandem (de)hydrogenation for the hydrogenation and C-methylation of carbonyls, offers advantages over traditional methods, including milder reaction conditions, improved safety, greater selectivity, and enhanced sustainability. This account provides a comprehensive overview of homogeneous catalysts reported for the transfer hydrogenation and C-methylation of various substrates, including ketones, chalcones, esters, and amides, using methanol as both a hydrogen donor and methylation source. We provide specific examples and mechanistic insights for each strategy, offering a thorough and concise overview of recent advancements from 2014 to 2024. 1 Introduction 2 Methanol Activation Strategies 3 Hydrogenation of Carbonyls 4 Methylation of Carbonyls 5 Outlook and Summary