Recent Advances in the α-Hydrazination (α-Amination) of Carbonyl Compounds

The electrophilic α-hydrazination (generally referred to as α-amination) of carbonyl compounds with dialkyl azodicarboxylates is a powerful approach for the preparation of synthetically useful intermediates such as α-amino aldehydes and ketones, α-amino acids, and β-amino alcohols. Many methods for the enantioselective α-hydrazination have been published in the past and many new approaches have been disclosed in the last decade that deal with previously unresolved issues such as the direct enantioselective α-hydrazination of α-branched ketones. The enantioselective α-hydrazination is the field where most significant advances have been attained thanks to new approaches, catalysts and techniques. With this review we intend to cover the literature that appeared between 2015 and 2024. We will classify the various methods according to the strategies for the enantioselective formation of the new C−N bond, mainly based on the formation of chiral enamines, enols and enolates. Miscellaneous methods are grouped at the end of the review. Where relevant, the application of α-hydrazino carbonyl compounds to the synthesis of target molecules will also be illustrated.