Recent progress in the synthesis of primary amine via direct reductive amination of aldehydes and ketones

Amines, especially primary amines, have been extensively employed in pesticide, medicine, dye and high molecular polymer as raw materials or intermediates. Recently, direct reductive amination of carbonyl compounds (aldehydes or ketones) has been a research focus for synthesizing primary amines. Heterogeneous and homogeneous catalysts based on noble and non-noble metals have been proven to be efficient for direct reductive amination of carbonyl compounds. In this paper, we carefully review the state of art of direct reductive amination of carbonyl compounds (one-pot method) to synthesize primary amines, including reaction profile, recent progress in catalysts, reaction conditions, the substrate scope and catalytic mechanism, especially the catalysts. Generally, heterogeneous catalysts are highly active and could be reused, while homogeneous catalysts have the advantages of high efficiency and high primary amines selectivity. On the other hand, noble catalysts like Pd, Rh and Ru are more active and expensive, so non-noble metal based catalysts like Co and Ni catalysts could be alternative for the sake of economic. Thus, the catalysts for direct reductive amination to synthesize primary amines with high efficiency, mild reaction condition and high universality should be developed. © 2022, Chemical Industry Press Co., Ltd.. All rights reserved.