Asymmetric Reductive Amination in Organocatalysis and Biocatalysis

This review summarizes the recent progress of organocatalytic and biocatalytic asymmetric reductive amination (ARA), a challenging but important topic for drug discovery and the pharmaceutical industry. At present, ARA can be divided into three categories: metal catalysis, organic catalysis, and biocatalysis. In the past decade, transition metal-catalysed ARA has been well established. Organocatalytic ARA has emerged as a powerful alternative to metal-catalysed ARA, the hydrogen sources used in organocatalytic ARA are usually Hantzsch esters, benzothiazolines, boranes, and hydrosilanes, which require Lewis base or phosphoric acid catalysts to activate them to give secondary chiral amines. It is worth mentioning that biocatalytic ARA has made remarkable progress in the last decade, amino acid dehydrogenases, amine dehydrogenases, opine dehydrogenases and imine reductases have been successfully used in ARA.