Direct Asymmetric Reductive Amination of Alkyl (Hetero)Aryl Ketones by an Engineered Amine Dehydrogenase

Abstract The direct asymmetric reductive amination of heteroaryl ketones has been a long‐standing synthetic challenge. Here we report the engineering of an amine dehydrogenase (AmDH) from Jeotgalicoccus aerolatus for the asymmetric synthesis of chiral α‐(hetero)aryl primary amines in excellent conversions (up to 99 %) and enantioselectivities (up to 99 % ee). The best AmDH variant ( Ja ‐AmDH‐M3 3 ) exhibited high activity and specificity toward alkyl (hetero)aryl ketones, even for those bearing a bulky alkyl chain. An efficient directed evolution approach based on molecular docking was implemented to enlarge the active pocket with a more hydrophobic entrance, which is responsible for the high activity. The Ja ‐AmDH‐M3 3 was also used for preparative‐scale synthesis of pharmaceutically relevant amines and a key intermediate of chiral pincer ligands, which highlighted its practical application in synthetic chemistry.