Stereocomplementary Synthesis of β‐Aryl Propanamines by Enzymatic Dynamic Kinetic Resolution‐Reductive Amination

Abstract Chiral β‐aryl propanamine is an important structure unit of bioactive molecules or drugs. But its efficient synthesis remains a challenging task. In this study, several enantiocomplementary imine reductases capable of dynamic kinetic resolution‐reductive amination of sixteen 2‐phenylpropanal derivatives of diverse structural characteristics with four different amines were identified through screening 196 imine reductases. Furthermore, ( S )‐IR60, ( R )‐IR74 and ( R )‐IR207 were applied to access a series of different β‐aryl propanamines with excellent ee values (90 to 99 %) and high isolated yields (36 to 79 %), and two of them were further transformed into 3‐methylindolines through intramolecular Buchwald‐Hartwig cross‐coupling and deallylation, providing an effective method to construct this class of pharmaceutically important compounds.