An Ammonium-Formate-Driven Trienzymatic Cascade for ω-Transaminase-Catalyzed ( R )-Selective Amination

( R )-Amination mediated by ( R )-specific ω-transaminases generally requires costly d -alanine in excess to obtain the desired chiral amines in high yield. Herein, a one-pot, trienzymatic cascade comprising an ( R )-specific ω-transaminase, an amine dehydrogenase, and a formate dehydrogenase was developed for the economical and eco-friendly synthesis of ( R )-chiral amines. Using inexpensive ammonium formate as the sole sacrificial agent, the established cascade system enabled efficient ω-transaminase-mediated ( R )-amination of various ketones, with high conversions and excellent ee (>99%); water and CO 2 were the only waste products.