Enantioselective Synthesis of anti-β-Hydroxy-α-Amido Esters by Asymmetric Transfer Hydrogenation in Emulsions

Herein, we present two methods for an asymmetric transfer hydrogenation through the dynamic kinetic resolution of α‐amido‐β‐ketoesters. These procedures yield the corresponding anti‐β‐hydroxy‐α‐amido esters in good yields and with good diastereo‐ and enantioselectivities. First, the scope of the reduction of α‐amido‐β‐ketoesters by using triethylammonium formate azeotrope is examined. Then, an emulsion technology with sodium formate is explored, which allows for broader substrate scope, faster reaction times, and lower catalyst loading. Furthermore, these reactions are operationally simple and can be set up in air. Emulsions do the trick! A new method is disclosed for an asymmetric transfer hydrogenation combined with a dynamic kinetic resolution of α‐amido‐β‐ketoesters to yield the corresponding anti‐β‐hydroxy‐α‐amido esters (see scheme). This reaction has a broad substrate scope, including alkyl, alkenyl, and aryl substrates, and is performed in aqueous media.