Catalytic Enantioselective and Diastereoselective Addition of Aldehyde‐Derived Enecarbamates to α‐Oxo Aldehydes

Added benefits : Catalytic enantio‐ and diastereoselective addition of aldehyde‐derived enecarbamates to aldehydes is reported (see scheme). A copper(I)–diimine complex works well as the catalyst and the catalyst loading is not more than 1 mol % in most cases. By taking advantage of this reaction, the total synthesis of (2 S ,3 S ,4 S )‐3‐hydroxy‐4‐methylproline has been accomplished.