Catalytic Asymmetric Addition of Dimethylzinc to α-Keto Esters

Significance

This work describes a practical protocol for the enantioselective addition of di­methylzinc to α-keto esters. The chiral reaction products can be useful intermediates in the synthesis of natural products and biologically active molecules. A readily available amide derived from mandelic acid has been used as a catalyst. A good enantioselectivity of the reaction is only obtained for aryl and hetaryl keto esters. For those substrates, ee values are in the range of 75-90%, while the enantioselectivity is somewhat lower for the substrates bearing an aliphatic chain. The process is operationally simple and practical.