Chiral Squaramide Catalyzed Enantioselective Michael Addition of Cyclic 1,3-Diketones to β,γ-Unsaturated α-Keto Esters

A stereoselective methodology was developed to construct synthetically and pharmaceutically useful chiral chromene derivatives. In the presence of a newly designed bifunctional tertiary amine-squaramide organocatalyst, the Michael addition between cyclic 1,3-diketones and beta,gamma-unsaturated alpha-ketoesters occurred smoothly to provide the desired products with high to excellent yields (84%similar to 97%) and enantioselectivies (79%similar to 97% ee). This catalytic protocol was compatible with a range of structurally distinct beta,gamma-unsaturated alpha-ketoesters.

Automated summary

A stereoselective methodology has been developed to construct synthetically and pharmaceutically useful chiral chromene derivatives with high yields and enantioselectivities.