Amine-Squaramide Catalyzed Asymmetric Michael Addition of Cyclic Diketones and beta,gamma-unsaturated alpha-keto Esters

A novel tertiary amine squaramide has been successfully developed and applied to catalyze the asymmetric Michael addition between cyclic diketones and beta,gamma-unsaturated alpha-ketoesters. The catalyst system performed well with a low catalyst loading of 1 mol% under mild reaction conditions. A series of synthetically and pharmaceutically useful chiral bicyclic compounds were obtained with both high yields (up to 97%) and excellent enantioselectivities (up to 97% ee).