Organocatalytic asymmetric conjugate addition of cyclic 1,3-dicarbonyl compounds to β,γ-unsaturated α-ketoesters

Abstract

The conjugate addition of cyclic 1,3-dicarbonyl compounds to β;,γ-unsaturated α-keto-esters was studied using a series of chiral bifunctional organocatalysts. Takemoto's catalyst was found to be most efficient for this transformation. Excellent yields and good enantioselectivities were achieved for a variety of β,γ-unsaturated α-keto-esters and cyclic 1,3-dicarbonyl compounds. A bifunctional catalytic mechanism is proposed. The method provides a new asymmetric synthetic route for chiral courmarin derivatives. © ARKAT USA, Inc.