Synthesis And Application Of New Cinchona Catalysts

?,?-Unsaturated aldehydes are highly reactive molecules and have been broadly utilized in a variety of catalytic transformations.Hower,the cataytic,regioselective and stereoselective ?-functionalization of ?,?-unsaturated aldehydes represents a highly challenging for asymmetric synthesis.All attempts to solve this problem must address the challenge of site selectivity as well as stereoselectivity.The direct and enantioselective ?-alkylation of ?-substituted ?,?-unsaturated aldehydes under dienamine catalysis has been achieved by using chiral primary amine catalysts and chiral phosphoric acid co-catalysts.Hower,high loadings and appropriate configutation of chiral phosphoric acid are required and more importantly,they are expensive.Therefore,we herein report newly developed primary aminocatalysts including acid group introduced by covalent modification derived from cinchona alkaloids to avoid the usage of chiral phosphoric acid additives and their application in enantioselective ?-alkylation of ?-substituted ?,?-unsaturated aldehydes with stabilized benzhydryl carbocation.Catalyst containing acetic group yield ?-alkylation products in good yields(up to 94%)with up to 90% ee.