The Study Of Asymmetric Michael Addition Reaction Of Aldehydes And Ketones To Nitroolefins Catalyzed By Small-molecule Organocatalysts

In this dissertation,eleven thioureas and sulfonamides were designed and synthesized from hydroxyproline.The synthetic methods toward those small organocatalysts were also studied to establish the basis for their further applications.It was found that the best catalyst was the 4-trifluoromethanesulfonamidyl prolinol tert-butyldiphenylsilyl ether 57a when these bifunctional organocatalysts were used to catalyze the asymmetric Michael addition reaction of cyclohexanone toβ-nitrostyrene.The influence of solvent,reactive temperature,catalyst loading and additive etc on the reactivity and enantioselectivity were optimized systematically. The experimental results demonstrated that excellent yield(＞99%),high diastereoselectivity(up to 98%dr) and enantioselectivity(up to 99%) were achieved when the reaction proceeded in acetonitrile at 0℃with 5 mol%catalyst and 5 mol% benzoic acid as additive.