Design And Synthesis Of Chiral Organocatalysts And Their Applications In The Asymmetric Michael Addition Reactions Of Ketones To Nitroolefins

Part 1 Synthesis of Chiral Thiourea by SubstitutionThe 1,3-diphenylthiourea could be substituted by achiral or chiral amines. Using this method, a series of achiral and chiral thiourea have been synthesized in good to excellent yields. All new compounds have been fully characterized by IR, 1H NMR, 13C NMR, and HRMS. The X-ray analysis of single crystal of chiral thiourea 7d has shown that there are two kinds of molecules of different conformations in one crystal unit. They differ in the orientation of the two benzene rings, syn or anti.Part 2 Design and Synthesis of Chiral Organocatalysts and Their Applications in the Asymmetric Michael Addition Reactions of Ketones to NitroolefinsI Synthesis of Alaninamide Organocatalysts and Their Applications in the Asymmetric Addition of Cyclohexanone to Nitrostyrene Different amino-alcohols derived from L-alanine, L-valine, L-phenylglycine, L-phenylalanine reacted with L-alanine separately and a series of novel alaninamide organocatalysts were synthesized. They were applied to the asymmetric addition of cyclohexanone toβ-nitrostyrene and the desired product was obtained with ee up to 95%. Some factors influencing diastereoselectivity and enantioselectivity, such as the structure of organocatalyst and substrate, additive and it`s loading, were discussed.II Synthesis of organocatalysts containing pyrrolidine and their applications in the asymmetric addition of cyclohexanone to nitrostyrenePyrrolidine-thiourea and other prolinamide organocatalysts derived from natural L-proline were synthesized and investigated in the asymmetric addition of cyclohexanone to nitrostyrene. The influence of the organocatlysts` structure to the yield and enantioselectivity of the product was discussed.