Syntheses Of New Axial Chiral Catalysts And The Applications For Enantioselective Reactions

Chiral compounds are very common in both natural and synthetic products,so there are a large number of enantiomers.An enantiomer is something that doesn't exactly coincide with its mirror image but there is a compound that can exactly the same as it mirror image.Although the structure is similar,there are some differences in physical and chemical properties,mainly reflect in optical rotation and steric hindrance.It is applied to asymmetric chemical reactions and used as a chiral catalyst to participate in the reaction.In this reaction,the different steric hindrance catalyst is used to synthesize products of a certain configuration,and then the product enantioselectivity are determined by the difference of optical rotation of enantiomers to evaluate the catalytic effect.This method is simple,reliable,accurate and has been widely used in various asymmetric reactions.In the first chapter,the development of present situation for catalytic reactions,and the research progress of chiral catalysts are reviewed,including transition metal complexation catalysts and catalysts with small molecule.In the second chapter,based on the previous research group,the existing double carboline skeleton in the research group was modified and applied to the asymmetric reduction reaction of ketoimide.The catalyst modificative mainly involves the introduction of thioether substituents at the C-3,C-3? sites and the oxidative of m-CPBA to produce axial chiral dicarboline sulfones N,N'-dioxides.The catalytic effect of the catalyst was investigated in the asymmetric reduction reaction of ketoimide.The experimental results show that this kind of catalyst has high catalytic activity to the reduction reaction of ketoimide,among which tert-butyl sulfone is the best.The optimal reaction condition of the catalytic reaction was summarized through experimental exploration,that is,catalyst 21e(10 mol %)was used to react in DCM solution for 12 hours at-10 ?,and the highest enantioselectivity of 96% ee and 95% yield could be obtained.In the third chapter,on the basis of the research in the second chapter,the catalyst was used for allylation of aldehydes.The experimental results show that this kind of catalyst also has a certain catalytic effect on the allyl reaction of aldehydes,but its catalytic effect is general.The optimum condition for the experiment to explore the reaction is catalyst 21c(5 mol %)in DCM solvent for 16 h at-80 ?.Enantioselectivity was generally as high as 63% ee,while the reaction has a higher yield,up to 97%.