Study On Asymmetric Catalytic Addition Of Intercalene With Central Chiral Metal Rhodium(Ⅲ) Complex

There are many chiral phenomena in nature,and chiral substances are closely related to our lives.In view of the importance of chiral compounds to human beings,how to obtain chiral compounds more easily has been one of the key research objects of scientists since the 20 th century.Asymmetric catalysis is usually divided into two catalytic modes,one is the organic small molecule catalytic mode and the other is the metal catalytic mode.For the system catalyzed by small organic molecules,the process is basically to form a stable transition state through the hydrogen bond interaction between molecules,and then control the generation of chirality.However,the high amount of catalyst is one of the shortcomings of the catalytic system.However,the system using metal catalysis mainly uses chiral ligands and metals to form complexes in situ to form catalysts.Metal acts as the coordination of Lewis acid and the reaction substrate.Metal does not provide a chiral environment,and the ligand controls the chirality.Chiral octahedral metal complexes are different from the above,and the peripheral ligands coordinate with the metal to form a rigid structure that makes the metal chiral.Usually,such octahedral chiral metal complexes have a strong rigid structure,and the transition state conformation is relatively stable in the reaction,so the products have excellent enantioselectivity and high yield.The first part of this thesis is a literature review,investigating the application of metal-center complexes,and summarizing the research progress of asymmetric intercalation.The second part mainly introduces the study of the asymmetric catalytic reaction of o-methyl aromatic nitro compound and unsaturated ketone.We have established the asymmetric vinyl Michael addition of unsaturated ketones to2-methyl-3,5-dinitrobenzoate catalyzed by a chiral rhodium catalyst.This system can synthesize a variety of optically pure compounds containing imidazole and 3,5-dinitrobenzene backbones with yields ranging from 64 to 98% and ee contents ranging from 88 to 98%.This is not only the first Michael addition reaction with 2-methyl-3,5-dinitrobenzoate as the substrate catalyzed by chiral metal center complexes,but also enriches the derivatives and synthesis methods of 2-methyl-3,5-dinitrobenzoate.In addition,this protocol has clear advantages in terms of reaction activity and enantiomer selectivity.When the chiral rhodium catalyst was reduced to 0.06 mol %,gram-order reactions were still achieved and 95% of the desired ee was obtained.The third part describes the study of the intercalated addition reaction of coumarin derivatives and unsaturated ketones catalyzed asymmetrically by the central chiral metal rhodium complex.We have developed an asymmetric Michael addition reaction of unsaturated ketones with 3-cyano-4-methylcoumarin catalyzed by a chiral octahedral metal rhodium complex catalyst.This system can synthesize a variety of optically pure compounds containing imidazole and coumarin backbones with yields ranging from 41 to 99% and enantioselectivity ranging from 82 to 98%.This reaction is the first example of Michael addition from a metal rhodium complex based on 3-cyano-4-methyl coumarin with asymmetric catalysis,which provides reliable theoretical support for the synthesis of 3-cyano-4-methyl coumarin derivatives in the future.