Studies On Transition Metal Catalyzed Asymmetric Decarboxylative Mannich Reaction And Decarboxylative Cycloaddition

The decarboxylation of carboxylic acids and their derivatives play an important role not only in the physiological processes of organisms,but also in the field of organic synthesis.Carboxylic acids and their derivatives have a wide variety of species in nature.Among them,malonic acid half esters and Münchnones are representative compouds,which are widly studied and applied in the decaboxylative reactions.In this dissertation,asymmetric decarboxylative addition of malonic acid half ester and decarboxylative cycloaddtion reactions of Münchnones(including azlactones)were studied,which were discribed in three chapters as followed.Chapter 1,according to the classsification of reactants,the introduction contains two sections.In section 1,the development of catalytic asymmetric decarboxylative addition of malonic acid half esters with electrophilics were summaried,which was classified as catalytic asymmetric decarboxylative Aldol reactions,Mannich reactions,Michael addition reactions and other addition reactions.The product types of the above reaction centers and their significance were discussed.Meanwhile,the influence of the catalytic system on the yield and enantioselectivity of the reaction was analyzed.In section 2,the development and application of decarboxylative cycloaddition of Münchnones(including azlactones)with unsaturated hydrocarbons were summaried,which focusing on the critical parameters of structure of reactants and products,reaction yields and regionselectivities.In Charpter 2,we have developed an enantioselective decarboxylative Mannich reaction of malonic acid half esters(MAHEs)with cyclic aldimines by employing the copper(I)/(R,R)-Ph-Box complex as a chiral catalyst.The desired ?-amino esters were obtained in good to high yields with excellent enantioselectivities.Furthermore,one of the corresponding Mannich products could be readily transformed into chiral chroman-4-amines with 62% total yield and 92% ee,which is a key intermediate of the human Bradykinin B1 receptor antagonist.In Charpter 3,we have developed a novel silver catalyzed decarboxylative cycloadditions between the azlactones and benzylidenemalononitriles.The desired tetrasubstituted pyroles were obtained with 98:2 regionselectivities and 50-80% yields.The large scale(up to 10 gramme degree)reaction proceeded smoothly without loss of yield and regionselectivity.The results of control experiments and NMR detections suggested that this reaction processed the sequences of cycloaddtion followed by decarboxylation together with the elimination of HCN.