Study On The Alkylation Of Isatin Derived N-Benzyl Nitrone Catalyzed By Organic Base

As an excellent spin trapping agent,nitrones are prone to 1,3-dipolar cycloaddition reaction,mainly [3 + 2] addition reaction with olefins and their derivatives and other unsaturated compounds to form some extremely valuable five-membered heterocyclic compounds.The unique properties of nitrones reflect their basic conversion reactions,including the reaction of nitrones with nucleophiles or free radicals,C-H functionalization,and various cycloaddition reactions.Compared with the corresponding imines,nitrones have the characteristics of easy handling,good stability,easy availability and fast reaction rate.Moreover,due to the stability of the configuration and its chelation with oxygen in some cases,nitrone is more likely to undergo addition reactions with diastereomeric and enantioselectivity,and the formation of selective carbon-carbon bonds It is widely used in various organic syntheses.In addition,in organic synthesis,based on the reaction characteristics of the isatin C-3 carbonyl group,different types of spiro-epoxidized indole skeletons can be synthesized in various ways.Because of its universality in many natural products and biologically active compounds,as well as its significant biological and pharmacological activity,it has received extensive attention based on the research of spirozation of isatin.The first chapter introduces the reaction and research progress of isatin and nitrone,as well as the structural characteristics and related research progress of electron-deficient olefins and MBH carbonate.The second chapter developed a DABCO-catalyzed [3 + 2] cycloaddition reaction of isatinderived N-benzyl nitrone and electron-poor olefin as the reaction substrate.And its structure is determined to be a five-membered spiral adduct.The effects of different catalysts,solvents,and reaction temperatures on the reaction were investigated.Under the optimal conditions,the scope of the substrate was screened.Under mild conditions,high-yield products can be obtained,and some products have been derivatized.And a preliminary study on the mechanism of the cycloaddition reaction was conducted.The third chapter studies the use of commercial quinidine or β-ICD as chiral catalysts to catalyze isatin-derived N-benzyl nitrone and MBH carbonate as substrates,catalyzed by chiral Lewis base.The effects of catalysts,solvents and reaction temperature on the reaction were investigated.The scope of the substrate was screened under optimized conditions,and the mechanism of the was preliminarily studied.