The Study On Strecker-type Reaction And [3+2] Cycloaddition Of Nitrones Catalyzed By Lewis Acid Mg(?)

This thesis mainly focuses on the synthetic methodology of nitrone compounds.Furthermore,the strecker reaction and [3+2] cycloaddition reaction of nitrones catalyzed by Mg(II)were investigated.This dissertation consists of four parts as following:The first chapter presented the progress for the synthesis of nitrone compounds,and introduced the important applications in organic reactions,such as Strecker reaction,fluoroalkylation,and cycloaddition.Due to the unique 1,3-dipolar property,[3+2] cycloaddition between alkenes and nitrones is one of the most thoroughly studied and widely used reactions.Besides,the isoxazolidine skeleton produced in cycloaddition shows a good biological activity and plays an important role in natural product and drug synthesis,which attracted the attention of pharmaceutical chemists.In the second part,we briefly studied the preparation methods of various nitrone compounds.A series of representative nitrones were synthesized through zinc powder reduction,sodium tungstate/hydrogen peroxide oxidation,and Mannich condensation by hydroxylamine and aldehydes.On this basis,chiral nitrones and cyclic chiral nitrones were also synthesized by using chiral amines or chiral amino alcohols as chiral sources.These preparations laid the foundation for the follow-up study.Thirdly,we have developed a highly efficient Strecker-type reaction of nitrone with trimethylsilyl cyanide catalyzed by Mg(II)to obtain the ?-cyanohydroxylamine.This method has the advantages of mild reaction condition,simple operation,short reaction time and high yield.In the last chapter,[3+2] cycloaddition was carried out by Mg(II)to form a series of novel isoxazolidine derivatives.In this part,the reactions between various alkenes with nitrones containing different electron-effect substituents on aromatic rings and between chiral nitrones with alkenes were both investigated in detail.The mechanism of the stereoselectivity were further studied.In addition,the isoxazolidine derivative was studied extensively to synthesize the ?-hydroxy-?-alkyl glutamic acid derivatives.