Copper-catalyzed Three-component Reactions Of Enaminone,Terminal Alkyne And Sulfonyl Azide

Multicomponent cascade reactions have become powerful tools for the synthesis of complex molecular skeletons by forming multiple carbon-carbon bonds and carbon hetero-bonds in one-pot reactions.Copper-catalyzed multi-component reactions of sulfonyl azides and acetylenes have attracted much attention by chemists.Usually,these multicomponent reactions consist of copper-catalyzed azide-acetylene cycloaddition reaction(CuAAC)to form 1,2,3-triazole,and then ring-opening rearrangement.At the same time,a molecule of nitrogen gas is released to form metallized ketene imines intermediates.After protonation,ketene imines are captured by different nucleophilic reagents to transfer various molecules.Electrophilic ketene imines have been extensively studied in nucleophilic addition,cascade reaction and cycloaddition reaction due to their high reactivity and convenient preparation.However,compared with the considerable progress in the study of electrophilic ketenimines,the transformations of nucleophilic metallized ketenimines are rare.Enaminone is a widely used synthetic synthon and has been used in the synthesis of a large number of fine molecules.In this paper,we have proved a new copper-catalyzed three-component reaction of aryl acetylene,sulfonyl azide and enaminone,involving copper-catalyzed alkyne-azide cycloaddition(CuAAC),Michael addition/elimination and 6? electrocyclization.The electrophilic ketene imines and metallized nucleophilic ketene imines were also used to form two products.Various aryl acetylenes and aryl enaminone can be used to react with sulfonyl azides to provide the desired products under mild reaction conditions.It is noteworthy that the method is also suitable for the preparation of imine coumarin analogues.Imine coumarins are commonly used as anti-cancer drugs,fluorescent indicators and dyes.In the first chapter,the progress of the reaction involving enaminone,sulfonyl ketenimine are introduced.In the second chapter,the three-component reactions of enaminone,aryl acetylene and sulfonyl azide catalyzed by copper and in the presence of base were introduced.A product was separated and its structure was determined to be iminolactone.The effects of different solvents,catalysts,bases and ligands on the reaction were investigated.The suitable range of substrates for enaminone,aryl acetylene and sulfonyl azide was screened.Medium yields were obtained under mild conditions.Some products were treated by dehydrogenation,desulfonation and hydrolysis,and the reaction mechanism for the formation of imine lactone was speculated.In the third chapter,the three-component reactions of enaminone,terminal alkyne and sulfonyl azide in the presence of copper catalyst and organic base were studied.Another product was separated and its structure was determined to be amidine.The effects of different solvents on the reaction were investigated.The suitable range of substrates for enaminone and terminal acetylene was screened.Medium to good yields were obtained under mild conditions.This method has great advantages in the synthesis of dimethylamidine.