[4+2] Annulation Reactions Of Allenoate And Cycloaddition Of Stable Sulfur Ylides With Coumarin Derivatives

Heterocyclic compounds are important organic compounds,more than 50%of organic compounds contain heterocycle nucleus.Especially in natural products,due to its versatile biological activities,heterocycles have play a rule role in pesticides,medicines,material chemistry and polymer chemistry and so on.More over,heterocycles are widely used in organic intermediates,organo catalysts,metal ligands,etc.In order to develop the synthetic methodology for constructing structural diverse heterocyclic compounds with potential biological activity,in this dissertation,three types of novel heterocyclic compounds were obtained by the cycloaddition reactions using the allenoate and stable sulfur ylide as substrates.Firstly,based on the properties of the allenoates,we attempt to use tertiary amine or tertiary phosphine as the catalyst in the hetero-Diels-Alder reaction of allenoates and unsaturated carbonyl compounds.In generally,allenoates can undergo cycloadditions as the C2 or C3 synthons and various cycloaddition products will be obtained.Fortunately,when1,4-enediones were used as the substrates,a series of pyran derivatives were yielded in the single configuration.Secondly,the[4+1]cycloaddition of stable sulfur ylides and coumarin imine derivatives were developed.This method takes advantages of mild condition,simple work-up,high yield as well as wide substrate scope,a series of pyrrolo[3,4-c]coumarin derivatives were generated in good yields.Moreover,the cycloadditions can also undergo successfully in "one-pot" procedure using the sulfur salts as the substrates by the addition of an equimolecular of the base.In addition,when 3-acylcoumarin derivatives were used as the substrates,a series of cyclopropancoumarin derivatives were obtained in good yields.This cycloaddition can undergo also in "one-pot" procedure using the sulfur salts as the substrates by the addition of an equimolecular of the base.