Study On The Synthesis Of Coumar In Compounds Via Visible-Light Photocatalysis

Visible-light catalytic activation of organic molecules in recent years has attracted attention of organic chemists.Due to its inherent characteristics of sustainability and environment friendly,the direct functionalization of C-H bonds by photo-redox catalysis has become a hot topic.On the other hand,the difunctionalization of alkynes has become a powerful tool for the construction of valuable organic compounds.Because of its high efficiency in the cascade formation of carbon-carbon and carbon-heteroatom bonds.In this field,a cascade free radical cyclization reaction of a 3-position functionalized coumarin via difunctionalization of a readily available alkynoate which has proven to be an effective strategy.At the same time,the structure of bioactive molecules in natural products,pharmaceuticals anticoagulant,anti-tumor,anti-malarial,anti-HIV and antimicrobial properties has been found widely.This paper consists of four parts:（1）In this dissertation,the synthesis of free triflate based on the visible light induction of 3-trifluoromethylated coumarin was developed.In this system,using aryl alkyne as raw material,trifluoromethane sulfonyl chloride as the source of trifluoromethane,Ru（bpy）₃Cl₂ as photocatalyst,under the condition of blue light irradiation.This reaction provides a more efficient,greener,and higher yield strategy for the synthesis of 3-trifluoromethylated coumarins.Because of its mild reaction conditions,easy operation and wide applicability of substrate,this method can be used to construct coumarin compound library conveniently and quickly.（2）Synthesis of trisubstituted vinyl sulfide which the coupling reaction of aryl alkyne and disulfide promoted by visible light in this thesis.It was developed that under mild reaction conditions,the olefin skeleton was de-coupled by oxidative coupling of acetylenic ester and diphenyl disulfide without photocatalyst.The reaction can be carried out efficiently only by light,which provides an efficient,green and high yield strategy for the synthesis of enyl sulfide.（3）The synthesis of neutral formylated 3-formylcoumarin and its derivatives by visible-light redox in this thesis.The reaction of alkyne ester compounds as substrate,1,3-dioxane as a solvent,supplemented by photochemical method to give 1,3-dioxolane coumarins（acetal structure）,to be hydrolysis mechanism formyl coumarins are obtained.A new formylation method of 3-aldehyde-based coumarins has been developed.（4）In this dissertation,a cheap and easy-to-handle trifluoromethanesulfonyl chloride was used as a chlorine source for the reaction,and a carbon-chlorine bond compound was constructed in one step with isoquinoline and quinoline compounds.The reaction was carried out under simple reaction conditions using DMF as solvent at room temperature.Isoquinoline and quinoline chlorides are obtained in good yields.