Three Component Regio-and Stereo-specific Selenosulfonylation Of Alkynes:Synthesis Of (E)-β-selenovinyl Sulfones

Vinyl sulfone compounds are basic building blocks of many bioactive molecules,and also stand for one of important intermediates in organic synthesis.Currently,the mainly synthesis methods include: oxidation of vinyl sulfide compounds,Knoevenagel condensation,β-elimination of selenosulfone or halogenated cyclosulfone,sulfonylation of alkenes/alkynes.Among them,the sulfonylation of alkynes attract much attention.The bifunctional reaction of alkynes introduce two atoms/functional groups into carboncarbon triple bonds simultaneously,and this method construct polysubstituted olefin skeleton in one step.The sulfonylation of alkynes is one of the simplest and straight routes to vinyl sulfones.At present,halosulfonylation,oxysulfonylation,carbosulfonylation and aminosulfonylation reactions of alkynes have been realized.However,these reactions are generally limited to terminal acetylenes and require high temperature.Therefore,it is of great theoretical significance and practical application value to develop new selenosulfonylation of alkynes with a wide range of substrates and mild reaction conditions.This thesis is divided into two parts:(a)copper-catalyzed selenosulfonation of alkynes,simple alkynes serve as starting materials,diphenylselenoether react as the selenium source and benzenesulfonyl hydrazine derivatives as the sulfonyl source.This reaction proceeds through: sulfonyl radical regiospecifically add to alkynes,forming a relatively stable β-sulfonyl vinyl radical.Subsequently,vinyl radical couple with phenyl selenol radical,E-β-selenide vinyl sulfone compounds are synthesized with high regio-and stereoslective.The reaction proceeds under very mild conditions and with a broad scope of substrates.The experimental operation is very simple.This reaction provides a new method for the selenosulfonylation of alkynes.(b)Selenosulfonylation of alkynes under photocatalysis.Using Eosin Y,a kind of organic dye,as photosensitizer,under the irradiation of blue light,E-β-selenide vinyl sulfones are prepared by starting with alkynes,diphenylselenoether and benzenesulfonyl hydrazine.