Visible Light Photocatalytic Oxidative Sulfonylation Of Alkenes With Aryl Sulfonic Acids

Vinyl sulfones containing C=C double bonds and sulfonyl group are widely used in organic synthesis as diverse intermediates and reagents.First,sulfonyl group is a strong electron-withdrawing group,therefore the C=C double bonds at vicinal positions become more electron deficient and can react with organometallic reagents and other nucleophiles.Second,sulfonyl moiety itself can be removed easily or further manipulated into other useful functional groups.Thus,the development of efficient approaches to synthesize such compounds is highly desirable.Solar light is a renewable and easily accessible energy without any pollution or toxicity.Thus the application of solar light in organic synthesis including the visible light-induced oxidation functionalization of alkenes has been one of the most important research focuses.To the best of our knowledge,there is no report about the synthesis of vinyl sulfones through visible light photoredox catalysis.In this thesis,we planed to combine TEMPO oxidation and visible light photoredox catalysis with the end of synthesizing vinyl sulfone compounds under mild conditions.First,the optimal reaction conditions were established through screening a series of reaction parameters,such as photocatalyst,solvent,base and so on.Second,substrates scope of aryl sulfonic acids and alkenes were investigated under the optimal reaction conditions.The variation of function groups on the benzene ring has no obvious influence on the reaction yield,and various substituted vinyl sulfones can be achieved under the standard conditions.All the synthesized substrates and products were characterized by NMR,M.P.and MS.Finally,a proposed mechanism was proposed according the previous literatures.