Studies On The C-S Bond Forming Reactions Via Transition Metal-free Cross Coupling Of Enamione ?-C-H Bond

Aryl/vinyl thioethers containing C(sp~2)-S bonds are prevalent in biologically relevant molecules and compounds with other potential applications.In the past decade,rapid progress has taken place in the research area of C(sp~2)-S construction,and a large number of efficient new catalytic systems as well as structurally versatile substrates have been identified for such reactions.In this thesis,by focusing on the C-S bond forming reactions with C-H bond functionalization,we have explored and established some new synthetic methods to construct C(sp~2)-S bonds by means of the enaminone ?-C-H functionalization.First,based on our research interest in enaminone chemistry and the functionalization of C-H bonds,without using any transition metal catalyst,we have achieved the cross coupling reactions between enaminones and thiophenoles by employing potassium iodate as catalyst,which allowed the direct sulfenylation of the enaminone ?-C(sp~2)-H and established a generally applicable method for the synthesis of thio-functionalized enamines.The bio-mass available ethyl lactate has been used the as medium,which caters to the ceritaria of sustainable development.Subsequently,to extend the application of the C-S bond forming reaction on the basis of the previous work,the facile synthesis of 3-sulfenylated chromones has been realized via KIO3-catalyzed domino C-H bond sulfenylation and the subsequent C-N cleavage-based C-O bond formation with o-hydroxylphenyl functionalized enaminones and thiophenols in the environmentally benign conditions using bio-available green medium ethyl lactate(EL).Further more,we explored the source C(sp~2)-S bond formation reaction by employing different thio source.By using odourless sulfonhydrazides as the alerantive subtrates of thiophenols to react with enaminones.Based on systematic investigation,we have successfully achieved the tandem reactions between o-hydroxylphenyl enaminones and sulfonyl hydrazines for the synthesis of3-sulfenylated chromones.A class of sulfenylated chromones are furnished via the catalysis of KIO3.Finally,on the basis of the sulfonyl chromone synthesis,we have made efforts in establishing the method for synthesis 3-sulfonyl chromones via tandem reactionsinvolving C(sp~2)-H sulfonylation.After systematic screening and optimization on the reactions conditions,we developed the iodine-catalyzed method for selective synthesis of 3-sulfonyl chromones via the reactions of o-hydroxylphenyl functionalized enaminones and sulfonyl hydrazines.The reactions run at room temperature,providing a green and facile route for the synthesis of 3-sulfonyl chromones.