Study On Visible-Light-Driven/Copper-Mediated Olefin And C(sp~3)-H Functionalization

Photoredox catalysis is one of the most prominent arenas in synthetic organic chemistry.It not only greatly enhances the synthetic value of free radical reactions,but also made possible the development of new strategies to tackle formidable synthetic problems.Ruthenium and iridium pyridinyl complexes are currently the mostly used photocatalysts for synthetic purposes.Although they are highly effective and versatile to enable various types of reactions,these noble metal complexes have the problems of high cost and toxicity,and it is highly desirable to develop new cheap and less toxic first-row transition metal catalysts to replace these noble ones.Copper complexes are one of the most promising candidates in this line,and their potential value as photocatalysts has been well demonstrated by recent studies.With an aim to develop new copper-mediated photocatalytic methods,this dissertation investigated the copper-catalyzed alkene azidation reactions and the remote C（sp³）-H functionalization of ketone oxime esters.Moreover,new copper complexes were prepared and characterized.The main contents of the paper are as follows:The first chapter is a literature review,where the recent progress made on the visible-light-driven and copper-mediated organic reactions is introduced according to the types of copper photocatalysts.The second,third,fourth and fifth chapters describe the research work of this dissertation,and the results are summarized below:（1）By using[Cu（dap）₂]PF₆ as photocatalyst and Zhdankin reagent（IBA-N₃）as the azide source and oxidant,the azidation/difunctionalization of arene alkenes was realized under visible light irradiation.It was found that the electronic nature of the substituent on the phenyl ring attached to carbon-carbon double bond has a large influence on the reaction consequence.Accordingly,three different products,which correspond to azidation/amidation,azidation/acyloxylation and diazidation,were obtained.Mechanistic investigation indicates that these products were formed via distinct pathways.（2）Visible-light-driven intramolecular cyclization and remote C（sp³）-H pentafluorobenzoyloxylation of oxime esters were realized by using[Cu（DPEphos）（bcp）]PF₆ and[Cu（dpp）₂]PF₆ as photocatalyst,respectively.The reactions were used to prepare a variety of dihydropyrrole derivatives andγ-functionalized ketone compounds.The key process in these reactions involves the generation of the iminyl radical and its subsequent intramolecular 1,5-hydrogen atom transfer.（3）Five new[Cu（I）（N^P）（N^N）]-types copper（I）complexes were synthesized and characterized.Their photochemical and electrochemical properties were investigated.These complexes not only have strong absorption in visible light region,but also exhibit strong reducing capability.（4）The cascade reactions of copper mediated alkynes and various sulfonyl chlorines were realized a series ofα,β-unsaturated pyrrolidone compounds which contained vinyl sulfone.Mechanistic investigation indicates that the reaction process involves radical pathway.The reaction provides a new strategy for the synthesis of polysubstituted pyrrolidone.