Selective Intermolecular 1,2-Alkylarylation Of Alkenes And Alkynes Via Photoredox And Nickel Synergistic Catalysis

The construction of carbon-carbon(C-C)bonds is one of the most important tools in chemical synthesis,and it plays a vital role in increasing the diversity of molecules.Therefore,the development of efficient methods for C-C bond construction is of partialer interest.Unsaturated hydrocarbon is a kind of cheap,easily available and widely used chemical raw materials.Transition metal catalyzed for selective dicarbofunctionalization of alkenes and alkynes,to construct polysubstituted alkanes or olefin compounds has been widely concerned by chemists.However,this transformation still has significant challenges particularly the control of reactivity and stereoselectivity.Therefore,the development of new catalytic system to realize the efficient and selective dicarbofunctionalization reaction of alkenes and alkynes has very important significance and prospects.Based on the synergistic catalytic strategy of visible-light photoredox and nickel catalysis,this thesis focuses on developing of three-component selective alkylarylation of alkenes and alkynes,and mainly divided into the following three parts.Part Ⅰ: With tertiary alkyl cesium oxalate as the radical precursor and aryl halide as the electrophile through visible-light photoredox and nickel synergistic catalysis,the threecomponent alkyl arylation reaction of olefins was first realized.The reaction allows for the functional groups good compatibility,such as fluorine,chlorine,aldehydes,ketones,esters,sulfones,ethers,amides and heterocycles etc,and this reaction demonstrates excellent substrate scope,activated olefins,non-activated olefins,aryl halides,heterocyclic halides and various tertiary alkyl cesium oxalates allowing synthesizing of a series of complex compounds with diversified structures in good to medium yields.Part Ⅱ: With chiral BIOX ligands,the three-component alkylarylation reaction of acrylates with aryl bromides and potassium alkyl trifluoroborate was reported by the use of visible-light photoredox and nickel synergistic catalysis.This reaction can efficiently construct a series of important chiral α-aryl ester compounds with excellent yield and enantioselectivity under neutral redox conditions.Mechanism calculations and experimental studies show that the enantioselective alkylarylation reaction of olefins co-catalyzed by visible-light photoredox and nickel has undergone a Ni(0)/Ni(Ⅱ)/Ni(Ⅲ)catalytic cycle,in which free radical addition to the triplet tetrahedral Ni(Ⅱ)species is the stereoscopic determining step.Part Ⅲ: With tertiary alkyl cesium oxalate as the radical precursor and aryl halide as the electrophile through the strategy of visible-light photoredox and nickel synergistic catalysis,the stereoselective three-component alkylarylation reaction of terminal alkynes was reported for the first time.In the dual catalytic cycle reaction process,the isomerization of olefins E→Z is realized through the combination of the single electron transfer process(SET)and the triplet-triplet energy transfer process(TTET),generating thermodynamically unstable multi-substituted cis-olefins with excellent selectivity.The mild reaction conditions and good substrate applicability lay the foundation for the stereoselective difunctionalization of alkyne based on visible-light photoredox and transition metal catalysis.