Study On Photo-Induced Sulfonyl/Alkylation Of Alkenes And Alkynes

Difunctionalization of alkenes and alkynes can forge two chemical bonds in one step,thus enabling the construction of complex compounds with high efficiency.However,the control of chemoselectivity,regioselectivity and stereoselectivity of these reactions are challenging and remain underexplored.Therefore,it is of great significance to develop new catalytic systems to enable the difunctionalization of unsaturated hydrocarbons with chemo-,regio-and stereo-selectivity.This dissertation focuses on the photo-induced radical mediated difunctionalization of alkenes and alkynes,which is mainly divided into the following three parts:Part I:Utilizing the strategy of photoredox-nickel dual catalysis,we have reported a stereodivergent sulfonyl-alkenylation of alkynes with vinyl triflate and sodium sulfite under mild conditions by using Ru（dtbbpy）₃（PF₆）₂as photocatalyst,Ni（OAc）₂·4H₂O or Ni Cl₂·dppf as nickel catalysts and terpyridine or 1,10-phen as ligands.Different from previous reports,this strategy can enable the stereo-divergent synthesis of cis and trans sulfonyl 1,3-diene compounds by changing the combinations of nickels and ligands from the same set of simple starting materials.Part II:Utilizing the strategy of photoredox-nickel dual catalysis,we have achieved stereoselective dialkylation reaction of electron-deficient internal olefins by using Ni Cl₂·DME as the catalyst,tripyridine as the ligand,alkyl bromide as the coupling partner and 4-alkyl-DHP as the free radical precursor.This reaction avoids the use of sensitive metal reagents.Part III:We have developed the trans-sulfonyl heteroarylation reaction of electron-rich internal olefins with sulfinates and heteroaryl chlorides via photoactive EDA complexes,enabling construction ofβ-sulfonyl five-membered hetero-aromatic compounds with excellent regioselectivity.