Nickel-Catalyzed Selective C(sp~2)-H Bond Functionalization Assisted By N,N- And N,O-Bidentate Directing Groups

The transition-metal-catalyzed C–H bond functionalization and its specific catalytic activity have received widely attention and have achieved remarkable results in catalyzed the unactivated chemical bonds.Due to the relatively low price of nickel catalyst and naturally abundant,as well as good and specific catalytic activity,nickel-catalyzed direct functionalization of unactivated C-H bonds has aroused great interest.In recent years,the introduction of bidentate chelation-assisted organic transformation has become a powerful strategy for the regioselective functionalization of the C–H bonds.Assisted by the direction groups,the activity and orientation of the reaction can be well regulated.Based on the above research experience,my research focused mainly on selective C(sp~2)–H bond functionalization assisted by N,N-and N,O-bidentate directing groups via nickel catalyst.With the aid of these groups,the C(sp~2)–H bond of the difluoroalkylation,arylation reaction are studied and the research works are listed as follows:1.A simple nickel-catalyzed acylated(8-amino)quinoline and brominated difluoride in the presence of KHCO3 as base in 1,4-dioxane as solvent to achieve the site-selective C-H bond di?uoroalkylation of 8-aminoquinolines on the C5-position.The reaction was carried out for the first time to achieve selective C–H bond activation of 8-aminoquinoline compounds under nickel catalysis and was successfully reacted with functionalized difluoromethyl bromides and its derivatives.The reaction has broad substrate scope and provides a facile and useful access to the corresponding C5-functionalized di?uoromethylated quinolines in good to excellent yields.2.2-Benzamidopyridine 1-oxides and aromatic halides as the reaction substrates in the presence of nickel bromide as catalyst,o-nitrobenzoic acid as ligand,tetrabutyl ammonium bromide as additive,sodium carbonate as base in toluene at 150 oC can achieve the activation of aromatic amide.This method utilizes a nickel-catalyzed direct arylation to achieve a regioselective activation reaction with an aromatic amide containing N,Obidentate groups.The ortho-arylation reaction can be achieved with halogenated(iodo,bromo,chloro)aromatics.The reaction has broad substrate scope and the yield is moderate,which provides a new path for the ortho-functionalization of aromatic amide.