The Construction Of Carbon-Carbon And Carbon-Hetero Bond Via Copper Promoted C-H Functionalization

The construction of carbon-carbon bond and carbon-hetero bond is hotspot in organic synthesis and attracts more and more organic chemists,attention.Transition metal catalyzed C-H functionalization has emerged as a powerful,excellent regioselective and atom-economical strategy for the organic synthesis.Consequently,the application of transition-metal catalyzed C-H functionalization for carbon-carbon bond,carbon-hetero bond formation of small organic molecules and the synthesis of heterocyclic ring contributed to both the theory of organic chemistry development and the chemical industry application.Based on previous reports,we developed transition metal catalyzed C-H amination,arylation,silylation,phosphorylation and annulation reaction based on C-H functionalization.Firstly,copper-catalyzed C-H functionalization for C-N and C-Si bond formation were studied respectively.A facile,efficient,and simple protocol for direct oxidative C-H amination of benzoxazoles with primary amines through copper-catalyzed C-H bond activation using tert-butyl peroxide(TBP)as oxidant has been developed.A variety of substituted aminobenzoxazoles were synthesized with good to excellent yields,with the yield up to 95%.Secondary and tertiary amines were also applicable for the reaction.Meanwhile,an efficient and stereoselective synthesis of vinylsilanes via copper catalyzed direct silylation of alkenes with silanes was developed.This study may provide a low-cost and environmentally benign alternative to currently employed precious metal systems for alkene silylation.Moreover,the transformation exhibited a broad substrate scope and good functional group tolerance.Next,copper and other metal cocatalyzed C-H functionalization for C-C and C-P bond formation were studied respectively.Arylation of heterocycles has received significant attention in recent years because the heteroarenes are important structural units frequently found in biologically active molecules,organic materials,and pharmaceuticals.Consequently,an efficient protocol for regioselective arylation of thiazole derivatives at the 2-position via palladium-and copper-catalyzed C-H bond activation under ligand-free conditions was developed.Palladium inserted halogenated aromatics to achieve arylation,copper cocatalyzed to achieve selective arylation.Meanwhile,alkenylphosphine oxides and β-ketophosphonates are extremely useful classes of phosphorous-containing organic compounds,owing to their bioactivity and wide-ranging applications in various synthetically useful transformations.A copper/iron-cocatalyzed C-H phosphorylation for the synthesis of phosphine oxides was developed.Finally,cooper mediated annulation reaction based on C-H functionalization was studied.Indolizines are one of the important fused nitrogen containing heterocycles and are also an important chemical building block in synthetic,organic and biological chemistry.Due to their importance in organic and biological chemistry,the development of simple and efficient methods to prepare functionalized indolizines has become important in organic synthesis.A copper mediated radical oxidative annulation of 2-(pyridin-2-y1)acetate derivatives withα,β-unsaturated carboxylic acids was developed.Moreover,the use of copper with DTBP made this reaction system free of strong bases,poisonous ligands and additives.