| Carbon-Carbon bond construction strategy has been one of the most important research areas in organic synthesis,such as Suzuki,Heck,Sonogashira,Ullmann and Tsuji-Trost reaction,which is widely used in medicines,natural products,organic functional materials and other fields.However,the traditional organic synthesis methods have some shortcomings,involving,high catalyst usage,difficulty in recycling catalyst and producing a lot of organic wastes.Therefore,much attention is focused on reducing the loading usage of catalyst,improving the utilization of catalyst and reducing environmental pollution.In recent decades,the research achievements of nanomaterials have been widely used in biomedicine,energy,environment,microelectronics,sensing,electrochemical catalysis and other fields,and have made outstanding achievements.However,research in the field of organic synthesis is only in its infancy.Compared with single-metal nanomaterials,bimetallic nanomaterials are not simple addition,but have the characteristics of adjustable composition and synergistic effect,and have unique properties.Bimetallic nanocatalyzer has the advantages of high catalytic efficiency,easy separation,recyclability,low load and low reaction cost in organic reaction.Therefore,the application of bimetallic nanomaterials to catalyze organic reactions is one of the new strategies to develop economical,green and efficient organic chemistry.In addition,visible light catalysis has recently attracted much attentions.Compared with traditional organic reactions,visible light catalysis requires green energy,simple reaction device and mild reaction conditions,thus providing a promising new way of green and energy-saving technology for organic synthesis.In this context,this paper explored the construction of C-C bond by different catalytic system,mainly includeing:1)Bimetallic nanomaterial catalysts have attracted wide attention,due to their larger specific surface area,excellent stability and catalytic performance.A large number of studies have proved that Pd is a kind of versatile catalyst with a wide range of catalytic properties,and platinum(Pt)and Pd are adjacent to each other and have similar electronic structures.The preparation of Pd and Pt into bimetallic nanomaterials is bound to have a significant effect on improving the stability and catalytic performance in organic reactions.This chapter were prepared by one-pot wet chemical method without using any seeds,templates or toxic organic solvents.The bimetallic nanomaterials showed excellent catalytic activity and compatibility for Suzuki cross-coupling reaction in water-ethanol solution without the assistant of ligand.Moreover,the catalyst can be recovered by simple thermal filtration and reused for at least 6 times without any significant reduction of catalytic activity.2)The catalytic performance of nanomaterials has a great relationship with their composition,size,structure and morphology,etc.Bimetallic nanomaterials have attracted wide attention in the field of catalysis,because of compared with single metal,their have unmatched tunability in composition and structure,showing excellent physical and chemical properties.Therefore,the design and controllable synthesis of bimetallic nanomaterials has the great significance to study the structure-activity relationship of catalysts,increase the life of catalysts and improve catalytic activity.In this context,bimetallic Pd-Cu nanowires were prepared by using ethyl phenyl polyethylene glycol(NP-40)as structure directing and stabilizing agent.The obtained bimetallic nano-catalyst showed excellent catalytic activity for the ligandless water-phase Suzuki cross-coupling reaction under mild conditions,and the catalyst was easily recovered and reused for at least 5 times without significant loss of catalytic activity.3)Biphenyls are commonly found in natural product molecules with biological activities,which are widely used in the fields,like pesticides,medicine,coatings,dyes and organic materials.As a classical method,Ullmann coupling reactions has been widely used.However,the classical Ullmann reduction coupling required the equivalent metal Cu as the catalyst,and the reaction also need to be carried out at a high temperature(>200?)In this chapter,a simple and feasible method for the controllable synthesis of bimetallic Pd-Au nano-chains was developed.The nano-catalyst showed high catalytic performance and could be reused for the coupling of aryl or alkyl halides(X=I,Br,Cl)in aqueous solutions.4)C-H bonds are common chemical bonds,which are found in almost all organic compounds.C-H bond has very high bond energy,because of the electronegativity between carbon and hydrogen elements are similar,leads to the polarity of C-H bonds is small,these factors make it has high stability The C-H under mild conditions in selective catalytic activation,build other carbon bonds exist the double challenges of thermodynamics and kinetics,is one of the key problems in chemical research.In this chapter,a graphene-supported PtPd-Pt porous nanosphere was developed,using the modified Hummers method to prepare the graphene.The morphology,composition and structure of the prepared nanomaterials were analyzed by means of transmission electron microscopy(TEM),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The characterization results confirmed that the prepared bimetallic nanomaterials were porous spherical nanomaterials.The obtained catalyst was developed to catalyze an unactivated sp3 C-H bond homo-coupling reaction,which was carried out under mild conditions without solvents,ligands,or directing groups.The results show that this catalytic system is a new strategy with high atomic economy,simple steps and low cost.5)N-Heteroarenes are among the most prevalent motifs in druglike compounds.Notably,by 2014,over 84%of FDA approved drugs contain at least one nitrogen,with 60%containing nitrogen heterocycles.In the past few decades,the functionalization of pyrimidine has made of a significant progress,one of the typical methods is Minisci reaction,however the Minisci reactions need to use strong oxidizer,and under heating conditions,the regional selectivity and functional group compatibility of traditional Minisci reactions were not satisfied.Photoredox catalyzed combined with Minisci reaction can achieve milder reaction conditions and significantly improve the reaction efficiency.However,acidic systems still limit the compatibility of functional groups and hinder the development of late functionalization of complex substrates.Hence,the selective photoredox catalyzed the alkylation of N-heterarylsulfone was investigated,and some challenging heteraryl compounds with medical value,especially sugars and unprotected amines were synthesized without acids and oxidants. |
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