Ligand assisted copper-catalyzed Ullmann cross coupling reaction of bromaminic acid with amines

Three types of ligands have been developed for copper-catalyzed Ullmann cross coupling reaction of bromaminic acid with amines in aqueous solution. Ligands with large steric hindrance and strong electron-donating capacity were beneficial to the reaction. UV–Vis and CV analyses demonstrated that these ligands had strong coordination with copper(I), implying the effect of ligand coordination ability on the stability and catalytic activity of catalytic system.

Cu(OAc)_2 catalyzed Sonogashira cross-coupling reaction in amines

A simple Cu（OAc）2 catalyzed Sonogashira coupling protocol is presented. It was found that the couplings of a variety of aryl halides with terminal alkynes were conducted smoothly to afford the corresponding desired products in moderate to excellent yields, using Cu（OAc）2 as the catalyst and Et3N as the solvent.

Polybinaphthyls of (R)-3,3′-Diiodo-2,2′-binaphtho-20-crown-6 with p-Divinylbenzene via Heck Cross-coupling Reaction

The present paper deals with the polymerization of ( R ) 3,3′ diiodo 2,2′ binaphtho 20 crown 6 with \{ p divinylbenzene\} under Heck coupling reaction condition. Both the monomers and the polymer were analyzed by NMR, FTIR, UV, CD, fluorescent spectroscopy, polarimetry, GPC and elemental analysis. The polymer can emit a strong blue fluorescence and is expected to have the potential application in the polarized blue light emitting sensors. The chiral conjugated polymer exhibits a strong Cotton effect in its Circular Dichroism(CD ) spectrum, indicating the high rigidity of the polymer backbone.

Hydrogen-Assisted C-C Coupling on Reaction of CuC3H-Cluster Anion with CO

A fundamental study on C-C coupling,that is the crucial step in the Fischer-Tropsch synthesis(FTS)process to obtain multi-carbon products,is of great importance to tailor catalysts and then guide a more promising pathway.It has been demonstrated that the coupling of CO with the metal carbide can represent the early stage in the FTS process,while the related mechanism is elusive.Herein,the reactions of the CuC3H-and CuC3-cluster anions with CO have been studied by using mass spectrometry and theoretical calculations.The experimental results showed that the coupling of CO with the C3H-moiety of CuC3H can generate the exclusive ion product COC3H-.The reactivity and selectivity of this reaction of CuC3H-with CO are greatly higher than that of the reaction of CuC3-with CO,and this H-assisted C-C coupling process was rationalized by theoretical calculations.

Recent Advances of Modern Protocol for C-C Bonds—The Suzuki Cross-Coupling

Over the past 20 years, small molecule solid phase synthesis has become a powerful tool in the discovery of novel molecular materials. In the development of organic chemistry, the carbon-carbon bond formation has always been one of the most useful and fundamental reaction. The current review summarizes recent developments in metal-catalyzed coupling reactions. The following method is discussed in detail—the cross-coupling of aryl halides with aryl boronic acids (the Suzuki coupling), and the others C-C bond formation reactions as the palladium-catalyzed reaction between an aryl and (or) alkyl halide and a vinyl functionality (the Heck reaction);and the palladium-catalyzed cross-coupling reaction of organostannyl reagents with a variety of organic electrophiles (the Stille reaction)—are mentioned.

Theoretical Study on the Mechanism of Sonogashira Coupling Reaction

The mechanism of palladium-catalyzed Sonogashira cross-coupling reaction has been studied theoretically by DFT （density functional theory） calculations. The model system studied consists of Pd（PH3）2 as the starting catalyst complex, phenyl bromide as the substrate and acetylene as the terminal alkyne, without regarding to the co-catalyst and base. Mechanistically and energetically plausible catalytic cycles for the cross-coupling have been identified. The DFT analysis shows that the catalytic cycle occurs in three stages： oxidative addition of phenyl bromide to the palladium center, alkynylation of palladium（Ⅱ） intermediate, and reductive elimination to phenylacetylene. In the oxidative addition, the neutral and anionic pathways have been investigated, which could both give rise to cis-configured palladium（Ⅱ） diphosphine intermediate. Starting from the palladium（Ⅱ） diphosphine intermediate, the only identifiable pathway in alkynylation involves the dissociation of Br group and the formation of square-planar palladium（Ⅱ） intermediate, in which the phenyl and alkynyl groups are oriented cis to each other. Due to the close proximity of phenyl and alkynyl groups, the reductive elimination of phenylacetylene proceeds smoothly.

Microwave Irradiated Palladium-Catalyzed Cascade Type Cross Coupling of Phenols and Halides for the Synthesis of Polyphenolic Ethers

A mild, cascade type methodology was developed for the synthesis of polyphenolic ethers by the palladium-catalyzed cross coupling of phenols and halo compounds under microwave heating. In most cases, reactions run in neat conditions and in some cases, IPA/water mixture, and 1,4-dioxane were employed as solvents to furnish the products. By applying this new method, we were able to synthesize and purify a good number of polyether compounds with complete spectral data.

Single-atom Pd catalyst anchored on Zr-based metal-organic polyhedra for Suzuki-Miyaura cross coupling reactions in aqueous media

The challenge for single-atom catalysts in various C-C cross coupling reaction exists in the development of solid supporting materials.It has been desired tofind a supporting material designed in molecular level to anchor a single-atom catalyst and provide high degree of dispersion and substrate access in aqueous media.Here,we prepared discrete cages of metal-organic polyhedra anchoring single Pd atom(MOP-BPY(Pd))and successfully performed a Suzuki-Miyaura cross coupling reaction with various substrates in aqueous media.It was revealed that each tetrahedral cage of MOP-BPY(Pd)has 4.5 Pd atoms on average and retained its high degree of dispersion up to 3 months in water.The coupling efficiencies of the Suzuki-Miyaura cross coupling reaction exhibited more than 90.0%for various substrates we have tested in the aqueous media,which is superior to those of the molecular Pd complex and metal-organic framework(MOF)anchoring Pd atoms.Moreover,MOP-BPY(Pd)was successfully recovered and recycled without performance degradation.

Engineering single–atom active sites anchored covalent organic frameworks for efficient metallaphotoredox C-N cross–coupling reactions

Photoredox catalysis has become an indispensable solution for the synthesis of small organic molecules.However,the precise construction of single-atomic active sites not only determines the catalytic performance,but also avails the understanding of structure–activity relationship.Herein,we develop a facile approach to immobilize single-atom Ni sites anchored porous covalent organic framework(COF)by use of 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline and 2,6-diformylpyridine(Ni SAS/TD-COF).Ni SAS/TDCOF catalyst achieves excellent catalytic performance in visible-light-driven catalytic carbon–nitrogen cross-coupling reaction between aryl bromides and amines under mild conditions.The reaction provides amine products in excellent yields(71%–97%)with a wide range of substrates,including aryl and heteroaryl bromides with electron-deficient,electron-rich and neutral groups.Notably,Ni SAS/TD-COF could be recovered from the reaction mixture,corresponding to the negligible loss of photoredox performance after several cycles.This work provides a promising opportunity upon rational design of single-atomic active sites on COFs and the fundamental insight of photoredox mechanism for sustainable organic transformation.

Arylhydrazones Derivatives Containing a Benzothiazole Moiety, Efficient Ligands in the Palladium-Catalyzed Mizoroki-Heck and Suzuki-Miyaura Cross-coupling Reactions under IR Irradiation

A simple arylhydrazone containing the benzothiazole moiety which may be used as an efficient ligand in the palladium-catalyzed Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions, under infrared irradiation as an alternative source of energy, is presented. The reactions proceeded with extremely high efficiency under mild conditions and produced very good yields.

Heterogeneous h-BN@Cyclodextrin@Pd（II） Nanomaterial： Fabrication, Characterization and Application as a Highly Efficient and Recyclable Catalyst for C-C Coupling Reactions

An efficient and ligand-free method for the Suzuki and Heck cross-coupling reactions has been success- fully developed using h-BN-supported palladium as the catalyst. This green methodology represents a cost-effective and operationally convenient process for the synthesis of biaryls, stilbenes and acrylates. Wide scope of substrates, good to excellent yields, low reaction time, water as solvent, ligand-free, non-toxicity and recyclability of the catalyst are the main merits of these protocols. In addition, the h-BN@y-CD@Pd（II） nanomaterial has been fully characte- rized by TG, SEM, IR, XRD, XPS and ICP-AES analysis. And it could be easily recovered and reused for at least nine times without any considerable loss of catalytic activity. Above all, this work demonstrates the possibility of using cyclodextrin-modified h-BN as an efficient support for the hydrophilic heterogeneous catalysts.

Synthesis of N-Heterocyclic Carbine Silver(Ⅰ)and Palladium(Ⅱ)Complexes with Acylated Piperazine Linker and Catalytic Activity in Three Types of C-C Coupling Reactions

Main observation and conclusion Two bis-imidazolium salts LH_(2)·Cl_(2) and LH_(2)·(PF_(6))_(2) with acylated piperazine linker and two N-heterocyclic carbene(NHC)silver(Ⅰ)and palladium(Ⅱ)complexes[L_(2)Ag_(2)](PF_(6))_(2)(1)and[L_(2)Pd_(2)Cl_(4)](2)were prepared.The crystal structures of LH_(2)·Cl_(2) and 1 were confirmed by X-ray analysis.In 1,one 26-membered macrometallocycle was generated through two silver(Ⅰ)ions and two bidentate ligands L.The catalytic activity of 2 was investigated in Sonogashira,Heck-Mizoroki and Suzuki-Miyaura reactions.The results displayed that these C-C coupling reactions can be smoothly carried out under the catalysis of 2.

Stereoselective Synthesis of 1,3-Enynylstannanes via Palla-dium Catalyzed Cross-Coupling Reactions of (Z)-α-Bromovinylstannanes

Based on the different reactivity of stannyl and bromo groups, (Z)-α-bromovinylstannanes can undergo the cross-coupling reaction with alkynyl Grignard reagents in the presence of tetrakis(triphenylphosphine)palladium(0) catalyst in THF at room temperature to afford stereoselectively 1,3-enynylstannanes in good yields.

Cu（OAc）2/Pyrimidines-Catalyzed Cross-coupling Reactions of Aryl Iodides and Activated Aryl Bromides with Alkynes under Aerobic, Solvent-free and Palladium-free Conditions

Excellent results have been achieved in the Cu（OAc）2-catalyzed Sonogashira cross-couplings of aryl iodides and activated aryl bromides utilizing TBAF （tetrabutylammonium fluoride） as the base and 4,6-dimethoxypyrimidin-2-amine as the ligand. It is noteworthy that the reaction is conducted under aerobic, solvent-free and palladium-free conditions.

Transition-Metal-Free Allylic Defluorination Cross-Electrophile Coupling Employing Rongalite

Comprehensive Summary The conversion of CF3-alkenes to gem-difluoroalkenes using reductive cross-coupling strategy has received much attention in recent years,however,the use of green and readily available reducing salt to mediate these reactions remains to be explored.In this work,a concise construction of gem-difluoroalkenes,which requires neither a catalyst nor a metal reducing agent,was established.Rongalite,a safe and inexpensive industrial product,was employed as both a radical initiator and reductant.This procedure was compatible with both linear and cyclic diaryliodonium salts,enabling a wide variety of substrates(>70 examples).The utility of this approach was demonstrated through gram-scale synthesis and efficient late-stage functionalizations of anti-inflammatory drugs.

Elastic scattering and total reaction cross sections of^(6)Li examined via a microscopic continuum discretized coupled-channels model

We present a systematic study of 6Li elastic scattering and total reaction cross sections at incident energies around the Coulomb barrier within the continuum discretized coupled-channels(CDCC)framework,where 6Li is treated in anα+d two-body model.Collisions with 27Al,64Zn,138Ba,and 208Pa are analyzed.The microscopic optical potentials(MOP)based on Skyrme nucleon-nucleon interaction forαand d are adopted in CDCC calculations and satisfactory agreement with the experimental data is obtained without any adjustment on MOPs.For comparison,αand d global phenomenological optical potentials(GOP)are also used in CDCC analysis and a reduction of no less than 50%on the surface imaginary part of deuteron GOP is required for describing the data.In all cases,the 6Li breakup effect is significant and provides repulsive correction to the folding model potential.The reduction on the surface imaginary part of GOP of deuteron reveals a strong suppression of the reaction probability of deuteron as a component of 6Li when compared with that of a free deuteron.Further investigation is performed by considering the d breakup process equivalently within the dynamic polarization potential approach,and the results show that d behaves in a manner similar to a tightly bound nucleus in 6Li induced reactions.

A nickel-iron layered double hydroxide-supported Au catalyst for efficient electrocatalytic C-C coupling reaction coupled with H_(2) production

Coupling of cathodic H_(2) production with electrosynthesis of organic compounds not only solves the problem of sluggish oxygen evolution reaction(OER) kinetics, but also produces valuable chemicals. However, this strategy has rarely been explored for direct and selective C(sp~3)-H activation to construct C-C bonds, which could significantly enhance the synthetic efficiency in organic synthesis. Here, we report a nickel-iron layered double hydroxide-supported gold catalyst(Au/NiFe-LDH) for efficient electrocatalytic C-C coupling reaction in direct C(sp~3)-H alkynylation of tertiary aliphatic amines with 1-iodoalkynes, which is coupled with H_(2) production. Specifically, triethylamine and 1-iodoalkynes undergo efficient alkynylation to afford propargylamine in high yield(79%) and recycling ability without addition of external oxidants, coupling with 78-fold higher H_(2) productivity compared with water splitting under the same potential. This work may shed light on OER-substituted reaction towards C-C bond formation reactions under mild conditions.

Cross-coupling reaction of cy-clopropylboronic acids with a-ryl ω-halo-oxo-perfluoroalkyl-sulfonates

The cross-coupling reaction of cyclopropylbo-ronic acids with aryl ω-halo-oxo-perfluoroalkylsulfonates is investigated. It was found that the stereodefined cyclopro-pylboronic acids can readily react with aryl ω-halo-oxo-perfluoroalkylsulfonates to give the corresponding cross-coupling products in high yields under the appropriate conditions and in the presence of transition metal catalysts. For the reaction of various aryl perfluoroalkyJsulfonates bearing the substituents, the use of corresponding bases was essential. During these reactions, the cyclopropyl configurations of cyclopropylboronic acids are retained. Thus, the procedure provides a new convenient route to stereodefined cyclopropane derivatives from phenols and commerce-available ω-chloro-oxo-perfluoroalkylsulfonyl fluoride.

Palladium-phosphinous acid complexes catalyzed Suzuki cross-coupling reaction of heteroaryl bromides with phenylboronic acid in water/alcoholic solvents

Highly active, air-stable and water-soluble palladium-phosphinous acid complexes have been applied to Suzuki cross-coupling reaction of heteroaryl bromides under mild conditions in water/alcoholic solvents. Suzuki cross-coupling reaction of heteroaryl bromides with phenylboronic acid occurred efficiently using palladium phosphinous acid complexes （POPd） and phase transfer catalyst （tetrabutylammonium bromide and polyethylene glycol） in water/ethanol mixture, water/propanol mixture and neat water respectively, the corresponding yields of cross-coupling heteroaryl-aryls were satisfied. The tert-butyl substituted ligand di-tert-butylphosphino in combination with POPd was found to be more active than the same family derived catalysts dipalladium complexes POPdl and POPd2, and other two kinds of Pd-catalysts Pd（PPh3）4 and Pd2（dba）3. The mechanism of Suzuki cross-coupling reaction between heteroaryl bromides and phenylboronic acid in water was proposed with respect to the key role of phase transfer catalyst on the transmetallation step. Compared with other solid phase transfer catalysts, TBAB was tested as the ideal one. The alkalinity of base and the molar proportion between POPd and TBAB were investigated in water and alcoholic solvents. Notably, in the presence of TBAB adding alcoholic solvents into water enhanced the yields of target products. However in terms of the liquid phase transfer catalyst of PEGs, mixing water into PEGs could slightly decrease the yields with respect to the water free PEGs bulk phase, which was probably due to the homogenous liquid conditions in pure PEGs and weak interactions between PEGs and heteroaryl bromide molecules in water depending on their molecular chain lengths.

2-Aminopyridine functionalized cellulose based Pd nanoparticles： An efficient and ecofriendly catalyst for the Suzuki cross-coupling reaction

A palladium catalyst supported on 2-amino- pyridine functionalized cellulose was synthesized and fully characterized by inductively coupled plasma atomic emission spectroscopy, transmission electron microscope, Fourier transform infrared spectroscopy, thermogravi- metric analysis and X-ray photoelectron spectrometry. This catalyst can be applied in the Suzuki cross-coupling reaction of aryl halides with arylboronic acids in 50% ethanol to afford biaryls in good yields, and easily recycled by simple filtration after reaction without the loss of metal Pd.