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Oxidation of m-Phenoxytoluene with Ceric Trifluoroacetate
Ceric trifluoroacetate in aqueous trifluoroacetic acid has been found to be especially effective for the oxidation of activated toluenes to the corresponding aldehydes.Ceric ion is consumed in stoichiometric amounts but can be regenerated electrochemically at high current efficiencies (95 percent).A detailed study of the oxidation of m-phenoxytoluene to m-phenoxybenzaldehyde is presented.A study of the reaction mechanism, which involves both cations and radical cations, led to a choise of cosolvents which stabilize these intermediates and thus increase the yield of aldehyde formation.
Marrocco, Matt,Brilmyer, George
p. 1487 - 1491
(1983)
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Synthesis and characterization of nano-cellulose immobilized phenanthroline-copper (I) complex as a recyclable and efficient catalyst for preparation of diaryl ethers, N-aryl amides and N-aryl heterocycles
Functionalized nanocellulose was prepared and employed for immobilization of phenanthroline-copper(I) complex to afford cellulose nanofibril grafted heterogeneous copper catalyst [CNF-phen-Cu(I)]. This nanocatalyst was well characterized using FT-IR, NMR, XRD, CHNS, AAS, TGA, EDX and SEM. The activities of the synthesized catalyst were examined in the synthesis of diaryl ethers via C-O cross-coupling of phenols and aryl iodides, as well as, the preparation of N-aryl amides and N-aryl heterocycles through C-N cross-coupling of amides and N-H heterocycle compounds with aryl halides. In this trend, various substrates containing electron-donating and electron-withdrawing groups were exploited to evaluate the generality of this catalytic protocol. Accordingly, the catalyst demonstrated remarkable catalytic efficiency for both C-N and C-O cross-coupling reactions, thereby resulting in good to excellent yields of the desired products. Furthermore, the recoverability experiments of the catalyst showed that it can be readily retrieved by simple filtration and successfully reused several times with negligible loss of its catalytic activity.
Aghili, Nora,Hosseinzadeh, Rahman,Mavvaji, Mohammad
(2022/01/03)

Ligand- and Counterion-Assisted Phenol O-Arylation with TMP-Iodonium(III) Acetates
High reactivity of trimethoxyphenyl (TMP)-iodonium(III) acetate for phenol O-arylation was achieved. It was first determined that the TMP ligand and acetate anion cooperatively enhance the electrophilic reactivity toward phenol oxygen atoms. The proposed method provides access to various diaryl ethers in significantly higher yields than the previously reported techniques. Various functional groups, including aliphatic alcohol, boronic ester, and sterically hindered groups, were tolerated during O-arylation, verifying the applicability of this ligand- and counterion-assisted strategy.
Kikushima, Kotaro,Miyamoto, Naoki,Watanabe, Kazuma,Koseki, Daichi,Kita, Yasuyuki,Dohi, Toshifumi
supporting information
p. 1924 - 1928
(2022/03/27)

Using Data Science To Guide Aryl Bromide Substrate Scope Analysis in a Ni/Photoredox-Catalyzed Cross-Coupling with Acetals as Alcohol-Derived Radical Sources
Ni/photoredox catalysis has emerged as a powerful platform for C(sp2)–C(sp3) bond formation. While many of these methods typically employ aryl bromides as the C(sp2) coupling partner, a variety of aliphatic radical sources have been investigated. In principle, these reactions enable access to the same product scaffolds, but it can be hard to discern which method to employ because nonstandardized sets of aryl bromides are used in scope evaluation. Herein, we report a Ni/photoredox-catalyzed (deutero)methylation and alkylation of aryl halides where benzaldehyde di(alkyl) acetals serve as alcohol-derived radical sources. Reaction development, mechanistic studies, and late-stage derivatization of a biologically relevant aryl chloride, fenofibrate, are presented. Then, we describe the integration of data science techniques, including DFT featurization, dimensionality reduction, and hierarchical clustering, to delineate a diverse and succinct collection of aryl bromides that is representative of the chemical space of the substrate class. By superimposing scope examples from published Ni/photoredox methods on this same chemical space, we identify areas of sparse coverage and high versus low average yields, enabling comparisons between prior art and this new method. Additionally, we demonstrate that the systematically selected scope of aryl bromides can be used to quantify population-wide reactivity trends and reveal sources of possible functional group incompatibility with supervised machine learning.
Doyle, Abigail G.,Gandhi, Shivaani S.,Jiang, Shutian,Kariofillis, Stavros K.,Martinez Alvarado, Jesus I.,?urański, Andrzej M.
supporting information
p. 1045 - 1055
(2022/01/19)

Magnetization of graphene oxide nanosheets using nickel magnetic nanoparticles as a novel support for the fabrication of copper as a practical, selective, and reusable nanocatalyst in C-C and C-O coupling reactions
Catalyst species are an important class of materials in chemistry, industry, medicine, and biotechnology. Moreover, waste recycling is an important process in green chemistry and is economically efficient. Herein, magnetic graphene oxide was synthesized using nickel magnetic nanoparticles and further applied as a novel support for the fabrication of a copper catalyst. The catalytic activity of supported copper on magnetic graphene oxide (Cu-ninhydrin@GO-Ni MNPs) was investigated as a selective, practical, and reusable nanocatalyst in the synthesis of diaryl ethers and biphenyls. Some of the obtained products were identified by NMR spectroscopy. This nanocatalyst has been characterized by atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), wavelength dispersive X-ray spectroscopy (WDX), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM) techniques. The results obtained from SEM shown that this catalyst has a nanosheet structure. Also, XRD and FT-IR analysis show that the structure of graphene oxide and nickel magnetic nanoparticles is stable during the modification of the nanoparticles and synthesis of the catalyst. The VSM curve of the catalyst shows that this catalyst can be recovered using an external magnet; therefore, it can be reused several times without a significant loss of its catalytic efficiency. The heterogeneity and stability of this nanocatalyst during organic reactions was confirmed by the hot filtration test and AAS technique.
Hajjami, Maryam,Moradi, Parisa
p. 25867 - 25879
(2021/08/09)

Solvent-free palladium-catalyzed C–O cross-coupling of aryl bromides with phenols
A new solvent-free procedure for C–O cross-coupling between phenols and aryl bromides comprising of Pd2(dba)3/ButBrettPhos catalytic system is efficient for substrates bearing donor or acceptor, as well as bulky substituents.
Asachenko, Andrey F.,Bogachev, Vasilii N.,Cherkashchenko, Ilia R.,Lavrov, Konstantin V.,Minaeva, Lidiya I.,Nechaev, Mikhail S.,Rzhevskiy, Sergey A.,Sterligov, Grigorii K.,Topchiy, Maxim A.
p. 409 - 411
(2021/06/07)

L-Proline N-oxide dihydrazides as an efficient ligand for cross-coupling reactions of aryl iodides and bromides with amines and phenols
A novel catalytic system based on L-proline N-oxide/CuI was developed and applied to the cross-coupling reactions of various N- and O- nucleophilic reagents with aryl iodides and bromides. This strategy featured in the employment of an-proline derived dihydrazides N-oxide compound as the superior supporting ligand. By using this protocol, a variety of products, including N-arylimidazoles, N-arylpyrazoles, N-arylpyrroles, N-arylamines, and aryl ethers, were synthesized with up to 99% yield.
Ding, Zhiqiang,Nie, Nan,Chen, Tian,Meng, Lingxin,Wang, Gongshu,Chen, Zhangpei,Hu, Jianshe
supporting information

(2020/12/21)

Ni-catalyzed reductive decyanation of nitriles with ethanol as the reductant
A nickel-catalyzed reductive decyanation of aromatic nitriles has been developed, in which the readily available and abundant ethanol was applied as the hydride donor. Various functional groups on the aromatic rings, such as alkoxyl, amino, imino and amide, were compatible in this catalytic protocol. Heteroaryl, benzylic and alkenyl nitriles were also tolerated. Mechanistic investigation indicated that ethanol provided hydride efficientlyviaβ-hydride elimination in this reductive decyanation.
Wu, Ke,Ling, Yichen,Sun, Nan,Hu, Baoxiang,Shen, Zhenlu,Jin, Liqun,Hu, Xinquan
supporting information
p. 2273 - 2276
(2021/03/09)

Copper nanoparticle anchored biguanidine-modified Zr-UiO-66 MOFs: a competent heterogeneous and reusable nanocatalyst in Buchwald-Hartwig and Ullmann type coupling reactions
We have designed a functionalized metal-organic framework (MOF) of UiO topology as a support, with an extremely high surface area, adjustable pore sizes and stable crystalline coordination polymeric structure and implanted copper (Cu) nanoparticles thereon. The core three dimensional Zr-derived MOF (UiO-66-NH2) was modified with a biguanidine moiety following a covalent post-functionalization approach. The morphological and physicochemical features of the material were determined using analytical methods such as FT-IR, SEM, TEM, EDX, atomic mapping, XRD and ICP-OES. The SEM and XRD results justified the unaffected morphology of Zr-MOF after structural modifications. The as-synthesized UiO-66-biguanidine/Cu nanocomposite was catalytically explored in the aryl and heteroaryl Buchwald-Hartwig C-N and Ullmann type C-O cross coupling reactions with excellent yields. A library of biaryl amine and biaryl ethers was synthesized over the catalyst under mild and green conditions. Furthermore, the catalyst was isolated by centrifugation and recycled 11 times with no significant copper leaching or change in its activity.
Veisi, Hojat,Neyestani, Narges,Pirhayati, Mozhgan,Ahany Kamangar, Sheida,Lotfi, Shahram,Tamoradi, Taiebeh,Karmakar, Bikash
p. 22278 - 22286
(2021/07/02)

Synergistic effect of copper nanocrystals-nanoparticles incorporated in a porous organic polymer for the Ullmann C-O coupling r–eaction
A quinoxaline-based porous organic polymer (Q-POP) as a mesoporous organic copolymer was developed as a new platform for the immobilization of CuNPs and copper nanocrystals. The prepared materials were characterized by FT-IR, XRD, N2 adsorption-desorption isotherms, ICP, TGA, SEM, HR-TEM, EDX, and single-crystal X-ray crystallography. The obtained catalyst presented extraordinary catalytic activity towards Ullmann C–O coupling reactions with high surface area, hierarchical porosity, and excellent thermal and chemical stability. Due to its high porosity, and synergistic effect of copper nanocrystals incorporated in the polymer composite, the as-synthesized catalyst was successfully utilized for the Ullmann C–O coupling reaction of phenols and different aryl halides to prepare various diaryl ether derivatives. All types of aryl halides (except aryl fluorides) were screened in the Ullmann C–O coupling reaction with phenols to produce diaryl ethers in good to excellent yields (70–97 %), and it was found that aryl iodides have the best results. Besides, due to the strong interactions between CuNPs, N, and O-atoms of quinoxaline moiety existing in the polymeric framework, the copper leaching from the support was not observed. Furthermore, the catalyst was recycled and reused for five consecutive runs without significant activity loss.
Gorginpour, Forough,Zali-Boeini, Hassan
(2021/02/22)

Pd-Catalyzed Etherification of Nitroarenes
The Pd-catalyzed etherification of nitroarenes with arenols has been achieved using a new rationally designed ligand. Mechanistic insights were used to design the ligand so that both the oxidative addition and reductive elimination steps of a plausible catalytic cycle were facilitated. The catalytic system established here provides direct access to a range of unsymmetrical diaryl ethers from nitroarenes.
Matsushita, Naoki,Kashihara, Myuto,Formica, Michele,Nakao, Yoshiaki
supporting information
p. 2209 - 2214
(2021/07/20)

Catalysis with magnetically retrievable and recyclable nanoparticles layered with Pd(0) for C-C/C-O coupling in water
Nanoparticles layered with palladium(0) were prepared from nano-sized magnetic Fe3O4 by coating it with silica and then reacting sequentially with phenylselenyl chloride under an N2 atmosphere and palladium(ii) chloride in water. The resulting Fe3O4?SiO2?SePh?Pd(0) NPs are magnetically retrievable and the first example of NPs in which the outermost layer of Pd(0) is mainly held by selenium. The weight percentage of Pd in the NPs was found to be 1.96 by ICP-AES. The NPs were authenticated via TEM, SEM-EDX, XPS, and powder XRD and found to be efficient as catalysts for the C-O and C-C (Suzuki-Miyaura) coupling reactions of ArBr/Cl in water. The oxidation state of Pd in the NPs having size distribution from ～12 to 18 nm was inferred as zero by XPS. They can be recycled more than seven times. The main features of the proposed protocols are their mild reaction conditions, simplicity, and efficiency as the catalyst can be separated easily from the reaction mixture by an external magnet and reused for a new reaction cycle. The optimum loading (in mol% of Pd) was found to be 0.1-1.0 and 0.01-1.0 for O-arylation and Suzuki-Miyaura coupling, respectively. For ArCl, the required amount of NPs was more as compared to that needed for ArBr. The nature of catalysis is largely heterogeneous.
Joshi, Hemant,Sharma, Alpesh K.,Singh, Ajai K.
p. 6452 - 6459
(2020/02/25)

Palladium complexes of chalcogenoethanamine (S/Se) bidentate ligands: Applications in catalytic arylation of C[sbnd]H and O[sbnd]H bonds
This report describes the syntheses of N,E (E = S, Se) coordinated bidentate palladium complexes, by the reaction of N-(2-bromobenzyl)-2-(phenylthio/selanyl)ethanamine (3, 4) with [PdCl2(CH3CN)2]. The new ligands and palladium complexes were characterized by techniques like 1H, 13C{1H} NMR, IR, and elemental analysis. The coordination modes of ligand with palladium precursor in complexes 5 and 6 were authenticated by single crystal X-ray diffraction. The complexes possess distorted square planar geometry around palladium center. Thermally robust and air stable complexes 5 and 6 were used as catalyst for regioselective arylation of imidazole and O-arylation of phenol. In case of regioselective arylation of imidazole, the reaction proceeds smoothly under mild reaction conditions, only 2.0 mol% of catalyst loading is required to achieve high yield (76–92%). This protocol is applicable to a broad substrate scope showing excellent tolerance towards different functional groups. Whereas for O-arylation of phenol also only 2.0 mol% catalyst loading is sufficient to give good yield (71–92%) with excellent tolerance towards a broad range of functional groups. Among sulfur and selenium coordinated ligands, selenium ligand coordinated complex, was found to outperform the catalytic reactions in both cases as compare to sulfur ligand. The mercury and triphenylphosphine poisoning tests suggest homogeneous nature of catalysis.
Bhatt, Ramprasad,Bhuvanesh, Nattamai,Himanshi,Joshi, Hemant,Sharma, Alpesh K.
(2020/05/18)

Ni(II) complexes of tripodal N4 ligands as catalysts for alkane hydroxylation and O-arylation of phenol: Structural and reactivity effects induced by fluoro substitution
Nickel(II) complexes [NiII(L1-2)(OAc)(H2O)][BPh4] (1–2) and [NiII(L3)(OAc)][BPh4] (3) derived from fluorinated tripodal ligands viz. N-((6-fluoropyridin-2-yl)methyl)(pyridin-2-yl)-N-(pyridin-2-ylmethyl)methanamine (L1 or FTPA), N,N′-bis((6-fluoropyridin-2-yl)methyl)(pyridin-2-yl)methanamine (L2 or F2TPA) and tris((6-fluoropyridin-2-yl)methyl)amine (L3 or F3TPA) have been synthesized and characterized by spectroscopic (UV–visible, FT-IR, paramagnetic NMR), elemental analysis, electrochemistry and X-ray diffraction techniques. In structurally similar complexes 1 and 2, Ni(II) center has a distorted octahedral coordination geometry constituted by all the four N atoms of the ligands, one acetate group and a water molecule. Complex 3 has different structural aspects. It does not have the water molecule in the coordination sphere and contains one acetate group bound with metal center in a bidentate mode. All the complexes exhibit a one-electron oxidation corresponding to the NiII/NiIII redox couple, the potential of which is influenced by the donor functionalities of ligand. These complexes catalyze the oxidation of cyclohexane efficiently (turn over number: 586–698) and selectively (alcohol to ketone ratio: 7.9:1 to 8.4:1). The study also includes the catalysis of adamantane oxidation to a mixture of ketones and alcohols. Catalytic potential of all the three complexes (1–3) has also been screened for C–O coupling reactions of phenol with aryl halides. Among them, complex 1 is more efficient than 2 and 3 for such reactions.
Kerbib, Wissame,Kumar, Arun,Kumar, Sushil,Nautiyal, Divyanshu,Singh, Siddhant
(2020/12/28)

Exhaustive Reduction of Esters Enabled by Nickel Catalysis
We report a one-step procedure to directly reduce unactivated aryl esters into their corresponding tolyl derivatives. This is achieved by an organosilane-mediated ester hydrosilylation reaction and subsequent Ni/NHC-catalyzed hydrogenolysis. The resulting conditions provide a direct and efficient alternative to multi-step procedures for this transformation that often require the use of hazardous metal hydrides. Applications in the synthesis of -CD3-containing products, derivatization of bioactive molecules, and chemoselective reduction in the presence of other C-O bonds are demonstrated.
Cook, Adam,Prakash, Sekar,Zheng, Yan-Long,Newman, Stephen G.
supporting information
p. 8109 - 8115
(2020/05/20)

Trimethoxyphenyl (TMP) as a Useful Auxiliary for in situ Formation and Reaction of Aryl(TMP)iodonium Salts: Synthesis of Diaryl Ethers
Herein, we describe a synthetic approach for arylation that exploits the in situ formation and reaction of an unsymmetrical diaryliodonium salt. In this way, aryl iodides are used as reagents in a metal-free reaction with phenols, and a trimethoxyphenyl (TMP) group is used as a “dummy” group to facilitate transfer of a wide range of aryl moieties. The scope of aryl electrophiles and phenol nucleophiles is broad (>30 examples) and the yields are high (52–95%, 80% avg.). One-pot coupling reactions avoid the synthesis of diaryliodonium salts and provide opportunities for sequential reactions and novel chemoselectivity. (Figure presented.).
Gallagher, Rory T.,Basu, Souradeep,Stuart, David R.
supporting information
p. 320 - 325
(2019/12/11)

Diaza crown-type macromocycle (kryptofix 22) functionalised carbon nanotube for efficient Ni2+ loading; A unique catalyst for cross-coupling reactions
Raising the capability of supporting and suppressing the leaching possibility to a very insignificant level has still remained challenging for some class of transition metals, i.e. Ni2+. Here we present the covalent functionalisation of macrocyclic ligand, 4,13-diaza-18-crown-6 (kryptofix 22), on the surface of carbon nanotube (CNT), leading to a unique adsorptive capability for supporting Ni2+. This material was incorporated as a promising catalyst in coupling reactions including C[sbnd]C, CN, and CO[sbnd][sbnd] cross-coupling reactions. We demonstrate that the kryptofix 22 functionalisation on the surface of CNT has a key role in the enhancement of the adsorption capability Ni2+ and subsequent catalytic activity. We further prove that this ligand causes a significant boost in the recyclability of the reactions due to the extremely trivial Ni2+ leaching from the CNT's surface during the reactions.
Aalinejad, Michael,Doustkhah, Esmail,Pesyan, Nader Noroozi
(2020/07/13)

A novel magnetic polyacrylonotrile-based palladium Core?Shell complex: A highly efficientcatalyst for Synthesis of Diaryl ethers
The present article describes the synthesis of a new magnetic polyacrylonitrile-based Pd catalyst involving polyacrylonitrile modified via 2-aminopyridine as an efficient support to immobilize Pd nanoparticles. The simple reusability, easy separation and high stability of this Pd complex make it an excellent candidate to generate a C–O bond via Ph-X activation which is a really important subject in achieving biologically active compounds. It is worth to note access to good and high yields as well as broad substrate scope have resulted from superior reactivity of this catalyst complex. Furthermore, the structure of the magnetic polyacrylonitrile-based heterogeneous catalyst was characterized by fourier transmission infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), X-ray diffraction (XRD). Also, its thermal properties were studied by thermogravimetric analysis (TGA).
Eslami, Mohammad,Jarahiyan, Atefeh,Moghaddam, Firouz Matloubi,Pourjavadi, Ali
(2020/04/15)

CoII Immobilized on Aminated Magnetic-Based Metal–Organic Framework: An Efficient Heterogeneous Nanostructured Catalyst for the C–O Cross-Coupling Reaction in Solvent-Free Conditions
Abstract: In this paper, we report the synthesis of Fe3O4?AMCA-MIL53(Al)-NH2-CoII NPs based on the metal–organic framework structures as a magnetically separable and environmentally friendly heterogeneous nanocatalyst. The prepared nanostructured catalyst efficiently promotes the C–O cross-coupling reaction in solvent-free conditions without the need for using toxic solvents and/or expensive palladium catalyst. Graphic Abstract: [Figure not available: see fulltext.].
Mohammadinezhad, Arezou,Akhlaghinia, Batool
p. 332 - 352
(2020/01/11)

Cine-Silylative Ring-Opening of α-Methyl Azacycles Enabled by the Silylium-Induced C-N Bond Cleavage
Described herein is the development of a borane-catalyzed cine-silylative ring-opening of α-methyl azacycles. This transformation involves four-step cascade processes: (i) exo-dehydrogenation of alicyclic amine, (ii) hydrosilylation of the resultant enamine, (iii) silylium-induced cis-β-amino elimination to open the ring skeleton, and (iv) hydrosilylation of the terminal olefin. The present borane catalysis also works efficiently for the C-N bond cleavage of acyclic tertiary amines. On the basis of experimental and computational studies, the silicon atom was elucidated to play a pivotal role in the β-amino elimination step.
Zhang, Jianbo,Chang, Sukbok
supporting information
p. 12585 - 12590
(2020/08/21)

Thermal Stability of 4-tert-Butyl Diphenyl Oxide
Abstract: In the temperature range of 703–763 K, the thermal stability of 4-tert-butyl diphenyl oxide (4?TBDPO) has been studied, the components of the thermolysis reaction mass have been identified, a kinetic model of the process has been proposed, and the rate constants and parameters of the Arrhenius equation for all reactions under consideration have been calculated. The predominant role of isomerization transformations of 4-TBDPO has been found. A mechanism for the radical isomerization of the tert-butyl substituent has been proposed.
Shakun,Nesterova,Tarazanov,Spiridonov
p. 2123 - 2130
(2019/11/11)

Oxalic amide ligands, and uses thereof in copper-catalyzed coupling reaction of aryl halides
The present invention provides oxalic amide ligands and uses thereof in copper-catalyzed coupling reaction of aryl halides. Specifically, the present invention provides a use of a compound represented by formula I, wherein definitions of each group are described in the specification. The compound represented by formula I can be used as a ligand in copper-catalyzed coupling reaction of aryl halides for the formation of C—N, C—O and C—S bonds.
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(2020/01/09)

HETEROCYCLIC CARBOXYLIC ACID AMIDE LIGAND AND APPLICATIONS THEREOF IN COPPER CATALYZED COUPLING REACTION OF ARYL HALOGENO SUBSTITUTE
Provided are a heterocyclic carboxylic acid amide ligand and applications thereof in a copper catalyzed coupling reaction. Specifically, provided are uses of a compound represented by formula (I), definitions of radical groups being described in the specifications. The compound represented by formula (I) can be used as the ligand in the copper catalyzed coupling reaction of the aryl halogeno substitute, and is used or catalyzing the coupling reaction for forming the aryl halogeno substitute having C—N, C—O, C—S and other bonds.
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Paragraph 0268-0270

(2019/05/15)

Design of BNPs-TAPC Palladium Complex as a Reusable Heterogeneous Nanocatalyst for the O-Arylation of Phenols and N-Arylation of Amines
The thermally stable new heterogenous nanocatalyst BNPs@SiO2(CH2)3-TAPC-O-CH2CH2NH2-Pd(0) was synthesized, characterized and successfully applied in carbon-heteroatom (C–O and C–N) coupling reactions of aryl halides with phenols and amines. The formation of resultant nanocatalyst was approved by FT-IR, XRD, TGA, XPS and EDX techniques. The morphology of BNPs@SiO2(CH2)3-TAPC-O-CH2CH2NH2-Pd(0) was characterized using scanning and transmission electron microscopes. The leaching of palladium from the surface of the catalyst was studid by ICP-OES technique. Noteworthy, the highly active BNPs@SiO2(CH2)3-TAPC-O-CH2CH2NH2-Pd(0) can be easily recycled and reused for six times with negligible loss in its activity. Some remarkable advantages of this method are the shorter reaction times, milder conditions, no needs for an inert atmosphere, high yields and easy separation. Graphical Abstract: [Figure not available: see fulltext.].
Bahrami, Kiumars,Khodamorady, Minoo
p. 688 - 698
(2019/01/04)

Preparation method of diaryl ether compound
The invention relates to a preparation method of a diaryl ether compound. Particularly, under catalysis of chitosan supported cuprous oxide, an arylation reaction used for phenols is achieved, the corresponding diaryl ether compound is obtained, the technological condition is simple, the yield is good, operability is high, and wide functional group durability is achieved.
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Paragraph 0059; 0061; 0062

(2019/06/05)

Base-Mediated O-Arylation of Alcohols and Phenols by Triarylsulfonium Triflates
A mild and efficient protocol for O-arylation of alcohols and phenols (ROH) by triarylsulfonium triflates was developed under transition-metal-free conditions. Various alcohols, including primary, secondary and tertiary, and phenols bearing either electron-donating or electron-withdrawing groups on the aryl rings were smoothly converted to form the corresponding aromatic ethers in moderate to excellent yields. The reactions were conducted at 50 or 80 °C for 24 h in the presence of a certain base and showed good functional group tolerance. The base-mediated arylation with asymmetric triarylsulfonium salts could selectively transfer the aryl groups of sulfoniums to ROH, depending on their inherent electronic nature. The mechanistic studies revealed that the reaction might proceed through the nucleophilic attack of the in situ formed alkoxy or phenoxy anions at the aromatic carbon atoms of the C?S bonds of triarylsulfonium cations to furnish the target products.
Ming, Xiao-Xia,Tian, Ze-Yu,Zhang, Cheng-Pan
supporting information
p. 3370 - 3379
(2019/11/03)

CuCl heterogenized on metformine-modified multi walled carbon nanotubes as a recyclable nanocatalyst for Ullmann-type C-O and C-N coupling reactions
Herein, a novel MWCNTs-Met/CuCl nanocatalyst synthesis method by metformine covalent grafting on the surface of carbon nanotubes and subsequent coordination with a CuCl catalyst is described. The nanocatalyst formation was analyzed by FTIR, energy dispersive spectroscopy (EDS), Raman spectroscopy and ICP analysis. The nanocatalyst morphology was examined by transmission and scanning electron microscopies (TEM and SEM). Moreover, in the N-arylation of anilines and indole, the nanocatalyst (MWCNTs-Met/CuCl) could be successfully used by formation of intermolecular C(aryl)-N bonds of the relevant aryl halides (Ar-I, Ar-Br, Ar-Cl) with amines by coupling reactions of Ullmann-type. The O-arylation of substituted phenols is also promoted by this heterogeneous copper catalyst with different aryl iodides and bromides. Additionally, without any considerable loss in activity, the novel catalyst was recovered and recycled several times.
Akhavan, Elham,Hemmati, Saba,Hekmati, Malak,Veisi, Hojat
p. 2782 - 2789
(2018/02/19)

The First C?Cl Activation in Ullmann C?O Coupling by MOFs
It was found that introduction of only 0.03 mol % Ag(I) into the framework of Cu3(BTC)2 ? xH2O in maghemite anchored CuBTC activated the inert CuBTC astonishingly to exhibit unexpected high catalytic activity for C?Cl activation in coupling of chloroarenes with phenols without the use of expensive ligands. This is the first application of mixed-metal MOFs in the C?X activation. Putting reusability and activity together, a TON over 15000 was obtained which is the highest TON compared with all its precedents even better than the results by Pd catalysts.
Ramezani, Leila,Yahyazadeh, Asieh,Sheykhan, Mehdi
p. 4636 - 4651
(2018/09/21)

Immobilized palladium nanoparticles on MNPs@A-N-AEB as an efficient catalyst for C-O bond formation in water as a green Solvent
Palladium nanoparticles immobilized on the magnetic nanoparticles@2-amino-N-(2-aminoethyl) benzamide (MNPs@A-N-AEB.Pd0) have been presented as an efficient, and reusable magnetically heterogeneous catalyst for the C-O coupling reaction, namely Ullmann condensation reactions in an aqueous medium. This heterogeneous catalyst shows superior reactivity for the C-O arylation of different aryl halide (chloride, bromide, and iodide) with phenol derivatives to afford the desired products in good to excellent yields within short reaction time. Moreover, the catalyst can be easily recovered and reused for seven runs without loss of catalytic activity. The catalyst was characterized by several techniques, such as FT-IR, SEM, TEM, EDS, XRD, TGA and ICP-OES.
Moghaddam, Firouz Matloubi,Eslami, Mohammad
(2018/08/24)

Zirconium oxide complex anchored on boehmite nanoparticles as highly reusable organometallic catalyst for C–S and C–O coupling reactions
Boehmite nanoparticles were prepared by a simple and inexpensive procedure in water using commercially available materials without inert atmosphere. Then, the surface of the boehmite nanoparticles was modified using 3-mercaptopropyltrimethoxysilane and subsequently zirconium oxide was supported on the modified surface. Zirconium oxide supported on boehmite nanoparticles (Pr.S-ZrO@boehmite) was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and inductively coupled plasma technique. The catalytic application of Pr.S-ZrO@boehmite was studied in C–O and C–S coupling reactions for synthesis of valuable compounds such as ether and sulfide derivatives. All products were obtained in good to excellent yields and the catalyst could be recovered and reused several times without significant loss of catalytic efficiency. Furthermore, zirconium oxide is rarely used as catalyst for cross-coupling reactions.
Ghorbani-Choghamarani, Arash,Seydyosefi, Zeinab,Tahmasbi, Bahman
(2018/07/31)

Decarbonylative Methylation of Aromatic Esters by a Nickel Catalyst
A Ni-catalyzed decarbonylative methylation of aromatic esters was achieved using methylaluminums as methylating agents. Dimethylaluminum chlorides uniquely worked as the methyl source. Because of the Lewis acidity of aluminum reagents, less reactive alkyl esters could also undergo the present methylation. By controlling the Lewis acidity of aluminum reagents, a chemoselective decarbonylative cross-coupling between alkyl esters and phenyl esters was successful.
Okita, Toshimasa,Muto, Kei,Yamaguchi, Junichiro
p. 3132 - 3135
(2018/05/28)

Efficient and selective hydrogenation of C-O bonds with a simple sodium formate catalyzed by nickel
A Ni-catalyzed hydrogenation of C-O compounds with sodium formate is developed. Various esters, i.e. aryl, alkenyl, benzyl pivalates, and even the aryl ethers, were efficiently reduced with a loading of nickel catalysts down to 0.5 mol%. Reactive functional groups such as C-C double bonds, carbonyl, CN, MeS and halogen groups are tolerable. This reaction can be used for the modification of complex molecules and carried out at a large scale.
Xi, Xiaoxiang,Chen, Tieqiao,Zhang, Ji-Shu,Han, Li-Biao
p. 1521 - 1524
(2018/02/19)

Synthesis and characterization of MCM-41-Biurea-Pd as a heterogeneous nanocatalyst and using its catalytic efficacy in C–C, C–N and C–O coupling reactions
MCM-41-Biurea-Pd is introduced as a new, heterogeneous and reusable catalyst for C–C and C–heteroatom bond formation between various aryl halides, phenols and amines, in the presence of Ph3SnCl (Stille reaction) in PEG-400 as a green solvent at room temperature. The structure of the functionalized MCM-41 was analysed using various techniques.
Batmani, Hana,Noroozi Pesyan, Nader,Havasi, Forugh
(2018/07/31)

Mechanism of the Ullmann Biaryl Ether Synthesis Catalyzed by Complexes of Anionic Ligands: Evidence for the Reaction of Iodoarenes with Ligated Anionic CuI Intermediates
A series of experimental studies, along with DFT calculations, are reported that provide a detailed view into the mechanism of Ullmann coupling of phenols with aryl halides in the presence of catalysts generated from Cu(I) and bidentate, anionic ligands. These studies encompass catalysts containing anionic ligands formed by deprotonation of 8-hydroxyquinoline, 2-pyridylmethyl tert-butyl ketone, and 2,2,6,6-tetramethylheptane-3,5-dione. Three-coordinate, heteroleptic species [Cu(LX)OAr]- were shown by experiment and DFT calculations to be the most stable complexes in catalytic systems containing 8-hydroxyquinoline or 2-pyridylmethyl tert-butyl ketone and to be generated reversibly in the system containing 2,2,6,6-tetramethylheptane-3,5-dione. These heteroleptic complexes were characterized by a combination of 19F NMR, 1H NMR, and UV-vis spectroscopy, as well as ESI-MS. The heteroleptic complexes generated in situ react with iodoarenes to form biaryl ethers in high yields without evidence for an aryl radical intermediate. Measurements of 13C/12C isotope effects showed that oxidative addition of the iodoarene occurs irreversibly. This information, in combination with the kinetic data, shows that oxidative addition occurs to the [Cu(LX)OAr]- complexes and is turnover-limiting. A Hammett analysis of the effect of phenoxide electronic properties on the rate of the reaction of [Cu(LX)OAr]- with iodotoluene also is consistent with oxidative addition of the iodoarene to an anionic phenoxide complex. Calculations by DFT suggest that this oxidative addition is followed by dissociation of I- and reductive elimination of the biaryl ether from the resulting neutral Cu(III) complex.
Giri, Ramesh,Brusoe, Andrew,Troshin, Konstantin,Wang, Justin Y.,Font, Marc,Hartwig, John F.
supporting information
p. 793 - 806
(2018/01/26)

Palladium(II) complexes of N, N-diphenylacetamide based thio/selenoethers and flower shaped Pd16S7 and prismatic Pd17Se15 nano-particles tailored as catalysts for C-C and C-O coupling
2-Bromo-N,N-diphenylacetamide (P1) prepared by reacting diphenylamine with α-bromoacetyl bromide, on treatment with Na2S and Na2Se generated in situ, has resulted in thio and selenoether ligands, L1 ((Ph2NCOCH2)2S) and L2 ((Ph2NCOCH2)2Se), respectively. Reacting these ligands with Na2PdCl4 in ethanol at room temperature resulted in their complexes [Pd(L1/L2)2Cl2] (C1/C2). P1, L1, L2, C1 and C2 were characterized by 1H, 13C{1H} and 77Se{1H} NMR spectroscopy, IR spectroscopy and High resolution mass spectrometry (HR-MS). Single crystal structures of all the five compounds were determined by X-ray diffraction. In both C1 and C2 the geometry of Pd is nearly square planar. Flower shaped Pd16S7 (size 26-50 nm) and prismatic Pd17Se15 NPs (size 20-55 nm) were synthesized by a single source precursor route (thermolysis at ～280 °C in trioctylphosphine) from air and moisture insensitive C1 and C2, respectively. These shapes of the two nanophases were unknown hitherto. They were characterized by powder X-ray diffraction (PXRD), SEM-EDX and HR-TEM and found to show good catalytic activity for Suzuki-Miyaura (Pd loading 0.5 mol%; yield up to 96%) and C-O (Pd loading 0.5 mol%; yield up to 96%) coupling reactions (at 100 °C) of aryl bromides with phenylboronic acid and phenol, respectively. The complexes C1 and C2 were found very efficient for Suzuki-Miyaura and C-O coupling as revealed by their optimum loading of 0.0001-0.01 and 0.1 mol% of Pd, respectively, for the two reactions. The reuse of the complexes or NPs as a catalyst is demonstrated.
Singh, Poornima,Singh, Ajai K.
supporting information
p. 10037 - 10049
(2017/08/10)

Palladacycles of sulfated and selenated Schiff bases of ferrocene-carboxaldehyde as catalysts for O-arylation and Suzuki-Miyaura coupling
Schiff base ligands (L1: sulfated and L2: selenated) having a ferrocene core synthesized by reacting ferrocene-carboxaldehyde with 2-(phenylthio/seleno)ethylamine on treatment with Na2PdCl4 in the presence of NaOAc give cyclopalladated complexes [Pd(L1/L2-H)Cl] (1/2). Complex 1 of a sulfated Schiff base L1, on reacting with one equivalent of triphenylphosphine gives complex [Pd(L1-H)PPh3Cl] (3), formed due to cleavage of a Pd-S bond. With 2 such a reaction does not occur, as a Pd-Se bond being stronger than that of its sulfur analogue does not get cleaved. L1, L2 and their complexes 1-3 were authenticated with HR-MS, 1H, 13C{1H} and 77Se{1H} NMR spectroscopy. The single crystal structures of 1-3 were determined with X-ray diffraction. Palladium in all three complexes has nearly a square planar geometry. The Pd-S, Pd-Se and Pd-P bond distances are 2.4249(12), 2.5058(14) and 2.2445(17) ? respectively. The catalytic activity of complexes 1-3 was explored for O-arylation of phenol and Suzuki-Miyaura coupling (SMC) of phenylboronic acid with aryl bromides and chlorides. The optimum reaction time for SMC of ArBr is 3 h whereas for ArCl it is 6 h. The TON values of O-arylation catalyzed with complexes 1-3 are up to ～170 (TOF, 28 h?1) and SMC ～9300 (TOF, 3100 h?1) for the reaction time of the order of 3 and 6 h respectively. The catalytic process is somewhat more efficient with 2 (Pd bonded with a selenoether group), than 3, followed by 1.
Sharma, Alpesh K.,Joshi, Hemant,Bhaskar, Renu,Kumar, Satyendra,Singh, Ajai K.
p. 2485 - 2496
(2017/03/08)

N-Picolinamides as ligands in Ullman type C–O coupling reactions
Copper-catalyzed modified Ullmann coupling reactions creating C–O bonds, including diaryl ethers or phenols, are vital to organic synthesis. Synthesized N-phenyl-2-pyridinecarboxamide and its derivatives were used as ligands in conjunction with catalytic copper sources in the formation of various diaryl ethers and phenols. Various aryl and heteroaryl halides with electron donating and withdrawing groups were reacted with various phenols under mild reaction conditions providing moderate to excellent yields.
Damkaci, Fehmi,Sigindere, Cihad,Sobiech, Thomas,Vik, Erik,Malone, Joshua
supporting information
p. 3559 - 3564
(2017/10/05)

Copper-Catalyzed Diaryl Ether Formation from (Hetero)aryl Halides at Low Catalytic Loadings
Diaryl formation is achieved by coupling phenols and (hetero)aryl halides under the catalysis of CuI/N,N′-bis(2-phenylphenyl) oxalamide (BPPO) or CuI/N-(2-phenylphenyl)-N′-benzyl oxalamide (PPBO) at 90 °C using DMF or MeCN as the solvent. Only 0.2-2 mol % CuI and ligand are required for complete conversion, which represents the lowest catalytic loadings for a general Cu/ligand-catalyzed diaryl ether formation.
Zhai, Yuntong,Chen, Xiaofei,Zhou, Wei,Fan, Mengyang,Lai, Yisheng,Ma, Dawei
p. 4964 - 4969
(2017/05/12)

Cooperative Al-H Bond Activation in DIBAL-H: Catalytic Generation of an Alumenium-Ion-Like Lewis Acid for Hydrodefluorinative Friedel-Crafts Alkylation
The Ru-S bond in Ohki-Tatsumi complexes breaks oligomeric DIBAL-H structures into their more reactive monomer. That deaggregation is coupled to heterolytic Al-H bond activation at the Ru-S bond, formally splitting the Al-H linkage into hydride and an alumenium ion. The molecular structure of these Lewis pairs was established crystallographically, revealing an additional Ru-Al interaction next to the Ru-H and Al-S bonds. That bonding situation was further analyzed by quantum-chemical calculations and is best described as a three-center-two-electron (3c2e) donor-acceptor σ(Ru-H) → Al interaction. Despite the extra stabilization of the aluminum center by the interaction with both the sulfur atom and the Ru-H bond, the hydroalane adducts are found to be stronger Lewis acids and electrophiles than the free ruthenium catalyst and DIBAL-H in its different aggregation states. Hence, the DIBAL-H molecule and its Al-H bond are activated by the Ru-S bond, but these hydroalane adducts are not to be mistaken as sulfur-stabilized alumenium ions in a strict sense. The Ohki-Tatsumi complexes catalyze C(sp3)-F bond cleavage with DIBAL-H, and the catalytic setup is applied to hydrodefluorinative Friedel-Crafts alkylations. A broad range of CF3-substituted arenes is efficiently converted into unsymmetrical diarylmethanes with various arenes as nucleophiles. Computed fluoride-ion affinities (FIAs) of the hydroalane adducts as well as DIBAL-H in its aggregation states support this experimental finding.
Forster, Francis,Mets?nen, Toni T.,Irran, Elisabeth,Hrobárik, Peter,Oestreich, Martin
supporting information
p. 16334 - 16342
(2017/11/22)

Cu2O/SiC as efficient catalyst for Ullmann coupling of phenols with aryl halides
A Cu2O/SiC heterogeneous catalyst was prepared via a two-step liquid-phase method using diethylene glycol as both the solvent and the reducing agent. The catalyst was characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and H2 temperature-programmed reduction. All the results indicate that Cu is present on the SiC support primarily as Cu2O. The SEM and TEM results show that cubic Cu2O nanoparticles are uniformly dispersed on the β-SiC surface. The reaction conditions, namely the temperature, reaction time, and amounts of base and catalyst used, for the Ullmann-type C–O cross-coupling reaction were optimized. A model reaction was performed using iodobenzene (14.0 mmol) and phenol (14.0 mmol) with Cu2O/SiC (5 wt% Cu) as the catalyst, Cs2CO3 (1.0 equiv.) as the base, and tetrahydrofuran as the solvent at 150 °C for 3 h; a yield of 97% was obtained and the turnover frequency (TOF) was 1136 h?1. The Cu2O/SiC catalyst has a broad substrate scope and can be used in Ullmann-type C–O cross-coupling reactions of aryl halides and phenols bearing a variety of different substituents. The catalyst also showed high activity in the Ullmann-type C–S cross-coupling of thiophenol with iodobenzene and substituted iodobenzenes; a TOF of 1186 h?1 was achieved. The recyclability of the Cu2O/SiC catalyst in the O-arylation of phenol with iodobenzene was investigated under the optimum conditions. The yield decreased from 97% to 64% after five cycles. The main reason for the decrease in the catalyst activity is loss of the active component, i.e., Cu2O.
Wang, Yibing,Guo, Xiaoning,Lü, Manqian,Zhai, Zhaoyang,Wang, Yingyong,Guo, Xiangyun
p. 658 - 664
(2017/04/24)

A green approach for arylation of phenols using iron catalysis in water under aerobic conditions
The first efficient iron-catalyzed coupling of aryl iodides with phenols was developed exclusively with water as solvent. The reaction is performed with low cost and readily available FeCl3·6H2O and DMEDA catalytic system providing diaryl ethers in good to excellent yields. The effectiveness of this reaction was further revealed by compatibility with a wide range of functional groups. Moreover, the procedure is rendered simple as this transformation is carried out in the presence of air. Thus, the protocol represents a facile, economical and eco-friendly procedure to access diaryl ethers.
Sindhu, Kallikkakam S.,Ujwaldev, Sankuviruthiyil M.,Keerthi Krishnan,Anilkumar, Gopinathan
p. 146 - 150
(2017/03/17)

Ullmann Reaction Catalyzed by Heterogeneous Mesoporous Copper/Manganese Oxide: A Kinetic and Mechanistic Analysis
A heterogeneous copper oxide supported on mesoporous manganese oxide (meso Cu/MnOx) was explored for Ullmann-type cross-coupling reactions. An inverse micelle-templated evaporation-induced self-assembly method with in situ addition of copper was adopted to synthesize the mesoporous catalyst. Broad substrate scope and excellent functional group tolerability in C-O, C-N, and C-S bond formation reactions were observed using the optimized reaction conditions. The catalytic protocol was ligand free, and the catalyst was reusable without any significant loss of activity. The kinetic and Hammett analyses provided evidence for oxidative addition to a Cu(I) reaction center followed by nucleophilic addition and reductive elimination at the active copper oxide surface. Rate acceleration was observed for aryl halides with electron-withdrawing groups. The Hammett analysis determined ρ = +1.0, indicative of an oxidative addition, whereas the electronic effect in the phenol ring (ρ = -2.9) was indicative of coordination to a metal ion. Theoretically, the oxidative addition of the aryl halides is assisted by the ligand environment of the copper center. Relevant mechanistic implications are discussed on the basis of the experimental and computational results.
Mullick, Kankana,Biswas, Sourav,Kim, Chiho,Ramprasad, Ramamurthy,Angeles-Boza, Alfredo M.,Suib, Steven L.
p. 10290 - 10297
(2017/09/12)

Cellulose-supported N-heterocyclic carbene silver complex with pendant ferrocenyl group for diaryl ether synthesis
A cellulose-supported N-heterocyclic carbene Ag(I) complex has been synthesized by covalent grafting of ferrocenyl ionic liquid in the matrix of cellulose followed by metallation with silver oxide. The complex was employed as a heterogeneous catalyst in the synthesis of diaryl ethers. Reactions of a variety of phenols with aryl halides afford corresponding diaryl ethers in moderate to good yields. Recyclability experiments were executed successfully for five consecutive runs.
Jagadale, Megha,Salunkhe, Rajashri,Kumbhar, Arjun,Gajare, Shivanand,Rajmane, Mohan,Rashinkar, Gajanan
(2017/03/01)

Synthesis of copper nanoparticles supported on a microporous covalent triazine polymer: An efficient and reusable catalyst for O-arylation reaction
Copper nanoparticles were supported on a microporous covalent triazine polymer prepared by the Friedel-Crafts reaction (Cu@MCTP-1). The resulting material was characterized by powder X-ray diffraction, thermogravimetric analysis, N2 adsorption-desorption isotherms at 77 K, transmission electron microscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma optical emission spectroscopy, and Cu particles with an average size of 3.0 nm and a BET total surface area of ca. 1002 m2 g-1 were obtained. Cu@MCTP-1 was evaluated as a heterogeneous catalyst for the Ullmann coupling of O-arylation over a series of aryl halides and phenols without employing expensive ligands or inert atmosphere, which produced an excellent yield of the corresponding diaryl ethers. The catalyst could be recovered by simple centrifugation and was reusable at least five times with only a slight decrease in catalytic activity.
Puthiaraj, Pillaiyar,Ahn, Wha-Seung
p. 1701 - 1709
(2016/04/05)

CuI/oxalamide catalyzed couplings of (hetero)aryl chlorides and phenols for diaryl ether formation
Couplings between (hetero)aryl chlorides and phenols can be effectively promoted by CuI in combination with an N-aryl-N′-alkyl-substituted oxalamide ligand to proceed smoothly at 120 °C. For this process, N-aryl-N′-alkyl-substituted oxalamides are more effective ligands than bis(N-aryl)-substituted oxalamides. A wide range of electron-rich and electron-poor aryl and heteroaryl chlorides gave the corresponding coupling products in good yields. Satisfactory conversions were achieved with electron-rich phenols as well as a limited range of electron-poor phenols. Catalyst and ligand loadings as low as 1.5 mol % are sufficient for the scaled-up variants of some of these reactions. Aryl and alkyl: N-Aryl-N′-alkyl-substituted oxalamide ligands promote the CuI catalyzed coupling of (hetero)aryl chlorides and phenols at 120 °C more effectively than bis(N-aryl)-substituted oxalamides. A wide range of electron-rich and electron-poor aryl and heteroaryl chlorides were converted into the corresponding coupling products in good yields.
Fan, Mengyang,Zhou, Wei,Jiang, Yongwen,Ma, Dawei
supporting information
p. 6211 - 6215
(2016/05/24)

Modular Synthesis of Arylacetic Acid Esters, Thioesters, and Amides from Aryl Ethers via Rh(II)-Catalyzed Diazo Arylation
One-pot formation of arylacetic acid esters, thioesters, and amides via Rh(II)-catalyzed arylation of a Meldrum's acid-derived diazo reagent with electron-rich arenes is described. The methodology was used to efficiently synthesize an anticancer compound.
Best, Daniel,Jean, Micka?l,Van De Weghe, Pierre
p. 7760 - 7770
(2016/09/12)

Interface Engineering in Two-Dimensional Heterostructures: Towards an Advanced Catalyst for Ullmann Couplings
The design of advanced catalysts for organic reactions is of profound significance. During such processes, electrophilicity and nucleophilicity play vital roles in the activation of chemical bonds and ultimately speed up organic reactions. Herein, we demonstrate a new way to regulate the electro- and nucleophilicity of catalysts for organic transformations. Interface engineering in two-dimensional heteronanostructures triggered electron transfer across the interface. The catalyst was thus rendered more electropositive, which led to superior performance in Ullmann reactions. In the presence of the engineered 2D Cu2S/MoS2 heteronanostructure, the coupling of iodobenzene and para-chlorophenol gave the desired product in 92 % yield under mild conditions (100 °C). Furthermore, the catalyst exhibited excellent stability as well as high recyclability with a yield of 89 % after five cycles. We propose that interface engineering could be widely employed for the development of new catalysts for organic reactions.
Sun, Xu,Deng, Haitao,Zhu, Wenguang,Yu, Zhi,Wu, Changzheng,Xie, Yi
supporting information
p. 1704 - 1709
(2016/02/03)

Ullmann diaryl ether synthesis catalyzed by copper (I)/pyridine-functionalized silane
Ullmann-type diaryl ether synthesis was performed under mild conditions in DMF/K2CO3using a pyridinefunctionalized silane as a ligand. The productswere obtained in good yields. This method tolerates a variety of functional groups and is effective in the synthesis of hindered diaryl ethers and heteroaryl ethers.
Zhang, Baohua,Shi, Lanxiang,Guo, Ruixia,Liu, Sijie
p. 930 - 932
(2016/07/06)

Orthogonal Discrimination among Functional Groups in Ullmann-Type C-O and C-N Couplings
The copper-catalyzed arylation of nucleophiles has been established as an efficient methodology for the formation of C-C and C-heteroatom bonds. Considering the advances during the last two decades, the ligand choice plays a key role in such transformations and can strongly influence the catalytic efficiency. The applicability of these Ullmann-type coupling reactions regarding the orthogonal selectivity of different functional groups constitutes a challenging subject for current synthetic strategies. Herein, we report a useful toolkit of Cu-based catalysts for the chemoselective arylation of a wide-range of nucleophiles in competitive reactions using aryl iodides and bromides. We show in this work that the arylation of all kinds of amides can be orthogonal to that of amines (aliphatic or aromatic) and phenol derivatives. This high chemoselectivity can be governed by the use of different ligands, yielding the desired coupling products under mild conditions. The selectivity trends are maintained for electronically biased iodobenzene and bromobenzene electrophiles. Radical clock experiments discard the occurrence of radical-based mechanisms.
Rovira, Mireia,Soler, Marta,Güell, Imma,Wang, Ming-Zheng,Gómez, Laura,Ribas, Xavi
supporting information
p. 7315 - 7325
(2016/09/09)

CATALYTIC SYSTEM FOR CROSS-COUPLING REACTIONS
The present invention concerns a process for creating a Carbon-Carbon bond (C—C) or a Carbon-Heteroatom bond (C—HE) by reacting a compound carrying a leaving group with a nucleophilic compound carrying a carbon atom or a heteroatom (HE) that can substitute for the leaving group, creating a C—C or C—HE bond, wherein the reaction takes place in the presence of an effective quantity of a. a catalytic system comprising a ligand and at least a metal-based catalyst, such a metal catalyst being chosen among iron or copper compounds proviso that only a single metal is present.
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Paragraph 0303; 0304

(2016/06/06)

Copper and l-sodium ascorbate catalyzed hydroxylation and aryloxylation of aryl halides
CuSO4·5H2O and NaAsc catalyzed hydroxylation and C-O/C-S cross-coupling reactions of aryl halides with phenols or 4-methylbenzenethiol were described. A wide range of substrates and test cases highlight the synthetic utility of the approach. A series of phenols, diaryl ethers, alkylaryl ethers, and diaryl thioethers were synthesized in high yield.
Song, Guang-Lin,Zhang, Zhang,Da, Yu-Xia,Wang, Xi-Cun
p. 8823 - 8829
(2015/10/20)