- Thin film formation of Pd/reduced-graphene oxide and Pd nanoparticles at oil-water interface, suitable as effective catalyst for Suzuki-Miyaura reaction in water
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A facile and efficient route was used to synthesise Pd nanoparticles by reduction of an organopalladium(ii) complex, [PdCl2(cod)] (cod = cis,cis-1,5-cyclooctadiene), at the oil-water interface. Pd/reduced-graphene oxide and Pd free stabilizer n
- Jafar Hoseini,Dehghani, Modarres,Nasrabadi, Hasan
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- Pyridylamido hafnium complexes with a silylene bridge: Synthesis and olefin polymerization
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The synthesis and characterisation of six novel Cs-symmetric pyridylamido hafnium complexes with a silylene bridge of the type [ArPy(R2Si)NAr′]HfAlk2 are reported. Four complexes have been structurally characterised using single crystal X-ray diffraction. Appreciable differences between the solid state structures of these complexes and the pyridylamido hafnium complexes with a CRR′ bridge were noted. Reactions with B(C6F5)3, [Ph3C][B(C6F5)4] and [HMe2NPh][B(C6F5)4] yielded active catalysts for the homopolymerisations of propene and 1-hexene and ethene/1-octene copolymerization. In spite of the Cs-symmetry of the precatalysts, isotactically enriched polypropylene and poly(1-hexene) were obtained. The fact that the mechanism of the catalyst activation includes the insertion of alkene into the Hf-CAr bond was demonstrated. It was found that the structures of Ar and the R2Si bridge influence the activity, molecular weight capability and 1-octene affinity of the catalysts.
- Canich, Jo Ann M.,Hagadorn, John R.,Kulyabin, Pavel S.,Uborsky, Dmitry V.,Voskoboynikov, Alexander Z.
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- Azacycle-Directed Formal Aromatic C(sp2)-H Insertion with Cr(0) Fischer Carbene Complex via Oxidative Hydrogen Migration
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An azacycle-directed intermolecular aromatic C(sp2)-H functionalization of Cr(0) Fischer carbene complexes under catalyst-free conditions is reported. Arenes with pyridines, pyrimidine, and pyrazole as directing groups reacted with chromium(0) carbene com
- Qu, Shuanglin,Tong, Wen-Yan,Wang, Jianbo,Wang, Kang,Yao, Xing-Qi
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- Synthesis of Biaryls via Benzylic C-C Bond Cleavage of Styrenes and Benzyl Alcohols
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A metal-free oxidative coupling of styrenes and benzyl alcohols with arenes has been developed for the synthesis of biaryls. The reaction features a conspicuous benzylic C-C bond cleavage of styrenes and benzyl alcohols. The reaction with both substrates proceeds through a common aldehydic intermediate formed through oxidative C-C bond cleavage of alkene and oxidation of benzyl alcohols. The reaction proceeds efficiently over a broad range of substrates with excellent functional group tolerance.
- Kumar, Arvind,Shah, Bhahwal Ali
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- Cyclometalated Palladium NHC Complexes Bearing PEG Chains for Suzuki-Miyaura Cross-Coupling in Water
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We present the synthesis and characterization of four new polyethylene glycol (PEG) substituted palladium complexes bearing a cyclometalated 2-phenylimidazole ligand and an N-heterocyclic carbene (NHC) ligand. A solid-state structure reveals the chelating binding mode and the coiling of the PEG chain in the auxiliary ligand. The PEG substitution significantly increased the solubility of the complexes in several solvents, enabling the efficient Suzuki-Miyaura cross-coupling reaction of aryl chlorides in an aqueous medium. Under optimized reaction conditions, sterically demanding biphenyl compounds with up to three ortho substituents were accessible in good to excellent yields.
- Schroeter, Felix,Soellner, Johannes,Strassner, Thomas
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- Palladium nanoparticles supported on graphene and reduced graphene oxide as efficient recyclable catalyst for the Suzuki-Miyaura reaction of potassium aryltrifluoroborates Dedicated to the memory of Prof. Carlos F. Barbas III.
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Palladium nanoparticles supported on graphene platelets have been efficiently used as catalyst in the Suzuki-Miyaura coupling between aryl bromides and potassium aryltrifluoroborates using 0.1 mol% of Pd and potassium carbonate as base in MeOH/H2O as solvent at 80 °C. The reaction can be performed using conventional and microwave heating showing the catalyst high reusability, particularly with microwaves, where lower aggregation of Pd nanoparticles has been observed. A dissolution/re-deposition catalytic mechanism is proposed, based on the fact that palladium leaching to the solution is detected under microwave irradiation.
- Gómez-Martínez, Melania,Buxaderas, Eduardo,Pastor, Isidro M.,Alonso, Diego A.
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- Silica-coated magnetic nanoparticles functionalized cobalt complex: a recyclable and efficient catalyst for the C?C bond formation
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In this study, the Co-based catalyst was prepared by cobalt immobilization on the surface of functionalized silica-coated magnetic NPs (Fe3O4@SiO2-CT-Co) as a magnetically core–shell nanocatalyst and characterized by FT-IR, TGA, XRD, VSM, SEM, TEM, EDX, EDX mapping, and ICP techniques and appraised in the Suzuki–Miyaura cross-coupling reaction under mild reaction conditions. The results displayed the superparamagnetic behavior of the Fe3O4 NPs core encapsulated by SiO2 shell, and the size of the particles was estimated about 30?nm. Compared with the previously reported catalysts, the engineered Fe3O4@SiO2-CT-Co catalyst provided perfect catalytic performance for the Suzuki–Miyaura cross-coupling reaction in water as a green solvent and it was much cheaper in the comparison with the traditional Pd-based catalysts. Importantly, the durability of magnetic nanocatalyst was studied and observed that it is stable under the reaction conditions and could be easily reused for at least six successive cycles without any significant decrease in its catalytic activity. Graphic abstract: [Figure not available: see fulltext.]
- Haqjow, Hanif,Raoufi, Farveh
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- Nickel-catalyzed cross-coupling reaction of aryl fluorides and chlorides with Grignard reagents under nickel/magnesium bimetallic cooperation
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Nickel-catalyzed cross-coupling of Grignard reagents with aryl (poly)fluorides or (poly)chlorides can be achieved efficiently in the presence of a new triarylphosphine ligand bearing a nearby hydroxy group. The high reactivity and the unique chemoselectivity (ArF > ArOTf ? ArSR) of the catalysis have been attributed to synergy of nickel and magnesium atoms preorganized on the ligand, as has been surmised on the basis of theoretical modeling of the reaction mechanism. Copyright
- Yoshikai, Naohiko,Mashima, Hiroko,Nakamura, Eiichi
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- A phosphine-free, atom-efficient cross-coupling of aryl iodides with triarylindiums or trialkynylindiums catalyzed by immobilization of palladium(0) in MCM-41
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The first phosphine-free heterogeneous atom-efficient cross-coupling reaction of aryl iodides with triarylindiums or trialkynylindiums was achieved in THF at 68 °C by using 1 mol% of MCM-41-immobilized palladium(0)-Schiff base complex [MCM-41-N,N-Pd(0)] as catalyst, yielding a variety of unsymmetrical biaryls and arylalkynes in good to excellent yields. The heterogeneous palladium(0) catalyst could easily be prepared via a simple procedure from commercially readily available reagents, and recovered by filtration of the reaction solution and recycled at least 10 times without significant loss of activity.
- Lei, Zhiwei,Liu, Haiyi,Cai, Mingzhong
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- N,N′-bis(2-pyridinecarboxamide)-1,2-benzene palladium complex as a new efficient catalyst for Suzuki-Miyaura coupling reaction under phosphane free conditions Dedicated to Professor Mehdi Rashidi
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In this article, palladium complex of N,N′-bis(2-pyridinecarboxamide) -1,2-benzene has been introduced as a new catalyst for the Suzuki-Miyaura coupling reaction of aryl halides in water. The catalyst is easily prepared from the reaction of Pd(OAc)2 and N,N′-bis(2-pyridinecarboxamide)- 1,2-benzene ligand and has been characterized using 1H NMR, TGA, FT-IR, solid and liquid UV-Vis spectroscopy.
- Gholinejad, Mohammad,Shahsavari, Hamid R.
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- Transition-metal-free highly chemo- and regioselective arylation of unactivated arenes with aryl halides over recyclable heterogeneous catalysts
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A novel heterogeneous catalysis system using metal-organic frameworks as catalyst demonstrated excellent chemo- and regioselectivity for the direct arylation of unactivated arenes with aryl iodides/bromides without the assistance of any transition metals.
- Liu, Hongli,Yin, Biaolin,Gao, Zhiqiang,Li, Yingwei,Jiang, Huanfeng
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- Switchable Complexation between (O-Methyl)6-2,6-helic[6]arene and Protonated Pyridinium Salts Controlled by Acid/Base and Photoacid
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Complexation between (O-methyl)6-2,6-helic[6]arene and protonated pyridinium salts was investigated by 1H NMR, ESI-MS, and calculations. It was found that the host and the tested guests could form stable complexes and the binding and
- Shi, Qiang,Chen, Chuan-Feng
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- Pyridine ring formation through the photoreaction of arenecarbothioamides with diene-conjugated carbonyl compounds
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Irradiation of arenecarbothioamides with hexa-2,4-dienal in benzene solution gives 2-arylpyridines in moderate yields.
- Oda, Kazuaki,Nakagami, Rikiji,Nishizono, Naozumi,Machida, Minoru
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- (N-Heterocyclic carbene) ion-pair palladium complexes: Suzuki–Miyaura cross-coupling studies in neat water under mild conditions
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The synthesis and characterization of a series of (N-heterocyclic carbene)PdCl3?(NMe3H)+ ion-pair complexes are presented. Applying the quaternary ammonium salt as the function with NHC–Pd(II) complexes yields the new ion-pair complexes. The NHC–Pd(II) ion-pair complexes work well by undergoing the Suzuki–Miyaura reaction with aryl chloride substrates in water under mild conditions in air at room temperature. Twenty products resulting from Suzuki–Miyaura coupling reactions carried out in the presence of the new NHC–Pd(II) ion-pair complex under mild optimal conditions were examined to determine the optimum yields.
- Chen, Ming-Tsz,Lin, Yu-Hsuan,Jian, Kun-Han
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- Development of a palladium-catalyzed decarboxylative cross-coupling of (2-azaaryl)carboxylates with aryl halides Dedicated to Professor Melanie Sanford on receipt of the Tetrahedron Young Investigator Award
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A catalytic method for the decarboxylative coupling of 2-(azaaryl) carboxylates with aryl halides is described. The decarboxylative cross-coupling presented is mediated by a system catalytic in both palladium and copper without requiring stoichiometric amounts of organometallic reagents or organoboronic acids. This method circumvents additional synthetic steps required to prepare 2-azaaryl organometallics and organoborates as nucleophilic coupling partners, which are prone to protodemetallation and protodeborylation and produce potentially toxic byproducts.
- Haley, Christopher K.,Gilmore, Christopher D.,Stoltz, Brian M.
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- The effects of CO2pressure and pH on the Suzuki coupling of basic nitrogen containing substrates
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The Suzuki coupling reaction of basic nitrogen containing substrates (2-bromo- and 2-chloro-4-aminopyridine, and 2-bromo and 2-chloropyridine) with phenylboronic acid using Pd(TPP)2Cl2/K3PO4in acetonitrile-water
- Senter,Rumple,Medina-Ramos,Houle,Cheng,Gelbaum,Fisk,Holden,Pollet,Eckert,Liotta, Charles L.
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- Cobalt-catalyzed cross-coupling reaction of chloropyridines with grignard reagents
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Treatment of 2-chloropyridine with benzylmagnesium chloride in the presence of a catalytic amount of cobalt(II) acetylacetonate in dioxane afforded the corresponding cross-coupling product in excellent yield. Trimethylsilylmethyl and phenyl Grignard reagents also participated in similar cross-coupling reactions.
- Ohmiya, Hirohisa,Yorimitsu, Hideki,Oshima, Koichiro
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- (Diphosphine)Nickel-catalyzed negishi cross-coupling: An experimental and theoretical study
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The use of a strongly donating "(bis-dialkylphosphine)Ni" fragment promotes the catalytic coupling of a large range of ArCl and ArZnCl derivatives under mild conditions. Stoichiometric mechanistic investigations and DFT calculations prove that a Ni0/NiII cycle is operative in this system.
- Nicolas, Emmanuel,Ohleier, Alexia,D'Accriscio, Florian,Pécharman, Anne-Frédérique,Demange, Matthieu,Ribagnac, Philippe,Ballester, Jorge,Gosmini, Corinne,Mézailles, Nicolas
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- From the grafting of NHC-based Pd(II) complexes onto TiO2 to the in situ generation of Mott-Schottky heterojunctions: The boosting effect in the Suzuki-Miyaura reaction. Do the evolved Pd NPs act as reservoirs?
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The assumption that the real active species involved in the Suzuki-Miyaura reaction are homogeneous, heterogeneous or both is often proposed. However a lack of characterization of the true catalytic entities and their monitoring makes assumptions somewhat elusive. Here, with the aim of getting new insights into the formation of active species in the Suzuki-Miyaura reaction, a family of palladium(II) complexes bearing bis(NHC) ligands was synthesized for immobilization at the surface of TiO2. The studies reveal that once the complexes are anchored onto TiO2, the mechanism governing the catalytic reaction is different from that observed for the non-anchored complexes. All complexes evolved to Pd NPs at the surface of TiO2 under reaction conditions and released Pd species in the liquid phase. Also, this reactivity was boosted by the in situ generation of Mott-Schottky heterojunctions, opening new routes towards the design of heterogenized catalysts for their further implementation in reverse-flow reactors.
- De Tovar, Jonathan,Rataboul, Franck,Djakovitch, Laurent
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- Preparation of unsymmetrical biaryls via palladium-catalyzed coupling reaction of aryl halides
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The synthesis of unsymmetrical biaryls is achieved using Pd(OAc)2 as the catalyst. A great variety of aryl halides having electron withdrawing and electron donating functional groups in para, meta and ortho positions have been successfully coupled.
- Hassan, Jwanro,Hathroubi, Chokri,Gozzi, Christel,Lemaire, Marc
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- Suzuki and sonogashira cross-coupling reactions in water medium with a reusable poly(N -vinylcarbazole)-anchored palladium(II) complex
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Poly(3,6-dibenzaldimino-N-vinylcarbazole)-anchored palladium(II) complex has been synthesized and characterized by different physicochemical and spectroscopic techniques. The present complex shows excellent catalytic activities for Suzuki and Sonogashira coupling reactions under phosphine-free and copper-free reaction conditions in water medium. This immobilized catalyst can be easily separated and reused for further reactions for more than five times without noticeable loss in the catalytic activity. Georg Thieme Verlag Stuttgart · New York.
- Islam, Manirul,Mondal, Paramita,Roy, Anupam Singha,Tuhina, Kazi
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- NC Palladacycles and C,C-chelating phosphorus ylide complexes: Synthesis, X-ray characterization, and comparison of the catalytic activity in the Suzuki-Miyaura reaction
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Six secondary amine palladacycles bearing monodentate ligands (1a, 2a), 1,2-bis(diphenylphosphino)ethane (dppe) and 1,3-bis(diphenylphosphino)propane (dppp) containing bridging and bidentate ligands (1b, 2b-d), and four C,C-type phosphorus ylide complexes containing thiourea (tu) (3a), phenyl isothiocyanate (4a), and bridging and terminal azide groups (5 and 5a) have been synthesized. Resulting complexes have been characterized by elemental analyses, IR, 1H-, 13C{1H}-, and 31P{1H}-NMR spectroscopy with single crystal X-ray structure determination of 1a and 2a. The Pd in 1a and 2a occupies the center of a slightly distorted square planar environment formed by Caryl, Namine, Npyridine, and Cl. The catalytic efficiency of complexes showed that in most cases, amine palladacycles display better catalytic activities than the phosphorus ylide Pd(II) complexes. Comparison between bidentate and bridging dppe complexes showed that dppe-bridged dimer 2d has higher catalytic activity than dppe bidentate complex.
- Karami, Kazem,Hosseini-Kharat, Mahboubeh,Shirani-Sarmazeh, Zahra,Zahedi-Nasab, Reza,Rizzoli, Corrado,Lipkowski, Janusz
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- Efficient chromium(II)-catalyzed cross-coupling reactions between Csp 2 centers
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Low-toxicity chromium(II) chloride catalyzes at 25 C within minutes the coupling reactions of various (hetero)arylmagnesium reagents with N-heterocyclic halides, aromatic halogenated ketones or imines, and alkenyl iodides. Remarkably, much lower amounts o
- Steib, Andreas K.,Kuzmina, Olesya M.,Fernandez, Sarah,Flubacher, Dietmar,Knochel, Paul
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- Visible-Light-Driven C4-Selective Alkylation of Pyridinium Derivatives with Alkyl Bromides
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Reported herein is a general strategy for the photochemical cross-coupling between N-amidopyridinium salts and various alkyl bromides under photocatalyst-free conditions, granting facile access to various C4-alkylated pyridines. This approach exploits the intriguing photochemical activity of electron donor-acceptor (EDA) complexes between N-amidopyridinium salts and bromide, which provides a photoactive handle capable of generating silyl radicals and driving the alkylation process. The robustness of this protocol was further demonstrated by the late-stage functionalization of complex compounds under mild and metal-free conditions.
- Hong, Sungwoo,Jung, Sungwoo,Park, Seongjin,Shin, Sanghoon
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- Pd-catalyzed cross-coupling reactions of arenediazonium salts with arylsilanes and aryltrifluoroborates in water
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Pd-catalyzed cross-coupling reactions of various arenediazonium salts with ArSi(OR)3 and KArBF3 have been achieved in good to excellent yields under simple aerobic conditions in water at room temperature. The functional group tolerance makes these transformations as attractive alternatives to the traditional cross-coupling approaches. Furthermore, the sequence can also be performed in a one-pot domino process, omitting the isolation of the intermediate arenediazonium salt.
- Cheng, Kai,Zhao, Baoli,Hu, Sai,Zhang, Xian-Man,Qi, Chenze
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- A practical synthesis of biaryls and aromatic acetylenes by stille coupling in room-temperature ionic liquids
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The Stille cross-coupling reactions of aryl halides with aryl or alkynylstannanes have been achieved under mild conditions in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), affording the corresponding biaryls and aromatic acetylenes in good yields. Use of this solvent allows for facile recycling of the solvent and catalyst system, which can be used at least five times without loss of activity.
- Hao, Wenyan,Xi, Zhiwen,Cai, Mingzhong
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- Sustainable synthesis of quinolines (pyridines) catalyzed by a cheap metal Mn(I)-NN complex catalyst
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This study represents the first example of a bidentate phosphine-free manganese(I)-NN complex catalyst for the synthesis of quinolines (pyridines) through acceptorless dehydrogenative condensation of various secondary alcohols with amino alcohols. The coupling reactions occurred at 3 mol% catalyst loading and 110°C, and tolerated diverse functional groups. Moderate to excellent yields ranging from 45% to 89% were achieved after 12 hr of reaction. The present protocol provides a concise and environmentally friendly method for the construction of heterocyclic compounds.
- Chai, Huining,Tan, Weiqiang,Lu, Yuanyuan,Zhang, Guangyao,Ma, Jiping
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- Immobilization of Pd(II) on MOFs as a highly active heterogeneous catalyst for Suzuki-Miyaura and Ullmann-type coupling reactions
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Palladium chloride was successfully immobilized on MOF-253, a MOF material with un-coordinated 2,2′-bipyridine moieties, through post-synthetic modification. The coordination interaction between the 2,2′-bipyridine moieties and Pd cations in the MOF-253·PdCl2 material was demonstrated by X-ray photoelectron spectroscopy (XPS) analysis. The prepared MOF-253·0.05PdCl2 was shown to be highly active, selective, and recyclable for the Suzuki-Miyaura cross-coupling and Ullmann homocoupling of a wide range of aryl halides including electron-rich and electron-poor aryl iodides/bromides, heteroaryl iodides, and even aryl chlorides, affording the corresponding biaryl compounds in good to excellent yields under mild reaction conditions. It is suggested that the 2,2′-bipyridine moieties in MOF-253 provide electron-rich environment for Pd(II) cations, and thus facilitate the initial adsorption and insertion of aryl halides molecules to Pd active sites during the carbon-carbon coupling reactions. Moreover, MOF-253·PdCl2 showed remarkably higher activity than the homogeneous Pd(bpy)Cl2 and PdCl2(CH3CN)2, which might be due to the presence of charge transfers between adjacent ligands and metals in the MOF catalyst. The superior catalytic performances of metal ions immobilized on MOFs to their homogenous counterparts might bring new opportunities in the development of highly efficient metal catalysts combining advantages of both homogeneous and heterogeneous catalysis.
- Chen, Liyu,Gao, Zhiqiang,Li, Yingwei
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- Monosubstituted, Anionic Imidazolyl Ligands from N?H NHC Precursors and Their Activity in Pd-Catalyzed Cross-Coupling Reactions
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We report that treatment of several 2-diphenylphosphinoimidazoles with Pd(II) salts generates monosubstituted N?H NHC?Pd complexes via insertion into the C?P bond. Removal of the N?H proton in situ leads to anionic (X-type) or imidazolyl-Pd complexes that are highly stable and catalytically active, achieving up to 340,000 turnovers at 1 ppm catalyst loading in Suzuki-Miyaura reactions. DFT-calculated Tolman electronic parameters for the sterically small ligands suggest that these ligands are significantly more donating than traditional NHCs, which provides a rationale for rapid cross-coupling catalysis. Excellent reactivity is also demonstrated in Sonogashira reactions. (Figure presented.).
- Clark, Kyle J.,Ess, Daniel H.,Jensen, Christopher A.,Kenney, Karissa C.,Larson, Alexandra J. S.,Martinez, Erin E.,Michaelis, David J.,Nazari, S. Hadi,Smith, Stacey J.,Valdivia-Berroeta, Gabriel A.
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- Efficient cross-coupling reactions of aryl chlorides and bromides with phenyl- or vinyltrimethoxysilane mediated by a palladium/imidazolium chloride system
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diagram presented A combination of palladium acetate and the imidazolium salt IPr-HCI (1, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) has proven to be highly efficient in the cross coupling reactions of aryl bromides and electron-deficient aryl chlorides with phenyltrimethoxysilane or vinyltrimethoxysilane. The catalytic performance of this system was found to be comparable to that of systems using PCy3 and P(o-tol)3.
- Lee, Hon Man,Nolan, Steven P.
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- Dibenzofuran and dibenzothiophene based palladium(ii)/NHC catalysts-synthesis and applications in C-C bond formation
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In the quest for a new ligand system for Pd(ii)/NHCs, we developed new dibenzofuran and dibenzothiophene based palladium N-heterocyclic carbene catalysts D1-D6 in good yields. All the catalysts were characterized by multinuclear NMR spectroscopy and HRMS. The X-ray crystal structure of the representative dibenzothiophene based Pd(ii)/NHC D4 was determined. Among the precatalysts, D1 was shown to be highly effective in the Suzuki-Miyaura cross-coupling reaction of heterocyclic bromides with boronic acids. Besides, D1 affords diverse arylated benzoxazoles via direct C-H bond functionalization with substituted bromo derivatives.
- Karthik, Shanmugam,Gandhi, Thirumanavelan
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- Polystyrene-anchored Palladium(II) complex as an efficient and reusable catalyst for suzuki cross-coupling reaction in water medium
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A new polystyrene-anchored palladium(II) catalyst has been prepared and characterized by conventional spectroscopic methods and elemental analyses. The catalyst was found to be highly effective for the Suzuki cross-coupling reactions of aryl halides with arylboronic acid in water medium under phosphinefree reaction conditions. The optimal reaction conditions of the coupling were determined. The present heterogeneous Pd(II) catalyst was reusable as well as air-stable to allow easy use.
- Islam, Maninil,Mondal, Paramita,Tuhina, Kazi,Hossain, Dildar,Roy, Anupam Singha
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- Palladium nanoparticles on amphiphilic carbon spheres: A green catalyst for Suzuki-Miyaura reaction
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We report the use of palladium nanoparticles stabilized on amphiphilic glucose-derived carbon spheres as heterogeneous catalysts for Suzuki-Miyaura reactions. Reactions of aryl halides with various boronic acids in the presence of different bases and solvents including organic polar, non-polar and water as sole solvent without the aid of phase-transfer catalysts, under phosphine-free and aerobic conditions have been studied. Especially, deactivated aryl bromides and activated aryl chlorides afforded good isolated yields in pure water. The catalyst was reused for up to four cycles without any marked loss in the activity. Copyright
- Putta, Chandra Babu,Ghosh, Sutapa
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- Pd(0)-catalyzed Cu(I)-thiophene-2-carboxylate-mediated cross-coupling of heteroaromatic thioethers and boronic acids - First Liebeskind-Srogl reaction in water
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The first example of a Liebeskind-Srogl cross-coupling reaction in water as sole reaction solvent is reported. 2-(Methylthio)pyridine and 2-(methylthio)benzothiazole were reacted in the presence of a Pd(0) catalyst and copper(I) thiophene-2-carboxylate with a series of arylboronic acids. These cross coupling reactions in water proceeded well with electron-rich boronic acids and gave comparable yields to literature examples using organic solvents. Electron-poor boronic acids gave somewhat lower yields in aqueous medium.
- Koley, Moumita,Wimmer, Laurin,Schnuerch, Michael,Mihovilovic, Marko D.
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- Didocosyl selenide stabilized recyclable Pd(0) nanoparticles and coordinated palladium(ii) as efficient catalysts for Suzuki-Miyaura coupling
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First selenium ligand stabilized Pd(0) nanoparticles (~3-5 nm) catalyze Suzuki-Miyaura C-C coupling in short time and are recyclable (up to 94% yield after 5 reuses). The air stable compound [PdCl2(L1)2] shows high catalytic efficien
- Rao, Gyandshwar Kumar,Kumar, Arun,Kumar, Bharat,Singh, Ajai K.
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- Cross-coupling reaction of organobismuth dialkoxides with aryl bromides and iodides catalyzed by Pd(PPh3)4
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Cross-coupling reaction of organobismuth compounds bearing 2,6-pyridinedimethoxide ligands with aryl bromides and iodides was efficiently catalyzed by Pd(PPh3)4. Addition of two equivalents of Cs2CO3 or CsF impr
- Rao, Maddali L.N.,Shimada, Shigeru,Yamazaki, Osamu,Tanaka, Masato
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- Heterogeneous Suzuki and copper-free Sonogashira cross-coupling reactions catalyzed by a reusable palladium(II) complex in water medium
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A new polystyrene anchored Pd(II) azo complex has been synthesized and characterized. The present Pd(II) azo complex behaves as a very efficient heterogeneous catalyst in the Suzuki coupling and Sonogashira coupling reaction in water medium. Aryl halides, coupled with phenylboronic acids (Suzuki-Miyaura reaction) or terminal alkyne (Sonogashira reaction), smoothly afford the corresponding cross-coupling products in excellent yields (83-100% yield for Suzuki reaction and 68-96% yield for Sonogashira reaction of aryl halides) under phosphine-free reaction conditions in the presence of polystyrene anchored Pd(II) azo complex catalyst in water medium. Furthermore, the catalyst has shown good thermal stability and recyclability. This polymer-supported Pd(II) catalyst could be easily recovered by simple filtration of the reaction mixture and reused for more than six consecutive trials without a significant loss of its catalytic activity.
- Islam,Mondal, Paramita,Roy, Anupam Singha,Mondal, Sanchita,Hossain, Dilder
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- Rhodium-catalyzed cross-coupling of aryl carbamates with arylboron reagents
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A new method has been developed for the rhodium-catalyzed cross-coupling of aryl carbamates with organoboron reagents. The use of an NHC ligand bearing a 2-adamantyl group, i.e., I(2-Ad), is essential to the success of the reaction. The reaction involves the rhodium-mediated activation of the relatively inert C(aryl)-O bond of aryl carbamates.
- Nakamura, Keisuke,Yasui, Kosuke,Tobisu, Mamoru,Chatani, Naoto
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- Synthesis of 3-Arylbenzofuran-2-ylphosphines via Rhodium-Catalyzed Redox-Neutral C-H Activation and Their Applications in Palladium-Catalyzed Cross-Coupling of Aryl Chlorides
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A new class of aryl-heteroarylphosphines, 3-arylbenzofuran-2-ylphosphines, was synthesized by [Cp?Rh(III)]-catalyzed redox-neutral cyclization of N-phenoxyacetamides with 1-alkynylphosphine sulfides and oxides followed by reduction. This step-economic reaction proceeds in excellent regioselectivity with a broad substrate scope. The application of the resulting air-stable trivalent-phosphine containing dicyclohexylphosphino moiety in palladium-catalyzed Suzuki-Miyaura coupling and Buchwald-Hartwig amination of aryl chlorides is also described.
- Wang, Huanan,Wang, Baiquan,Li, Bin
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- Electrochemical synthesis of Pd nano particles on pencil- graphite and application for suzuki coupling reactions
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Synthesis of Pd nano particles by electrochemical deposition on pencil graphite has been carried out. Catalytic activity of these nanoparticles was tested for Suzuki coupling reactions. The heterogeneous catalyst was synthesized in 10 s and without use of hazardous reducing reagent. The catalyst showed excellent catalytic performance towards Suzuki cross coupling reaction in aqueous medium. The catalyst was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive X-ray analysis, thermo gravimetric analysis, inductively coupled plasma and EDX mapping techniques. Pd nano particles were found to have monodispersed nature with average particle size of 9-10 nm in diameter. The developed catalyst can be recycled up to five cycles without significant decrease in the product yield.
- Balsane, Kishor E.,Shelkar, Radheshyam S.,Nagarkar, Jayashree M.
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- β-Oxo amides: Inexpensive and efficient ligands for the palladium-catalyzed Suzuki-Miyaura cross-coupling reaction
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β-Oxo amides were found to be inexpensive and efficient ligands for the palladium-catalyzed Suzuki-Miyaura cross-coupling reaction. In the presence of palladium(II) acetate and N-(4-methoxyphenyl)-3-oxobutanamide (L7), a variety of aryl halides, including deactivated aryl chlorides and heteroaryl halides, were successfully coupled to arylboronic acids in moderate to excellent yields providing very high turnover numbers (maximum TON 950,000 and TOF 79,167). It is noteworthy that the reaction is conducted under mild and aerobic conditions. Georg Thieme Verlag Stuttgart.
- Li, Jin-Heng,Zhang, Yue-Hua,Song, Ren-Jie,Xie, Ye-Xiang,Deng, Chen-Liang,Liang, Yun
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- An efficient and reusable polymer-supported palladium catalyst for the Suzuki cross-coupling reactions of aryl halides
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A reusable, air-stable polymer-anchored palladium (II) Schiff base complex catalyst, P-[{(NCH)C6H4}Pd(OAc)]2 was prepared and was found to be highly active in Suzuki cross-coupling reactions of aryl halides with phenyl boronic acid in an aqueous medium to give biaryl products in high yields.
- Islam,Mondal,Roy, A. Singha,Mondal,Mobarak
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- Selectivity in palladium(0)-catalyzed cross-coupling reactions: Application to a tandem Stille reaction
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A tandem palladium-catalyzed cross-coupling reaction between a pyridyl triflate 1a and a variety of aryl bromides mediated by hexamethylditin is described. The reaction apparently proceeds via the intermediacy of the labile pyridylstannane 1b indicating that the oxidative addition of palladium(0) to the triflate, subsequent transmetalation with hexamethylditin and reductive elimination occurs selectively in the presence of the aryl halide.
- Hitchcock,Mayhugh,Gregory
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- Palladium(0)-mediated C-H bond activation of N-(naphthyl)salicylaldimine and related ligands: utilization of the resulting organopalladium complexes in catalytic C-C and C-N coupling reactions
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N-(Naphthyl)-4-R-salicylaldimines (R = OCH3, H and Cl; H2L1-H2L3) and 2-hydroxy-N-(naphthyl)naphthaldimine (H2L4) readily undergo, upon reaction with Na2[PdCl4] in the presence of triphenylphosphine, cyclopalladation via C-H bond activation at the peri-position to afford complexes of type [Pd(L)(PPh3)] (L = L1-L4). The C-H bond activation has been found to be mediated by palladium(0) formed in situ. A similar reaction of H2L1 with Na2[PdCl4] in the presence of 1,2-bis(diphenylphosphino)ethane (dppe), in a 2 : 2 : 1 mole ratio, yields a dinuclear complex of type [{Pd(L1)}2(dppe)]. Reaction of H2L1 with Na2[PdCl4] in the presence of 4-picoline (pic) yields [Pd(L1)(pic)]. The molecular structures of the six complexes have been determined by X-ray crystallography. The aldiminate ligand in each compound is coordinated to the metal center as a di-anionic tridentate ONC-donor, with the fourth coordination site occupied by a phosphine or picoline ligand. The new complexes show intense absorptions in the visible and ultraviolet regions, and the nature of the optical transitions has been analyzed by TDDFT calculations. The palladium complexes display notable efficiency in catalyzing C-C and C-N bond coupling reactions. The thermodynamics for the formation of the cyclometalated catalyst precursor [Pd(L2)(PPh3)] has been evaluated by DFT calculations.
- Dutta, Jayita,Richmond, Michael G.,Bhattacharya, Samaresh
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- Towards environmentally friendlier Suzuki-Miyaura reactions with precursors of Pd-NHC (NHC = N-heterocyclic carbene) complexes
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The preparation of [NHC·H][Pd(η3-R-allyl)Cl2] complexes is disclosed and represents a facile, atom-economical, environmentally friendly and rapid synthesis. These palladates are immediate synthetic precursors to the well-known [Pd(NHC)(η3-R-allyl)Cl] complexes. Their activation leading to catalytically relevant species has been studied in the Suzuki-Miyaura reaction. The need for an activation step prior to the catalysis was examined. The reaction scope showcases its ease and breadth in terms of functional group tolerance. Electron-donating and electron-withdrawing aryl chlorides and bromides were coupled effectively as well as heteroatom-containing and sterically hindered aryl halides. The catalytic reaction was conducted in ethanol with a weak and inexpensive inorganic base.
- Zinser, Caroline M.,Warren, Katie G.,Meadows, Rebecca E.,Nahra, Fady,Al-Majid, Abdullah M.,Barakat, Assem,Islam, Mohammad S.,Nolan, Steven P.,Cazin, Catherine S. J.
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- Stereoselective sp2-sp2 bond formation via Negishi cross-coupling of vinylic tellurides and 2-heteroarylzinc chlorides
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The Negishi cross-coupling reaction of vinylic- and aryltellurides with heteroarylzinc chlorides catalyzed by PdCl2/CuI is described. This cross-coupling reaction is general and permits the formation of a new sp 2-sp2 carbon bond in good yields and high stereoselectivity.
- Zeni, Gilson,Alves, Diego,Braga, Antonio L.,Stefani, Helio A.,Nogueira, Cristina W.
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- Reduced graphene oxide supported Ni nanoparticles: A high performance reusable heterogeneous catalyst for Kumada-Corriu cross-coupling reactions
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Reduced graphene oxide (RGO) has emerged as an excellent 2D catalyst support. A high concentration of air stable Ni(0) nanoparticles (~40 wt%) of average size 11 nm can be loaded on reduced graphene oxide. In this article Kumada-Corriu cross-coupling reactions have been studied extensively using RGO supported 40 wt% Ni nanoparticles (Ni/RGO-40) as a heterogeneous catalyst. The reaction conditions were optimized by performing the cross-coupling between 4-iodoanisole and phenylmagnesium chloride in the presence of a catalytic amount of Ni/RGO-40. A detailed study of the catalysis was performed by varying the haloarenes and Grignard reagents under the optimized conditions with yields of 91-72%. The products were characterized by 1H and 13C NMR spectroscopy. The catalyst was found to be significantly reusable. Finally the recovered Ni/RGO-40 was characterized by X-ray diffraction (XRD) and Raman spectroscopy and found to be unaffected. Considering the catalytic performance, reusability and economic reasons, Ni/RGO-40 can be of technological importance.
- Bhowmik, Koushik,Sengupta, Debasish,Basu, Basudeb,De, Goutam
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- The effect of some additives on the Stille Pd0-catalyzed cross-coupling reaction
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It has been found that the addition of cupric oxide to the cross-coupling reaction (Stille reaction) of 2-tributylstannylpyridine with various halobenzenes and heterocyclic halides leads to a much faster reaction and higher yields. This is also the case for the formation of thieno-1,6-naphthyridine from 2-(2-trimethylstannyl-3-pyridyl)-1,3-dioxolane and t-butyl-N-(2-bromo-3-thienyl)carbamate.
- Gronowitz, Salo,Bjoerk, Patrick,Malm, Johan,Hoernfeldt, Anna-Britta
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- Evaluation of P-bridged biaryl phosphine ligands in palladium-catalysed Suzuki-Miyaura cross-coupling reactions
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A family of biaryl phosphacyclic ligands derived from phobane and phosphatrioxa-adamantane frameworks is described. The rigid biaryl phosphacycles are efficient for Suzuki-Miyaura cross-coupling of aryl bromides and chlorides. In particular, coupling reactions of the challenging sterically hindered and heterocyclic substrates were viable at room temperature.
- Holzapfel, Cedric W.,Lamola, Jairus L.,Maumela, Munaka Christopher,Moshapo, Paseka T.
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p. 26883 - 26891
(2021/08/17)
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- Fe3O4-SAHPG-Pd0 nanoparticles: A ligand-free and low Pd loading quasiheterogeneous catalyst active for mild Suzuki–Miyaura coupling and C-H activation of pyrimidine cores
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This paper reports a green magnetic quasiheterogeneous efficient palladium catalyst in which Pd0 nanoparticles have been immobilized in self-assembled hyperbranched polyglycidole (SAHPG)-coated magnetic Fe3O4 nanoparticles (Fe3O4-SAHPG-Pd0). This catalyst has been used for effective ligandless Pd catalyzed Suzuki–Miyaura coupling reactions of different aryl halides with substituted boronic acids at room temperature and in aqueous media. Herein, SAHPG is used as support; it also acts as a reducing agent and stabilizer to promote the transformation of PdII to Pd0 nanoparticles. Also, this environmental friendly quasiheterogeneous catalyst is employed for the first time in the synthesis of new pyrimido[4,5-b]indoles via oxidative addition/C-H activation reactions on the pyrimidine rings, which were obtained with higher yield and faster than when Pd(OAc)2 was used as the catalyst. Interestingly, the above-mentioned catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled several times with no significant decrease in the catalytic activity.
- Azizollahi, Hamid,Eshghi, Hossein,García-López, José-Antonio
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- Introduction of a Recyclable Basic Ionic Solvent with Bis-(NHC) Ligand Property and The Possibility of Immobilization on Magnetite for Ligand- and Base-Free Pd-Catalyzed Heck, Suzuki and Sonogashira Cross-Coupling Reactions in Water
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A new versatile and recyclable NHC ligand precursor has been developed with ligand, base, and solvent functionalities for the efficient Pd-catalyzed Heck, Suzuki and Sonogashira cross-coupling reactions under mild conditions. Furthermore, NHC ligand precursor was immobilized on magnetite and its catalytic activity was also evaluated towards the coupling reactions as a heterogeneous catalyst. The NHC ligand precursor was prepared with imidazolium functionalization of TCT followed by a simple ion exchange by hydroxide ions. However, the results revealed an excellent catalytic activity for the both homogeneous and heterogeneous catalytic systems. 1.52?g.cm?3 and 1194 cP was obtained for the density and viscosity of the NHC ligand precursor respectively. On the other hand, the heterogeneous type could be readily recovered from the reaction mixture and reused for several times while preserving its properties. Heterogeneous nature of the magnetic catalyst was studied by hot filtration, mercury poisoning, and three-phase tests. High to excellent yields were obtained for all entries for the both homogeneous and heterogeneous catalysts, which reflects the high consistency of the catalyst. Graphic Abstract: [Figure not available: see fulltext.]
- Min, Qingwang,Miao, Penghua,Chu, Deyu,Liu, Jinghan,Qi, Meijuan,Kazemnejadi, Milad
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p. 3030 - 3047
(2021/02/16)
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- Magnetic covalently immobilized nickel complex: A new and efficient method for the Suzuki cross-coupling reaction
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In this study, an efficient procedure was reported to prepare Fe3O4@SiO2 magnetic nanoparticles (MNPs) with immobilized nickel NPs. In order to increase the activity of this catalyst, creatine as a ligand with high content of nitrogen atoms was linked onto the magnetic core–shell structure. Then, Ni(II) ions were coordinated on the surface of the silica-coated MNPs and reduced to Ni(0) NPs to obtain the final catalyst. The catalytic activity of the prepared catalyst was studied for the synthesis of biaryl derivatives via the Suzuki–Miyaura cross-coupling reaction in high yields. The catalyst could also be recovered and reused with no loss of activity over five successful runs.
- Keyhaniyan, Mahdi,Khojastehnezhad, Amir,Eshghi, Hossein,Shiri, Ali
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- A recyclable self-supported nanoporous PdCu heterogeneous catalyst for aqueous Suzuki-Miyaura cross-coupling
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Nanoporous PdCu (NP-PdCu) was prepared by the dealloying strategy from a PdCuAl ternary alloy precursor and characterized systematically using SEM, TEM, XRD, and XPS. NP-PdCu was demonstrated to be a competent self-supported heterogenous catalyst for Suzuki-Miyaura cross-coupling, affording a series of synthetically valuable biaryl compounds in good to excellent yields. This catalyst could be easily separated from the productviacentrifugation and reused several times without obvious loss of catalytic performance.
- Chen, Jie,Du, Jialei,Liu, Fushan,Wang, Bin,Wang, Leichen,Xia, Hehuan,Xiang, Daili,Xu, Caixia,Zhang, Yuanyuan,Zhao, Yiwei
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supporting information
p. 11641 - 11644
(2021/11/12)
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- Anchored PdCl2 on fish scale: an efficient and recyclable catalyst for Suzuki coupling reaction in aqueous media
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PdCl2 anchored on fish scale (FS) complex were intended to a heterogeneous catalyst for ligand-free Suzuki coupling reaction in aqueous media. The catalyst FS-PdCl2 was characterized by FT-IR, powder XRD, XPS and SEM. FS-PdCl2 complex has been successfully implemented for Suzuki coupling reactions of various halogenated aromatics with arylboronic acid to provide the corresponding biaryl compounds under environmentally friendly conditions (40 °C, water solvent). Moreover, the efficient catalyst shows excellent stability and recyclability, and its catalytic activity without any decrease after 8 times consecutive reused.
- Yang, Quanlu,Yang, Fawang,Zhang, Ying,Hou, Juanjuan,Li, Jiankun,Cheng, Jinkui,Wu, Shang,Zhan, Huiying,Zhang, Xinghui,Shi, Haixiong
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supporting information
(2020/12/25)
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- Compound, luminescent layer guest material, organic electroluminescent device and display device
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The invention provides a compound as shown in a general formula (I). The compoundcan be used for an organic electroluminescent device as a guest material of a luminescent layer. The compound comprises a natural heterocyclic ring and iridium (Ir) coordinated structure, and the light emitting wavelength of the compound can be effectively regulated and controlled. When the compound is used as a guest material of a light-emitting layer, the light-emitting efficiency and the light stability of the organic electroluminescent device can be improved. In addition, the compound provided by the invention is small in molecular weight, is applied to a light-emitting layer, is relatively low in evaporation temperature, and is beneficial to processing. The invention also provides a luminescent layer guest material containing the compound shown in the general formula (I), an organic electroluminescent device and a display device.
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Paragraph 0112; 0121-0123; 0155-0156; 0164-0166; 0170; ...
(2021/06/22)
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- Inhibition of (dppf)nickel-catalysed Suzuki-Miyaura cross-coupling reactions by α-halo-N-heterocycles
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A nickel/dppf catalyst system was found to successfully achieve the Suzuki-Miyaura cross-coupling reactions of 3- and 4-chloropyridine and of 6-chloroquinoline but not of 2-chloropyridine or of other α-halo-N-heterocycles. Further investigations revealed that chloropyridines undergo rapid oxidative addition to [Ni(COD)(dppf)] but that α-halo-N-heterocycles lead to the formation of stable dimeric nickel species that are catalytically inactive in Suzuki-Miyaura cross-coupling reactions. However, the corresponding Kumada-Tamao-Corriu reactions all proceed readily, which is attributed to more rapid transmetalation of Grignard reagents.
- Burton, Paul M.,Cooper, Alasdair K.,Donohoe, William,Greaves, Megan E.,Kennedy, Alan R.,Nelson, David J.,Ronson, Thomas O.
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p. 14074 - 14082
(2021/11/12)
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- Triptycene ring metal palladium compound and application thereof
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The invention discloses a triptycene cyclometalated palladium compound and an application thereof. The triptycene cyclometalated palladium compound has the following general formula, wherein three RAscan be the same or different and are respectively and independently expressed as R1-(Z1-A1-Z2)x-,wherein the three RBs can be the same or different and are respectively and independently expressed asR2-(Z3-A2-Z4)y-, the two RCs may be the same or different, each independently expressed as R3-(Z5-A3-Z6)z-. The triptycene cyclometalated palladium compound provided by the invention has a triptycenelarge-steric-hindrance group, and can stabilize a zero-valent palladium intermediate in a catalytic cycle, so that the catalytic efficiency is improved, the use amount of a catalyst can be reduced tobe less than ten thousandth, and the compound is simple in synthesis step, high in yield, relatively low in cost and suitable for various substrates, and the method has an important application valuefor researching the progress and application of the coupling reaction.
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Paragraph 0093-0101
(2021/02/24)
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- Complexes: Easily Synthesized, Highly Active Pd(II)-NHC Precatalysts for Cross-Coupling Reactions
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We report the synthesis, characterization, and reactivity of [(NHC)PdCl2(aniline)] complexes. These well-defined, air- and moisture-stable catalysts are highly active in the Suzuki-Miyaura cross-coupling of amides by N-C(O) activation as well as in the Suzuki-Miyaura cross-coupling of esters, aryl chlorides, and Buchwald-Hartwig amination. Most crucially, this study introduces broadly available anilines as stabilizing ligands for well-defined Pd(II)-NHC catalysts. The availability of various aniline scaffolds, including structural and electronic diversity, has a significant potential in fine-tuning of challenging cross-couplings by Pd-NHCs. The parent catalyst in this class, [Pd(IPr)(AN)Cl2], has been commercialized in collaboration with Millipore Sigma, offering broad access for reaction screening and optimization.
- Xia, Qinqin,Shi, Shicheng,Gao, Pengcheng,Lalancette, Roger,Szostak, Roman,Szostak, Michal
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p. 15648 - 15657
(2021/10/25)
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- 2-Phosphinoimidazole Ligands: N-H NHC or P-N Coordination Complexes in Palladium-Catalyzed Suzuki-Miyaura Reactions of Aryl Chlorides
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We report the synthesis of two palladium 2-(dialkylphosphino)imidazole complexes and demonstrate their activity as catalysts for Suzuki-Miyaura reactions with (hetero)aryl chlorides at room temperature. Our mechanistic studies demonstrate that these palladium complexes exist as an equilibrium mixture between the P-N coordinated and N-H NHC forms of ligand. Our studies suggest that the N-H NHC form may be important for high catalytic activity in Suzuki-Miyaura reactions with aryl chlorides. These reactions proceed at or near room temperature in good to excellent yields. Heteroaryl chlorides are also reactive at lower catalyst loadings.
- Martinez, Erin E.,Larson, Alexandra J. S.,Fuller, Sydney K.,Petersen, Kathryn M.,Smith, Stacey J.,Michaelis, David J.
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supporting information
p. 1560 - 1564
(2021/05/29)
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- Metal-Free Deoxygenation of Amine N-Oxides: Synthetic and Mechanistic Studies
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We report herein an unprecedented combination of light and P(III)/P(V) redox cycling for the efficient deoxygenation of aromatic amine N-oxides. Moreover, we discovered that a large variety of aliphatic amine N-oxides can easily be deoxygenated by using only phenylsilane. These practically simple approaches proceed well under metal-free conditions, tolerate many functionalities and are highly chemoselective. Combined experimental and computational studies enabled a deep understanding of factors controlling the reactivity of both aromatic and aliphatic amine N-oxides.
- Lecroq, William,Schleinitz, Jules,Billoue, Mallaury,Perfetto, Anna,Gaumont, Annie-Claude,Lalevée, Jacques,Ciofini, Ilaria,Grimaud, Laurence,Lakhdar, Sami
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p. 1237 - 1242
(2021/06/01)
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- Highly Chemoselective Deoxygenation of N-Heterocyclic N-Oxides Using Hantzsch Esters as Mild Reducing Agents
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Herein, we disclose a highly chemoselective room-temperature deoxygenation method applicable to various functionalized N-heterocyclic N-oxides via visible light-mediated metallaphotoredox catalysis using Hantzsch esters as the sole stoichiometric reductant. Despite the feasibility of catalyst-free conditions, most of these deoxygenations can be completed within a few minutes using only a tiny amount of a catalyst. This technology also allows for multigram-scale reactions even with an extremely low catalyst loading of 0.01 mol %. The scope of this scalable and operationally convenient protocol encompasses a wide range of functional groups, such as amides, carbamates, esters, ketones, nitrile groups, nitro groups, and halogens, which provide access to the corresponding deoxygenated N-heterocycles in good to excellent yields (an average of an 86.8% yield for a total of 45 examples).
- An, Ju Hyeon,Kim, Kyu Dong,Lee, Jun Hee
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supporting information
p. 2876 - 2894
(2021/02/01)
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- Chromium-Catalyzed Reductive Cleavage of Unactivated Aromatic and Benzylic C-O Bonds
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Reductive cleavage of aromatic and benzylic C-O bonds by chromium catalysis is reported. This deoxygenative reaction was promoted by low-cost CrCl 2precatalyst combined with poly(methyl hydrogen siloxane) as the mild reducing agent, providing a strategy in forming reduced motifs by cleavage of unactivated C-O bonds. A range of functional groups such as bromide, chloride, fluoride, hydroxyl, amino, and alkoxycarbonyl can be retained in the reduction.
- Yuan, Shuqing,Ling, Liang,Tang, Jinghua,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 3343 - 3350
(2021/07/02)
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- A new Pd(II)-supported catalyst on magnetic SBA-15 for C-C bond formation via the Heck and Hiyama cross-coupling reactions
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Magnetic mesoporous silica composite (MNP@SiO2-SBA) was obtained via embedding magnetite nanoparticles between SBA-15 channels. It was silylated with N-(3-(trimethoxysilyl)propyl)picolinamide (TMS-PCA) and then complexed with Pd(II). The obtained supported Pd(II) catalyst (MNP@SiO2-SBA-PCA) was characterized by conventional methods. The prepared magnetic catalyst showed high activity in the Heck and Hiyama reactions under optimal reaction conditions, including solvent, amount of catalyst, base, and temperature. Aryl bromides and iodides showed better results than aryl chlorides, and the catalyst exhibited noticeable stability and reused several times.
- Rahimi, Leila,Mansoori, Yagoub,Nuri, Ayat,Koohi-Zargar, Behzad,Esquivel, Dolores
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- Aerobic Cu and amine free Sonogashira and Stille couplings of aryl bromides/chlorides with a magnetically recoverable Fe3O4@SiO2 immobilized Pd(II)-thioether containing NHC
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Two value added C–C cross coupling reactions; Sonogashira and Stille couplings were achieved at milder conditions in the catalytic presence of a magnetically recoverable heterogeneous catalyst Fe3O4@SiO2@NHC^SPh-Pd(II). The catalyst was earlier reported for Suzuki-Miyaura reaction, and as an extension of its catalytic efficiency, the Stille and Sonogashira cross coupling reactions under aerobic condition has been explored in present report. The Sonogashira coupling of aryl bromides and terminal alkynes produced an excellent yield (~96% at 0.25 mol% Pd) of the desired coupling product under copper and amines free conditions. Moreover, an excellent Stille coupling of readily available and more latent aryl chlorides and trialkylstannane was obtained (yields up to 95% at 0.25 mol% Pd) in absence of toxic fluorides additives. The broad substrate scope of the catalyst for both the coupling reactions and the magnetically recoverable feature of catalyst make this reaction highly desirable for industrial applications of present heterogeneous catalysis.
- Khandaka, Himanshu,Sharma, Kamal Nayan,Joshi, Raj Kumar
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supporting information
(2021/02/20)
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- Cobalt-Catalyzed Coupling of Aryl Chlorides with Aryl Boron Esters Activated by Alkoxides
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The cobalt-catalyzed Suzuki biaryl cross-coupling of aryl chloride substrates with aryl boron reagents, activated with more commonly used bases, remained a significant unmet challenge in the race to replace platinum group metal catalysts with Earth-abundant metal alternatives. We now show that this highly desirable process can be realized using alkoxide bases, provided the right counterion is employed, strict stoichiometric control of the base is maintained with respect to the aryl boron reagent, and the correct boron ester is selected. Potassium tert-butoxide works well, but any excess of the base first inhibits and then poisons the catalyst. Lithium tert-butoxide performs very poorly, while even catalytic amounts of lithium additives also poison the catalyst. Meanwhile, a neopentane diol-based boron ester is required for best performance. As well as delivering this sought-after transformation, we have undertaken detailed mechanistic and computational investigations to probe the possible mechanism of the reaction and help explain the unexpected experimental observations.
- Tailor, Sanita B.,Manzotti, Mattia,Smith, Gavin J.,Davis, Sean A.,Bedford, Robin B.
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p. 3856 - 3866
(2021/04/07)
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- Selective C-O Bond Reduction and Borylation of Aryl Ethers Catalyzed by a Rhodium-Aluminum Heterobimetallic Complex
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We report the catalytic reduction of a C-O bond and the borylation by a rhodium complex bearing an X-Type PAlP pincer ligand. We have revealed the reaction mechanism based on the characterization of the reaction intermediate and deuterium-labeling experiments. Notably, this novel catalytic system shows steric-hindrance-dependent chemoselectivity that is distinct from conventional Ni-based catalysts and suggests a new strategy for selective C-O bond activation by heterobimetallic catalysis.
- Hara, Naofumi,Nakao, Yoshiaki,Saito, Teruhiko,Seki, Rin
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supporting information
p. 6388 - 6394
(2021/05/31)
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- Importance of Two-Electron Processes in Fe-Catalyzed Aryl-(hetero)aryl Cross-Couplings: Evidence of Fe0/FeIICouple Implication
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We demonstrate in this work that two drastically distinct mechanisms can be involved in aryl-(hetero)aryl Fe-mediated cross-couplings between Grignard reagents and organic halides, depending on the nature of the latter. (Hetero)aryl electrophiles, which easily undergo one-electron reduction, can be involved in a FeII/FeIII coupling sequence featuring an in situ generated organoiron(II) species, akin to their aliphatic analogues. On the other hand, less easily reduced substrates can be activated by transient Fe0 species formed by the reduction of the precatalyst. In this case, the coupling mechanism relies on two-electron elementary steps involving the Fe0/FeII redox couple and proceeds by an oxidative addition/reductive elimination sequence. Hammett analysis shows that both those elementary steps are faster for electrophiles substituted by electron-withdrawing groups. The two mechanisms discussed herein can be involved concomitantly for electrophiles displaying an average oxidative power. Attesting to the feasibility of the aforementioned bielectronic mechanism, high-spin organoiron(II) intermediates formed by two-electron oxidative addition onto (hetero)aryl halides in catalytically relevant conditions were also characterized for the first time. Those results are sustained by paramagnetic 1H NMR, kinetics monitoring, and density functional theory (DFT) calculations.
- Wowk, Vincent,Rousseau, Lidie,Lefèvre, Guillaume
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supporting information
p. 3253 - 3266
(2021/10/12)
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- Ligand-to-metal charge transfer of a pyridine surface complex on TiO2for selective dehydrogenative cross-coupling with benzene
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Dehydrogenative cross-coupling (DCC) between pyridine and benzene proceeded selectively using a TiO2 photocatalyst under visible light irradiation at optimized concentrations of the substrates. Visible light induces ligand-to-metal charge transfer (LMCT) between pyridine and a TiO2 surface to give a pyridine radical cation, which produces a pyridyl radical by its deprotonation or oxidation of another pyridine molecule. The pyridyl radical attacks a benzene ring to form an sp2C-sp2C bond and a hydrogen atom is subsequently removed to complete DCC. Selective excitation of the pyridine LMCT complex in the presence of an excess amount of benzene would be the key for higher selectivity. This journal is
- Hishitani, Shinichiro,Naniwa, Shimpei,Yamamoto, Akira,Yoshida, Hisao
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p. 11366 - 11373
(2021/05/31)
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- Fate of Cobaltacycles in Cp*Co-Mediated C-H Bond Functionalization Catalysis: Cobaltacycles May Collapse upon Oxidation via Co(IV) Species
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Recent reports have identified Cp*Co-based complexes to be powerful catalysts for aromatic C-H bond activation under oxidative conditions. However, little is known about the speciation of Cp*Co species during catalysis. We now show that key intermediates, Cp*CoIII metallacycles derived from 2-phenylpyridine (phpy-H), react swiftly in solution with one-electron oxidants to irreversibly collapse by a cyclocondensation of the organic ligands to afford cationic alkaloids in yields of >70%. A low-temperature EPR analysis of a mixture of the cobaltacycle with the tritylium cation reveals the signatures of trityl and Co(IV)-centered radicals. Electrochemical analyses show that the oxidation of these cobaltacycles is irreversible and gives rise to several products in various amounts, among which the most salient ones are a cationic alkaloid resulting from the cyclocondensation of the phpy and Cp? ligands and the dimeric cation {[Cp*Co]2(μ-I)3}+. DFT investigations of relevant noncovalent interactions using QTAIM-based NCI plots and intrinsic bond strength indexes suggest a ligand-dependent predisposition by NCI-coding for the Co(IV)-templated cyclocondensation, the computed reaction network energy profile for which supports the key roles of a short-lived Co(IV) metallacycle and of a range of triplet state organocobalt intermediates.
- Bailly, Corinne,Choua, Sylvie,Cornaton, Yann,Deraedt, Christophe,Djukic, Jean-Pierre,Karmazin, Lydia,Kyritsakas, Nathalie,Le Breton, Nolwenn,Ruhlmann, Laurent,Wu, Fule
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supporting information
p. 2624 - 2642
(2021/08/20)
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- Base-Activated Latent Heteroaromatic Sulfinates as Nucleophilic Coupling Partners in Palladium-Catalyzed Cross-Coupling Reactions
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Heteroaromatic sulfinates are effective nucleophilic reagents in Pd0-catalyzed cross-coupling reactions with aryl halides. However, metal sulfinate salts can be challenging to purify, solubilize in reaction media, and are not tolerant to multi-step transformations. Here we introduce base-activated, latent sulfinate reagents: β-nitrile and β-ester sulfones. We show that under the cross-coupling conditions, these species generate the sulfinate salt in situ, which then undergo efficient palladium-catalyzed desulfinative cross-coupling with (hetero)aryl bromides to deliver a broad range of biaryls. These latent sulfinate reagents have proven to be stable through multi-step substrate elaboration, and amenable to scale-up.
- Blakemore, David C.,Cook, Xinlan A. F.,Moses, Ian B.,Pantaine, Lo?c R. E.,Sach, Neal W.,Shavnya, Andre,Willis, Michael C.
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supporting information
p. 22461 - 22468
(2021/09/09)
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- Rhodium(III)-Catalyzed Aryl Borrowing Amination of Diaryl Methanols Containing Pyridine-Directing Groups
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The rhodium(III)-catalyzed aryl borrowing amination of various diaryl methanols with sulfonamides have been developed. The amination of alcohols via C?C bond activation is less developed and remains a challenge. These aryl borrowing reactions feature mild reaction conditions, good functional group tolerance, and compatibility with a wide range of alcohols, overall comprising an atom- and step-economic procedure. Mechanistic studies indicate that a rhodacycle complex exist during the aryl borrowing amination reaction. (Figure presented.).
- Liu, Zheng-Qiang,Tao, Jing,Zhuang, Xin,Hong, Chuan-Ming,Luo, Zhen,Wu, Yu-Fei,Li, Qing-Hua,Liu, Tang-Lin
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supporting information
p. 5279 - 5283
(2021/09/29)
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- Cobalt-catalyzed cross-coupling reactions of aryl- And alkylaluminum derivatives with (hetero)aryl and alkyl bromides
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A simple cobalt complex, such as Co(phen)Cl2, turned out to be a highly efficient and cheap precatalyst for a host of cross-coupling reactions involving aromatic and aliphatic organoaluminum reagents with aryl, heteroaryl and alkyl bromides. New C(sp2)-C(sp2) and C(sp2)-C(sp3) bonds were formed in good to excellent yields and with high chemoselectivity, under mild reaction conditions.
- Dilauro, Giuseppe,Messa, Francesco,Bona, Fabio,Perrone, Serena,Salomone, Antonio
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supporting information
p. 10564 - 10567
(2021/10/19)
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- Desulfonative Suzuki–Miyaura Coupling of Sulfonyl Fluorides
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Sulfonyl fluorides have emerged as powerful “click” electrophiles to access sulfonylated derivatives. Yet, they are relatively inert towards C?C bond forming transformations, notably under transition-metal catalysis. Here, we describe conditions under which aryl sulfonyl fluorides act as electrophiles for the Pd-catalyzed Suzuki–Miyaura cross-coupling. This desulfonative cross-coupling occurs selectively in the absence of base and, unusually, even in the presence of strong acids. Divergent one-step syntheses of two analogues of bioactive compounds showcase the expanded reactivity of sulfonyl fluorides to encompass both S?Nu and C?C bond formation. Mechanistic experiments and DFT calculations suggest oxidative addition occurs at the C?S bond followed by desulfonation to form a Pd-F intermediate that facilitates transmetalation.
- Bahadori, Maryam,Brykczyńska, Daria,Chatelain, Paul,Moran, Joseph,Muller, Cyprien,Rowley, Christopher N.,Sau, Abhijit
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supporting information
p. 25307 - 25312
(2021/10/25)
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- Synthesis of Bis-heteroaryls Using Grignard Reagents and Pyridylsulfonium Salts
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Herein are reported ligand-coupling reactions of Grignard reagents with pyridylsulfonium salts. The method has wide functional group tolerance and enables the formation of bis-heterocycle linkages, including 2,4′-, 2,3′-, and 2,2′-bipyridines, as well as pyridines linked to pyrimidines, pyrazines, isoxazoles, and benzothiophenes. The methodology was successfully applied to the synthesis of the natural products caerulomycin A and E.
- Horan, Alexandra M.,Duong, Vincent K.,McGarrigle, Eoghan M.
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supporting information
p. 9089 - 9093
(2021/11/30)
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- Nickel-Catalyzed Reductive 2-Pyridination of Aryl Iodides with Difluoromethyl 2-Pyridyl Sulfone
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A novel nickel-catalyzed reductive cross-coupling between aryl iodides and difluoromethyl 2-pyridyl sulfone (2-PySO2CF2H) enables C(sp2)-C(sp2) bond formation through selective C(sp2)-S bond cleavage, which demonstrates the new reactivity of 2-PySO2CF2H reagent. This method employs readily available nickel catalyst and sulfones as cross-electrophile coupling partners, providing facile access to biaryls under mild reaction conditions without pregeneration of arylmetal reagents.
- Miao, Wenjun,Ni, Chuanfa,Xiao, Pan,Jia, Rulong,Zhang, Wei,Hu, Jinbo
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supporting information
p. 711 - 715
(2021/01/26)
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- Visible-Light-Induced 1,3-Aminopyridylation of [1.1.1]Propellane with N-Aminopyridinium Salts
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Through the formation of an electron donor–acceptor (EDA) complex, strain-release aminopyridylation of [1.1.1]propellane with N-aminopyridinium salts as bifunctional reagents enabled the direct installation of amino and pyridyl groups onto bicyclo[1.1.1]pentane (BCP) frameworks in the absence of an external photocatalyst. The robustness of this method to synthesize 1,3-aminopyridylated BCPs under mild and metal-free conditions is highlighted by the late-stage modification of structurally complex biorelevant molecules. Moreover, the strategy was extended to P-centered and CF3 radicals for the unprecedented incorporation of such functional groups with pyridine across the BCP core in a three-component coupling. This practical method lays the foundation for the straightforward construction of new valuable C4-pyridine-functionalized BCP chemical entities, thus significantly expanding the range of accessibility of BCP-type bioisosteres for applications in drug discovery.
- Shin, Sanghoon,Lee, Seojin,Choi, Wonjun,Kim, Namhoon,Hong, Sungwoo
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supporting information
p. 7873 - 7879
(2021/03/08)
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- Site-selective direct C-H pyridylation of unactivated alkanes by triplet excited anthraquinone
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Site-selective C-H functionalization in chemical feedstocks is a challenging and useful reaction in the broad field of chemical research. Here, we report a modular photochemical platform for the site-selective C-H pyridylation of unactivated hydrocarbons via the unique synergistic effects of triplet excited anthraquinone and an amidyl radical-based reverse hydrogen atom transfer (RHAT) agent. The selective pyridylation of tertiary and secondary C(sp3)-H bonds in abundant chemical feedstocks was achieved by employing various N-aminopyridinium salts in a highly selective fashion, thus providing a new catalytic system for the direct construction of high-value-added compounds under ambient reaction conditions. Moreover, this operationally simple protocol is applicable to a variety of linear-, branched-, and cyclo-alkanes and more complex molecules with high degrees of site selectivity under visible-light conditions, which provides rapid and straightforward access to versatile synthons for upgrading feedstocks under mild, metal-free reaction conditions.
- Lee, Wooseok,Jung, Sungwoo,Kim, Minseok,Hong, Sungwoo
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supporting information
p. 3003 - 3012
(2021/03/01)
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- A facile and versatile electro-reductive system for hydrodefunctionalization under ambient conditions
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A general electrochemical system for reductive hydrodefunctionalization is described, employing the inexpensive and easily available triethylamine (Et3N) as a sacrificial reductant. This protocol is characterized by facile operation, sustainable conditions, and exceptionally wide substrate scope covering the cleavage of C-halogen, N-S, N-C, O-S, O-C, C-C and C-N bonds. Notably, the selectivity and capability of reduction can be conveniently switched by simple incorporation or removal of an alcohol as a co-solvent.
- Huang, Binbin,Guo, Lin,Xia, Wujiong
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p. 2095 - 2103
(2021/03/26)
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- Anchoring Positively Charged Pd Single Atoms in Ordered Porous Ceria to Boost Catalytic Activity and Stability in Suzuki Coupling Reactions
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Single-atom (SA) catalysis bridging homogeneous and heterogeneous catalysis offers new opportunities for organic synthesis, but developing SA catalysts with high activity and stability is still a great challenge. Herein, a heterogeneous catalyst of Pd SAs anchored in 3D ordered macroporous ceria (Pd-SAs/3DOM-CeO2) is developed through a facile template-assisted pyrolysis method. The high specific surface area of 3DOM CeO2 facilitates the heavily anchoring of Pd SAs, while the introduction of Pd atoms induces the generation of surface oxygen vacancies and prevents the grain growth of CeO2 support. The Pd-SAs/3DOM-CeO2 catalyst exhibits excellent activity toward Suzuki coupling reactions for a broad scope of substrates under ambient conditions, and the Pd SAs can be stabilized in CeO2 in long-term catalytic cycles without leaching or aggregating. Theoretical calculations indicate that the CeO2 supported Pd SAs can remarkably reduce the energy barriers of both transmetalation and reductive elimination steps for Suzuki coupling reactions. The strong metal-support interaction contributes to modulating the electronic state and maintaining the stability of Pd SA sites. This work demonstrates an effective strategy to design and synthesize stable single-atom catalysts as well as sheds new light on the origin for enhanced catalysis based on the strong metal-support interactions.
- Tao, Xueqin,Long, Ran,Wu, Di,Hu, Yangguang,Qiu, Ganhua,Qi, Zeming,Li, Benxia,Jiang, Ruibin,Xiong, Yujie
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- Catalysis with magnetically retrievable and recyclable nanoparticles layered with Pd(0) for C-C/C-O coupling in water
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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.
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p. 6452 - 6459
(2020/02/25)
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- Design, synthesis and application of triazole ligands in suzuki miyaura cross coupling reaction of aryl chlorides
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DFT calculations have been demonstrated to be a valuable tool for the mechanistic study of reaction which is difficult to acquire from pure experimental techniques. Structural, electronic and coordination aspects of synthesized triazole ligands were investigated theoretically by structure optimization on Gaussian 09 package by DFT approach at B3LYP/6-31G (d, p). HOMO-LUMO energy gaps correlated to its chemical reactivity and this information applied to interpret the role of ligand in the formation of ligand-metal complex. Electron rich environment around the triazole core stabilized the HOMO orbital and made these electrons available to form complex with Pd centre. The DFT calculations provide a plausible mechanism for the reaction that is consistent with the available experimental facts. A series of triazole ligands have been synthesized via efficient 1,3-dipolar cycloaddition of readily available azide and alkynes for coordination to Pd centre. Characterization of all the synthesized compounds was done by FTIR, 1H NMR, 13C NMR and HRMS. Their ligand-Pd complexes provided excellent yields in the Suzuki-Miyaura coupling reactions (up to 92% yield) of unactivated aryl chlorides. Ligand 4-(2,6-dimethoxyphenyl)-1-phenyl-1H-1,2,3-triazole (L2) was found to be most effective ligand because of electron donating 2,6 dimethoxy phenyl moiety attached to triazole ring at 4-position that facilitated the formation of electron rich ligand-catalyst complex. The complex favoured the oxidative addition step of Pd across the aryl chloride substrate and thus allowed for the development of highly active ligand-catalyst system for Suzuki reaction. During computational analysis, 4-(2,6-dimethoxyphenyl)-1-phenyl-1H-1,2,3-triazole (L2) also showed lowest band gap due to electron rich distribution pattern on the HOMO that are involve in ligand-Pd complex formation. Conclusively, these triazoles ligands were found to be more competent and attractive for palladium catalyst because of simplistic pathway for the synthesis of triazole motif and the ease of individual tuning of the substituents on triazole core or exocyclic to it.
- Jabeen, Sobia,Khera, Rasheed Ahmad,Iqbal, Javed,Asgher, Muhammad
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- Air-stable Pd(0) catalyst bearing dual phosphine ligands: a detailed evaluation of air stability and catalytic property in cross-coupling reactions
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We have synthesised an air-stable Pd(0) catalyst bearing donor and acceptor phosphine ligands (Complex1). This study revealed the long-term air stability and catalytic property of Complex1as a catalyst for cross-coupling reactions, where it was stable in air for eight months. DFT calculations revealed that the acceptor ligands in Complex1decreased the HOMO energy level, which provided the observed air stability. Complex1successfully served as a catalyst for direct C-H arylation reactions and Suzuki-Miyaura cross-coupling reactions, and catalysed the reaction of a relatively inactive substrate, 2-chrolopyridine, which could not be achieved by conventional, air-stable Pd(0) catalysts. Isolating the intermediates of the coupling reactions revealed that each intermediate possessed the donor ligand (PCy3), which was determined to be responsible for imparting the high catalytic activity exhibited by Complex1.
- Sato, Ryota,Kanbara, Takaki,Kuwabara, Junpei
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p. 12814 - 12819
(2020/10/02)
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- A Mild Method for Electrochemical Reduction of Heterocyclic N-Oxides
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Deoxygenation of heteroaromatic N-oxides is commonly accomplished using chemical or enzymatic methods. In this work, we report on an expedient protocol for electrochemical reduction of pyridine N-oxide derivatives under mild conditions. A diverse range of mono- and bis N-oxides were converted into the corresponding nitrogen bases in good yields. Importantly, the method is highly selective towards N-oxides and tolerates challenging halo and nitro substituents in the heteroaromatic ring.
- Fukazawa, Yasuaki,Rubtsov, Aleksandr E.,Malkov, Andrei V.
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supporting information
p. 3317 - 3319
(2020/05/25)
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- Small organic molecules with tailored structures: Initiators in the transition-metal-free C-H arylation of unactivated arenes
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Simple, small organic molecules containing nitrogen and oxygen atoms in their structures have been disclosed to catalyze transition-metal-free C-H arylation of unactivated arenes with aryl iodides in the presence of tBuOK. In this article, an optimized catalytically active molecule, (2-(methylamino)phenyl)methanol, was designed. A broad range of aryl iodides could be converted into the corresponding arylated products at 100 °C over 24 h with good to excellent yields. Mechanistic experiments verified that radicals participated in this catalytic transformation and that the cleavage of the aromatic C-H bond was not the rate determining step. A K+ capture experiment by 18-crown-6 emphasized the significance of the cation species of the strong base. Fourier transform infrared spectroscopy proved that the catalytic system was activated by the hydrogen bonds between small organic molecules and tBuOK. Also, a clear mechanism was proposed. This transition-metal-free method affords a promising system for efficient and inexpensive synthesis of biaryls via a user-friendly approach, as confirmed by scale-up experiments.
- Chen, Suqing,Chen, Wenjun,Chen, Yu,Liu, Zhenghui,Mu, Tiancheng,Wang, Peng,Yan, Zhenzhong
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p. 14500 - 14509
(2020/04/27)
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- NaH-mediated direct C-H arylation in the presence of 1,10-phenanthroline
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Transition-metal-free coupling of haloarenes with unactivated arenes has been developed in the presence of NaH and 1,10-phenanthroline. Various haloarenes bearing methyl, methoxy, halogen (fluoride, chloride, and bromide), cyano, trifluoromethyl, ester, and amide groups can be cross-coupled with unactivated arenes, or heteroarenes in this reaction.
- Nozawa-Kumada, Kanako,Iwakawa, Yuki,Onuma, So,Shigeno, Masanori,Kondo, Yoshinori
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supporting information
p. 7773 - 7776
(2020/07/27)
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- Air-Stable Fe3O4@SiO2-EDTA-Ni(0) as an Efficient Recyclable Magnetic Nanocatalyst for Effective Suzuki-Miyaura and Heck Cross-Coupling via Aryl Sulfamates and Carbamates
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The synthesis of inexpensive and novel air-stable Ni(0) nanoparticles immobilized on the EDTA-modified Fe3O4@SiO2 nanocatalyst was investigated in Suzuki-Miyaura and Heck cross-coupling reactions. This catalytic system displayed a greatly improved substrate scope for the carbon–carbon bond formations starting from a wide range of green and economical electrophiles aryl and heteroaryl carbamates and sulfamates via highly efficient method under mild, operationally simple reaction conditions. The synthesized heterogeneous catalyst was also fully characterized by FT-IR, TEM, XRD, DLS, FE-SEM, UV–Vis, EDX, XPS, TGA, NMR, VSM, ICP and elemental analysis techniques. The heterogeneous magnetic nanocatalyst can easily be recovered by an external magnetic field and reused for the next reactions for at least seven times with negligible leaching of catalyst and no substantial decrement in the activity. All these highlights have made the present protocol an interesting, simple and environmentally benign process with low catalyst loading and easy manipulations.
- Dindarloo Inaloo, Iman,Majnooni, Sahar,Eslahi, Hassan,Esmaeilpour, Mohsen
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- Self-Assembled Multilayer Iron(0) Nanoparticle Catalyst for Ligand-Free Carbon-Carbon/Carbon-Nitrogen Bond-Forming Reactions
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Self-assembled multilayer iron(0) nanoparticles (NPs, 6-10 nm), namely, sulfur-modified Au-supported Fe(0) [SAFe(0)], were developed for ligand-free one-pot carbon-carbon/carbon-nitrogen bond-forming reactions. SAFe(0) was successfully prepared using a well-established metal-nanoparticle catalyst preparative protocol by simultaneous in situ metal NP and nanospace organization (PSSO) with 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine (Si-DHP) as a strong reducing agent. SAFe(0) was easy to handle in air and could be recycled with a low iron-leaching rate in reaction cycles.
- Akiyama, Toshiki,Arisawa, Mitsuhiro,Haneoka, Hitoshi,Harada, Kazuo,Hasegawa, Jun-Ya,Honma, Tetsuo,Mashima, Kazushi,Sato, Yoshihiro,Shimoda, Shuhei,Shio, Yasunori,Suzuki, Takeyuki,Tamenori, Yusuke,Tsurugi, Hayato,Tsuruta, Kazuki,Wada, Yuki,Yamada, Makito
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supporting information
p. 7244 - 7249
(2020/10/12)
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- A new approach to large scale production of dimethyl sulfone: A promising and strong recyclable solvent for ligand-free Cu-catalyzed C-C cross-coupling reactions
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Dimethyl sulfone (DMSN) was easily prepared through efficient oxidation of dimethyl sulfoxide (DMSO) and used as a strong and green solvent for organic reactions. A mixture of HNO3/NaOCl was used as an oxidizing agent for efficient oxidation of DMSO to DMSN. The effect of DMSN was evaluated for copper-catalyzed coupling reactions. It is worth noting that DMSN could play the role of a ligand for copper ions. A general survey was accomplished for various types of C-C cross-coupling reactions catalyzed by CuI in DMSN in the absence of any ligand. Moderate to good yields were achieved for Sonogashira, Heck, and Suzuki cross-coupling reactions. Finally, DMSN was recovered and reused for several consecutive runs without any loss of its activity.
- Cheng, Shen,Wei, Wei,Zhang, Xingyu,Yu, Hewei,Huang, Mingming,Kazemnejadi, Milad
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p. 2069 - 2076
(2020/04/07)
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- Palladium (II)–Salan Complexes as Catalysts for Suzuki–Miyaura C–C Cross-Coupling in Water and Air. Effect of the Various Bridging Units within the Diamine Moieties on the Catalytic Performance
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Water-soluble salan ligands were synthesized by hydrogenation and subsequent sulfonation of salens (N,N’-bis(slicylidene)ethylenediamine and analogues) with various bridging units (linkers) connecting the nitrogen atoms. Pd (II) complexes were obtained in reactions of sulfosalans and [PdCl4]2?. Characterization of the ligands and complexes included extensive X-ray diffraction studies, too. The Pd (II) complexes proved highly active catalysts of the Suzuki–Miyaura reaction of aryl halides and arylboronic acid derivatives at 80 ?C in water and air. A comparative study of the Pd (II)–sulfosalan catalysts showed that the catalytic activity largely increased with increasing linker length and with increasing steric congestion around the N donor atoms of the ligands; the highest specific activity was 40,000 (mol substrate) (mol catalyst × h)?1. The substrate scope was explored with the use of the two most active catalysts, containing 1,4-butylene and 1,2-diphenylethylene linkers, respectively.
- Bunda, Szilvia,Joó, Ferenc,Kathó, ágnes,Udvardy, Antal,Voronova, Krisztina
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supporting information
(2020/09/18)
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- Sulfur(IV)-Mediated Unsymmetrical Heterocycle Cross-Couplings
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Despite the tremendous utilities of metal-mediated cross-couplings in modern organic chemistry, coupling reactions involving nitrogenous heteroarenes remain a challenging undertaking – coordination of Lewis basic atoms into metal centers often necessitate elevated temperature, high catalyst loading, etc. Herein, we report a sulfur (IV) mediated cross-coupling amendable for the efficient synthesis of heteroaromatic substrates. Addition of heteroaryl nucleophiles to a simple, readily-accessible alkyl sulfinyl (IV) chloride allows formation of a trigonal bipyramidal sulfurane intermediate. Reductive elimination therefrom provides bis-heteroaryl products in a practical and efficient fashion.
- Zhou, Min,Tsien, Jet,Qin, Tian
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supporting information
p. 7372 - 7376
(2020/04/09)
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- PHOSPHINE FREE COBALT BASED CATALYST, PROCESS FOR PREPARATION AND USE THEREOF
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The present invention discloses a phosphine free cobalt based catalyst of formula (I) and a process for preparation thereof. The present invention further discloses a process for the synthesis of aromatic heterocyclic compounds of formula (II) and pyrazine derivative using the phosphine free cobalt based catalyst of formula (I).
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Paragraph 0068; 0142; 0143-0144
(2020/12/29)
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- Synthesis of Pyridines, Quinolines, and Pyrimidines via Acceptorless Dehydrogenative Coupling Catalyzed by a Simple Bidentate P^ N Ligand Supported Ru Complex
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A ruthenium hydrido chloride complex (1) supported by a simple, heteroleptic bidentate P^N ligand (L1) containing a diarylphosphine and a benzannulated phenanthridine donor arm is reported. In the presence of base, complex 1 catalyzes multicomponent reactions using alcohol precursors to produce structurally diverse molecules including pyridines, quinolines, and pyrimidines via acceptorless dehydrogenative coupling pathways. Notably, L1 does not bear readily (de)protonated Br?nsted acidic or basic groups common to transition metal catalysts capable of these sorts of transformations, suggesting metal-ligand cooperativity does not play a significant role in the catalytic reactivity of 1. A rare example of an η2-aldehyde adduct of ruthenium was isolated and structurally characterized, and its role in acceptorless dehydrogenative coupling reactions is discussed.
- Mondal, Rajarshi,Herbert, David E.
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supporting information
p. 1310 - 1317
(2020/04/15)
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