- Abnormal-NHC Palladium(II) Complexes: Rational Synthesis, Structural Elucidation, and Catalytic Activity
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Reaction of a C2-arylated imidazolium iodide (IPrPh)I (1) (IPrPh = 1,3-bis(2,6-diisopropylphenyl)-2-phenyl-imidazolium) with PdCl2 in the presence of Ag2O affords abnormal N-heterocyclic carbene (aNHC) palladium complexes (aIPrPh)PdCl2 (2) and (aIPrPh)2PdCl2 (3) (aIPrPh = 1,3-bis(2,6-diisopropylphenyl)-2-phenyl-imidazol-4-ylidene). Treatment of 2 with a pyridine gives Pd-PEPPSI-type complexes (aIPrPh)PdCl2(L) (L = pyridine (py), 5; L = 3-chloropyridine (3Cl-py), 6). Compounds 5 and 6 are also accessible by a one-pot reaction of 1, PdCl2, and Ag2O in a pyridine solvent. While the use of a conventional base K2CO3 leads to the formation of mixed halide complexes (aIPrPh)Pd(Cl)I(L) (7, L = py; 8, L = 3Cl-py), iodide derivatives (aIPrPh)PdI2(L) (9, L = py; 10, L = 3Cl-py) can be selectively prepared with addition of an excess of KI to the reaction mixture. Albeit in a low yield, a putative transmetalation agent {(aIPrPh)2Ag}AgI2 (4) has been isolated and characterized. Compounds 2-10 are air stable crystalline solids and have been characterized by elemental analysis, mass spectrometry, and NMR spectroscopic studies. Molecular structures of 2-10 have been established by single crystal X-ray diffraction analyses. Catalytic activity of three representative compounds 2, 5, and 6 has been tested for the Suzuki-Miyaura cross-coupling reactions.
- Rottsch?fer, Dennis,Schürmann, Christian J.,Lamm, Jan-Hendrik,Paesch, Alexander N.,Neumann, Beate,Ghadwal, Rajendra S.
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- Electron transfer behavior of pincer-type {RhNO}8 complexes: Spectroscopic characterization and reactivity of paramagnetic {RhNO}9 complexes
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The electrochemistry of the {RhNO}8 complexes [Rh(PCP tBu)(NO)][BF4] (1+), [Rh(PCP tBuCH2)(NO)][BF4] (2+), and Rh(PCPtBu)(NO)Cl (3) was studied. Both four-coordinate complexes 1+ and 2+ exhibit a reversible reduction within the CH2Cl2 solvent window. Nevertheless, the chemical or electrochemical reduction of 1+ and 2+ in CH 2Cl2 led to the formation of the five-coordinate {RhNO}8 complexes 3 and Rh(PCPtBuCH2)(NO)Cl (4), respectively, through chloride abstraction from CH2Cl 2 by the one-electron-reduced {RhNO}9 species [Rh(PCP tBu)(NO)]? (1?) and [Rh(PCP tBuCH2)(NO)]? (2?), as has been observed for many other 17-electron paramagnetic complexes. The new complex 4 was fully characterized by multinuclear NMR techniques, IR, X-ray diffraction, CV, UV-vis, and elemental analysis. On the other hand, the five-coordinate complexes 3 and 4 show only one irreversible oxidation in CH2Cl2 and two irreversible reductions in THF. The {RhNO}9 complex 1? could be obtained quantitatively by one-electron reduction of 1+ with cobaltocene in nonchlorinated solvents and was characterized by IR, EPR, and 1H NMR in solution. Activation of carbon-halogen bonds by complex 1? was observed by studying the reactivity of 1? with some aryl halides, giving in all cases the {RhNO}8 Rh(PCPtBu)(NO)X (X = Cl -, 3, or X = I-, 6) as the only rhodium complex, while a complex with coordination of the aryl moiety was not observed as a stable final product in any case. The fate of the aryl organic radicals could be determined in some cases. In addition, DFT calculations were performed to elucidate the electronic structure of 1? and to support the observed reactivity.
- Pellegrino, Juan,Gaviglio, Carina,Milstein, David,Doctorovich, Fabio
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- PEPPSI-effect on suzuki-miyaura reactions using 4,5-dicyano-1,3-dimesitylimidazol-2-ylidene-palladium complexes: A comparison between trans-ligands
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The PEPPSI (Pyridine Enhanced Precatalyst Preparation, Stabilization and Initiation) complexes 12-15 with the structure [PdCl2{(CN)2IMes}(3-R-py)] (12: R = H; 13: R = Cl; 14: R = Br; 15: R = CN) bearing the maleonitrile-based N-heterocyclic carbene (NHC) (CN)2IMes ({(CN)2IMes}: 4,5-dicyano-1,3-dimesitylimidazol-2-ylidene) were prepared. Solid state structures of 14 and 15 were obtained. Complexes 14 and 15 adopt a slightly distorted square-planar coordination geometry in the solid state with the substituted pyridine ligand trans to the NHC. Catalytic activities of precatalysts 12-15 were studied and subsequently compared to complexes [PdCl2{(CN)2IMes}(PPh3)] (4) and [PdCl(dmba){(CN)2IMes}] (5) recently reported by our group in the Suzuki-Miyaura reaction of various aryl halides and phenylboronic acid. Reactions using previously reported [PdCl2(IMes)(py)] (IMes: 1,3-dimesitylimidazol-2-ylidene) (1) were also carried out and their results contrasted to those involving 12-15, 4 and 5. Differences in initiation rates and the catalytically active species related to the seven complexes in regards to the "throw away ligand" were investigated. Poisoning experiments with mercury show that palladium nanoparticles are responsible for the catalytic activity.
- Baier, Heiko,Kelling, Alexandra,Holdt, Hans-Jürgen
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- Ag(i)-Mediated hydrogen isotope exchange of mono-fluorinated (hetero)arenes
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An efficient approach to install deuterium into mono-fluorinated (hetero)arenes by a Ag2CO3/Sphos-mediated HIE protocol with D2O as the deuterium source has been disclosed. This method showed a specific site selectivity of deuteration at the α-position of the fluorine atom, which is complementary to the existing transition metal-catalyzed HIE process.
- Hu, Guang-Qi,Huang, Wei,Li, En-Ci,Zhang, Hong-Hai
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- Efficient and Economical Preparation of Hypercrosslinked Polymers-palladium Based on Schiff Base as Recyclable Catalyst for Suzuki-Miyaura Reactions
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A novel hypercrosslinked polymer (HCP) was prepared via Friedel-Crafts alkylation reaction of Schiff base with benzene and formaldehyde dimethyl acetal (FDA) promoted by FeCl3. The HCP was then metalated with Pd(II) to form heterogeneous catalyst. The protocol featured low cost, mild conditions, readily available materials, easy separation and high yield. Physicochemical methods, including IR, N2 sorption, ICP, TGA, XPS, SEM, EDX, and TEM, were used to characterize the catalyst structure and composition. The results reveal that the heterogeneous catalyst possesses high specific surface area, large pore volume, good chemical and thermal stability, and highly dispersed palladium. The heterogeneous catalysts were applied in Suzuki-Miyaura coupling reaction to evaluate their catalytic performance. The experiments reflected that the HCPs-Pd(OAc)2 was an efficient catalyst for Suzuki-Miyaura reactions with the yield of biaryl up to 99%, while the TON could reach 2250. The reusability test showed the catalyst was easily recovered and reused for at least six times without obvious decrease in activity.
- Gao, Xiyue,Lin, Hongwei,Liu, Shasha,Luo, Qionglin,Ouyang, Yuejun,Xiang, Bailin,Xiang, Dexuan,Yao, Huan,Zhang, Li
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supporting information
p. 1879 - 1882
(2021/10/29)
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- Palladium nanoparticles encapsulated in polyimide nanofibers: An efficient and recyclable catalyst for coupling reaction
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In this study, palladium-encapsulated poly(amic acid) (Pd@PAA) nanofibers were prepared by electrospinning, followed by thermal imidization to synthesize palladium-encapsulated polyimide (Pd@PI) nanofibers. Scanning electron microscopy (SEM) images confirmed the preparation of uniform and smooth Pd@PAA and Pd@PI nanofibers. Thermogravimetric analysis (TGA) results reveal that the Pd@PI nanofibers possessed excellent thermal stability. The dispersion of palladium nanoparticles in the polyimide nanofibers was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The catalysis results show that this Pd@PI fibrous catalyst was very efficient to catalyze the cross-coupling reactions of aromatic iodides with n-butyl acrylate (Heck reaction) or phenylboronic acid derivatives (Suzuki reaction) to afford the desired products in good to excellent yields. Moreover, the Pd@PI catalyst could be easily separated and recovered from the reaction mixture by simple filtration due to the regular fibrous structure and reused for 10 times for both Heck and Suzuki reactions without obvious loss of its initial catalytic activity. Thus, the Pd@PI nanofiber catalyst holds great potential in chemical industry in terms of its excellent catalytic activity and stability.
- Du, Yijun,Gou, Faliang,Gao, Danning,Liu, Zhifeng,Shao, Linjun,Qi, Chenze
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- Radical Decarboxylative Carbometalation of Benzoic Acids: A Solution to Aromatic Decarboxylative Fluorination
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Abundant aromatic carboxylic acids exist in great structural diversity from nature and synthesis. To date, the synthetically valuable decarboxylative functionalization of benzoic acids is realized mainly by transition-metal-catalyzed decarboxylative cross couplings. However, the high activation barrier for thermal decarboxylative carbometalation that often requires 140 °C reaction temperature limits both the substrate scope as well as the scope of suitable reactions that can sustain such conditions. Numerous reactions, for example, decarboxylative fluorination that is well developed for aliphatic carboxylic acids, are out of reach for the aromatic counterparts with current reaction chemistry. Here, we report a conceptually different approach through a low-barrier photoinduced ligand to metal charge transfer (LMCT)-enabled radical decarboxylative carbometalation strategy, which generates a putative high-valent arylcopper(III) complex, from which versatile facile reductive eliminations can occur. We demonstrate the suitability of our new approach to address previously unrealized general decarboxylative fluorination of benzoic acids.
- Xu, Peng,López-Rojas, Priscila,Ritter, Tobias
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supporting information
p. 5349 - 5354
(2021/05/05)
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- Functionalized chitosan as a novel support for stabilizing palladium in Suzuki reactions
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Chitosan is a versatile polysaccharide in different domains due to facile modification and good biodegradability. In this paper, taking advantage of such functional properties, we have developed a stabilizer agent [OCMCS-SB] produced from chitosan, and palladium was successfully immobilized on this designed stabilizer [OCMCS-SB-Pd(II)]. The obtained complex was illuminated by 13C CP-MAS NMR, FT-IR, TGA, XRD, XPS, SEM, TEM and ICP-OES analyses. Due to the interactions of primary hydroxyl groups on chitosan, Schiff base and carboxy groups, the Pd complex showed excellent reactivity (up to 99 %) and stability towards Suzuki reactions in eco-friendly medium. Subsequently, the reusability experiments for OCMCS-SB-Pd(II) formed from chitosan were examined in five consecutive cycles, which showed no appreciable decrease in activity. Furthermore, a reasonably trifunctional complex structure was proposed. The present bio-based system offers a promising approach in utilizing such biopolymers in organic transformations.
- Dong, Yahao,Bi, Jiajun,Ming, Shujun,Zhang, Shoute,Zhu, Dajian,Meng, Di,Li, Tao
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- Palladium supported on triazolyl-functionalized hypercrosslinked polymers as a recyclable catalyst for Suzuki-Miyaura coupling reactions
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A novel hypercrosslinked polymers-palladium (HCPs-Pd) catalyst was successfully preparedviathe external cross-linking reactions of substituted 1,2,3-triazoles with benzene and formaldehyde dimethyl acetal. The preparation of HCPs-Pd has the advantages of low cost, mild conditions, simple procedure, easy separation and high yield. The catalyst structure and composition were characterized by N2sorption, TGA, FT-IR, SEM, EDX, TEM, XPS and ICP-AES. The HCPs were found to possess high specific surface area, large micropore volume, chemical and thermal stability, low skeletal bone density and good dispersion for palladium chloride. The catalytic performance of HCPs-Pd was evaluated in Suzuki-Miyaura coupling reactions. The results show that HCPs-Pd is a highly active catalyst for the Suzuki-Miyaura coupling reaction in H2O/EtOH solvent with TON numbers up to 1.66 × 104. The yield of biaryls reached 99%. In this reaction, the catalyst was easily recovered and reused six times without a significant decrease in activity.
- Lin, Hongwei,Liu, Cijie,Liu, Shasha,Luo, Qionglin,Ouyang, Yuejun,Shu, You,Xiang, Dexuan,Xu, Wei,Zheng, Lijuan
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p. 17123 - 17128
(2020/05/18)
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- Palladium Immobilized on 2,2′-Dipyridyl-Based Hypercrosslinked Polymers as a Heterogeneous Catalyst for Suzuki–Miyaura Reaction and Heck Reaction
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Abstract: 2,2′-Bipyridine was successfully integrated into the skeleton of hypercrosslinked polymers networks (HCPs-bipy) via Friedel–Crafts reaction and Scholl coupling reaction, and PdCl2 was locked in this network polymers by coordination with pyridine motif. The preparation of HCPs-bipy has the advantages of low cost, mild conditions, easy separation and high yield. FT-IR, TGA, N2 sorption, ICP, XPS, SEM, EDX and TEM was employed to characterize the structure and composition of the heterogeneous catalysts. The result indicates that HCPs-bipy-Pd possess high specific surface areas, large microporous volume, thermal stability, and highly dispersion of palladium species. HCPs-bipy-Pd can be applied in Suzuki–Miyaura reactions and Heck reactions as robust heterogeneous catalyst to afford high yield. The reusability test demonstrates that HCPs-bipy-Pd could be recovered and reused for at least five times without losing catalytic activity. Graphic Abstract: [Figure not available: see fulltext.].
- Liu, Cijie,Xu, Wei,Xiang, Dexuan,Luo, Qionglin,Zeng, Shunqin,Zheng, Lijuan,Tan, Yujie,Ouyang, Yuejun,Lin, Hongwei
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p. 2558 - 2565
(2020/03/23)
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- Highly active PdCu/graphene catalyst for an efficient Suzuki cross-coupling reaction
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A graphene supported Pd-Cu bimetallic catalyst (Pd-Cu/G) has been successfully fabricated by a simple one-pot solvothermal reaction. X-ray diffraction (XRD) analysis as well as morphology characterization demonstrated that Pd-Cu nanoparticles (NPs) are uniformly distributed on the graphene nanosheets. When adopted as the catalyst for the Suzuki cross-coupling reaction, this hybrid exhibited excellent catalytic activity (99.9% conversion) as well as desirable selectivity (99.9%). After recycling five times, the high yield and selectivity were well maintained, illustrating the high durability of this catalyst. This journal is
- M., Xiaojing,Gao, Lingfeng,Weng, Zhentao,Yang, Hua,Sun, Xu
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supporting information
p. 20525 - 20529
(2020/12/28)
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- C-C coupling formation using nitron complexes
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A series of RuII (1), RhIII (2), IrIII (3, 4), IrI (5) and PdII (6-9) complexes of the 'instant carbene' nitron were prepared and characterized by 1H- and 13C-NMR, FT-IR and elemental analysis. The molecular structures of complexes 1-4 and 6 were determined by X-ray diffraction studies. The catalytic activity of the complexes (1-9) was evaluated in alpha(α)-alkylation reactions of ketones with alcohol via the borrowing hydrogen strategy under mild conditions. These complexes were able to perform this catalytic transformation in a short time with low catalyst and base amounts under an air atmosphere. Also, the PdII-nitron complexes (6-9) were applied in the Suzuki-Miyaura C-C coupling reaction and these complexes successfully initiated this reaction in a short time (30 minutes) using the H2O/2-propanol (1.5?:?0.5) solvent system. The DFT calculations revealed that the Pd0/II/0 pathway was more preferable for the mechanism
- Sevim, Mehmet,Kavukcu, Serdar Batikan,Kinal, Arma?an,?ahin, Onur,Türkmen, Hayati
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supporting information
p. 16903 - 16915
(2020/12/18)
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- NHC-Pd complex heterogenized on graphene oxide for cross-coupling reactions and supercapacitor applications
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N-heterocyclic carbene (NHC)-palladium(II) complex (GO@NHC-Pd) was synthesized on graphene oxide (GO) support via a simple and cost-effective multistep approach. The spectroscopic, microscopic, thermal, and surface analyses of GO@NHC-Pd confirmed the successful formation of the catalyst. The investigation of catalytic activity showed that GO@NHC-Pd was very effective in Suzuki–Miyaura as well as Hiyama cross-coupling. Being heterogeneous in nature, GO@NHC-Pd was recovered after each reaction cycle easily and reused for up to nine and six cycles in Suzuki–Miyaura and Hiyama cross-coupling, respectively, without significant loss of activity. Further exploration of the supercapacitor performance of GO@NHC-Pd catalyst assembled in a two-electrode cell configuration shown a maximum attained capacitance of 105.26 F/g at a current density of 0.1 A/g with good cycling stability of 96.89% over 2,500 cycles.
- Kandathil, Vishal,Siddiqa, Aisha,Patra, Abhinandan,Kulkarni, Bhakti,Kempasiddaiah, Manjunatha,Sasidhar,Patil, Shivaputra A.,Rout, Chandra Sekhar,Patil, Siddappa A.
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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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- Palladium catalyst immobilized on functionalized microporous organic polymers for C-C coupling reactions
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Two microporous organic polymer immobilized palladium (MOP-Pd) catalysts were prepared from benzene and 1,10-phenanthroline by Scholl coupling reaction and Friedel-Crafts reaction, respectively. The structure and composition of the catalyst were characterized by FT-IR, TGA, N2 sorption, SEM, TEM, ICP-AES and XPS. MOP-Pd catalysts were found to possess high specific surface areas, large pore volume and low skeletal bone density. Moreover, the immobilized catalyst also had advantages, such as readily available raw materials, chemical and thermal stability, and low synthetic cost. The Pd catalyst is an effective heterogeneous catalyst for carbon-carbon (C-C) coupling reactions, such as the Heck reaction and Suzuki-Miyaura reaction, affording good to high yields. In these reactions, the catalyst was easily recovered and reused five times without significant activity loss.
- Xu, Wei,Liu, Cijie,Xiang, Dexuan,Luo, Qionglin,Shu, You,Lin, Hongwei,Hu, Yangjian,Zhang, Zaixing,Ouyang, Yuejun
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p. 34595 - 34600
(2019/11/11)
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- Palladium immobilized on functionalized hypercrosslinked polymers: A highly active and recyclable catalyst for Suzuki-Miyaura coupling reactions in water
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Heterogeneous catalysts have shown advantages such as high stability, good recyclability and easy separation from reactants over homogeneous catalysts in recent years. In this paper, three pyridine-functionalized N-heterocyclic carbene-palladium complexes (HCP-Pd) were successfully synthesized via a simple external cross-linking reaction. In each catalyst (i.e., complex), palladium (Pd) was immobilized on the hypercrosslinked polymer (HCP) via formation of a six-membered ring by Pd2+ and the bidentate ligands of NHC and pyridine. The structure and composition of HCP-Pd were characterized by SEM, TEM, N2 sorption, FT-IR, TGA and XPS. The catalytic performances of these catalysts in a Suzuki-Miyaura coupling reaction were also studied. The results prove that HCP-Pd is a very effective heterogeneous catalyst for the Suzuki-Miyaura coupling reaction of various aryl halides with aryl boronic acid in an aqueous medium under mild conditions.
- Liu, Xi,Xu, Wei,Xiang, Dexuan,Zhang, Zaixing,Chen, Dizhao,Hu, Yangjian,Li, Yuanxiang,Ouyang, Yuejun,Lin, Hongwei
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supporting information
p. 12206 - 12210
(2019/08/12)
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- A Highly Active Catalyst System for Suzuki-Miyaura Coupling of Aryl Chlorides
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A series of new Pd(II) complexes with simple structures were designed and synthesized for Suzuki-Miyaura coupling reactions of aryl chlorides. The new Pd(II) complexes contain bidentate amine ligands, and their structures were characterized by single-crystal X-ray diffraction. They are highly efficient for Suzuki-Miyaura coupling reactions of aryl chlorides with low catalyst loadings (0.01 mol %) in aqueous media at room temperature. Two possible reaction pathways involving a PdII/0/II and a PdII/IV/II catalytic cycle are proposed, and the mechanism was further investigated using density functional theory (DFT) calculations.
- Liu, Guiyan,Han, Fangwai,Liu, Chengxin,Wu, Hongli,Zeng, Yongfei,Zhu, Rongjiao,Yu, Xia,Rao, Shuang,Huang, Genping,Wang, Jianhui
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p. 1459 - 1467
(2019/03/19)
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- From agriculture residue to catalyst support; A green and sustainable cellulose-based dip catalyst for C–C coupling and direct arylation
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The core characteristics of a perfect catalyst include good activity, simple design, excellent stability, easy recovery from reaction mixture, recyclability, and have the provision for easy scale up. The ease in synthesis, recyclability and scale up makes the dip catalyst a major contender in this regard which possess most of the aforementioned characteristics. In this work, we report a dip catalyst made of cellulose, isolated from agriculture residue (sugarcane bagasse), in which biogenically synthesized palladium nanoparticles were dispersed. The prepared dip catalyst was characterized by FESEM, EDS, XRD, ATR-IR, TGA, TEM, XPS and ICP-OES analysis. Also, the activity of the dip catalyst was studied in the Suzuki-Miyaura cross-coupling reaction and was found to give excellent conversion with 15 recycles. Further, the activity of dip catalyst in C5-arylation of 2-substituted thiophenes was evaluated for which promising yields were obtained.
- Kandathil, Vishal,Kempasiddaiah, Manjunatha,B. S., Sasidhar,Patil, Siddappa A.
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- Pd-nanoparticles catalyzed denitrogenative coupling of aryl halides with arylhydrazines: Greener approach for biaryls synthesis under ligand-free condition
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The greener approach for the synthesis of biaryl using palladium nanoparticle (Pd–NPs) catalyzed denitrogenative coupling between aryl hydrazine and aryl halides under ligand-free condition has been described. The phytochemicals of the black pepper extract plays a dual role in reduction of PdII to Pd0 and acts as stabilizing agent for Pd–NPs. The electronically diver's arylhydrazines and commercially available aryl halides are used for the synthesis of symmetrical and unsymmetrical biaryls in good to excellent yield. The mechanism is well supported by control experiment and the recyclability, turnover number and turnover frequency of biogenically synthesized Pd–NPs is studied.
- Hegde, Rajeev V.,Ghosh, Arnab,Patil, Siddappa A.,Dateer, Ramesh B.
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supporting information
(2019/12/09)
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- Aryl-Fluoride Bond-Forming Reductive Elimination from Nickel(IV) Centers
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The treatment of pyridine- and pyrazole-ligated NiII σ-aryl complexes with Selectfluor results in C(sp2)-F bond formation under mild conditions. With appropriate design of supporting ligands, diamagnetic NiIV σ-aryl fluoride intermediates can be detected spectroscopically and/or isolated during these transformations. These studies demonstrate for the first time that NiIV σ-aryl fluoride complexes participate in challenging C(sp2)-F bond-forming reductive elimination to yield aryl fluoride products.
- Meucci, Elizabeth A.,Ariafard, Alireza,Canty, Allan J.,Kampf, Jeff W.,Sanford, Melanie S.
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p. 13261 - 13267
(2019/09/07)
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- Ni: Vs. Pd in Suzuki-Miyaura sp2-sp2 cross-coupling: A head-to-head study in a comparable precatalyst/ligand system
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The Suzuki-Miyaura reaction is a cornerstone method for sp2-sp2 cross-coupling in industry. There has been a concerted effort to enable the use of Ni catalysis as an alternative to Pd in order to mitigate cost and improve sustainability. Despite significant advances, ligand development for Ni-catalyzed Suzuki-Miyaura cross-coupling remains underdeveloped when compared to Pd and, as a consequence, ligands for Ni-catalyzed processes are typically taken from the Pd arena. In this study we evaluate the effect of using a similar Ni and Pd precatalyst based on a common bidentate ligand (dppf) in a head-to-head format for the most common type of biaryl couplings, establishing the practical implications of direct replacement of Pd with Ni, and identifying the potential origins of these observations in a mechanistic context.
- West, Matthew J.,Watson, Allan J. B.
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supporting information
p. 5055 - 5059
(2019/06/03)
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- Hypervalent Iodine(III)-Catalyzed Balz–Schiemann Fluorination under Mild Conditions
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An unprecedented hypervalent iodine(III) catalyzed Balz–Schiemann reaction is described. In the presence of a hypervalent iodine compound, the fluorination reaction proceeds under mild conditions (25–60 °C), and features a wide substrate scope and good functional-group compatibility.
- Xing, Bo,Ni, Chuanfa,Hu, Jinbo
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p. 9896 - 9900
(2018/07/31)
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- Application of trivalent iodine compounds as catalysts in Bal-Schiemann reaction
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The invention discloses an application of trivalent iodine compounds shown in formula I and/or II in the description and used as catalysts in Bal-Schiemann reaction. The trivalent iodine compounds areused as the catalysts in the Bal-Schiemann reaction, so that the Bal-Schiemann reaction can be conducted at room temperature or near room temperature when a thermochemical method is used, and the reaction has mild reaction conditions, wide substrate use range and short reaction time, and is safe and easy to operate, products are easy to separate, and raw materials are simple and low in toxicity.
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Paragraph 0153; 0158
(2018/10/19)
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- NITROGEN-CONTAINING BIOPOLYMER-BASED CATALYSTS, THEIR PREPARATION AND USES IN HYDROGENATION PROCESSES, REDUCTIVE DEHALOGENATION AND OXIDATION
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The present invention relates to a process for the preparation of a nitrogen containing biopolymer-based catalyst by pyrolysis of a metal complex with a nitrogen-containing biopolymer and to the nitrogen containing biopolymer-based catalysts obtainable by this process. In particular, the invention relates to a nitrogen containing biopolymer-based catalyst comprising metal particles and at least one nitrogen containing carbon layer. The invention also relates to the use of a nitrogen containing biopolymer-based catalyst in a hydrogenation process, preferably in a process for hydrogenation of nitroarenes, nitriles or imines; in a reductive dehalogenation process of C-X bonds, wherein X is CI, Br or I, preferably in a process for dehalogenation of organohalides or in a process for deuterium labelling of arenes via dehalogenation of organohalides; or in an oxidation process. Further, the invention relates to a metal complex with the nitrogen containing biopolymer, wherein the metal is a transition metal selected from the group consisting of manganese, ruthenium, cobalt, rhodium, nickel, palladium and platinum, preferably cobalt or nickel, and wherein the nitrogen containing biopolymer is selected from chitosan, chitin and a polyamino acid, preferably chitosan or chitin.
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Page/Page column 20-21
(2018/07/29)
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- Transition-Metal-Free C-H Arylation of Unactivated Arenes with 8-Hydroxyquinoline as a Promoter
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A method for the transition-metal-free direct C-H arylation of unactivated arenes is developed with aryl bromides as substrates and 8-hydroxyquinoline as an efficient promoter. A variety of biaryl compounds with structural diversity are obtained in moderate to high yields. Mechanistic studies reveal that the reaction proceeds via a homolytic aromatic substitution pathway.
- Zheng, Xuehua,Wu, Xu-Nian,Chen, Jing-Yi,Luo, Hai-Bin,Wu, Deyan,Wu, Yinuo
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p. 1721 - 1727
(2018/02/06)
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- Alumina as Solid-State Ligand in Enhancing the Redox Catalytic Property of Iron Oxide Grafted AlSBA-15 towards Arylation of Arene
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2–8 wt % iron has been grafted over SBA-15 and 10 wt % alumina grafted SBA-15 (AlSBA-15) through selective extraction deposition technique using LaFeO3 as iron precursor in acidic solution. DRS-UV spectra confirmed the presence of iron as isolated Fe(III), Fe(III)-clusters and amorphous FeOx oligomers. SEM-EDX mapping, FT-IR, XPS, HR-TEM and 27Al MAS NMR characterisation results confirmed that iron grafted over AlSBA-15 preferentially reside on the alumina. The donor-acceptor interaction of grafted iron ions with alumina atoms displaying Lewis acid properties stabilized iron at higher oxidation state Fe(III+δ). This increased the BE of Fe2p electrons (XPS) and shifted the temperature of iron reduction in 2–8 wt %Fe/AlSBA-15 materials to higher value (600 °C) compared with Fe/SBA-15 (H2-TPR). In arylation of benzene, 8 wt %Fe/AlSBA-15 demonstrated excellent redox catalytic activity with TOF close to homogeneous catalyst and 82 % biphenyl yield. The catalyst demonstrated consistent catalytic performance for 7 cycles.
- Rajendran, Chandran,Thirumoorthy, Kulandaivellu,Satishkumar, Govindaswamy,Landau, Miron V.
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p. 4768 - 4776
(2018/10/02)
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- Direct Aryl-Aryl Coupling without Pre-Functionalization Enabled by Excessive Oxidation of Two-Electron Ag(I)/Ag(III) Catalyst
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Reported herein is a catalytic platform for formation of unsymmetrical biaryls by the coupling between inert Csp2?CH3 and Csp2?H via a tandem catalytic strategy. The platform utilizes traditional AgNO3 catalyst and excess amount of K2S2O8 oxidant. The excessive oxidant present converts the traditional one-electron Ag(I)/Ag(II) chemistry to two-electron Ag(I)/Ag(III) one, enabling one-pot synthesis of aryl-aryl scaffolds by using unactivated cheap commodity chemicals. (Figure presented.).
- Singh, Ajay K.,Kim, Min-Gyu,Lee, Hyune-Jea,Singh, Rakhi,Cho, Seung Hwan,Kim, Dong-Pyo
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supporting information
p. 2032 - 2042
(2018/04/11)
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- METHOD FOR AROMATIC FLUORINATION
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Disclosed is a fluorination method comprising providing an aryl fluorosuifonate and a fluorinating reagent to a reaction mixture; and reacting the aryl fluorosuifonate and the fluorinating reagent to provide a fluorinated aryl species. Also disclosed is a fluorination method comprising providing, a salt comprising a cation and an aryloxyiate, and SO2F2 to a reaction mixture; reacting the SO2F2 and the ammonium salt to provide a fluorinated aryl species. Further disclosed a fluorination method comprising providing a compound having the structure Ar-OH to a reaction mixture; where A is an aryl or heteroaryl; providing SO2F2 to the reaction mixture; providing a fluorinating reagent to the reaction mixture; reacting the SO2F2, the fluorinating reagent and the compound having the structure Ar-OH to provide a fluorinated aryl species having the structure Ar-F.
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Paragraph 0047-0049
(2017/12/18)
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- ONE STEP DIRECT ARYLATION OF COMMODITY CHEMICALS TO SPECIALTY CHEMICALS BY TANDEM CATALYTIC PLATFORM
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The present invention relates to a continuous direct arylation process based on a tandem catalyst for synthesizing specialty chemicals. A method for synthesizing an aryl-aryl structure from a substrate selected from the group consisting of benzyl alcohol, benzyl amine and toluene which are low value added compounds is developed using a silver ion-containing tandem catalyst. The method is applied for synthesizing hexaphenyl arylene and can be applied for synthesizing high value added compounds (not only natural substances and chemical compounds but pharmaceutical and agricultural pesticide relative fields) directly from primary raw materials through the reaction.COPYRIGHT KIPO 2017
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Paragraph 0057; 0058; 0066-0103; 0106
(2018/02/28)
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- A Biomass-Derived Non-Noble Cobalt Catalyst for Selective Hydrodehalogenation of Alkyl and (Hetero)Aryl Halides
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Hydrodehalogenation is a straightforward approach for detoxifications of harmful anthropogenic organohalide-based pollutants, as well as removal of halide protecting groups used in multistep syntheses. A novel sustainable catalytic material was prepared from biowaste (chitosan) in combination with an earth-abundant cobalt salt. The heterogeneous catalyst was fully characterized by transmission electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy measurements, and successfully applied to hydrodehalogenation of alkyl and (hetero)aryl halides with broad scope (>40 examples) and excellent chemoselectivity using molecular hydrogen as a reductant. The general usefulness of this method is demonstrated by successful detoxification of non-degradable pesticides and fire retardants. Moreover, the potential of the catalyst as a deprotection tool is demonstrated in a multistep synthesis of (±)-peronatin B (alkaloid).
- Sahoo, Basudev,Surkus, Annette-Enrica,Pohl, Marga-Martina,Radnik, J?rg,Schneider, Matthias,Bachmann, Stephan,Scalone, Michelangelo,Junge, Kathrin,Beller, Matthias
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supporting information
p. 11242 - 11247
(2017/09/02)
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- An N-Heterocyclic Carbene-Nickel Half-Sandwich Complex as a Precatalyst for Suzuki-Miyaura Coupling of Aryl/Heteroaryl Halides with Aryl/Heteroarylboronic Acids
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A nickel half-sandwich complex supported by our original NHC ligand was developed as a robust precatalyst for Suzuki-Miyaura cross-coupling. The addition of PPh3 was a crucial element in the suppression of side reactions and in accelerating the cross-coupling reaction. By employing the optimal conditions, aryl-aryl, heteroaryl-aryl, and heteroaryl-heteroaryl couplings were achieved.
- Ando, Shin,Matsunaga, Hirofumi,Ishizuka, Tadao
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p. 1266 - 1272
(2018/06/18)
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- Mild, visible light-mediated decarboxylation of aryl carboxylic acids to access aryl radicals
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Herein we present the first example of aryl radical formation via the visible light-mediated decarboxylation of aryl carboxylic acids using photoredox catalysis. This method constitutes a mild protocol for the decarboxylation of cheap and abundant aryl carboxylic acids and tolerates both electron-rich substrates and those lacking ortho-substitution. The in situ formation of an acyl hypobromite is proposed to prevent unproductive hydrogen atom abstraction and trapping of the intermediate aroyloxy radical, enabling mild decarboxylation.
- Candish,Freitag,Gensch,Glorius
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p. 3618 - 3622
(2017/07/11)
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- Nucleophilic deoxyfluorination of phenols via aryl fluorosulfonate intermediates
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This report describes a method for the deoxyfluorination of phenols with sulfuryl fluoride (SO2F2) and tetramethylammonium fluoride (NMe4F) via aryl fluorosulfonate (ArOFs) intermediates. We first demonstrate that the reaction of ArOFs with NMe4F proceeds under mild conditions (often at room temperature) to afford a broad range of electronically diverse and functional group-rich aryl fluoride products. This transformation was then translated to a one-pot conversion of phenols to aryl fluorides using the combination of SO2F2 and NMe4F. Ab initio calculations suggest that carbon-fluorine bond formation proceeds via a concerted transition state rather than a discrete Meisenheimer intermediate.
- Schimler, Sydonie D.,Cismesia, Megan A.,Hanley, Patrick S.,Froese, Robert D.J.,Jansma, Matthew J.,Bland, Douglas C.,Sanford, Melanie S.
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supporting information
p. 1452 - 1455
(2017/02/10)
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- N-Doped porous carbon nanotubes: Synthesis and application in catalysis
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Uniform N-doped carbon nanotubes were obtained for the first time via a morphology-preserving thermal transformation of organic polymer nanotubes without any additional templates. These carbon nanotubes acted as a superior metal-free carbon catalyst for C-H arylation of benzene, reductive hydrogen atom transfer and oxidation reactions.
- Yang, Zhenzhen,Liu, Zhenghui,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Wang, Huan,Ji, Guipeng,Chen, Yu,Liu, Xinwei,Liu, Zhimin
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supporting information
p. 929 - 932
(2017/01/17)
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- Diamine bis(phenolate) and pendant amine bis(phenolate) ligands: Catalytic activity for the room temperature palladium-catalyzed Suzuki-Miyaura coupling reaction
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A series of amine bis(phenolate) ligands bearing aryl substituents of varying steric bulk are reported and characterized using single-crystal X-ray diffraction, NMR spectroscopy and high-resolution mass spectrometry experiments. Palladium complexes derived in situ from these ligands are evaluated as catalysts for the Suzuki-Miyaura coupling of phenylboronic acid and aryl bromides. High conversions are observed for these reactions in methanol solvent at low catalyst loadings (0.01 mol%), short reaction times (30 min) and mild temperatures (30°C). Conversion is observed for a range of substrates, and is found to depend on the nature of the external base and solvent employed. These findings demonstrate the utility of catalysts derived from late transition metal complexes of amine bis(phenolate) ligands, particularly those bearing bulky cumyl substituents.
- Bowser, Andrew K.,Anderson-Wile, Amelia M.,Johnston, Dean H.,Wile, Bradley M.
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- Catalytic Suzuki couplings by an amido pincer complex of palladium
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The catalytic feasibility of [PNP]PdCl, where [PNP]- = bis(2-diphenylphosphinophenyl)amide, on biaryl syntheses from Suzuki-type cross-coupling reactions is demonstrated. A number of electronically activated, unactivated, and deactivated (hetero)aryl bromides and iodides is viable to react with arylboronic acids. Of particular note of this catalysis is its success in the high yield production of sterically encumbered tri-ortho-substituted biaryls and its operative compatibility under aerobic conditions in aqueous solutions.
- Liang, Lan-Chang,Chien, Pin-Shu,Song, Liang-Hua
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- Mono- and dinuclear palladium(II) complexes containing both N-heterocyclic carbenes and tetrazole ligands as catalysts for Hiyama coupling
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Treatment of the dimeric compounds [Pd(μ-Cl)(Cl)(NHC)]2 with tetrazole ligands afforded a series of tetrazole ligand stabilized NHC-Pd complexes, including [PdCl2(IPr)(1H-tetrazole)] (1), [PdCl2(SIPr)(1H-tetrazole)] (2), [PdCl2(IPr)(1-phenyl-1H-tetrazole)] (3), [PdCl2(SIPr)(1-phenyl-1H-tetrazole)] (4), [Pd2(μ-Cl)(μ-5-phenyl-2H-tetrazole)Cl2(IPr)2] (5) and [Pd2(μ-Cl)(μ-5-pheny-2H-ltetrazole)Cl2(SIPr)2] (6) [IPr = N,N′-bis-(2,6-di(isopropyl)phenyl)imidazol-2-ylidene; SIPr = N,N′-bis-(2,6-di(isopropyl)phenyl)imidazolidin-2-ylidene]. Notably, compounds 1-4 are mononuclear NHC-Pd complexes, while compounds 5 and 6 show unprecedented μ-Cl and μ-5-phenyl-2H-tetrazole bridged dinuclear structures. The catalytic properties of the obtained NHC-Pd complexes in Hiyama coupling were initially investigated.
- Yang, Jin
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p. 9739 - 9745
(2016/11/11)
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- Magnetic Pd–Fe3O4 Heterodimer Nanocrystals as Recoverable Catalysts for Ligand-Free Hiyama Cross-Coupling Reactions
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Ligand-free Hiyama cross-coupling reaction was achieved through the use of Pd–Fe3O4 heterodimeric nanocrystals (1 mol% in Pd) as recyclable catalysts. The nanocrystal catalysts exhibited good activities accommodating a variety of substrates including aryl bromides and iodides with substituents of varying electronic and steric properties. Furthermore, the nanocrystal catalyst could be conveniently recovered with the aid of an external magnet and recycled five times without the loss of catalytic activity to a considerable degree.
- Lee, Woong-Sup,Byun, Sangmoon,Kwon, Jungmin,Kim, B. Moon
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p. 1992 - 1997
(2016/12/16)
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- An Indefinitely Air-Stable σ-NiII Precatalyst for Quantitative Cross-Coupling of Unreactive Aryl Halides and Mesylates with Aryl Neopentylglycolboronates
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Three classes of Ni precatalysts based on π-NiII, π-Ni0 and σ-NiII complexes have been elaborated and employed in different laboratories for the functionalization and cross-coupling of otherwise inert aryl C-O, C-Cl, and C-F electrophiles. Various Ni precatalysts, ligands, boron sources, and reaction conditions that were developed in various research groups, necessitated the selection of the most suitable conditions for desired cross-coupling partners. Here a universal, bench-stable, easily prepared NiIICl(1-naphthyl)(PCy3)2/PCy3 σ-complex, for efficient and quantitative cross-coupling of aryl chlorides, bromides, iodides, mesylates, and fluorides with aryl neopentylglycolboronates is reported. This precatalyst will most probably help to advance the applications of Ni catalysis in organic, supramolecular, and macromolecular synthesis and will provide an easier access to the selection of reaction conditions for various transformations.
- Malineni, Jagadeesh,Jezorek, Ryan L.,Zhang, Na,Percec, Virgil
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supporting information
p. 2795 - 2807
(2016/08/31)
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- Continuous-Flow Synthesis of Biaryls by Negishi Cross-Coupling of Fluoro- and Trifluoromethyl-Substituted (Hetero)arenes
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A continuous-flow method for the regioselective arylation of fluoroarenes and fluoropyridines has been developed. The telescoped procedure reported here consists of a three-step metalation, zincation, and Negishi cross-coupling sequence, providing efficient access to a variety of functionalized 2-fluorobiaryl products. Precise temperature control of the metalation step, made possible by continuous-flow technology, allowed for the efficient preparation of the arylated products in high yields and short residence times. Additionally, several examples of the regioselective arylation of benzotrifluoride derivatives are also provided.
- Roesner, Stefan,Buchwald, Stephen L.
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supporting information
p. 10463 - 10467
(2016/08/24)
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- Electron-Poor, Fluoro-Containing Arylboronic Acids as Efficient Coupling Partners for Bis(1,5-cyclooctadiene)nickel(0)/Tricyclohexylphosphine-Catalyzed Cross-Coupling Reactions of Aryl Arenesulfonates
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The use of electron-poor, fluoro-containing arylboronic acids as general coupling partners for nickel(0)/tricyclohexylphosphine-catalyzed cross-coupling of aryl arenesulfonates is described. Electron-poor fluoro-containing arylboronic acids were found to react faster than electron-rich/neutral arylboronic acids, with (4-methoxyphenyl)(4-methylbenzenesulfonato-κO)bis(tricyclohexylphosphine)nickel. Bis(1,5-cyclooctadiene)nickel(0)/tricyclohexylphosphine, (4-methoxyphenyl)(4-methylbenzenesulfonato-κO)bis(tricyclohexylphosphine)nickel and bis(tricyclohexylphosphine)nickel(II) bromide were all found to be efficient catalysts/catalyst precursors. (Figure presented.) .
- Chen, Wen-Bo,Xing, Chun-Hui,Dong, Jie,Hu, Qiao-Sheng
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supporting information
p. 2072 - 2076
(2016/07/16)
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- Newly-generated Al(OH)3-supported Pd nanoparticles-catalyzed Stille and Kumada coupling reactions of diazonium salts, (Het)aryl chlorides
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A ligand-free Pd/Al(OH)3 nano-catalyst which is prepared by one-pot three-component method using Pd(PPh3)4, tetra (ethylene glycol), and aluminum tri-sec-butoxide exhibits excellent catalytic activity in Stille cross-couplings of (Het)aryl chlorides, arenediazonium tetrafluoroborate salts with phenyltributylstannane, respectively, and Kumada couplings of (Het)aryl chlorides with various Grignard reagents. More importantly, these two processes show excellent functional group compatibility with moderate to good yields and they are also versatile with respect to not only (Het)aryl chlorides, but also diazonium salts, and heteroaryl Grignard reagents. The nano-catalyst could also be recycled and reused 5 times without loss of activity and decrease of yield.
- Li, Xing,Zhu, Tingting,Shao, Zhongqi,Li, Yingjun,Chang, Honghong,Gao, Wenchao,Zhang, Yongli,Wei, Wenlong
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supporting information
p. 69 - 75
(2015/12/23)
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- Polyureas derived from CO2 and diamines: highly efficient catalysts for C-H arylation of benzene
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Polyureas derived from CO2 and diamines were effective for C-H arylation of benzene in the presence of t-BuOK, producing biaryl products with various substituents in high yields up to 97%. Dual-activation of K+ and t-BuO-, and π,π-stacking interaction between the substrate and the polymer backbone may account for the superior activity.
- Liu, Zhenghui,Yang, Zhenzhen,Hao, Leiduan,Liu, Xinwei,Zhang, Hongye,Yu, Bo,Liu, Zhimin
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supporting information
p. 51 - 55
(2016/12/30)
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- Ligand-promoted oxidative cross-coupling of aryl boronic acids and aryl silanes by palladium catalysis
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The first cross-coupling reaction between aryl silanes and aryl boronic acids is described. This transformation represents one of the very few examples of coupling reactions between two nucleophilic organometallic reagents and provides a new method for the formation of biaryl compounds. The successful development of this reaction was enabled by the use of commercially available 2,2-bis(diphenylphosphino)-1,1-binaphthyl (BINAP) as the ligand. A small amount of BINAP (3 mol %) was sufficient to suppress the formation of the homocoupling products, and the reaction yielded the cross-coupling products with high selectivity under mild conditions, even when the ratio of the two coupling partners was 1:1.
- Yu, Jingxun,Liu, Jun,Shi, Guangfa,Shao, Changdong,Zhang, Yanghui
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supporting information
p. 4079 - 4082
(2015/03/30)
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- Photocatalytic Suzuki coupling reaction using conjugated microporous polymer with immobilized palladium nanoparticles under visible light
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Extensive research has been done to develop heterogeneous Pd catalysts for Suzuki coupling reactions, such as the immobilization or stabilization of Pd nanoparticles (NP) on silica, carbon nanotubes, polymers, metal oxides, dendrimers, and graphene layers. Upon photoirradiation, both the average energy and the effective flow of free electrons toward the Pd NPs would be amplified, which can be exploited and harvested to catalyze reactions. Suzuki coupling reactions are performed under homogeneous conditions using a variety of phosphine ligand or palladium catalytic complexes. Despite the relatively high efficiency of these homogeneous systems, the recovery of the costly and potentially toxic palladium catalysts remains as a pressing issue in the development toward a greener, more sustainable chemical industry.
- Wang, Zi Jun,Ghasimi, Saman,Landfester, Katharina,Zhang, Kai A. I.
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p. 1921 - 1924
(2015/04/14)
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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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supporting information
p. 5232 - 5235
(2015/11/18)
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- Ligand-controlled chemoselectivity in potassium tert-amylate-promoted direct C-H arylation of unactivated benzene with aryl halides
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Direct C-H arylation of unactivated benzene with aryl halides under various simple ligands (EDA, DMEDA, ethylene glycol, etc.) in the presence of potassium tert-amylate (t-AmOK) base at mild temperature (80 °C) have been developed. This transition-metal-free radical cross-coupling offers an efficient way to synthesize various biaryls in good yields through base-promoted homolytic aromatic substitution. And mechanistic investigations have provided insight into the chemoselectivity of couplings between haloiodobenzenes and benzene and showed that phenanthroline and its derivatives not only initiate these radical reactions like most of other ligands (EDA, DMEDA, ethylene glycol, etc.), but also participate in the electron transfer process of biaryl radical anion intermediates.
- Liu, Wei,Xu, Lige
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p. 4974 - 4981
(2015/06/25)
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- PhenoFluorMix: Practical chemoselective deoxyfluorination of phenols
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A practical deoxyfluorination with novel deoxyfluorinating reagent PhenoFluorMix, a mixture of N,N'-1,3-bis(2,6-diisopropylphenyl)chloroimidazolium chloride and CsF, is presented. PhenoFluorMix overcomes the challenges associated with hydrolysis of PhenoFluor. PhenoFluorMix does not hydrolyze, is readily available on decagram scale, and is storable in air. In this paper, we demonstrate the practicality of the reagent and exhibit the deoxyfluorination of a variety of phenols and heterocycles.
- Fujimoto, Teppei,Ritter, Tobias
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supporting information
p. 544 - 547
(2015/03/05)
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- Trans-chloro-(1-naphthyl)bis[tris-(4-methoxyphenyl)phosphane]-nickel(II) catalyzed Suzuki-Miyaura coupling of aryl chlorides with phenylboronic acid
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A readily accessible trans-chloro-(1-naphthyl)bis-[tris-(4-methoxyphenyl)phosphine]-nickel(II) [NiCl(MOTPP)2(1-naphthyl)] complex was prepared and applied successfully to the Suzuki-Miyaura coupling of aryl chlorides with phenylboronic acid. The pre-catalyst readily forms the catalytically active Ni(0) species in situ under mild conditions without an additional reducing reagent. The electron-rich methoxy moieties on the phosphine ligand may increase the electron density of Ni and thus accelerates the reaction rate of oxidative addition. Single crystal X-ray diffraction revealed the NiCl and NiC bonds were lengthened in comparison with those in NiCl(PPh3)2(1-naphthyl), presumably owing to the stronger electron donating ability of MOTPP, which would facilitate the oxidative addition step.
- Zheng, Xueli,Yang, Qin,Li, Ziyao,Zhu, Zhu,Cui, Xiaoyu,Fu, Haiyan,Chen, Hua,Li, Ruixiang
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p. 143 - 147
(2014/12/11)
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- Direct C-H arylations of unactivated arenes catalyzed by amido-functionalized imidazolium salts
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The synthesis of biaryls from unactivated arenes and a broad range of aryl bromides and chlorides via the direct C-H functionalization can be efficiently performed with the aid of amido-functionalized imidazolium salts as organocatalysts. This method avoids the use of toxic transition metal catalysts and organometallic reagents.
- Ghosh, Debalina,Lee, Jhen-Yi,Liu, Chian-Yu,Chiang, Yen-Hsin,Lee, Hon Man
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supporting information
p. 406 - 410
(2014/05/20)
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- Triphyrin catalyzed direct C-H arylation of benzene with aryl halides
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Transition-metal free direct C-H arylation of benzene with aryl halides was achieved by meso-aryl-substituted [14]triphyrins(2.1.1) catalysts in an air atmosphere. Various aryl halides underwent successful direct C-H arylation of benzene to give moderate to high yields of biaryls. A radical mechanism is proposed for this triphyrin catalyzed C-H arylation reaction.
- Xue, Zhao-Li,Qian, Ying Ying,Chan, Kin Shing
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supporting information
p. 6180 - 6183
(2015/02/19)
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