- Solvent-free palladium-catalyzed C–O cross-coupling of aryl bromides with phenols
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A new solvent-free procedure for C–O cross-coupling between phenols and aryl bromides comprising of Pd2(dba)3/ButBrettPhos catalytic system is efficient for substrates bearing donor or acceptor, as well as bulky substituents.
- Asachenko, Andrey F.,Bogachev, Vasilii N.,Cherkashchenko, Ilia R.,Lavrov, Konstantin V.,Minaeva, Lidiya I.,Nechaev, Mikhail S.,Rzhevskiy, Sergey A.,Sterligov, Grigorii K.,Topchiy, Maxim A.
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Read Online
- Synthesis of psoralen analogues based on dibenzofuran
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The syntheses of four novel psoralen derivatives, 6a-d, of the benzofurocoumarin (=benzofuro[1]benzopyranone) type containing an ester group are described. These compounds might be of interest in PUVA (psoralen long-wave ultraviolet radiation) therapy. The overall efficiency of the synthetic procedure is greatly limited by the low yields for the penultimate step, i.e., formylation of the dibenzofuranols 3a,c or protected dibenzofuranol 4d to the carboxaldehydes 5 (Scheme 4). However, the final stage to form the pyranone ring from 5a - d proceeds smoothly (Scheme 5).
- Oliveira, Ana M. A. G.,Raposo, M. Manuela M.,Oliveira-Campos, Ana M. F.,Griffiths, John,Machado, Antonio E. H.
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Read Online
- Magnetization of graphene oxide nanosheets using nickel magnetic nanoparticles as a novel support for the fabrication of copper as a practical, selective, and reusable nanocatalyst in C-C and C-O coupling reactions
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Catalyst species are an important class of materials in chemistry, industry, medicine, and biotechnology. Moreover, waste recycling is an important process in green chemistry and is economically efficient. Herein, magnetic graphene oxide was synthesized using nickel magnetic nanoparticles and further applied as a novel support for the fabrication of a copper catalyst. The catalytic activity of supported copper on magnetic graphene oxide (Cu-ninhydrin@GO-Ni MNPs) was investigated as a selective, practical, and reusable nanocatalyst in the synthesis of diaryl ethers and biphenyls. Some of the obtained products were identified by NMR spectroscopy. This nanocatalyst has been characterized by atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), wavelength dispersive X-ray spectroscopy (WDX), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM) techniques. The results obtained from SEM shown that this catalyst has a nanosheet structure. Also, XRD and FT-IR analysis show that the structure of graphene oxide and nickel magnetic nanoparticles is stable during the modification of the nanoparticles and synthesis of the catalyst. The VSM curve of the catalyst shows that this catalyst can be recovered using an external magnet; therefore, it can be reused several times without a significant loss of its catalytic efficiency. The heterogeneity and stability of this nanocatalyst during organic reactions was confirmed by the hot filtration test and AAS technique.
- Hajjami, Maryam,Moradi, Parisa
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p. 25867 - 25879
(2021/08/09)
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- Compound and light emitting device comprising the same
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A compound for a light emitting device, the compound being represented by Formula 1:wherein, in Formula 1, the variables are defined herein.
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Paragraph 0398-0401
(2021/09/14)
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- URJC-1-MOF as New Heterogeneous Recyclable Catalyst for C-Heteroatom Coupling Reactions
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Guillermo Calleja and co-workers from @urjc describe URJC-1-MOF as a new heterogeneous recyclable catalyst for c-heteroatom coupling reactions. The capacity of copper-based URJC-1-MOF as a MOF catalyst in cross-coupling reactions has been evaluated, focusing on the Chan-Lam-Evans arylation-type reactions on amines and alcohols without extra additives or ligands. The extraordinary chemical and structural stability of URJC-1-MOF and its good specific surface, make this material a promising alternative to homogeneous Cu (II) catalysts for cross-coupling reactions. URJC-1-MOF showed a remarkable catalytic activity for cross-coupling C?N and C?O reactions, higher than other heterogeneous and homogeneous copper-based catalyst, such as CuO, HKUST-1, Cu?MOF-74, Cu(OAc)2 and CuSO4?5H2O. Moreover, its easy recovery by simple filtration and reusability in successive runs without any loss of activity and stability, demonstrates the potential of URJC-1-MOF as an alternative catalyst for this kind of reactions in different chemical media of industrial interest.
- Mu?oz, Antonio,Leo, Pedro,Orcajo, Gisela,Martínez, Fernando,Calleja, Guillermo
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p. 3376 - 3380
(2019/07/04)
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- Zirconium oxide complex anchored on boehmite nanoparticles as highly reusable organometallic catalyst for C–S and C–O coupling reactions
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Boehmite nanoparticles were prepared by a simple and inexpensive procedure in water using commercially available materials without inert atmosphere. Then, the surface of the boehmite nanoparticles was modified using 3-mercaptopropyltrimethoxysilane and subsequently zirconium oxide was supported on the modified surface. Zirconium oxide supported on boehmite nanoparticles (Pr.S-ZrO@boehmite) was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and inductively coupled plasma technique. The catalytic application of Pr.S-ZrO@boehmite was studied in C–O and C–S coupling reactions for synthesis of valuable compounds such as ether and sulfide derivatives. All products were obtained in good to excellent yields and the catalyst could be recovered and reused several times without significant loss of catalytic efficiency. Furthermore, zirconium oxide is rarely used as catalyst for cross-coupling reactions.
- Ghorbani-Choghamarani, Arash,Seydyosefi, Zeinab,Tahmasbi, Bahman
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- Cu2O/SiC as efficient catalyst for Ullmann coupling of phenols with aryl halides
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A Cu2O/SiC heterogeneous catalyst was prepared via a two-step liquid-phase method using diethylene glycol as both the solvent and the reducing agent. The catalyst was characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and H2 temperature-programmed reduction. All the results indicate that Cu is present on the SiC support primarily as Cu2O. The SEM and TEM results show that cubic Cu2O nanoparticles are uniformly dispersed on the β-SiC surface. The reaction conditions, namely the temperature, reaction time, and amounts of base and catalyst used, for the Ullmann-type C–O cross-coupling reaction were optimized. A model reaction was performed using iodobenzene (14.0 mmol) and phenol (14.0 mmol) with Cu2O/SiC (5 wt% Cu) as the catalyst, Cs2CO3 (1.0 equiv.) as the base, and tetrahydrofuran as the solvent at 150 °C for 3 h; a yield of 97% was obtained and the turnover frequency (TOF) was 1136 h?1. The Cu2O/SiC catalyst has a broad substrate scope and can be used in Ullmann-type C–O cross-coupling reactions of aryl halides and phenols bearing a variety of different substituents. The catalyst also showed high activity in the Ullmann-type C–S cross-coupling of thiophenol with iodobenzene and substituted iodobenzenes; a TOF of 1186 h?1 was achieved. The recyclability of the Cu2O/SiC catalyst in the O-arylation of phenol with iodobenzene was investigated under the optimum conditions. The yield decreased from 97% to 64% after five cycles. The main reason for the decrease in the catalyst activity is loss of the active component, i.e., Cu2O.
- Wang, Yibing,Guo, Xiaoning,Lü, Manqian,Zhai, Zhaoyang,Wang, Yingyong,Guo, Xiangyun
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p. 658 - 664
(2017/04/24)
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- Ullmann Reaction Catalyzed by Heterogeneous Mesoporous Copper/Manganese Oxide: A Kinetic and Mechanistic Analysis
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A heterogeneous copper oxide supported on mesoporous manganese oxide (meso Cu/MnOx) was explored for Ullmann-type cross-coupling reactions. An inverse micelle-templated evaporation-induced self-assembly method with in situ addition of copper was adopted to synthesize the mesoporous catalyst. Broad substrate scope and excellent functional group tolerability in C-O, C-N, and C-S bond formation reactions were observed using the optimized reaction conditions. The catalytic protocol was ligand free, and the catalyst was reusable without any significant loss of activity. The kinetic and Hammett analyses provided evidence for oxidative addition to a Cu(I) reaction center followed by nucleophilic addition and reductive elimination at the active copper oxide surface. Rate acceleration was observed for aryl halides with electron-withdrawing groups. The Hammett analysis determined ρ = +1.0, indicative of an oxidative addition, whereas the electronic effect in the phenol ring (ρ = -2.9) was indicative of coordination to a metal ion. Theoretically, the oxidative addition of the aryl halides is assisted by the ligand environment of the copper center. Relevant mechanistic implications are discussed on the basis of the experimental and computational results.
- Mullick, Kankana,Biswas, Sourav,Kim, Chiho,Ramprasad, Ramamurthy,Angeles-Boza, Alfredo M.,Suib, Steven L.
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p. 10290 - 10297
(2017/09/12)
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- Synthesis of copper nanoparticles supported on a microporous covalent triazine polymer: An efficient and reusable catalyst for O-arylation reaction
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Copper nanoparticles were supported on a microporous covalent triazine polymer prepared by the Friedel-Crafts reaction (Cu@MCTP-1). The resulting material was characterized by powder X-ray diffraction, thermogravimetric analysis, N2 adsorption-desorption isotherms at 77 K, transmission electron microscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma optical emission spectroscopy, and Cu particles with an average size of 3.0 nm and a BET total surface area of ca. 1002 m2 g-1 were obtained. Cu@MCTP-1 was evaluated as a heterogeneous catalyst for the Ullmann coupling of O-arylation over a series of aryl halides and phenols without employing expensive ligands or inert atmosphere, which produced an excellent yield of the corresponding diaryl ethers. The catalyst could be recovered by simple centrifugation and was reusable at least five times with only a slight decrease in catalytic activity.
- Puthiaraj, Pillaiyar,Ahn, Wha-Seung
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p. 1701 - 1709
(2016/04/05)
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- Ullmann reaction through ecocatalysis: Insights from bioresource and synthetic potential
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We report the elaboration of novel bio-sourced ecocatalysts for the Ullmann coupling reaction. Ecocatalysis is based on the recycling of metals issued from phytoremediation or rehabilitation, and an innovative chemical valorization of the subsequent biomass in the field of catalysis. Here, we describe efficient copper accumulation by plants via phytoextraction and rhizofiltration. These phytotechnologies were revisited to demonstrate a novel potential of these natural resources for green chemistry. Taking advantage of the remarkable ability of the selected plants to accumulate Cu(ii) species into their roots or leaves, the latter can be directly used for the preparation of ecocatalysts, called Eco-Cu. The formed Eco-Cu catalysts are thoroughly characterized via ICP-MS, IR studies of pyridine sorption/desorption, TEM, XRD, SM and model reactions, in order to elucidate the chemical composition and catalytic activity of these new materials. Significant differences of properties and activities were observed between Eco-Cu and conventional Cu catalysts. Eco-Cu are highly active catalysts in Ullmann coupling reactions with lower Cu quantities compared to known copper catalysts.
- Clavé, Guillaume,Garel, Claire,Poullain, Cyril,Renard, Brice-Lo?c,Olszewski, Tomasz K.,Lange, Bastien,Shutcha, Mylor,Faucon, Michel-Pierre,Grison, Claude
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p. 59550 - 59564
(2016/07/06)
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- Ullmann diaryl ether synthesis catalyzed by copper (I)/pyridine-functionalized silane
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Ullmann-type diaryl ether synthesis was performed under mild conditions in DMF/K2CO3using a pyridinefunctionalized silane as a ligand. The productswere obtained in good yields. This method tolerates a variety of functional groups and is effective in the synthesis of hindered diaryl ethers and heteroaryl ethers.
- Zhang, Baohua,Shi, Lanxiang,Guo, Ruixia,Liu, Sijie
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p. 930 - 932
(2016/07/06)
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- Anchoring of Pd(ii) complex in functionalized MCM-41 as an efficient and recoverable novel nano catalyst in C-C, C-O and C-N coupling reactions using Ph3SnCl
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Anchored palladium(ii) in functionalized MCM-41 mesoporous silica was prepared and used as an efficient, recoverable and thermally stable heterogeneous nano catalyst for C-C, C-O and C-N bond formation in cross-coupling reactions in the presence of Ph3SnCl. MCM-41 was prepared trough hydrothermal synthesis using tetraethyl orthosilicate (Si(OC2H5)4) as silica source and cetyltrimethylammonium bromide (CTAB) as a template. The structure of functionalized MCM-41 was studied by FT-IR, XRD, SEM, TEM, TGA, EDS, ICP and BET techniques.
- Ghorbani-Choghamarani, Arash,Nikpour, Farzad,Ghorbani, Farshid,Havasi, Forugh
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p. 33212 - 33220
(2015/04/27)
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- A counteranion triggered arylation strategy using diaryliodonium fluorides
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A mild and transition metal-free counteranion triggered arylation strategy has been developed using diaryliodonium fluorides. The fluoride counteranion within the hypervalent iodonium species displays unusual reactivity that activates a phenolic O-H bond leading to electrophilic O-arylation. A wide range of phenols and diaryliodonium salts are compatible with this transformation under remarkably mild conditions. Furthermore, we pre-empt the wider implications of this strategy by demonstrating the compatibility of the arylation tactic with latent carbon nucleophiles.
- Chan,McNally,Toh,Mendoza,Gaunt
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p. 1277 - 1281
(2015/02/05)
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- The coupling reactions of aryl halides and phenols catalyzed by palladium and MOP-type ligands
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Palladium-catalyzed coupling reactions of aryl halides and phenols are described employing the bulky and electron-rich MOP-type ligands. When K3PO4 was used as base and toluene as solvent, the catalyst system exhibited high efficiency for the coupling reaction of the activated aryl halides. When NaH was used as base and o-xylene as solvent, unactivated aryl halides can be used as substrates.
- Zhang, Yi,Ni, Gang,Li, Chengjun,Xu, Sheng,Zhang, Zhaoguo,Xie, Xiaomin
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p. 4927 - 4932
(2015/06/23)
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- Graphene-supported Cu2O nanoparticles: An efficient heterogeneous catalyst for C-O cross-coupling of aryl iodides with phenols
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Cu2O/graphene as a heterogeneous catalyst can effectively ignite and catalyze the Ullmann C-O cross-coupling of aryl iodides with phenols under mild conditions. The yield of diphenyl ether from the cross-coupling of phenol and iodobenzene can reach up to 96% at 150 °C in 3 h, and the turnover frequency can be as high as 1282 h-1. Meanwhile, the catalyst exhibits activity for varieties of C-O cross-coupling of aryl iodides, bromides and chlorides with phenol derivatives to form the corresponding aryl ethers. This journal is
- Zhai, Zhaoyang,Guo, Xiaoning,Jiao, Zhifeng,Jin, Guoqiang,Guo, Xiang-Yun
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p. 4196 - 4199
(2015/02/19)
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- Synthesis of benzannulated heterocycles by twofold Suzuki-Miyaura couplings of cyclic diarylborinic acids
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Two-fold Suzuki-Miyaura cross-couplings of cyclic diarylborinic acids are described. This novel annulation method enables the synthesis of benzo-fused heterocycles from dihaloarenes or gem-dibromoolefins.
- Dimitrijevic, Elena,Cusimano, Madeline,Taylor, Mark S.
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supporting information
p. 1391 - 1394
(2014/03/21)
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- Arylation with unsymmetrical diaryliodonium salts: A chemoselectivity study
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Phenols, anilines, and malonates have been arylated under metal-free conditions with twelve aryl(phenyl)iodonium salts in a systematic chemoselectivity study. A new "anti-ortho effect" has been identified in the arylation of malonates. Several "dummy groups" have been found that give complete chemoselectivity in the transfer of the phenyl moiety, irrespective of the nucleophile. An aryl exchange in the diaryliodonium salts has been observed under certain arylation conditions. DFT calculations have been performed to investigate the reaction mechanism and to elucidate the origins of the observed selectivities. These results are expected to facilitate the design of chiral diaryliodonium salts and the development of catalytic arylation reactions that are based on these sustainable and metal-free reagents. Copyright
- Malmgren, Joel,Santoro, Stefano,Jalalian, Nazli,Himo, Fahmi,Olofsson, Berit
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supporting information
p. 10334 - 10342
(2013/09/02)
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- Nickel-catalyzed intramolecular C-H arylation using aryl pivalates as electrophiles
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This paper describes a method for nickel catalyzed intramolecular C-H arylation using aryl pivalates as electrophiles. The transformation is efficient for the synthesis of diverse electronically and sterically differentiated dibenzofurans. Additionally, the method could be expanded toward the synthesis of carbazoles. Preliminary mechanistic studies of the transformation are also described.
- Wang, Jiayi,Ferguson, Devin M.,Kalyani, Dipannita
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p. 5780 - 5790
(2013/07/19)
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- 2-Carbomethoxy-3-hydroxyquinoxaline-di-N-oxide as a novel ligand for the copper-catalyzed coupling reaction of phenols and aryl halides
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2-Carbomethoxy-3-hydroxyquinoxaline-di-N-oxide was identified as an efficient novel ligand for the copper-catalyzed coupling of aryl halides with various phenols under mild conditions. The catalytic system shows great functional-group tolerance and excellent reactive selectivity.
- Qiu, Yatao,Jia, Weijun,Yao, Zhiyi,Wu, Fanhong,Jiang, Sheng
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p. 1502 - 1510
(2013/05/08)
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- A heterogeneous nickel catalyst for the hydrogenolysis of aryl ethers without arene hydrogenation
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A heterogeneous nickel catalyst for the selective hydrogenolysis of aryl ethers to arenes and alcohols generated without an added dative ligand is described. The catalyst is formed in situ from the well-defined soluble nickel precursor Ni(COD)2 or Ni(CH2TMS)2(TMEDA) in the presence of a base additive, such as tBuONa. The catalyst selectively cleaves CAr-O bonds in aryl ether models of lignin without hydrogenation of aromatic rings, and it operates at loadings down to 0.25 mol % at 1 bar of H2 pressure. The selectivity of this catalyst for electronically varied aryl ethers differs from that of the homogeneous catalyst reported previously, implying that the two catalysts are distinct from each other.
- Sergeev, Alexey G.,Webb, Jonathan D.,Hartwig, John F.
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supporting information
p. 20226 - 20229
(2013/02/25)
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- Metal- and ligand-free Ullmann-type C-O and C-N coupling reactions promoted by potassium tert-butoxide
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A simple, metal- and ligand-free procedure for the Ullmann-type C-O coupling reactions has been achieved by allowing aryl bromides to react with a variety of phenols in the presence of t-BuOK. Moderate to excellent yields of O-arylation products are obtained under mild conditions in a short time. In addition, two examples of C-N coupling reactions are also reported. A benzyne mechanism is proposed according to the experiment data.
- Yang, Shuliang,Wu, Cunqi,Ruan, Mingbo,Yang, Yanqin,Zhao, Yongxia,Niu, Jiajia,Yang, Wei,Xu, Jingwei
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supporting information; experimental part
p. 4288 - 4292
(2012/09/22)
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- Copper(II) trans-bis-(glycinato): An efficient heterogeneous catalyst for cross coupling of phenols with aryl halides
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Copper(II) trans-bis-(glycinato) complex, easily prepared by the solid state reaction of copper(II) acetate and glycine (trans-[Cu(glyo) 2·H2O]) was found to be an efficient, recyclable, and high yielding catalyst for the Ullmann type synthesis of diaryl ethers via the cross coupling of phenols with aryl halides without using any additives at relatively low reaction temperature. The catalyst could easily be recovered by simple filtration and was reused for several runs with consistent catalytic activity.
- Verma, Sanny,Kumar, Neeraj,Jain, Suman L.
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experimental part
p. 4665 - 4668
(2012/09/05)
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- Metal-free arylation of oxygen nucleophiles with diaryliodonium salts
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Phenols and carboxylic acids are efficiently arylated with diaryliodonium salts. The reaction conditions are mild, metal free, and avoid the use of halogenated solvents, additives, and excess reagents. The products are obtained in good-to-excellent yields after short reaction times. Steric hindrance is very well tolerated, both in the nucleophile and diaryliodonium salt. The scope includes ortho- and halo-substituted products, which are difficult to obtain by metal-catalyzed protocols. Many functional groups are tolerated, including carbonyl groups, heteroatoms, and alkenes. Unsymmetric salts can be chemoselectively utilized to obtain products with hitherto unreported levels of steric congestion. The arylation has been extended to sulfonic acids, which can be converted to sulfonate esters by two different approaches. With recent advances in efficient synthetic procedures for diaryliodonium salts the reagents are now inexpensive and readily available. The iodoarene byproduct formed from the iodonium reagent can be recovered quantitatively and used to regenerate the diaryliodonium salt, which improves the atom economy. Copyright
- Jalalian, Nazli,Petersen, Tue B.,Olofsson, Berit
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p. 14140 - 14149,10
(2012/12/12)
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- Recyclable heterogeneous copper oxide on alumina catalyzed coupling of phenols and alcohols with aryl halides under ligand-free conditions
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An efficient alumina-supported CuO-catalyzed O-arylation of phenols and aliphatic alcohols with various aryl as well as heteroaryl halides under ligand-free conditions are reported. This protocol provides a variety of diaryl ether and bis-diaryl ether motifs by reacting different aryl/aliphatic halides with differently substituted phenols and saturated alcohols in the presence of a catalytic amount of CuO on alumina and KOH as a base at moderate temperature under nitrogen atmosphere. The described methodology is simple, straightforward and efficient to afford the cross-coupled products in high yields under ligand-free conditions. The explored catalyst is inexpensive, air-stable and recyclable up to three cycles.
- Swapna, Kokkirala,Murthy, Sabbavarapu Narayana,Jyothi, Mocharla Tarani,Nageswar, Yadavalli Venkata Durga
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supporting information; experimental part
p. 5978 - 5988
(2011/10/05)
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- Room temperature, metal-free synthesis of diaryl ethers with use of diaryliodonium salts
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A fast, high-yielding synthesis of diaryl ethers with use of mild and metal-free conditions has been developed. The scope includes bulky ortho-substituted diaryl ethers, which are difficult to obtain by metal-catalyzed protocols. Halo-substituents, racemization-prone amino acid derivatives, and heteroaromatics are also tolerated. The methodology is expected to be of high utility in the synthesis of complex molecules and in the pharmaceutical industry.
- Jalalian, Nazli,Ishikawa, Eloisa E.,Silva, Luiz F.,Olofsson, Berit
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p. 1552 - 1555
(2011/04/26)
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- Structure-based design, synthesis, and biological evaluation of lipophilic-tailed monocationic inhibitors of neuronal nitric oxide synthase
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Selective inhibitors of neuronal nitric oxide synthase (nNOS) have the potential to develop into new neurodegenerative therapeutics. Recently, we described the discovery of novel nNOS inhibitors (1a and 1b) based on a cis-pyrrolidine pharmacophore. These compounds and related ones were found to have poor blood-brain barrier permeability, presumably because of the basic nitrogens in the molecule. Here, a series of monocationic compounds was designed on the basis of docking experiments using the crystal structures of 1a,b bound to nNOS. These compounds were synthesized and evaluated for their ability to inhibit neuronal nitric oxide synthase. Despite the excellent overlap of these compounds with 1a,b bound to nNOS, they exhibited low potency. This is because they bound in the nNOS active site in the normal orientation rather than the expected flipped orientation used in the computer modeling. The biphenyl or phenoxyphenyl tail is disordered and does not form good protein-ligand interactions. These studies demonstrate the importance of the size and rigidity of the side chain tail and the second basic amino group for nNOS binding efficiency and the importance of the hydrophobic tail for conformational orientation in the active site of nNOS.
- Xue, Fengtian,Huang, Jinwen,Ji, Haitao,Fang, Jianguo,Li, Huiying,Martásek, Pavel,Roman, Linda J.,Poulos, Thomas L.,Silverman, Richard B.
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experimental part
p. 6526 - 6537
(2010/10/02)
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- General, mild, and intermolecular Ullmann-type synthesis of diaryl and alkyl aryl ethers catalyzed by diol-copper(I) complex
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(Chemical Equation Presented) A wide range of diaryl ethers and alkyl aryl ethers are synthesized through intermolecular C(aryl)-O bond formation from the corresponding aryl iodides/aryl bromides and phenols/alcohols through Ullmann-type coupling reaction in the presence of a catalytic amount of easily available (±)-diol L3-CuI complex under very mild reaction conditions. Less reactive aryl bromides can also be used for O-arylation of phenols under the same reaction conditions without increasing the reaction temperature, catalyst loading, and time. The catalytic system not only is capable of coupling hindered substrate but also tolerates a broad range of a series of functional groups.
- Naidu, Ajay B.,Jaseer,Sekar, Govindasamy
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supporting information; experimental part
p. 3675 - 3679
(2009/09/26)
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- Copper-mediated N- and O-arylations with arylboronic acids in a continuous flow microreactor: a new avenue for efficient scalability
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A continuous flow procedure has been elaborated for the copper(II)-mediated N- and O-arylation of a range of compounds with arylboronic acids using a commercial microreactor setup. The compounds could be continuously generated in good yields paving the way for efficient scalability.
- Singh, Brajendra K.,Stevens, Christian V.,Acke, Davy R.J.,Parmar, Virinder S.,Van der Eycken, Erik V.
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scheme or table
p. 15 - 18
(2009/04/10)
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- Iron-catalyzed C-O cross-couplings of phenols with aryl iodides
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(Chemical Equation Presented) Low-price coupling: A versatile, practical, and cost-efficient iron-catalyzed O-arylation protocol is applied to the synthesis of a variety of diaryl ethers, which are formed in high yields. Best results were obtained by using FeCl3 and a β-diketo ligand.
- Bistri, Olivia,Correa, Arkaitz,Bolm, Carsten
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p. 586 - 588
(2008/09/20)
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- An efficient BINAM-copper(II) catalyzed Ullmann-type synthesis of diaryl ethers
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A wide range of diaryl ethers are synthesized from the corresponding aryl iodides and phenols through Ullmann type coupling reactions in the presence of a catalytic amount of easily available BINAM-Cu(OTf)2 complex under mild reaction conditions. Less reactive aryl bromides have also been shown to react with phenols under identical reaction conditions to give good yields of the diaryl ethers without increasing the reaction temperature and time.
- Naidu, Ajay B.,Raghunath,Prasad,Sekar
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p. 1057 - 1061
(2008/09/18)
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- The selective reaction of aryl halides with KOH: Synthesis of phenols, aromatic ethers, and benzofurans
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The direct and selective synthesis of phenols from aryl/heteroaryl halides and KOH has been achieved through the use of highly active monophosphine-based catalysts derived from Pd2dba3 and ligands L1 or L2 and the biphasic solvent system 1,4-dioxane/H2O. We have also demonstrated a one-pot method of phenol formation/alkylation for the preparation of alkyl aryl ethers from aryl halides. In many instances, this protocol overcomes limitations in existing Pd-catalyzed coupling reactions of aliphatic alcohols with aryl halides. Finally, we demonstrate that substituted benzofurans can be prepared efficiently via a Pd-catalyzed phenol formation/cyclization protocol starting from 2-chloroaryl alkynes. Copyright
- Anderson, Kevin W.,Ikawa, Takashi,Tundel, Rachel E.,Buchwald, Stephen L.
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p. 10694 - 10695
(2007/10/03)
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- Chiral spiro compounds and their use in asymmetric catalytic reactions
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The present invention provides a chiral ligand, represented by a formula or its enantiomer: X and X′ can be independently O, NH, NR, NCOR or S; each of Z1-Z7 and Z1′-Z7′ can be independently H, alkyl, aryl, substituted alkyl, substituted aryl, alkoxyl, aryloxyl, nitro, amide, aryoxide, halide, hydroxyl, carboxylate, hetereoaryl, or a cyclic alkene, fused aryl, or cyclic ether group formed from any two adjacent Z groups or any two adjacent Z′ groups; Y and Y′ can be independently OH, OR, NH2, NHR, NR2, SH, PR2, OPR2, NHPR2, OP(OR)2, COOH, COOR, CONHR, or a linking group formed from Y and Y′ groups together. Processes of preparing these ligands, catalysts that employ them and methods of using the catalysts are also provided.
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Page/Page column 19
(2008/06/13)
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- Significantly improved method for the pd-catalyzed coupling of phenols with aryl halides: Understanding ligand effects
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(Chemical Equation Presented) A variety of diaryl ethers were synthesized by the Pd-catalyzed reaction of (hetero)-aryl halides and phenols. These reactions were achieved through the use of two new di-tert-butylphosphino biaryl ligands that overcome several limitations of previously described methods.
- Burgos, Carlos H.,Barder, Timothy E.,Huang, Xiaohua,Buchwald, Stephen L.
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p. 4321 - 4326
(2007/10/03)
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- Synthesis of diaryl ethers through the copper-catalyzed arylation of phenols with aryl halides using microwave heating
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The copper-catalyzed arylation of phenols with a variety of aryl halides using microwave heating is described.
- He, Huan,Wu, Yong-Jin
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p. 3445 - 3446
(2007/10/03)
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- PHENYL GLYOXAMIDES AS sPLA2 INHIBITORS
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A class of novel phenyl glyoxamides is disclosed together with the use of such compounds for inhibiting sPLA2 mediated release of fatty acids for treatment of conditions such as septic shock.
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- PHENYL GLYOXAMIDES AS SPLA2 INHIBITORS
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A class of novel phenyl glyoxamides is disclosed together with the use of such compounds for inhibiting SPLA2 mediated release of fatty acids for treatment of conditions such as septic shock.
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- Oxidativ Coupling of Phenols. Part 6. A Study of the Role of Spin Density Factors on the Product Composition in the Oxidations of 3,5-Dimethylphenol and Phenol
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Oxidations of both 3,5-dimethyphenol and phenol with di-t-butyl peroxide at 140 degC gave as the major product the ortho-ortho-C-C coupled dimer, while oxidations with di-t-butyl peroxyoxalate at room temperature give much more of the ortho-para-C-C dimer.The results are not consistent either with the spin density distribution in the phenoxyl radical intermediates or with steric effects being the major factor which determines the product composition.It is proposed that the two phenoxyl radicals involved in coupling preferentially approach each other in a 'sandwich like' manner with the oxigens in a 1,3-relationship.
- Armstrong, David R.,Cameron, Colin,Nonhebel, Derek C.,Perkins, Peter G.
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p. 563 - 568
(2007/10/02)
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- Polar Radicals. 17. On the Mechanism of Iodine Atom Transfer. A 9-I-2 Intermediate
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The atom-transfer reaction of iodine from an aryl iodide to a phenyl radical has been shown to proceed via a 9-I-2 ntermediate.The relative kinetics of the reactions of the intermediate were investigated by studying its mode of decomposition upon formation from the reduction of a series of unsymmetrically substituted diaryliodonium salts.The iodonium salts were reduced by the electron-transfer reactions with several reagents: di-tert-butyl nitroxide, sodium 2,6-di-tert-butylphenylate, and sodium phenylate.The reduction by electron transfer of the iodonium salts by the latter reaction gives high yields of diaryl ethers.The mechanism fo ether formation has been shown to proceed by two mechanistic pathways.For the diaryliodonium salts that have a p-cyano or p-nitro substituent, the ether is formed by a nucleophilic aromatic substitution; however, when the substituents were not strongly electron withdrawing, the mechanism resulting in ether formation involved electron transfer from the phenylate anion to the iodonium salt to form the phenoxy radical and a 9-I-2 intermediate.The intermediate decomposes to an aryl radical and an aryl iodide.The ether is formed from the efficient coupling of the aryl radical and the phenoxy radical.
- Tanner, Dennis D.,Reed, Darwin W.,Setiloane, B.P.
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p. 3917 - 3923
(2007/10/02)
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