- L-Proline N-oxide dihydrazides as an efficient ligand for cross-coupling reactions of aryl iodides and bromides with amines and phenols
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A novel catalytic system based on L-proline N-oxide/CuI was developed and applied to the cross-coupling reactions of various N- and O- nucleophilic reagents with aryl iodides and bromides. This strategy featured in the employment of an-proline derived dihydrazides N-oxide compound as the superior supporting ligand. By using this protocol, a variety of products, including N-arylimidazoles, N-arylpyrazoles, N-arylpyrroles, N-arylamines, and aryl ethers, were synthesized with up to 99% yield.
- Ding, Zhiqiang,Nie, Nan,Chen, Tian,Meng, Lingxin,Wang, Gongshu,Chen, Zhangpei,Hu, Jianshe
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supporting information
(2020/12/21)
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- Synergistic effect of copper nanocrystals-nanoparticles incorporated in a porous organic polymer for the Ullmann C-O coupling r–eaction
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A quinoxaline-based porous organic polymer (Q-POP) as a mesoporous organic copolymer was developed as a new platform for the immobilization of CuNPs and copper nanocrystals. The prepared materials were characterized by FT-IR, XRD, N2 adsorption-desorption isotherms, ICP, TGA, SEM, HR-TEM, EDX, and single-crystal X-ray crystallography. The obtained catalyst presented extraordinary catalytic activity towards Ullmann C–O coupling reactions with high surface area, hierarchical porosity, and excellent thermal and chemical stability. Due to its high porosity, and synergistic effect of copper nanocrystals incorporated in the polymer composite, the as-synthesized catalyst was successfully utilized for the Ullmann C–O coupling reaction of phenols and different aryl halides to prepare various diaryl ether derivatives. All types of aryl halides (except aryl fluorides) were screened in the Ullmann C–O coupling reaction with phenols to produce diaryl ethers in good to excellent yields (70–97 %), and it was found that aryl iodides have the best results. Besides, due to the strong interactions between CuNPs, N, and O-atoms of quinoxaline moiety existing in the polymeric framework, the copper leaching from the support was not observed. Furthermore, the catalyst was recycled and reused for five consecutive runs without significant activity loss.
- Gorginpour, Forough,Zali-Boeini, Hassan
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- Aromatic ether compound or the sulfhydryl compound
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[Problem] Aromatic ether compounds and aromatic sulfide compound of this new technology to[Solution] In general formula (1a), (1b), (1c) palladium or nickel compound or a phosphine compound represented by the compound comprising a transition metal compound in the presence of a transition metal catalyst, (A1) is represented by compounds having hydroxy carbon C a-OH or (A2) with a compound represented by the sulfhydryl carbon C a-SH, nitro group (- NO2 ) To react with an aromatic nitro compound (B), (A1) to the compound of the aromatic nitro compound (C1) or the reaction product of an aromatic ether compounds (B) hetero coupling (A2) of the compounds of the reaction product of an aromatic sulfide compound of an aromatic nitro compound (C2) generating (B) hetero coupling characterized by comprising the step of, aromatic ether compounds or aromatic sulfide compound. [Drawing] no
- -
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Paragraph 0072; 0074; 0077; 0109
(2021/11/19)
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- 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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- A novel magnetic polyacrylonotrile-based palladium Core?Shell complex: A highly efficientcatalyst for Synthesis of Diaryl ethers
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The present article describes the synthesis of a new magnetic polyacrylonitrile-based Pd catalyst involving polyacrylonitrile modified via 2-aminopyridine as an efficient support to immobilize Pd nanoparticles. The simple reusability, easy separation and high stability of this Pd complex make it an excellent candidate to generate a C–O bond via Ph-X activation which is a really important subject in achieving biologically active compounds. It is worth to note access to good and high yields as well as broad substrate scope have resulted from superior reactivity of this catalyst complex. Furthermore, the structure of the magnetic polyacrylonitrile-based heterogeneous catalyst was characterized by fourier transmission infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), X-ray diffraction (XRD). Also, its thermal properties were studied by thermogravimetric analysis (TGA).
- Eslami, Mohammad,Jarahiyan, Atefeh,Moghaddam, Firouz Matloubi,Pourjavadi, Ali
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- CoII Immobilized on Aminated Magnetic-Based Metal–Organic Framework: An Efficient Heterogeneous Nanostructured Catalyst for the C–O Cross-Coupling Reaction in Solvent-Free Conditions
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Abstract: In this paper, we report the synthesis of Fe3O4?AMCA-MIL53(Al)-NH2-CoII NPs based on the metal–organic framework structures as a magnetically separable and environmentally friendly heterogeneous nanocatalyst. The prepared nanostructured catalyst efficiently promotes the C–O cross-coupling reaction in solvent-free conditions without the need for using toxic solvents and/or expensive palladium catalyst. Graphic Abstract: [Figure not available: see fulltext.].
- Mohammadinezhad, Arezou,Akhlaghinia, Batool
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p. 332 - 352
(2020/01/11)
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- Palladium nanoparticles supported on cysteine-functionalized MNPs as robust recyclable catalysts for fast O- and N-arylation reactions in green media
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A magnetically robust recyclable nanocatalyst was fabricated by immobilizing of Pd onto the surface of cysteine-functionalized magnetic nanoparticles (MNPs?Cys-Pd). This nanocatalyst was characterized using various techniques such as FT-IR, XRD, TEM, SEM, EDX, VSM, and ICP. The application of catalyst (MNPs?Cys-Pd) was investigated for O-arylation and N-arylation reactions. This phosphine-free complex was found as highly efficient heterogeneous catalyst in green media and mild reaction conditions. In addition, it gave excellent recyclability without significant deactivation after ten cycles.
- Hajipour, Abdol R.,Khorsandi, Zahra,Fatemeh Mohammadi Metkazini
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- Immobilized palladium nanoparticles on MNPs@A-N-AEB as an efficient catalyst for C-O bond formation in water as a green Solvent
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Palladium nanoparticles immobilized on the magnetic nanoparticles@2-amino-N-(2-aminoethyl) benzamide (MNPs@A-N-AEB.Pd0) have been presented as an efficient, and reusable magnetically heterogeneous catalyst for the C-O coupling reaction, namely Ullmann condensation reactions in an aqueous medium. This heterogeneous catalyst shows superior reactivity for the C-O arylation of different aryl halide (chloride, bromide, and iodide) with phenol derivatives to afford the desired products in good to excellent yields within short reaction time. Moreover, the catalyst can be easily recovered and reused for seven runs without loss of catalytic activity. The catalyst was characterized by several techniques, such as FT-IR, SEM, TEM, EDS, XRD, TGA and ICP-OES.
- Moghaddam, Firouz Matloubi,Eslami, Mohammad
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- The First C?Cl Activation in Ullmann C?O Coupling by MOFs
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It was found that introduction of only 0.03 mol % Ag(I) into the framework of Cu3(BTC)2 ? xH2O in maghemite anchored CuBTC activated the inert CuBTC astonishingly to exhibit unexpected high catalytic activity for C?Cl activation in coupling of chloroarenes with phenols without the use of expensive ligands. This is the first application of mixed-metal MOFs in the C?X activation. Putting reusability and activity together, a TON over 15000 was obtained which is the highest TON compared with all its precedents even better than the results by Pd catalysts.
- Ramezani, Leila,Yahyazadeh, Asieh,Sheykhan, Mehdi
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p. 4636 - 4651
(2018/09/21)
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- Interface Engineering in Two-Dimensional Heterostructures: Towards an Advanced Catalyst for Ullmann Couplings
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The design of advanced catalysts for organic reactions is of profound significance. During such processes, electrophilicity and nucleophilicity play vital roles in the activation of chemical bonds and ultimately speed up organic reactions. Herein, we demonstrate a new way to regulate the electro- and nucleophilicity of catalysts for organic transformations. Interface engineering in two-dimensional heteronanostructures triggered electron transfer across the interface. The catalyst was thus rendered more electropositive, which led to superior performance in Ullmann reactions. In the presence of the engineered 2D Cu2S/MoS2 heteronanostructure, the coupling of iodobenzene and para-chlorophenol gave the desired product in 92 % yield under mild conditions (100 °C). Furthermore, the catalyst exhibited excellent stability as well as high recyclability with a yield of 89 % after five cycles. We propose that interface engineering could be widely employed for the development of new catalysts for organic reactions.
- Sun, Xu,Deng, Haitao,Zhu, Wenguang,Yu, Zhi,Wu, Changzheng,Xie, Yi
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supporting information
p. 1704 - 1709
(2016/02/03)
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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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- Chemoselective and ligand-free synthesis of diaryl ethers in aqueous medium using recyclable alumina-supported nickel nanoparticles
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An economical and eco-compatible ligand-free protocol for the synthesis of diaryl ethers has been developed using easily accessible alumina-supported nickel nanoparticles as a stable recyclable heterogeneous catalyst in aqueous medium along with a surfactant (SDS) and a mild base (K2CO3). Various sensitive functional groups like allyl, alkoxycarbonyl, formyl, oxo, chloro, bromo, amine and nitro were tolerated in the aforesaid method. Excellent chemoselectivity was demonstrated through competition experiments.
- Ghatak, Avishek,Khan, Sagar,Roy, Rimi,Bhar, Sanjay
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supporting information
p. 7082 - 7088
(2015/02/02)
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- Highly active recyclable heterogeneous Pd/ZnO nanoparticle catalyst: Sustainable developments for the C-O and C-N bond cross-coupling reactions of aryl halides under ligand-free conditions
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Efficient Pd supported on ZnO nanoparticles for the ligand-free O-arylation and N-arylation of phenols and various N-H heterocycles with aryl chlorides, bromides, and iodides were readily synthesized and characterized. The amount of palladium on ZnO is 9.84 wt% (0.005 g of the catalyst contains 462 × 10-8 mol% of Pd) which was determined by ICP analysis. This nano sized Pd/ZnO with an average particle size of 20-25 nm and specific surface area 40.61 m2 g-1 was used as a new reusable heterogeneous catalyst for the formation of C-O and C-N bonds in organic synthesis. This protocol gives the arylated product in satisfactory yields without any N2 or Ar flow. The catalyst can be recovered and recycled several times without marked loss of activity.
- Hosseini-Sarvari, Mona,Razmi, Zahra
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p. 44105 - 44116
(2014/12/10)
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- Copper-catalyzed Ullmann-type synthesis of diaryl ethers assisted by salicylaldimine ligands
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A series of salicylaldimine ligands were designed to promote the copper-catalyzed Ullmann cross-coupling reaction. After a screening process, 2-((2-isopropylphenylimino)methyl)phenol was found to serve as a good supporting ligand for this reaction. Employing this Schiff-base ligand as a new supporting ligand, the copper-catalyzed coupling reactions of aryl bromides and aryl iodides with various phenols successfully proceeded in good yields under mild conditions. Various diaryl ethers were obtained with excellent yields in dioxane in the presence of K3PO4 and a catalytic amount of copper(I) salt.
- Qian, Cun-Wei,Lv, Wen-Lin,Zong, Qian-Shou,Wang, Mao-Yuan,Fang, Dong
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p. 337 - 340
(2014/02/14)
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- Ligand free copper-catalyzed heterogeneous O-arylation reaction under green condition
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A highly porous Zn-based iso-reticular metal-organic framework (IRMOF-3) has been selected for covalent modification. Pyridine-2-aldehyde has been used to decorate the free amine group of IRMOF-3 in the porous matrix. Schiff base moiety thus generated has been availed to anchor copper(II) ions to prepare the desired catalyst that catalyzes O-arylation reactions heterogeneously under mild reaction conditions. Porous catalyst demonstrates size selectivity in products when various substrates undergo O-arylation with α and β-naphthol.
- Maity, Tanmoy,Saha, Debraj,Das, Soma,Bhunia, Susmita,Koner, Subratanath
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p. 141 - 148
(2014/12/10)
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- A highly stable and active magnetically separable Pd nanocatalyst in aqueous phase heterogeneously catalyzed couplings
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An active and stable magnetically separable Pd nanocatalyst was prepared and characterized. The nanocatalyst exhibited excellent activities and reusabilities in aqueous phase processes including the O-arylation of phenols and Sonogashira cross-coupling reactions. The proposed protocol features mild reaction conditions and an extraordinary simplicity and efficiency using NaOH as base in water.
- Zolfigol, Mohammad Ali,Khakyzadeh, Vahid,Moosavi-Zare, Ahmad Reza,Rostami, Abed,Zare, Abdolkarim,Iranpoor, Nasser,Beyzavi, Mohammad Hassan,Luque, Rafael
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p. 2132 - 2140
(2013/09/24)
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- An Ullmann C-O coupling reaction catalyzed by magnetic copper ferrite nanoparticles
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Herein, an efficient method for the Ullmann C-O coupling reaction between various kinds of phenols and aryl halides, including amino, ketone, cyano, methyl, methoxy, fluoro, chloro and bromo derivatives, is described. The catalyst used, copper ferrite (CuFe2O4) nanoparticles, are easily made, air-stable, and of low cost. The catalyst can be recycled easily just by using an external magnet. Even in the presence of sensitive substituents, the reaction proceeds successfully to provide the desired products in high yields without protection of other functional groups. Copyright
- Yang, Shuliang,Wu, Cunqi,Zhou, Hua,Yang, Yanqin,Zhao, Yongxia,Wang, Chenxu,Yang, Wei,Xu, Jingwei
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supporting information
p. 53 - 58
(2013/03/13)
-
- Palladium nanoparticles supported on silica diphenylphosphinite as efficient catalyst for C-O and C-S arylation of aryl halides
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Silica diphenylphosphinite (SDPP) can be easily obtained through direct phosphorylation of silica gel. Further reaction of SDPP with Pd(II) produces nano Pd(0)/SDPP. This nano Pd(0) catalyst exhibits excellent reactivity for the C-O and C-S arylation of different aryl iodides, bromides and chloride with phenols and thiophenols. This heterogeneous catalyst shows excellent recyclability and can be easily recovered and reused for several runs. Copyright
- Iranpoor, Nasser,Firouzabadi, Habib,Rostami, Abed
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p. 501 - 506
(2013/09/23)
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- Triphenyltin chloride as a new source of phenyl group for C-heteroatom and C-C bond formation
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Ph3SnCl is introduced as a very suitable source of phenyl group for coupling with phenols, amines, and thiols in the presence of Cu(OAc)2 in Et3N at room temperature to give aryl ethers, amines, and arylthio ethers in high yields. In addition, the application of Ph3SnCl in the Stille coupling of aryl halides in the presence of Pd(0) catalyst in PEG 400 at 110C is discussed.
- Iranpoor, Nasser,Firouzabadi, Habib,Elham, Etemadi Davan,Rostami, Abed,Nematollahi, Arash
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p. 123 - 130
(2013/10/01)
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- Potassium tert-butoxide-mediated synthesis of unsymmetrical diaryl ethers, sulfides and selenides from aryl bromides
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Potassium tert-butoxide mediated carbon-chalcogen C-E (E=O, S and Se) coupling reaction has been studied from aryl bromide and phenol/aryl disulfide/diselenide substrates. A series of unsymmetrical diaryl chalcogenides were accessed from aryl bromide and diaryl dichalcogenide precursors by using 2.5 equiv of potassium tert-butoxide in DMSO at 80 C. Unsymmetrical diaryl ethers were also obtained by using phenol precursors at 40-45 C. Aryl bromides with methyl, trifluoromethyl, methoxy and nitro substituents showed compatibility in the carbon-chalcogen bond forming reaction. 4-Methoxy, methyl, trifluoromethyl substituted bromobenzene substrates gave two regioisomers: 3-substituted and 4-substituted diaryl chalcogenides when reacted with phenols/diaryl disulfides/diselenides. Formation of two regioisomeric diaryl chalcogenides in the reaction mixture suggests that potassium tert-butoxide reacts with bromobenzene to produce benzyne intermediate, which subsequently reacts with diaryl dichalcogenides and finally give a regioisomeric mixture of 4-substituted and 3-substituted diaryl chalcogenides.
- Kumar, Amit,Bhakuni, Bhagat Singh,Prasad, Ch. Durga,Kumar, Shailesh,Kumar, Sangit
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p. 5383 - 5392
(2013/07/04)
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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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- Thermally decomposed Cu-Fe-hydrotalcite: A novel highly active catalyst for o-arylation of naphthol and phenols by aryl halides
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A novel, efficient and environmentally benign method has been reported for the synthesis of diaryl ethers by the o-arylation of napthol or phenols with aryl halides in dimethylformamide (as a solvent) under reflux, using a novel heterogeneous catalyst (having redox properties), obtained from thermal decomposition of Cu-Fe at 600 °C in the absence of externally added base. The catalyst comprises Cu(II) and Fe(III) species (oxides and hydroxides), which are uniformly distributed during the catalyst formation. The catalyst can be easily separated from the reaction mixture, simply by filtration and reused several times without a significant loss of its activity.
- Choudhary,Dumbre,Yadav,Bhargava
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p. 132 - 136
(2013/01/15)
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- Methenamine as an efficient ligand for copper-catalyzed coupling of phenols with aryl halides
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Employing methenamine as a new supporting ligand, the copper-catalyzed coupling reactions of aryl bromides or aryl iodides with various phenols successfully proceeded in good yields under mild conditions. A series of diaryl ethers were obtained with excellent yields in the presence of K 3PO4 and copper(I) salt. Copyright
- Qian, Cunwei,Zong, Qianshou,Fang, Dong
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experimental part
p. 199 - 203
(2012/03/11)
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- Low catalyst loadings for copper-catalyzed O-arylation of phenols with aryl and heteroaryl halides under mild conditions
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A practical and mild strategy has been developed for the cross-coupling of O-arylation of phenol with differently substituted aryl halides and heteroaryl iodides using low catalyst loading of copper iodide under low operating temperature in DMF with TMHD as the ligand and Cs2CO3 as the base. This method tolerates a variety of functional groups including sterically hindered phenols and heteroaryl iodides to afford products in good to excellent yields (up to 95%). Georg Thieme Verlag Stuttgart. New York.
- Yong, Fui-Fong,Teo, Yong-Chua,Yan, Yaw-Kai,Chua, Guan-Leong
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supporting information; experimental part
p. 101 - 106
(2012/02/03)
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- Highly efficient copper catalytic system for the O-arylation of phenol with iodoarene
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An efficient Cu-catalyzed O-arylation was carried out by involving phenols with iodoarenes to afford various substituted diarylether derivatives with tiny loading of Cu2O and 1H-imidazole-4-carboxylic acid as catalytic system under mild conditions, which provided good to excellent yields with good tolerance of functional groups.
- Cheng, An-Yi,Hsieh, Jen-Chieh
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supporting information; experimental part
p. 71 - 75
(2012/01/31)
-
- Ligand free, highly efficient synthesis of diaryl ether over copper fluorapatite as heterogeneous reusable catalyst
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A novel ligand-free, highly efficient, and an inexpensive method has been developed by using ecofriendly, heterogeneous reusable copper fluorapatite (CuFAP) catalyst for the synthesis of diaryl ethers from the cross coupling reaction of the various substituted aryl halides (fluoride, chloride, bromide, and iodide) with the potassium salts of various substituted phenols in the presence of N-methyl 2-pyrrolidone (NMP) as a solvent at 120 °C. The protocol obtained the corresponding cross coupling products in good to excellent yield. The CuFAP catalyst was recovered by simple filtration from the reaction mixture and reused several times without the loss of catalytic activity.
- Mulla, Shafeek A.R.,Inamdar, Suleman M.,Pathan, Mohsinkhan Y.,Chavan, Santosh S.
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experimental part
p. 1826 - 1829
(2012/05/04)
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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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- Efficient iron/copper-cocatalyzed o-arylation of phenols with bromoarenes
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Low catalytic amount CuI and Fe(acac)3 were found to effectively promote the C-O cross-coupling reaction in the presence of K2CO 3 as the base. A serious of diaryl ethers with different substitutents can be synthesized in good to excellent yields. This efficient and economic method is attractive for applications on an industrial scale. Georg Thieme Verlag Stuttgart New York.
- Liu, Xiaoyan,Zhang, Songlin
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supporting information; experimental part
p. 268 - 272
(2011/03/20)
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- Copper(I) Phenoxide complexes in the etherification of aryl halides
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"Chemical Equation Presented" No copping out! Copper(I) phenoxide complexes containing chelating ligands (see picture), proposed intermediates in copper-catalyzed etherification of aryl halides, have been synthesized and fully characterized. The kinetic and chemical competence of the isolated complexes are demonstrated for the synthesis of aryl phenyl ethers, and experiments provide evidence against mechanistic pathways involving the formation of either free or caged radicals.
- Tye, Jesse W.,Weng, Zhiqiang,Giri, Ramesh,Hartwig, John F.
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supporting information; experimental part
p. 2185 - 2189
(2010/06/19)
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- CuO nanoparticles catalyzed C-N, C-O, and C-S cross-coupling reactions: Scope and mechanism
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CuO nanoparticles have been studied for C-N, C-O, and C-S bond formations via cross-coupling reactions of nitrogen, oxygen, and sulfur nucleophiles with aryl halides. Amides, amines, imidazoles, phenols, alcohols and thiols undergo reactions with aryl iodides in the presence of a base such as KOH, Cs 2CO3, and K2CO3 at moderate temperature. The procedure is simple, general, ligand-free, and efficient to afford the cross-coupled products in high yield.
- Jammi, Suribabu,Sakthivel, Sekarpandi,Rout, Laxmidhar,Mukherjee, Tathagata,Mandai, Santu,Mitra, Raja,Saha, Prasenjit,Punniyamurthy, Tharmalingam
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supporting information; experimental part
p. 1971 - 1976
(2009/07/01)
-
- Glyoxal bis(phenylhydrazone) as promoter for CuI-catalyzed O-arylation of phenols with bromoarenes
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A very simple bishydrazone-type ligand, glyoxal bis(phenylhydrazone) (L1), was found to effectively promote the CuI-catalyzed O-arylation of phenols with aryl bromides. This cross-coupling reaction proceeded in acetonitrile at 60-80 °C in the presence of K3PO4 as base. A diverse array of phenols and bromoarenes was employed as substrates to afford diaryl ethers in good to excellent yields, and some base-sensitive groups, such as ester, aldehyde, and ketone groups, can survive under the mild reaction conditions.
- Liu, Yu-Hua,Li, Gang,Yang, Lian-Ming
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experimental part
p. 343 - 346
(2009/04/19)
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- Nano-CuO-catalyzed ullmann coupling of phenols with aryl halides under ligand-free conditions
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Nano copper oxide has been found to be a highly efficient and reusable catalyst for the C-O cross-coupling of phenols with aryl halides under ligand-free conditions. With DMSO as solvent, Cs2CO3 and KOH are suitable bases for the cross-coupling reactions with phenyl iodides and bromides, respectively. Diaryl ethers with different substituted groups can be synthesized in moderate-to-good yields. The catalyst can be recycled at least five times without obvious loss in catalytic activity. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Zhang, Jintang,Zhang, Zuhui,Wang, Ye,Zheng, Xiaoqi,Wang, Zhiyong
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scheme or table
p. 5112 - 5116
(2009/06/06)
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- A Superior Synthesis of Diaryl Ethers by the Use of Ultrasound in the Ullmann Reaction
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The use of ultrasound in the reactions of phenols with bromoarenes, in the presence of potassium carbonate and copper(I) iodide but without added solvent, gives better yields of diaryl ethers (typically 70-90percent) at lower temperature (140 deg C) than is customary for traditional Ullmann reactions; the role of ultrasound is primarily to break up the particles of the inorganic solids.
- Smith, Keith,Jones, Dennis
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p. 407 - 408
(2007/10/02)
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- Carbon-Oxygen Bond-Cleavage Reactions by Electron Transfer. 4. Electrochemical and Alkali-Metal Reductions of Phenoxynaphthalenes
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The reductions of 1- (1) and 2-phenoxynaphthalene (2) to their respective radical anions were observed at -2.42 and -2.48 V vs SCE.Cyclic voltammetric and chronoamperometric studies indicate that both radical anions have half-lives that are greater than 100 s in dry N,N-dimethyloformamide.Controlled-potential elektrolysis of the ethers resulted in relatively slow , regioselective carbon-oxygen bond cleavage to produce phenol and naphthalene .The intermediacy of the naphthyl radical or the naphthyl anion in the reductive pathway was tested by the use of anintramolecular radical trap in the form of a 2-(3'-butenyl) substituent, i.e., 2-(3'butenyl)-1-phenoxynaphthalene (3).Formation of 1-methylbenzindan (4) upon the electrochemical reduction of 3 in the absence and presence of D2O confirmed the presence of the 2-(3'butenyl)naphthyl radical in the radical-anion cleavage mechanism.Reduction of the phenoxynaphthalenes with Na/HMPA in tetrahydrofuran resulted in slow regioselektive cleavage while reduction with Na-K alloy/tetraglyme quantitatively cleaved the ether bond more rapidly.The intermediacy of the naphthyl anion, which is produced via the ether dianion in the Na-K alloy reduction, was demonstrated by the reduction of 3 at -78 and 0 deg C.Reduction of 3 at -78 deg C produced only 2-(3'-butenyl)naphthalene (5) whereas reduction at 0 deg C produced both 5 and 4, the latter by anionic cyclization
- Thornton, Todd A.,Ross, Gerald A.,Patil, Dilip,Mukaida, Kenichi,Warwick, Jeffrey O.,et al.
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p. 2434 - 2440
(2007/10/02)
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- Process for the selective production of dihydroxybenzenes
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The known nuclear hydroxylation of phenol or substituted phenols or phenol ethers with organic solutions of hydrogen peroxide in the presence of a catalyst is carried out in improved manner by employing both (1) a special, practically water free solution of hydrogen peroxide in an organic solvent which forms an azeotrope with water, which azeotrope boils below the boiling point of hydrogen peroxide, and (2) selenium dioxide as a catalyst. Through this, the nuclear hydroxylation is substantially simpler than previously. Besides, for the first time, it is possible to control the ortho to para ratio or the two ortho ratios to each other.
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- IMPROVED ULLMANN SYNTHESIS OF DIARYL ETHERS
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Several diaryl ethers have been synthesized by using indefinitely stable and easily available copper(I) phenylacetylenide as condensing agent in Ullmann condensation reaction.
- Afzali, A.,Firouzabadi, H.,Khalafi-nejad, A.
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p. 335 - 340
(2007/10/02)
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