- Ligand- and Counterion-Assisted Phenol O-Arylation with TMP-Iodonium(III) Acetates
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High reactivity of trimethoxyphenyl (TMP)-iodonium(III) acetate for phenol O-arylation was achieved. It was first determined that the TMP ligand and acetate anion cooperatively enhance the electrophilic reactivity toward phenol oxygen atoms. The proposed method provides access to various diaryl ethers in significantly higher yields than the previously reported techniques. Various functional groups, including aliphatic alcohol, boronic ester, and sterically hindered groups, were tolerated during O-arylation, verifying the applicability of this ligand- and counterion-assisted strategy.
- Kikushima, Kotaro,Miyamoto, Naoki,Watanabe, Kazuma,Koseki, Daichi,Kita, Yasuyuki,Dohi, Toshifumi
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p. 1924 - 1928
(2022/03/27)
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- Preparation and characterization of Cu based on 5,5'-bistetrazole as a recyclable metal-organic framework and application in synthesis of diaryl ether by the Ullmann coupling reaction
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Cu based on 5,5′-bistetrazole ([Cu2BT · 2H2O] n) as a recyclable metal-organic framework (MOF) heterogeneous catalyst was characterized by FT-IR, 13C NMR, XRD, SEM, EDX, BET, BJH, and ICP-AES analysis. The catalytic activity of the catalyst was probed through the Ullmann reaction for synthesis of diaryl ether derivatives from two component reactions of aromatic arylhalides and phenol derivatives in DMSO. Simple procedure, high yields, short reaction time, and environmentally benign methods are advantages of this protocol. The catalyst was readily separated by simple filtration and reusable without significant loss of its catalytic efficiency.
- Noorpoor, Zeinab,Tavangar, Saeed
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p. 1651 - 1662
(2021/05/10)
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- 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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- Copper nanoparticle anchored biguanidine-modified Zr-UiO-66 MOFs: a competent heterogeneous and reusable nanocatalyst in Buchwald-Hartwig and Ullmann type coupling reactions
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We have designed a functionalized metal-organic framework (MOF) of UiO topology as a support, with an extremely high surface area, adjustable pore sizes and stable crystalline coordination polymeric structure and implanted copper (Cu) nanoparticles thereon. The core three dimensional Zr-derived MOF (UiO-66-NH2) was modified with a biguanidine moiety following a covalent post-functionalization approach. The morphological and physicochemical features of the material were determined using analytical methods such as FT-IR, SEM, TEM, EDX, atomic mapping, XRD and ICP-OES. The SEM and XRD results justified the unaffected morphology of Zr-MOF after structural modifications. The as-synthesized UiO-66-biguanidine/Cu nanocomposite was catalytically explored in the aryl and heteroaryl Buchwald-Hartwig C-N and Ullmann type C-O cross coupling reactions with excellent yields. A library of biaryl amine and biaryl ethers was synthesized over the catalyst under mild and green conditions. Furthermore, the catalyst was isolated by centrifugation and recycled 11 times with no significant copper leaching or change in its activity.
- Veisi, Hojat,Neyestani, Narges,Pirhayati, Mozhgan,Ahany Kamangar, Sheida,Lotfi, Shahram,Tamoradi, Taiebeh,Karmakar, Bikash
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p. 22278 - 22286
(2021/07/02)
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- Radical and ionic mechanisms in rearrangements of o-tolyl aryl ethers and amines initiated by the Grubbs-stoltz reagent, et3SiH/KOtbu
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Rearrangements of o-tolyl aryl ethers, amines, and sulfides with the Grubbs-Stoltz reagent (Et3SiH + KOtBu) were recently announced, in which the ethers were converted to o-hydroxydiarylmethanes, while the (o-tol)(Ar)NH amines were transformed into dihydroacridines. Radical mechanisms were proposed, based on prior evidence for triethylsilyl radicals in this reagent system. A detailed computational investigation of the rearrangements of the aryl tolyl ethers now instead supports an anionic Truce-Smiles rearrangement, where the initial benzyl anion can be formed by either of two pathways: (i) direct deprotonation of the tolyl methyl group under basic conditions or (ii) electron transfer to an initially formed benzyl radical. By contrast, the rearrangements of o-tolyl aryl amines depend on the nature of the amine. Secondary amines undergo deprotonation of the N-H followed by a radical rearrangement, to form dihydroacridines, while tertiary amines form both dihydroacridines and diarylmethanes through radical and/or anionic pathways. Overall, this study highlights the competition between the reactive intermediates formed by the Et3SiH/KOtBu system.
- Kolodziejczak, Krystian,Murphy, John A.,Stewart, Alexander J.,Tuttle, Tell
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- Benzylic C?H Functionalisation by [Et3SiH+KOtBu] leads to Radical Rearrangements in o-tolyl Aryl Ethers, Amines and Sulfides
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Reaction of Et3SiH+KOtBu with diaryl ethers, sulfides and amines that feature an ortho alkyl group leads to rearrangement products. The rearrangements arise from formation of benzyl radicals, likely formed through hydrogen atom abstraction by triethylsilyl radicals. The rearrangements involve cyclisation of the benzyl radical onto the partner arene, which, from computation, is the rate determining step. In the case of diaryl ethers, Truce-Smiles rearrangements arise from radical cyclisations to form 5-membered rings, but for diarylamines, cyclisations to form dihydroacridines are observed. (Figure presented.).
- Arokianathar, Jude N.,Kolodziejczak, Krystian,Bugden, Frances E.,Clark, Kenneth F.,Tuttle, Tell,Murphy, John A.
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supporting information
p. 2260 - 2267
(2020/05/06)
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- Trimethoxyphenyl (TMP) as a Useful Auxiliary for in situ Formation and Reaction of Aryl(TMP)iodonium Salts: Synthesis of Diaryl Ethers
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Herein, we describe a synthetic approach for arylation that exploits the in situ formation and reaction of an unsymmetrical diaryliodonium salt. In this way, aryl iodides are used as reagents in a metal-free reaction with phenols, and a trimethoxyphenyl (TMP) group is used as a “dummy” group to facilitate transfer of a wide range of aryl moieties. The scope of aryl electrophiles and phenol nucleophiles is broad (>30 examples) and the yields are high (52–95%, 80% avg.). One-pot coupling reactions avoid the synthesis of diaryliodonium salts and provide opportunities for sequential reactions and novel chemoselectivity. (Figure presented.).
- Gallagher, Rory T.,Basu, Souradeep,Stuart, David R.
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p. 320 - 325
(2019/12/11)
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- Pd based on 2-Aminopyrimidine and 1H-benzo[d]imidazol-2-amine functionalizedFe3O4 nanoparticles as novel recyclable magnetic nanocatalysts for Ullmann coupling reaction
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In this study, Pd based on 2-Aminopyrimidine and 1H-benzo[d]imidazol-2-amine functionalized Fe3O4 magnetic nanoparticles [(Pd-APM-PSi-Fe3O4) and (Pd-BIA-PSi-Fe3O4)] was designed and used for the synthesis of di aryl ether by Ulmann cross-coupling reactions. Ulmann reaction performed with mixing of the arylhalides and phenol derivatives in DMF solvent. The prepared catalysts were characterized with various analytical techniques such as FT-IR, XRD, TGA, SEM, TEM, EDX, ICP and VSM. Pd-APM-PSi-Fe3O4 and Pd-BIA-PSi-Fe3O4 catalysts demonstrated good to excellent yields catalytic efficiency for Ulmann reactions in comparison with to commercial palladium catalysts. The catalyst is easily recycled and reused without loss of the catalytic activity. The combined merits of reusable catalyst conditions make the condensation with safe operation, no leaching of pd into environment, low pollution, rapid access to products and simple workup. Also, these novel magnetic nanocatalysts are superior to the industry standard Pd in every relevant aspect. They feature a way higher initial activity, a much more convenient separation, better recycling, and less contamination of the products. Last but not least, they can be very easily prepared from commercially available Fe3O4 nanoparticles using standard laboratory equipment.
- Chen, Jin,Dai, Linfang,Li, Jiayu,Mohammadnia, Majid
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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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- Preparation and characterization of isatin complexed with Cu supported on 4-(aminomethyl) benzoic acid-functionalized Fe3O4 nanoparticles as a novel magnetic catalyst for the Ullmann coupling reaction
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Isatin complexed with Cu supported on 4-(aminomethyl) benzoic acid-functionalized Fe3O4 nanoparticles (Cu-IS-AMBA-MNPs) as a new catalyst was designed, prepared and characterized by appropriate analyses. The heterogeneous reusable catalyst was successfully used for the efficient and widespread syntheses of diaryl ethers and diarylamines via the Ullmann coupling reaction. This green catalyst was easily removed, reused several times with no significant loss of its activity, and provided a clean synthesis with excellent yield and reduced time.
- Khodaei, Mohammad Mehdi,Alizadeh, Abdolhamid,Haghipour, Maryam
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p. 2727 - 2747
(2019/02/13)
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- Magnetically recyclable nano copper/chitosan in O-arylation of phenols with aryl halides
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Interaction of chitosan (CS) with Fe3O4, followed by embedding Cu nanoparticles (NPs) on the magnetic surface through adsorption of Cu2+, and its reduction to Cuo via NaBH4, offers a reusable efficient catalyst (Fe3O4/CS-Cu NPs) that is employed in cross-coupling reactions of aryl halides with phenols, which affords the corresponding diaryl ethers, with good to excellent yields. The catalyst is completely recoverable from the reaction mixture by using an external magnet. It can be reused four times, without significant loss in its catalytic activity.
- Mousavi Mashhadi, Seyed Ali,Kassaee, Mohamad Z.,Eidi, Esmaiel
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- Decarbonylative Methylation of Aromatic Esters by a Nickel Catalyst
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A Ni-catalyzed decarbonylative methylation of aromatic esters was achieved using methylaluminums as methylating agents. Dimethylaluminum chlorides uniquely worked as the methyl source. Because of the Lewis acidity of aluminum reagents, less reactive alkyl esters could also undergo the present methylation. By controlling the Lewis acidity of aluminum reagents, a chemoselective decarbonylative cross-coupling between alkyl esters and phenyl esters was successful.
- Okita, Toshimasa,Muto, Kei,Yamaguchi, Junichiro
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p. 3132 - 3135
(2018/05/28)
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- Cellulose-supported N-heterocyclic carbene silver complex with pendant ferrocenyl group for diaryl ether synthesis
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A cellulose-supported N-heterocyclic carbene Ag(I) complex has been synthesized by covalent grafting of ferrocenyl ionic liquid in the matrix of cellulose followed by metallation with silver oxide. The complex was employed as a heterogeneous catalyst in the synthesis of diaryl ethers. Reactions of a variety of phenols with aryl halides afford corresponding diaryl ethers in moderate to good yields. Recyclability experiments were executed successfully for five consecutive runs.
- Jagadale, Megha,Salunkhe, Rajashri,Kumbhar, Arjun,Gajare, Shivanand,Rajmane, Mohan,Rashinkar, Gajanan
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- A green approach for arylation of phenols using iron catalysis in water under aerobic conditions
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The first efficient iron-catalyzed coupling of aryl iodides with phenols was developed exclusively with water as solvent. The reaction is performed with low cost and readily available FeCl3·6H2O and DMEDA catalytic system providing diaryl ethers in good to excellent yields. The effectiveness of this reaction was further revealed by compatibility with a wide range of functional groups. Moreover, the procedure is rendered simple as this transformation is carried out in the presence of air. Thus, the protocol represents a facile, economical and eco-friendly procedure to access diaryl ethers.
- Sindhu, Kallikkakam S.,Ujwaldev, Sankuviruthiyil M.,Keerthi Krishnan,Anilkumar, Gopinathan
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p. 146 - 150
(2017/03/17)
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- Evaluation of fluorinated biphenyl ether pro-drug scaffolds employing the chemical-microbial approach
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Incorporation of fluorine in a drug can dramatically affect its metabolism and methods to assess the effect of fluorine substitution on drug metabolism are required for effective drug design. Employing a previously developed chemical-microbial method the metabolism of a series of fluorinated biphenyl ethers was determined. The substrates were synthesized via Ullmann-type condensation reactions between bromotoluene and fluorophenol. The ethers were incubated with the fungus Cunninghamella elegans, which oxidises xenobiotics in an analogous fashion to mammals, generating a number of hydroxylated biphenyl ethers and acids. The propensity of the fluorinated ring to be hydroxylated depended upon the position of the fluorine atom, and the oxidation of the methyl group was observed when it was meta to the oxygen. The experiments demonstrate the applicability of the method to rapidly determine the effect of fluorine substitution on CYP-catalysed biotransformation of pro-drug molecules.
- Hampton, Alex S.,Mikulski, Lena,Palmer-Brown, William,Murphy, Cormac D.,Sandford, Graham
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p. 2255 - 2258
(2016/04/20)
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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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- Air-stable palladium(0) phosphine sulfide catalysts for Ullmann-type C-N and C-O coupling reactions
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This paper describes an efficient procedure for palladium(0)-catalyzed N-arylation and O-arylation of aryl halides by Ullmann-type cross coupling reaction under mild reaction conditions in a short reaction time. Two phosphine sulphide ligands and their corresponding Pd(0) complexes namely [Pd(p2S2)(dba)] and [Pd(pp3S4)(dba)], were synthesized, where p2S2 is 1,2-bis(diphenylphosphino)ethane disulfide, pp3S4 is tris[2-(diphenylphosphino)ethyl]phosphine tetrasulfide and dba is dibenzylideneacetone. Optimal reaction conditions were determined for the arylation reactions using iodobenzene and benzimidazole by varying temperature, solvent, base and catalyst loading. The cross coupling reactions were carried out taking iodobenzenes/bromobenzenes and a wide variety of substituted aryl amines/phenols/alcohols with different steric and electronic properties to afford the desired N-aryl amines/diaryl ethers/alkyl aryl ethers in good to excellent yield (70-94%).
- Majumder, Arpi,Gupta, Ragini,Mandal, Mrinmay,Babu, Madhu,Chakraborty, Debashis
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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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- CsF/clinoptilolite: An efficient solid base in SNAr and copper-catalyzed Ullmann reactions
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CsF/clinoptilolite was found to be an efficient solid base catalyst for both SNAr and Ullmann ether reactions. A general and efficient one-step procedure was developed for the synthesis of biaryl ethers via direct coupling of electron-deficient aryl halides to phenols using CsF/clinoptilolite. The protocol was also applied to electron-rich aryl halides by addition of a catalytic amount of copper oxide nanoparticles. Both SNAr and Ullmann reactions were rapid and provided good to excellent yields.
- Keipour, Hoda,Hosseini, Abolfazl,Afsari, Amir,Oladee, Razieh,Khalilzadeh, Mohammad A.,Ollevier, Thierry
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- Barberry fruit extract assisted in situ green synthesis of Cu nanoparticles supported on a reduced graphene oxide-Fe3O4 nanocomposite as a magnetically separable and reusable catalyst for the O-arylation of phenols with aryl halides under ligand-free conditions
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In situ synthesis of copper nanoparticles (NPs) supported on a reduced graphene oxide (RGO)-Fe3O4 nanocomposite was carried out with barberry fruit extract as a reducing and stabilizing agent. The morphology and structure of the Cu/RGO-Fe3O4 nanocomposite was fully characterized by means of X-ray diffraction (XRD), Fourier transformed infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), Raman, energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). Cu/RGO-Fe3O4 was a promising catalyst for the O-arylation of phenols with aryl halides under ligand-free conditions. A diverse range of diaryl ethers were obtained in a good to high yield. Furthermore, due to the magnetic separability and high stability of the composite the catalyst could be separated conveniently from the reaction mixtures by an external permanent magnet and recycled multiple times without loss of catalytic activity.
- Nasrollahzadeh, Mahmoud,Maham, Mehdi,Rostami-Vartooni, Akbar,Bagherzadeh, Mojtaba,Sajadi, S. Mohammad
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p. 64769 - 64780
(2015/08/18)
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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
-
supporting information
p. 7082 - 7088
(2015/02/02)
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- Impregnated copper on magnetite as catalyst for the O-arylation of phenols with aryl halides
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Nanoparticle Fe3O4 encapsulated CuO, as a heterogeneous catalyst, is a facile system for the synthesis of diaryl ethers by the cross-coupling reaction of various substituted aryl halides with various substituted phenols, which avoids using any type of expensive ligand and can be recovered from the reaction mixture by using a simple magnet. Moreover, this catalyst can be reused three times with high catalytic activity.
- Zhang, Ying-Peng,Shi, Ai-Hong,Yang, Yun-Shang,Li, Chun-Lei
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p. 141 - 145
(2014/02/14)
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- Carbon nanofiber supported copper nanoparticles catalyzed Ullmann-type coupling reactions under ligand-free conditions
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A carbon nanofiber supported copper nanoparticle (CuNP/CNF) catalyst was prepared and used for Ullmann-type couplings under ligand-free conditions. The catalyst exhibited high catalytic activity in C-O and C-N bond formation couplings. This journal is
- Li, Hongqiang,Li, Chunping,Bai, Jie,Zhang, Chenglin,Sun, Weiyan
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p. 48362 - 48367
(2014/12/10)
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- Synthesis of highly functionalized diaryl ethers by copper-mediated O-arylation of phenols using trivalent arylbismuth reagents
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Highly functionalized diaryl ethers were prepared by copper(II) acetate mediated O-arylation reaction of phenols using trivalent organobismuthanes. The reaction is performed under simple conditions and tolerates a wide diversity of functional groups on the phenol and on the organobismuth reagent. Substoichiometric amounts of catalyst can be used by performing the reaction under an oxygen atmosphere. The N-arylation of pyridones is also reported. Highly functionalized diaryl ethers were prepared by a copper(II) acetate mediated O-arylation reaction of phenols using trivalent organobismuthanes (see scheme). The reaction is performed under simple conditions and tolerates a wide diversity of functional groups on the phenol and on the organobismuth reagent. Substoichiometric amounts of catalyst can be used by performing the reaction under an oxygen atmosphere. The N-arylation of pyridones is also reported. FG=functional group.
- Crifar, Cynthia,Petiot, Pauline,Ahmad, Tabinda,Gagnon, Alexandre
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supporting information
p. 2755 - 2760
(2014/03/21)
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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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- A highly active reusable polymer anchored copper catalyst for C-O, C-N and C-S cross coupling reactions
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A new furfural functionalized polymer-amine grafted with copper catalyst has been designed and employed for the N-arylation, O-arylation and S-arylation reactions under an open air condition to afford the corresponding coupled products in good to excellent yields. This solid supported catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), UV-vis spectroscopy and scanning electron microscope (SEM). The developed catalyst can be facilely recovered and reused five times without significant decrease in activity and selectivity. This result confirms that the polymer anchored complex was not leached during the reaction, suggesting the true heterogeneous nature of the catalyst.
- Islam, Sk.Manirul,Salam, Noor,Mondal, Paramita,Roy, Anupam Singha,Ghosh, Kajari,Tuhina
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- Betti base as an efficient ligand for copper-catalyzed ullmann coupling of phenol with aryl halides
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GRAPHICAL ABSTRACT A simple, general, and highly efficient Betti base ligand has been developed for copper-catalyzed Ullmann coupling of phenol with aryl halides without the protection of an inert atmosphere. The reaction proceeds smoothly in the presence of K2CO3 as the base and dimethylsulfoxide as the solvent. The catalyst was reused several times with no evident loss of catalytic activity and is environmentally friendly.
- Yang, Li,Yang, Qichao,Shi, Jianxin,Wang, Yufang,Zhang, Mingjie
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supporting information
p. 2468 - 2477
(2014/08/05)
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- KF/Clinoptilolite, an effective solid base in Ullmann ether synthesis catalyzed by CuO nanoparticles
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Employing KF/Clinoptilolite as an efficient base the cross-coupling reactions of various phenols with aryl iodides could be successfully carried out in the presence of copper oxide nanoparticles. The C-O coupling products were obtained in moderate to good yields (62-87%) for a variety of substrates. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2014.
- Khalilzadeh, Mohammad A.,Keipour, Hoda,Hosseini, Abolfazl,Zareyee, Daryoush
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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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- Ligand-free catalytic system for the synthesis of diarylethers over Cu 2O/Cu-CNTs as heterogeneous reusable catalyst
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Various substituted diarylether derivatives were prepared by using heterogeneous reusable Cu2O- and Cu-coated carbon nanotubes (Cu 2O/Cu-CNTs) as catalyst under ligand-free conditions, which provided good to excellent yields. The catalyst was characterized by TEM, XRD, and AAS analysis. The effects of solvent, base, and amount of catalyst for the O-arylation were investigated. The catalyst could be recovered by simple filtration from the reaction mixture without further treatment and reused several times with consistent catalytic activity. In addition, CNTs could also be recovered from the used Cu2O/Cu-CNTs by a simple acid treatment.
- Zhang, Ying-Peng,Jiao, Ya-Cong,Yang, Yun-Shang,Li, Chun-Lei
-
supporting information
p. 6494 - 6497
(2013/11/19)
-
- 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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- 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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- Preparation of carbon nanotube-supported α-Fe2O 3@CuO nanocomposite: A highly efficient and magnetically separable catalyst in cross-coupling of aryl halides with phenols
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Herein, we introduce the first magnetic CuO nanoparticles based on carbon nanotubes as a highly intriguing magnetic catalyst in Ullmann-type coupling of aryl halides with phenols. Two facile procedures were used for the preparation of this magnetically separable catalytic system. Having been treated with FeSO4 and then H2O2, nanotubes accommodated the resulting iron hydroxides on the walls. The resulting nanocomposite was then exposed to argon atmosphere at 450°C giving rise to a carbon nanotube-supported α-Fe2O3 compound. Ultimately, copper acetate was hydrolysed in the presence of CNT supported α-Fe 2O3 at 100°C and our novel catalyst was gained. Some spectroscopic and microscopic techniques such as Infrared spectroscopy (IR), X-ray diffraction spectroscopy (XRD), Vibrational sample magnetometry (VSM), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH), Inductively coupled plasma (ICP), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) corroborated the structure of the catalyst. The catalyst synthesized showed good activity in C-O cross coupling reactions affording the highest rate of completion. Magnetic feature of the catalyst helped facile separation of it from the reaction medium. The catalyst could also be reused up to six times without any loss of its activity.
- Saberi, Dariush,Sheykhan, Mehdi,Niknam, Khodabakhsh,Heydari, Akbar
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p. 2025 - 2031
(2013/07/26)
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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)
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- 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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- An in situ generated CuI/metformin complex as a novel and efficient catalyst for C-N and C-O cross-coupling reactions
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An in situ generated complex of copper(I) and a biguanide, namely metformin, was found to be a highly efficient homogeneous catalyst in N/O-arylation reactions. The O-arylation of substituted phenols with various aryl iodides and bromides was also achieved using this copper catalyst to afford diaryl ethers in good to excellent yields in DMF. This heterogeneous copper catalyst also promotes the N-arylation of imidazole with a variety of aryl halides (Cl, Br, I) in acetonitrile.
- Ghorbani-Vaghei, Ramin,Hemmati, Saba,Veisi, Hojat
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p. 7095 - 7099
(2013/12/04)
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- Mesoporous nitrogen-doped carbon for copper-mediated Ullmann-type C-O/-N/-S cross-coupling reactions
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Copper-driven Ullmann-type cross-coupling reactions are regarded as one of the most important methods for the C-O, C-N, C-S and some other bonds formation. Herein, we report that mesoporous nitrogen-doped carbon materials with high nitrogen content function as novel, active and recyclable N-type heterogeneous promoters for copper-catalyzed cross-couplings. By using CuI as the catalyst and a mesoporous nitrogen-doped carbon material as the promoter, the Ullmann-type coupling reactions of various aryl halides with phenols, amines, imidazol, and thiophenols at 100 °C gave the corresponding products in good yields. Inspired by the efficiency of mesoporous nitrogen-doped carbon material as a promoter, nitrogen-doped carbon supported CuO nanoparticles are prepared and successfully employed as efficient heterogeneous catalysts in the C-O cross-coupling reactions. Furthermore, the nitrogen-doped carbon material supported CuO can be simply recycled by centrifugation and reused at least four times with trace copper leaching. The mesoporous nitrogen-doped carbon materials as heterogeneous promoters or copper-based catalyst supports may represent a promising catalyst system in modern Ullmann chemistry, which indeed could lead to improved processing steps.
- Zhang, Pengfei,Yuan, Jiayin,Li, Haoran,Liu, Xiaofeng,Xu, Xuan,Antonietti, Markus,Wang, Yong
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p. 1890 - 1895
(2013/03/13)
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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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p. 20226 - 20229
(2013/02/25)
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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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supporting information
p. 14140 - 14149,10
(2012/12/12)
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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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- 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)
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- A reusable polymer supported copper catalyst for the C-N and C-O bond cross-coupling reaction of aryl halides as well as arylboronic acids
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A simple and industrially viable protocol for C-N and C-O coupling was reported here. The polymer supported heterogeneous copper catalyst was prepared from chloromethyl polystyrene using a simple procedure. O-Arylation of substituted phenols with various aryl halides was achieved using this copper catalyst in DMSO medium. This heterogeneous copper catalyst, also efficiently works for the N-arylation of N-H heterocycles with aryboronic acids in methanol. This catalyst was also effective in amination reaction of primary amines with aryl halides as well as arylboronic acids in DMSO medium. The effects of solvent, base and temperature for the O-Arylation and amination reactions were reported. Further, the catalyst can be easily recovered quantitatively by simple filtration and reused up to several times without sufficient loss of its catalytic activity.
- Islam, Sk.Manirul,Mondal, Sanchita,Mondal, Paramita,Roy, Anupam Singha,Tuhina,Salam, Noor,Mobarak, Manir
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experimental part
p. 4264 - 4274
(2012/01/06)
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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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- Surfactant-free single-nano-sized colloidal Cu nanoparticles for use as an active catalyst in Ullmann-coupling reaction
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Surfactant-free, single-nano-sized copper nanoparticles (Cu NPs) (size: about 2 nm) were prepared by the DMF reduction method. The Cu NPs showed high catalytic activity (with a turnover number (TON) of up to 2.2 × 10 4) in Ullmann-type cross-coupling of aryl halides with phenols under ligand-free conditions. The Royal Society of Chemistry 2012.
- Isomura, Yuto,Narushima, Takashi,Kawasaki, Hideya,Yonezawa, Tetsu,Obora, Yasushi
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supporting information; experimental part
p. 3784 - 3786
(2012/06/16)
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- 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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- Fe3O4@mesoporouspolyaniline: A highly efficient and magnetically separable catalyst for cross-coupling of aryl chlorides and phenols
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A high surface, magnetic Fe3O4@mesoporouspolyaniline core-shell nanocomposite was synthesized from magnetic iron oxide (Fe 3O4) nanoparticles and mesoporouspolyaniline (mPANI). The novel porous magnetic Fe3O4 was obtained by solvothermal method under sealed pressure reactor at high temperature to achieve high surface area. The mesoporouspolyaniline shell was synthesized by in situ surface polymerization onto porous magnetic Fe3O4 in the presence of polyvinylpyrrolidone (PVP) and sodium dodecylbenzenesulfonate (SDBS), as a linker and structure-directing agent, through 'blackberry nanostructures' assembly. The material composition, stoichiometric ratio and reaction conditions play vital roles in the synthesis of these nanostructures as confirmed by variety of characterization techniques. The role of the mesoporouspolyaniline shell is to stabilize the porous magnetic Fe3O4 nanoparticles, and provide direct access to the core Fe3O4 nanoparticles. The catalytic activity of magnetic Fe3O 4@mesoporousPANI nanocomposite was evaluated in the cross-coupling of aryl chlorides and phenols. Copyright
- Arundhathi,Damodara,Likhar, Pravin R.,Kantam, M. Lakshmi,Saravanan,Magdaleno, Travis,Kwon, Sun Hee
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supporting information; experimental part
p. 1591 - 1600
(2011/08/03)
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- Open air O-arylation reaction of phenols with aryl halides catalyzed by polymer-anchored copper(II) complexes
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Two copper complexes were synthesized from macroporous chloromethylated polystyrene beads. The first one was prepared by sequential attachment of imidazole and copper acetate with chloromethylated polystyrene-divinyl benzene copolymer, and the second one was prepared from 4-vinylpyridine and copper acetate with chloromethylated polystyrene-divinyl benzene copolymer. These catalysts showed excellent catalytic activity in O-arylation reaction of aryl halides with phenol in dimethylsulfoxide using potassium carbonate at 130 °C under open air conditions to give diaryl ethers in high yields. Less reactive aryl bromides and aryl chlorides have also been shown to react with phenols to give good yields of the diaryl ethers. The effects of various parameters such as solvent, catalyst from different copper salt and base on the reaction system were studied. The reaction is applicable to a wide variety of substituted aryl halides and phenols with different steric and electronic properties. These catalysts were recovered by simple filtration, and the reusability experiments showed that these catalysts can be used five times without much loss in the catalytic activity.
- Islam, Manirul,Mondal, Sanchita,Mondal, Paramita,Roy, Anupam Singha,Hossain, Dildar,Mobarak, Manir
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experimental part
p. 1 - 11
(2012/02/01)
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- Potassium fluoride supported on natural nanoporous zeolite: A new solid base for the synthesis of diaryl ethers
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An efficient and inexpensive synthesis of diaryl ethers has been developed. The process involves the nucleophilic aromatic substitution of electron-deficient aryl halides and phenols and is mediated by potassium fluoride/Clinoptilolite (KF/CP) in dimethyl sulfoxide (DMSO). The approach affords good to excellent yields of the arylated products without the need for additional cation capture. The solid base is also efficient in the Ullmann ether synthesis. A new, inexpensive solid base for the synthesis of diaryl ethers has been developed. Clinoptilolite, a natural zeolite with a high tendency for cation capture, combined with potassium fluoride, provides an efficientsolid base for the deprotonation of phenols in nucleophilic reactions. The same solid base acts as a reliable base for the copper-catalyzed synthesis of diaryl ethers. Copyright
- Khalilzadeh, Mohammad A.,Hosseini, Abolfazl,Pilevar, Afsaneh
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experimental part
p. 1587 - 1592
(2011/04/22)
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- Dimethyl sulfoxide/potassium hydroxide: A superbase for the transition metal-free preparation of cross-coupling products
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Potassium hydroxide (KOH) in dimethyl sulfoxide (DMSO) forms a superbasic medium that allows one to access cross-coupling products from reactions between aryl halides with various sulfur-, oxygen- and nitrogen-based nucleophiles under transition metal-free conditions. Copyright
- Yuan, Yu,Thome, Isabelle,Kim, Seok Hwan,Chen, Duanteng,Beyer, Astrid,Bonnamour, Julien,Zuidema, Erik,Chang, Sukbok,Bolm, Carsten
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experimental part
p. 2892 - 2898
(2011/01/05)
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