- Room Temperature C-H Arylation of Benzofurans by Aryl Iodides
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A robust method of room temperature direct arylation for benzofuran is reported. This discovery allows for mild arylation by commercially available aryl iodides with complete C-2 regioselectivity and tolerates a range of functional groups, including heat sensitive groups. Mechanistically, a Heck-type oxyarylation product from a direct arylation process is reported as a key piece of evidence for a carbopalladation intermediate.
- Mayhugh, Amy L.,Luscombe, Christine K.
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supporting information
p. 7079 - 7082
(2021/09/18)
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- Acid-promoted selective synthesis of trifluoromethylselenolated benzofurans with Se-(trifluoromethyl) 4-methylbenzenesulfonoselenoate
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A Br?nsted acid-promoted trifluoromethylselenolation of benzofurans was disclosed by using Se-(trifluoromethyl) 4-methylbenzenesulfonoselenoate as a stable and easily prepared electrophilic trifluoromethylselenolating reagent. A wide range of SeCF3-substituted benzofuran derivatives were obtained in moderate to good yields with excellent regioselectivity. The tandem cyclization/trifluoromethylselenolation procedure of 1-methoxy-2-(arylethynyl)benzenes were also realized by engaging FeCl3 as the catalyst.
- Liu, Juyan,Tian, Miaomiao,Li, Ankun,Ji, Liangshuo,Qiu, Di,Zhao, Xia
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supporting information
(2021/02/01)
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- New transmetalation reagents for the gold-catalyzed visible light-enabled C(sp or sp2)-C(sp2) cross-coupling with aryldiazonium salts in the absence of a photosensitizer
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The scope of photosensitizer-free visible light-driven gold-catalyzed cross-coupling was evaluated by a wide variety of organoboron and organosilicon species using four equivalents of aryldiazonium salts and (4-CF3-C6H4)3PAuCl in MeOH. In addition, a C(sp or sp2)-C(sp2) cross-coupling of organotrimethylsilanes and aryldiazonium salts was investigated. The reactions can be conducted under very mild reaction conditions, with a reduced amount of aryldiazonium salt (1.2 equiv.) by using a catalytic amount of Ph3PAuNTf2 in MeCN under irradiation with blue LEDs at room temperature.
- Witzel, Sina,Sekine, Kohei,Rudolph, Matthias,Hashmi, A. Stephen K.
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p. 13802 - 13804
(2018/12/14)
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- Synthesis of Benzofurans and Indoles from Terminal Alkynes and Iodoaromatics Catalyzed by Recyclable Palladium Nanoparticles Immobilized on Siliceous Mesocellular Foam
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Herein, we report on the utilization of a heterogeneous catalyst, consisting of Pd nanoparticles supported on a siliceous mesocellular foam (Pd0-AmP-MCF), for the synthesis of heterocycles. Reaction of o-iodophenols and protected o-iodoanilines with acetylenes in the presence of a Pd nanocatalyst produced 2-substituted benzofurans and indoles, respectively. In general, the catalytic protocol afforded the desired products in good to excellent yields under mild reaction conditions without the addition of ligands. Moreover, the structure of the reported Pd nanocatalyst was further elucidated with extended X-ray absorption fine-structure spectroscopy, and it was proven that the catalyst could be recycled multiple times without significant loss of activity.
- Bruneau, Alexandre,Gustafson, Karl P. J.,Yuan, Ning,Tai, Cheuk-Wai,Persson, Ingmar,Zou, Xiaodong,B?ckvall, Jan-E.
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supporting information
p. 12886 - 12891
(2017/09/25)
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- Palladium-catalyzed phosphine-free direct C-H arylation of benzothiophenes and benzofurans involving MIDA boronates
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With high regioselectivity, a series of benzoheterocyclic compounds were synthesized via palladiium-catalyzed phosphine-free C-H arylation of benzothiophenes/benzofurans with aryl MIDA boronates at 30-50 °C in moderate to excellent yields. MIDA boronates were used in C-H arylation of heterocycles for the first time. Under the optimal conditions, the benzothiophenes could be transformed into the β-arylbenzothiophenes, and the benzofurans gave only α-aryl-substituted products.
- Wang, Zhiwei,Li, Yabo,Yan, Beiqi,Huang, Mengmeng,Wu, Yangjie
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supporting information
p. 531 - 536
(2015/03/04)
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- Palladacycles derived from arylphosphinamides for mild Suzuki-Miyaura cross-couplings
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We present a type of palladacyclic complexes derived from arylphosphinamides which can be used as efficient and versatile precatalysts for mild Suzuki-Miyaura cross-coupling. With the presence of 1.0 mol% of palladacycles, a wide variety of aryl bromides and boronic acids could be coupled very efficiently at ambient temperature and under air atmosphere without the need of external supporting ligands. Moreover, the mild conditions also allow for smooth coupling of electron-deficient, i.e., the less stable aryl triflates. In addition to the highly catalytic activity, the palladacyclic complexes can be very easily prepared through a two-step procedure from the readily affordable diphenyl-phosphinic chloride and exhibit excellent stability toward air and moisture. Due to these prominent properties, the new palladacycles would find practical use in Suzuki-Miyaura couplings.
- Wu, Guo-Jie,Han, Fu-She,Zhao, Yu-Long
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p. 69776 - 69781
(2015/09/01)
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- Fluorination of 2-substituted benzo[b]furans with Selectfluor
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An efficient protocol was developed to access 3-fluoro-2-hydroxy-2-substituted benzo[b]furans with Selectfluor as the fluorinating reagent in MeCN and water. By utilizing SOCl2/Py as the dehydrating agent, the compounds above were readily conve
- Wang, Mingliang,Liu, Xixi,Zhou, Lu,Zhu, Jidong,Sun, Xun
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supporting information
p. 3190 - 3193
(2015/03/18)
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- One-Pot preparation of 2-arylbenzofurans from oximes with diaryliodonium triflate
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A variety of 2-arylbenzofurans were obtained in good yields by the O-arylation of oximes with diaryliodonium triflates, followed by the treatment with HCl in dioxane under warming conditions through the [3,3]-sigmatropic reaction. The present reaction is one-pot transition metal-free method for the preparation of various 2-arylbenzofurans from oximes, which are easily available from the reaction of alkyl aryl ketones with hydroxylamine.
- Miyagi, Kotaro,Moriyama, Katsuhiko,Togo, Hideo
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p. 2122 - 2136
(2015/01/09)
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- Room-temperature arylation of arenes and heteroarenes with diaryliodonium salts by photoredox catalysis
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Aryl radicals produced by irradiation of diaryliodonium salts with visible light under the catalysis of [Ru(bpy)3]2+ undergo coupling with a wide range of arenes and heteroarenes, affording various biaryls through direct C-H arylation at room temperature. Georg Thieme Verlag Stuttgart · New York.
- Liu, Yu-Xia,Xue, Dong,Wang, Jia-Di,Zhao, Cong-Jun,Zou, Qing-Zhu,Wang, Chao,Xiao, Jianliang
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supporting information
p. 507 - 513
(2013/04/10)
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- Radical arylation of phenols, phenyl ethers, and furans
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Radical arylations of parasubstituted phenols and phenyl ethers proceeded with good regioselectivity at the ortho position with respect to the hydroxy or alkoxy group. The reactions were conducted with arenediazonium salts as the aryl radical source, titaniumACHTUNGTRENUNG(III) chloride as the reductant, and diluted hydrochloric acid as the solvent. Substituted biaryls were obtained from hydroxy- and alkoxy-substituted benzylamines, phenethylamines, and aromatic amino acids. The methodology described offers a fast, efficient, and cost-effective new access todiversely functionalized biphenyl alcohols and ethers. Free phenolic hydroxyl groups, aromatic and aliphatic amines, as well as amino acid substructures, are well tolerated. Two examples for the applicability of the methodology are the partial synthesis of a b-secretase inhibitor and the synthesis of a calciumchannel modulator
- Wetzel, Alexander,Pratsch, Gerald,Kolb, Roman,Heinrich, Markus R.
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experimental part
p. 2547 - 2556
(2010/06/17)
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- Methods and systems for preparing fused heterocyclic compounds using copper(I) catalysts
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A copper(I)-catalyzed procedure for the synthesis of benzo[b]heterocycles. This protocol can be used to synthesize a variety of 2-arylbenzo[b]furans and indoles in good to excellent yields. This method can tolerate a variety of functional groups, does not require the use of expensive additives and is palladium-free.
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Page/Page column 6-8; 21
(2009/01/24)
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- Copper(I)-catalyzed coupling of terminal acetylenes with aryl or vinyl halides
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Synthetic protocols using copper(I) catalysts for the formation of diaryl acetylenes, 1,3-enynes, benzofurans and indoles are described. Georg Thieme Verlag Stuttgart.
- Saejueng, Pranorm,Bates, Craig G.,Venkataraman
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p. 1706 - 1712
(2007/10/03)
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- Synthesis of 2-Arylbenzo[b]furans via Copper(I)-Catalyzed Coupling of o-Iodophenols and Aryl Acetylenes
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(Equation Presented) We report a copper(I)-catalyzed procedure for the synthesis of 2-arylbenzo[b]furans. This protocol can be used to synthesize a variety of 2-arylbenzo[b]furans in good to excellent yields. This method can tolerate a variety of functional groups, does not require the use of expensive additives, and is palladium-free.
- Bates, Craig G.,Saejueng, Pranorm,Murphy, Jaclyn M.,Venkataraman
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p. 4727 - 4729
(2007/10/03)
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- Poly(ethylene glycol) supported liquid phase synthesis of biaryls
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The liquid phase synthesis of biaiyls via Suzuki cross-coupling reaction on polyethylene glycol) supports (PEGs) is described. The reaction is exemplified by parallel coupling of polymer bound aryl halides with boronic acids. Four different PEGs were employed as soluble polymer supports for parallel synthesis. The generated libraries include both sterically hindered aryl halides (2b, 2d) and boronic acids. The reactions were run in the homogeneous phase and the synthetic sequences performed in parallel fashion. Quantitative conversion in the Suzuki couplings was verified by 1H-NMR analysis (3a-r). The polymer bound products were isolated in good to excellent (52% to 98%) yields by either simple precipitation of the soluble support or column filtration.
- Blettner, Carsten G.,K?nig, Wilfried A.,Stenzel, Wolfgang,Schotten, Theo
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p. 295 - 297
(2007/10/03)
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- Palladium-catalyzed reaction of o-ethynylphenols, o-((trimethylsilyl)ethynyl)phenyl acetates, and o-alkynylphenols with unsaturated triflates or halides: A route to 2-substituted-, 2,3-disubstituted-, and 2-substituted-3-acylbenzo[b]furans
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The reaction of o-ethynylphenols 3 with a wide variety of unsaturated halides or triflates 6 in the presence of Pd(OAc)2(PPh3)2, CuI, and Et3N (procedure A) gives 2-vinyl- and 2-arylbenzo[b]furans 7, in good to high yield, through a palladium-catalyzed coupling followed by an in situ cyclization step. Small amounts of 2,3-disubstituted-benzo[b]furans 8 are usually isolated as side products. In some cases, however, compounds 8 are generated in significant yield or even as the main products. The formation of 8 can be prevented by employing alternative procedures (B and C) that use o-((trimethylsilyl)ethynyl)phenyl acetates 5 as starting building blocks. Procedure B is based on the palladium-catalyzed reaction of 5 with 6 in the presence of Pd(PPh3)4, Et3N, and n-Bu4NF, followed by the hydrolysis of the resultant coupling derivative 12 under basic conditions. Procedure C affords 7 through an in situ coupling cyclization of 5 with 6 in the presence of Pd(PPh3)4 and KOBu(t). The utilization of o-alkynylphenols 9 as the starting alkynes in the palladium-catalyzed reaction with 6 leads to the formation of 2,3-disubstituted-benzo[b]furans 13 through an annulation process promoted by σ-vinyl- and σ-arylpalladium complexes generated in situ. The best results in this case are obtained by using KOAc and Pd(PPh3)4. In the presence of KOAc and Pd(PPh3)4, and under an atmosphere of carbon monoxide, the reaction of o-alkynylphenols with 6 provides 2-vinyl- and 2-aryl-3-acylbenzo[b]furans 14.
- Arcadi,Cacchi,Del Rosario,Fabrizi,Marinelli
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p. 9280 - 9288
(2007/10/03)
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- PALLADIUM-CATALYZED ARYLATION OF FURAN, THIOPHENE, BENZOFURAN AND BENZOTHIOPHENE
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Treatment of ?-electron sufficient aromatic heterocycles such as furan, thiophene, benzofuran and benzothiophene with aryl bromides in the presence of tetrakis(triphenyphosphine)palladium gave the corresponding 2-aryl aromatic heterocycles.
- Ohta, Akihiro,Akita, Yasuo,Ohkuwa, Teruya,Chiba, Mari,Fukunaga, Ryuichi,et al.
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p. 1951 - 1958
(2007/10/02)
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