- Copper-Mediated Fluorination of Aryl Trisiloxanes with Nucleophilic Fluoride
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A method for the nucleophilic fluorination of heptamethyl aryl trisiloxanes to form fluoroarenes is reported. The reaction proceeds in the presence of Cu(OTf)2 and KHF2 as the fluoride source under mild conditions for a broad range of heptamethyltrisiloxyarenes with high functional group tolerance. The combination of this method with the silylation of aryl C?H bonds enables the regioselective fluorination of non-activated arenes controlled by steric effects following a two-step protocol.
- Dorel, Ruth,Boehm, Philip,Schwinger, Daniel P.,Hartwig, John F.
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supporting information
p. 1759 - 1762
(2020/02/05)
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- Photoredox catalysis with aryl sulfonium salts enables site-selective late-stage fluorination
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Photoredox catalysis, especially in combination with transition metal catalysis, can produce redox states of transition metal catalysts to facilitate challenging bond formations that are not readily accessible in conventional redox catalysis. For arene functionalization, metallophotoredox catalysis has successfully made use of the same leaving groups as those valuable in conventional cross-coupling catalysis, such as bromide. Yet the redox potentials of common photoredox catalysts are not sufficient to reduce most aryl bromides, so synthetically useful aryl radicals are often not directly available. Therefore, the development of a distinct leaving group more appropriately matched in redox potential could enable new reactivity manifolds for metallophotoredox catalysis, especially if arylcopper(iii) complexes are accessible, from which the most challenging bond-forming reactions can occur. Here we show the conceptual advantages of aryl thianthrenium salts for metallophotoredox catalysis, and their utility in site-selective late-stage aromatic fluorination.
- Li, Jiakun,Chen, Junting,Sang, Ruocheng,Ham, Won-Seok,Plutschack, Matthew B.,Berger, Florian,Chabbra, Sonia,Schnegg, Alexander,Genicot, Christophe,Ritter, Tobias
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- Application of trivalent iodine compounds as catalysts in Bal-Schiemann reaction
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The invention discloses an application of trivalent iodine compounds shown in formula I and/or II in the description and used as catalysts in Bal-Schiemann reaction. The trivalent iodine compounds areused as the catalysts in the Bal-Schiemann reaction, so that the Bal-Schiemann reaction can be conducted at room temperature or near room temperature when a thermochemical method is used, and the reaction has mild reaction conditions, wide substrate use range and short reaction time, and is safe and easy to operate, products are easy to separate, and raw materials are simple and low in toxicity.
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Paragraph 0153-0154; 0158-0159
(2018/10/19)
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- Hypervalent Iodine(III)-Catalyzed Balz–Schiemann Fluorination under Mild Conditions
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An unprecedented hypervalent iodine(III) catalyzed Balz–Schiemann reaction is described. In the presence of a hypervalent iodine compound, the fluorination reaction proceeds under mild conditions (25–60 °C), and features a wide substrate scope and good functional-group compatibility.
- Xing, Bo,Ni, Chuanfa,Hu, Jinbo
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p. 9896 - 9900
(2018/07/31)
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- Microflow fluorinations of benzynes: Efficient synthesis of fluoroaromatic compounds
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Fluorinated aromatic compounds are found in a variety of biologically active compounds, including clinical drugs and agrochemicals. Therefore, the synthesis of aryl fluorides is particularly important in the medicinal and process chemistry fields. In this
- Ikawa, Takashi,Masuda, Shigeaki,Akai, Shuji
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p. 1153 - 1164
(2018/12/10)
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- Synthetic method of 3,4-dimethoxy fluorobenzene as6-fluoro-L-dopa intermediate
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A synthetic method of 3,4-dimethoxy fluorobenzene as a 6-fluoro-L-dopa intermediate comprises the following steps: (i) 50-70 mL of an ethyl difluoroiodoacetate solution and 50 mL of acetone are added to a reaction vessel equipped with a stirrer, a thermom
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Paragraph 0018; 0019; 0020
(2016/11/14)
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- PhenoFluorMix: Practical chemoselective deoxyfluorination of phenols
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A practical deoxyfluorination with novel deoxyfluorinating reagent PhenoFluorMix, a mixture of N,N'-1,3-bis(2,6-diisopropylphenyl)chloroimidazolium chloride and CsF, is presented. PhenoFluorMix overcomes the challenges associated with hydrolysis of PhenoFluor. PhenoFluorMix does not hydrolyze, is readily available on decagram scale, and is storable in air. In this paper, we demonstrate the practicality of the reagent and exhibit the deoxyfluorination of a variety of phenols and heterocycles.
- Fujimoto, Teppei,Ritter, Tobias
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supporting information
p. 544 - 547
(2015/03/05)
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- Synthesis of fluorinated aromatic compounds by one-pot benzyne generation and nucleophilic fluorination
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The fluorination of substituted benzenes using fluoride ions under mild reaction conditions has been one of the most important challenges for the synthesis of biologically active fluorinated aromatic compounds; however, only a few synthetically useful methods are known. In this paper, it is reported that the nucleophilic fluorination of benzynes, generated from either 2-(trialkylsilyl)phenyl nonafluorobutanesulfonates or 2-(trialkylsilyl)phenols, meets this challenge. In particular, the fluorination starting from 2-(trialkylsilyl)phenols for fabricating aryl fluorides involves three sequential reactions in one-pot: the nonaflylation of phenols, benzyne generation, and nucleophilic fluorination of the benzynes. The regioselectivities of these reactions are controlled by the substituents at the C3-position of the benzynes. CSIRO 2014.
- Ikawa, Takashi,Masuda, Shigeaki,Nishiyama, Tsuyoshi,Takagi, Akira,Akai, Shuji
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p. 475 - 480
(2014/04/03)
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- Cu-catalyzed fluorination of diaryliodonium salts with KF
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A mild Cu-catalyzed nucleophilic fluorination of unsymmetrical diaryliodonium salts with KF is described. This protocol preferentially fluorinates the smaller aromatic ligand on iodine(III). The reaction exhibits a broad substrate scope and proceeds with high chemoselectivity and functional group tolerance. DFT calculations implicate a CuI/CuIII catalytic cycle.
- Ichiishi, Naoko,Canty, Allan J.,Yates, Brian F.,Sanford, Melanie S.
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p. 5134 - 5137
(2013/10/22)
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- Continuous flow reactor for Balz-Schiemann reaction: A new procedure for the preparation of aromatic fluorides
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A facile and highly efficient procedure for the preparation of aromatic fluorides by Balz-Schiemann reaction via two continuous flow reactors has been set up. The continuous diazotization reactor was run at about 25 °C with residence times of 10-20 s, and the continuous fluorodediazoniation reactor was performed with a residence time of 1 min in high yields. The reaction times can be greatly reduced by increasing temperature and thereby taking advantage of superior mass and heat transfer of a continuous flow system.
- Yu, Zhi-Qun,Lv, Yan-Wen,Yu, Chuan-Ming,Su, Wei-Ke
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p. 1261 - 1263
(2013/03/14)
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- Radiosynthesis and evaluation of [18F]Selectfluor bis(triflate)
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(Figure Presented) Selectfluor, one of the most reactive and commonly used electrophilic fluorinating N-F reagents, has been radiolabeled with 18F. The resulting new [18F]-labeled N-F reagent is safe, nontoxic, and easy to handle. The combined use of [18F]Selectfluor bis(triflate) and AgOTf allows for the preparation of electron-rich 18F-aromatic compounds through a simple "shake and mix" protocol at room temperature (see scheme; SA=specific activtiy).
- Teare, Harriet,Robins, Edward G.,Kirjavainen, Anna,Forsback, Sarita,Sandford, Graham,Solin, Olof,Luthra, Sajinder K.,Gouverneur, Veronique
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supporting information; experimental part
p. 6821 - 6824
(2010/12/25)
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- Improved arene fluorination methodology for I(III) salts
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(Equation Presented). The use of low polarity aromatic solvents (benzene or toluene) and/or the removal of inorganic salts results in dramatically improved yields of fluorinated arenes from diaryliodonium salts. This methodology is shown to "scale down" to the conditions used typically for radiotracer synthesis.
- Wang, Bijia,Qin, Linlin,Neumann, Kiel D.,Uppaluri, Shriharsha,Cerny, Ronald L.,DiMagno, Stephen G.
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supporting information; experimental part
p. 3352 - 3355
(2010/11/02)
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- Fluoride-promoted ligand exchange in diaryliodonium salts
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Diaryliodonium salts are shown to undergo rapid, fluoride-promoted aryl exchange reactions at room temperature in acetonitrile. Aryl exchange is shown to be exquisitely sensitive to the concentration of fluoride ion in solution; fast exchange is observed as the fluoride concentration approaches a stoichiometric amount at 50 mM substrate concentration. The reaction is slowed, but not halted if benzene is the solvent, indicating that free fluoride ion or a four-coordinate anionic I(III) species may be responsible for the exchange. The fluoride-promoted aryl exchange reaction is general and allows direct measurement of the relative stabilities of diaryliodonium salts featuring different aryl substituents. The aryl exchange reaction may be of practical use for the preparation of hitherto inaccessible diaryliodonium salts, thus it also has implications for labeling radiotracers for molecular imaging with 18F-fluoride (t1/2 = 109.7 min).
- Wang, Bijia,Cerny, Ronald L.,Uppaluri, Shriharsha,Kempinger, Jayson J.,Dimagno, Stephen G.
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scheme or table
p. 1113 - 1121
(2011/02/25)
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- Preparation process of fluorine substituted aromatic compound
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A preparation process of a fluorine substituted aromatic compound comprising reacting an alkali metal or alkali earth metal salt of an aromatic compound having a hydroxy group with an organic fluorinating agent is disclosed. As a representative fluorinating agent, a bis-dialkylamino-difluoromethane compound, for example, 2,2′-difluoro-1,3-dimethylimidazolidine, is exemplified. According to the process, an industrially useful fluorinated aromatic compound, for example, a fluorobenzene, a fluorine substituted benzophenone, a fluorine substituted diarylsulfone can be prepared with ease in economy without specific equipment.
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- TRANSITION METAL ARENE COMPLEXES IN REACTIONS WITH NUCLEOPHILIC REAGENTS. XV. NUCLEOPHILIC REPLACEMENT OF THE FLUORINE ATOM BY THE METHOXY GROUP CATALYSED BY (η-BENZENE)(η-ETHYLTETRAMETHYLCYCLOPENTADIENYL)-RHODIUM(III) IN THE REACTION OF FLUOROARENES WITH METHANOL
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The replacement of the fluorine atom by a methoxy group in the reaction of fluoroarenes with methanol is efficiently catalysed by 2+(PF6-)2, which permits the synthesis of alkyl aryl ethers under mild conditions without using alkali.Evidence was obtained indicating that the catalysis is a consequence of activation of the fluoroarenes upon their reversible ?-coordination with the 2+ fragmant.The yield of the products of the methanolysis of fluorobenzene and its derivatives and also of 1-fluoronaphthalene depends significantly on the structure of the aryl group and in creases in the series: 2-FC6H4F 2,4,6-Me3C6H2F 2-ClC6H4F 4-HOC6H4F 3,4-Me2C6H3F 1-C10H7F 2-, 3- and 4-MeC6H4F or MeOC6H4F C6H5F.The effect of the concentration of the methanol and the catalyst and of temperature on the reaction rate was studied.
- Goryunov, L. I.,Litvak, V. V.,Shteingarts, V. D.
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p. 1112 - 1118
(2007/10/02)
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- SYNTHESIS OF 2,3-DIMETHOXY-5-FLUORO- AND 4,5-DIMETHOXY-2-FLUORO-SUBSTITUTED PHENYLACETIC AND PHENYLACETOHYDROXAMIC ACIDS
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Many-stage methods were developed for the synthesis of 2,3-dimethoxy-5-fluorophenylacetic acid from 3-methyl-4,5-dimethoxyaniline and 4,5-dimethoxy-2-fluorophenylacetic acid from 3,4-dimethoxyaniline.Methods were also developed for their conversion into t
- Daukshas, V. K.,Martinkus, R. S.,Kuleshyus, V. A.
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p. 465 - 467
(2007/10/02)
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