- Diazaphospholene-Catalyzed Hydrodefluorination of Polyfluoroarenes with Phenylsilane via Concerted Nucleophilic Aromatic Substitution
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The metal-free catalytic C-F bond activation of polyfluoroarenes was achieved with diazaphospholene as the catalyst and phenylsilane as the terminal reductant. Density functional theory calculations suggested a concerted nucleophilic aromatic substitution mechanism.
- Zhang, Jingjing,Zhao, Xiao,Yang, Jin-Dong,Cheng, Jin-Pei
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supporting information
p. 294 - 300
(2022/01/03)
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- Transition-Metal-Free Catalytic Hydrodefluorination of Polyfluoroarenes by Concerted Nucleophilic Aromatic Substitution with a Hydrosilicate
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A transition-metal-free catalytic hydrodefluorination (HDF) reaction of polyfluoroarenes is described. The reaction involves direct hydride transfer from a hydrosilicate as the key intermediate, which is generated from a hydrosilane and a fluoride salt. The eliminated fluoride regenerates the hydrosilicate to complete the catalytic cycle. Dispersion-corrected DFT calculations indicated that the HDF reaction proceeds through a concerted nucleophilic aromatic substitution (CSNAr) process.
- Kikushima, Kotaro,Grellier, Mary,Ohashi, Masato,Ogoshi, Sensuke
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supporting information
p. 16191 - 16196
(2017/11/27)
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- Synthesis of chloropolyfluoroarenes from polyfluoroarenethiols and PCl5
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Replacement of the thiol group in polyfluoroarenethiols with chlorine was performed by treating with PCl5 as chlorinating agent. By heating in ampules at 200-220°C polyfluoro- and polyfluorochloroarenethiols with PCl5 mono- and dichloropolyfluoroarenes and also 1,2,4-trifluorotrichlorobenzene were synthesized. Dichloropolyfluoroarenes contain chlorine atoms in ortho- and para-positions.
- Nikul'shin,Maksimov,Platonov
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p. 200 - 205
(2016/04/19)
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- Reactions of polyfluorobenzenethiols with polyhalomethanes and their derivatives in an alkaline medium
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New process direction was found in the reaction of polyfluoroarenethiols with fluorodichloromethane, chloroform, and bromoform in an alkaline medium consisting in the replacement of the thiol group by a hydrogen atom. This process competes with the formation of expected products, dihalomethyl polyfluoro-aryl sulfides and tris(arylsulfanyl)methanes. In reaction of 2,3,5,6-tetrafluorobenzenethiol with dichloro-methane bis(2,3,5,6-tetrafluorophenylsulfanyl)methane was obtained. Reactions of polyfluoroarenethiols with pentafluorobenzyl chloride occur mainly with the substitution of the chlorine atom, with pentafluorobenzal chloride and with pentafluorobenzotrichloride a substitution of a fluorine atom in the para-position takes place.
- Bredikhin,Maksimov,Gatilov, Yu. V.,Kireenkov,Platonov
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p. 1551 - 1559
(2015/12/30)
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- Copper-catalyzed hydrodefluorination of fluoroarenes by copper hydride intermediates
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Breaking bad: Efficient copper-catalyzed C-F bond activation has been achieved by replacing fluorine with hydrogen. A copper hydride is proposed as the active intermediate, which proceeds through a nucleophilic attack on the fluorocarbon, as determined by experimental and theoretical results (see structure; C gray, H white, Cu light red, F light blue; distances in ?).
- Lv, Hongbin,Cai, Yuan-Bo,Zhang, Jun-Long
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supporting information
p. 3203 - 3207
(2013/04/23)
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- Catalytic C-F bond activation of perfluoroarenes by tricoordinated gold(I) complexes
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We report the first example of gold catalyzing C-F bond activation for perfluoroarenes in the presence of silanes. Tricoordinated gold(I) complexes supported by Xantphos-type ligands, such as Xantphos and tBuXantphos ligands, exhibit efficacy in the hydrodefluorination (HDF) of various types of perfluoroarenes. For [tBuXantphosAu(AuCl2)], the highest turnover number is up to 1000 in the HDF of pentafluoronitrobenzene with diphenylsilane. An examination of functional group tolerance shows the orthogonality of this gold(I) catalytic protocol to ketone, ester, carboxylate, alkynyl, alkenyl and amide groups, suggesting its potential application in chemoselective C-F activations. Mechanistic studies show that the equilibrium between tetracoordinated [L2Au]+ and [LAu]+ is important for the reactivity of gold catalysts, which is dependent on the sterically bulky group of Xantphos-type ligands. Furthermore, computational studies for the possible reaction pathways suggest that direct oxidative addition of C-F bonds by gold(I) cation might be the key step during these catalytic reactions. Copyright
- Zhan, Jin-Hui,Lv, Hongbin,Yu, Yi,Zhang, Jun-Long
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experimental part
p. 1529 - 1541
(2012/07/14)
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- Organofluorine sulfur-containing compounds: V. Joint pyrolysis with chlorine or bromine of polyfluoroarenethioles, polyfluorohetarenethioles, and their derivatives
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Joint pyrolysis with chlorine and bromine of polyfluoroarenethiols, -hetarenethiols, and their derivatives at 300-650°C furnished polyfluorocompounds containing chlorine and bromine. 2005 Pleiades Publishing, Inc.
- Platonov,Maksimov,Dvornikova,Nikul'shin
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p. 1647 - 1653
(2007/10/03)
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- Method for producing tetrakis ( fluoroaryl) borate-magnesium compound
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Fluoroaryl magnesium halide is reacted with a boron compound so that a molar ratio of the fluoroaryl magnesium halide to the boron compound is not less than 3.0 and not more than 3.7, so as to produce a tetrakis (fluoroaryl) borate·magnesium compound. With this method, there occurs no hydrogen fluoride which corrodes a producing apparatus and requires troublesome waste water treatment.
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- REACTION OF PERFLUOROARYL HALIDES WITH REDUCED SPECIES OF SULFUR DIOXIDE (HSO2(-), SO2(2-), S2O4(2-))
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Rongalite (sodium hydroxymethanesulfinate), sodium dithionite, and aminoiminomethanesulfinic acid (AIMS) reduce perfluoroiodobenzene in N,N-dimethylformamide to pentafluorobenzene.In the presence of added D2O or CH3OD, deuteriopentafluorobenzene is formed. p-Dinitrobenzene does not inhibit the reduction, and addition of norbonene did not result in trapping of any radical intermediates.Reaction of pentafluoroiodobenzene with sodium benzenesulfinate gave 1,4-dibenzenesulfonyl-2,3,5,6-tetrafluorobenzene.A halophilic attack mechanism is suggested for the reduction reaction.Chloropentafluorobenzene did not react under the same conditions as the iodide; at elevated temperatures in the presence of sodium bicarbonate and Rongalite the fluorine para to the chlorine was reduced.Reduction of the chloride to pentafluorobenzene is minor.In the absence of bicarbonate, the chloride gave also a mixture of sulfides believed to be derived from decomposition of the Rongalite to hydrogen sulfide.Some reaction with dimethylamine from decomposition of DMF also is observed.
- Grady, B. J.,Dittmer, D. C.
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p. 151 - 172
(2007/10/02)
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