- Electrochemical reduction of decafluorobenzil in DMF on a platinum electrode
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The mechanism of electrochemical reduction of decafluorobenzil on a platinum electrode in DMF was investigated by cyclic voltammetry. The first reduction peak corresponded to a reversible single-electron transfer leading to the formation of a relatively stable anion-radical whose ESR spectrum was registered and characterized. The second peak corresponded to the reduction of the anion-radical into an unstable dianion that quickly reacted with initial decafluorobenzil, and the arising species (or its transformation product) at the given potential underwent further reduction. The effect of fluorine on the potentials and on the mechanism of the electrochemical reduction of decafluorobenzil was considered.
- Vasil'eva,Irtegova
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- Preparative electrochemical reduction of decafluorobenzil
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Preparative electrochemical reduction of decafluorobenzil in DMF on a platinum electrode at the potential of the first peak afforded decafluorobenzophenone as the principal product. The reaction mixture lacked products of hydrodefluorination of the decafluorobenzil or of its reduction at the C=O group.
- Vasil'Eva,Starichenko
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- Formation of polyfluorofluorenes in the reactions of perfluoro-1,1-diphenylalkanes with antimony pentafluoride
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Perfluoro-1,1-diphenylethane heated with SbF5 at 130 °C with further treatment of the reaction mixture with HF-pyridine and then with water, gave perfluorinated 9‐methylfluorene and 9-methyl-1,2,3,4-tetrahydrofluorene. Perfluoro-1,1-diphenylpro
- Mezhenkova, Tatyana V.,Karpov, Victor M.,Zonov, Yaroslav V.
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- Substituted 4-(1H-1,2,3-triazol-1-yl)-tetrafluorobenzoates: Selective synthesis and structure
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Regioselective, simple and fast synthesis of a series of [2 + 3]-cycloaddition products, 2-11, 4-(4-RC2HN3)C6F4CO2Et (2: R = Ph; 3: R = CMe2OH; 4: R = CH2OH; 5: R = CO2Et; 6: R = n-C5H11; 7: R = CH2O-o-C6H4CHO; 8: R = CH2O-p-C6H4NHBoc; 9: R = CH2O-p-C6H4CH2OH; 10: R = CH2O2CC6F5; 11: R = p-C6H4Bu-t), in reaction between ethyl 4-azido-2,3,5,6-tetrafluorobenzoate, 1, and a number of substituted alkynes was elaborated under conditions of copper-catalyzed click chemistry reaction. The optimized conditions include application of CuBr and Et3N in dichloromethane. The structure of compounds 2-11 was investigated in solution by 1D and 2D NMR and IR spectroscopy. The molecular structure of 2 in solid state was established by X-ray analysis.
- Solodukhin, Nikolai N.,Borisova, Nataliya E.,Churakov, Andrei V.,Zaitsev, Kirill V.
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- Highly fluorinated aryl-substituted tris(indazolyl)borate thallium complexes: Diverse regiochemistry at the B-N bond
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The synthesis and characterization (mainly by 19F NMR and X-ray diffraction) of highly fluorinated aryl-4,5,6,7-tetrafluoroindazoles and their corresponding thallium hydrotris(indazolyl)borate complexes are reported [aryl = phenyl, pentafluorophenyl, 3,5-dimethylphenyl, 3,5-bis(trifluoromethyl)phenyl]. Thanks to N-H???N hydrogen bonds, the indazoles crystallize as dimers that pack differently depending on the nature of the aryl group. The thallium hydrotris(indazolyl)borate complexes Tl[Fn-Tp4Bo,3aryl] resulting from the reaction of aryl-4,5,6,7-tetrafluoroindazoles [aryl = phenyl, 3,5-dimethylphenyl, 3,5-bis(trifluoromethyl)phenyl] with thallium borohydride adopt overall C3v symmetry with the indazolyl groups bound to boron via their N-1 nitrogen in a conventional manner. When the perfluorinated pentaphenyl-4,5,6,7-tetrafluoroindazole is reacted with thallium borohydride, a single regioisomer of Cs symmetry having one indazolyl ring bound to boron via its N-2 nitrogen, TlHB(3-pentafluorophenyl-4,5,6,7-tetrafluoroindazol- 1-yl)2(3-pentafluorophenyl-4,5,6,7-tetrafluoroindazol-2-yl) Tl[F27-Tp(4Bo,3C6F5)*], is obtained for the first time. Surprisingly, the perfluorinated dihydrobis(indazolyl)borate complex Tl[F 18-Bp3Bo,3C6F5], an intermediate on the way to the hydrotris(indazolyl)borate complex, has Cs symmetry with two indazolyl rings bound to boron via N-2. The distortion of the coordination sphere around Tl and the arrangement of the complexes in the crystal are discussed.
- Ojo, Wilfried-Solo,Jacob, Kane,Despagnet-Ayoub, Emmanuelle,Munoz, Bianca K.,Gonell, Sergio,Vendier, Laure,Nguyen, Viet-Hoang,Etienne, Michel
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scheme or table
p. 2893 - 2901
(2012/04/23)
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- Silver compounds in synthetic chemistry. Part 2: A convenient synthesis of 2,3,4,5,6-pentafluorophenones, C6F5COR, from pentafluorophenylsilver, AgC6F5, and the corresponding acid chlorides, RCOCl
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2,3,4,5,6-Pentafluorophenones are formed selectively from the reactions of pentafluorophenylsilver and carboxylic acid chlorides in moderate to excellent yields.
- Kremlev, Mikhail M.,Tyrra, Wieland,Naumann, Dieter,Yagupolskii, Yurii L.
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p. 1327 - 1331
(2007/10/03)
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- Generation, Reactions, Direct Observation, and Kinetics of Decafluorodiphenylcarbene
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Bis(pentafluorophenyl)diazomethane (1a) was prepared, and reactivities of perfluorodiphenylcarbene (2a) generated by photolysis of 1a were investigated not only in terms of product analysis but also by using matrix isolation spectroscopy as well as laser flash photolysis techniques.Product distributions observed in the reactions of 2a in benzene, cyclohexane, and trans-1,2-dichloroethylene suggested that 2a reacted with those substrates with moderate reactivities toward carbene mostly in its singlet state presumably owing to the increased electrophilicity induced by fluorine substituents while the reaction with the alkane C-H bonds in concerted fashion was retarded partly due to steric effect in the singlet state which thus decayed to the triplet states that underwent predominantly H atom abstraction forming tetraarylethane.Photolysis of 1a in Ar matrix at 10 K produced 2a which was observed by IR and UV and shown to react with doped O2 to produce ultimately perfluorobenzoate by way of the carbonyl oxide and dioxirane, both intermediates being characterized by IR and UV/vis spectroscopy.Laser flash photolysis of 1a in acetonitrile solution produced a transient absorption (λ = 320 nm) due to bis(pentafluorophenyl)methyl radical (14a) obviously produced by H atom abstraction of the triplet 2a, which was trapped by oxygen to generate the carbonyl oxide (11a) showing its absorption maximum at 400 nm (τ = 5 ms) and also by 1,4-cyclohexadiene to form the methyl radical (14a) with the rate constant of 1.1E7 M-1 s-1.The lifetime of the triplet 2a was estimated to be ca. 1 μs.
- Tomioka, Hideo,Mizutani, Kenzoh,Matsumoto, Kenji,Hirai, Katsuyuki
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p. 7128 - 7134
(2007/10/02)
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- THE SYNTHESIS AND REARRANGEMENT REACTIONS OF 2,3,4,5,6-PENTAFLUOROBENZYL METHYL SULPHOXIDE AND 1,1-BIS(PENTAFLUOROPHENYL)METHYL METHYL SULPHOXIDE
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2,3,4,5,6-Pentafluorobenzyl methyl sulphoxide (6) and 1,1-bis(pentafluorophenyl)methyl sulphoxide (9) were synthesised from hexafluorobenzene and sodium methylsulphinylmethide.Flash vapour phase thermolysis of (6) at 410 degC gave 2,2',3,3'4,4',5,5'6,6'-decafluorodibenzyl (11) whereas static vapour phase thermolysis at 140-190 deg C gave (11), 2,3,4,5,6-pentafluorobenzyl alcohol (12) and 2,2'3,3'4,4'5,5'6,6'-decafluorodibenzyl disulphide (13).Decaflourobenzophenone (14) and bis(pentafluorophenyl)methanol (15) are thermolysis products of compound (9) at 115-122 deg C, accompanied by 4-methanoyl-nonafluorobenzophenone (16) formed by the thermolysis of (19), the unisolated material derived from (9) by nucleophilic substitution of one para-fluorine by CH3SOCH2-.Central to the formation of (12), (13), (14), (15) and (16) are sulphenate esters formed by '1,2'-rearrangements, while homolysis of the C-SO(CH3) bond in (6) and dimerisation of the radical gives (11).
- Brooke, Gerald M.,Ferguson, J. A. K. Jamie
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p. 263 - 276
(2007/10/02)
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