389-40-2Relevant articles and documents
NHC Nickel Catalyzed Hiyama- and Negishi-Type Cross-Coupling of Aryl Fluorides and Investigations on the Stability of Nickel(II) Fluoroaryl Alkyl Complexes
Kuntze-Fechner, Maximilian W.,Kerpen, Christoph,Schmidt, David,H?ring, Mathias,Radius, Udo
, p. 1767 - 1775 (2019/03/11)
The reactivity of [Ni(iPr2Im)4(μ-COD)] 1 (iPr2Im = 1,3-diisopropyl-imidazolin-2-ylidene, COD = 1,4-cyclooctadiene) in Hiyama- and Negishi-type cross-coupling reactions as well as the synthesis of several novel nickel fluoroaryl alkyl complexes is reported. Hiyama coupling of 1.1 equiv. perfluoroaromatics and 1 equiv. PhSi(OR)3 (R = Me, Et) with 5 mol-% of 1 as catalyst leads to the C–C coupling product ArF–Ph in good to fair yields. In presence of the additive NMe4F alkoxy transfer from PhSi(OR)3 to the perfluoroarene occurs to yield ArF–OR and PhSiF(OR)2. Negishi cross-coupling between C6F6 or C7F8 (1 equiv.), diorganozinc reagents [ZnR2] (R = Me, Et) (2.1 equiv.) and 5 mol-% 1 as the catalyst in toluene at 115 °C leads to ArF–R only in traces. However, NMR experiments revealed that nickel alkyl complexes are readily formed from the reaction of trans-[Ni(iPr2Im)2(F)(ArF)] with [ZnR2] (R = Me, Et). In course of these investigations, a series of novel nickel alkyl complexes trans-[Ni(iPr2Im)2(R)(ArF)] (R = Me, ArF = C6F5 2, C7F7 3, C12F9 4; R = Et, ArF = C6F5 5, C7F7 6, C12F9 7) have been synthesized in stoichiometric reactions starting from trans-[Ni(iPr2Im)2(F)(ArF)] (ArF = C6F5, C7F7, C12F9) and [ZnR2] (R = Me, Et) in thf at –78 °C. As these nickel alkyl complexes 2–7 are stable at room temperature in solution for several days with respect to reductive elimination, their thermal stability was investigated. Heating trans-[Ni(iPr2Im)2(Me)(C6F5)] 2 for 24 hours at 100 °C leads to 91 % unreacted complex 2 and only traces of reductive elimination product, i.e. C6F5Me, are formed. Furthermore, the nickel ethyl complex trans-[Ni(iPr2Im)2(Et)(C6F5)] 5 is also very stable, even with respect to β-hydride elimination. After heating this complex to 100 °C for 24 hours there is still 26 % unreacted 5 left.
A five-fluoro phenol preparation method
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Paragraph 0092; 0093; 0094; 0097; 0098, (2018/03/24)
The invention relates to a preparation method for pentafluorophenol. By taking hexafluorobenzene as an initial raw material, pentafluorophenol is prepared through etherification reaction and cracking reaction or by taking hexafluorobenzene as the initial raw material, pentafluorophenol is prepared by virtue of a one-step method. The preparation method provided by the invention does not need high temperature and pressurization, is less in energy consumption, and does not use expensive hydroiodic acid, so that the cost of the raw materials is low. Moreover, wastewater generated by etherification reaction is less, so that the preparation method is environmental-friendly; Cracking is carried out in a solvent, the material stirring effect is good, the reaction temperature is easy to control, and industrialization is easy to implement.
Quantitative estimation of the reactivity of perfluorinated methylbenzenes and benzocycloalkenes in nucleophilic substitution reactions
Rodionov, Peter P.,Osina, Ol'Ga I.,Platonov, Vyacheslav E.,Yakobson, Georg G.
, p. 986 - 993 (2007/10/02)
The kinetics of the reactions of perfluorinated xylenes, mesitylene, p-cymene, benzocycloalkenes (benzocyclobutene, indane, tetralin) and octafluoronaphthalene with sodium methoxide and piperidine have been studied.Rate constants of the reactions of perfluorinated aromatic compounds with sodium methoxide (taking into account one reaction centre) are shown to incease in the order: hexafluorobenzene perfluoro-p-xylene ca.= perfluoro-p-cymene octafluorotoluene ca.= perfluoro-m-xylene perfluoromesitylene ca.= perfluoro-o-xylene.In the reactions with piperidine, a different sequence was observed: hexafluorobenzene perfluoro-p-xylene perfluoro-p-cymene perfluoromesitylene perfluoro-m-xylene octafluorotoluene perfluoro-o-xylene.In the reactions of perfluorobenzocycloalkenes with sodium methoxide and piperidine, the reactivity grows by about a factor of 2 with increase of the perfluoroalicyclic ring size by one CF2-group, in the following order: perfluorobenzocyclobutene perfluoroindan perfluorotetralin.
REACTION OF AROMATIC COMPOUNDS WITH NUCLEOPHILIC REAGENTS IN LIQUID AMMONIA. V. THE MECHANISM AND DIRECTION OF HYDROXYLATION OF p-SUBSTITUTED NITROBENZENES WITH POTASSIUM HYDROXIDE
Malykhin, E. V.,Kolesnichenko, G. A.,Shteingarts, V. D.
, p. 1048 - 1056 (2007/10/02)
In the reaction of p-substituted nitrobenzenes 4-XC6H4NO2 (X = Cl, Br, I) with potassium hydroxide and oxygen in liquid ammonia (-33 deg C) the corresponding 5-substituted 2-nitrophenols are formed with high yields.Under analogous conditions 4-fluoronitrobenzene and 1,4-dinitrobenzene are converted into 4-nitrophenol.When K18OH was used, the hydroxyl group of the reaction products contained the 18O isotope preferentially in both cases.The action of KO2 and K2O2 in the presence of oxygen on 4-chloronitrobenzene or of oxygen on the product from the reduction of 4-chloronitrobenzene with potassium leads to the formation of 4-nitrophenol.This set of experimental data agrees with the scheme for the hydroxylation of p-substituted nitrobenzenes with alkali and oxygen in liquid ammonia involving the formation of anionic ? complexes for both directions of the process and their oxidation by molecular oxygen in the case of substitution of a hydrogen atom.
REACTION OF AROMATIC COMPOUNDS WITH NUCLEOPHILIC REAGENTS IN LIQUID AMMONIA. II. NUCLEOPHILIC SUBSTITUTION IN NITROHALOGENO AND POLYFLUORINATED AROMATIC COMPOUNDS
Shtark, A. V.,Kizner, T. A.,Shteingarts, V. D.
, p. 2051 - 2056 (2007/10/02)
The possibility of aromatic nucleophilic substitution in liquid ammonia was investigated for the case of the reaction of p-nitrochlorobenzene, 2,4-dinitrochlorobenzene, hexafluorobenzene, bromopentafluorobenzene, pentafluorobenzene, and octafluoronaphthalene with a series of charged nucleophiles (potassium hydroxide and sulphite, alcoholates, sodium azide, thiophenolate, phenolate, and sulfide) at -70 to -33 deg C.It was shown that alkyl ethers of p-nitrophenol, phenyl p-nitrophenyl sulfide, 2,4-dinitrophenyl azide, polyfluorinaqted phenols, and their ethers can be obtained with good yields.Comparisons of the results with published data on the rate of the same reactions in other solvents shows that liquid ammonia is highly effective as a solvent for aromatic nucleophilic substitution reactions and in some cases makes it possible to avoid side processes.
Partially Fluorinated Heterocyclic Compounds. Part 16. Preparation of Furan Derivatives from Pentafluorophenyl and Heptafluoro-2-naphthyl Prop-2-ynyl Ethers with Aromatic Compounds, and the Isolation of Hydrogen-abstraction Products
Brooke, Gerald M.
, p. 107 - 110 (2007/10/02)
Pentafluorophenyl and heptafluoro-2-naphthyl prop-2-ynyl ethers react in N,N-diethylaniline to give among other products 2-methylfuran derivatives formed by hydrogen-abstraction reactions, and 2-(diethylaminobenzyl)furan derivatives ; the 2-fluoromethylfuran (16) is also formed from (5).No aromatic substitution products are obtained from (5) with nitrobenzene or benzylidyne trifluoride.It was not possible to distinguish between homolytic and heterolytic fission of the aliphatic C-F bonds in the Claisen rearrangement intermediates (8) and (9) involved in these reactions.
