- Activation of nucleophilic fluorination by salts in ionic liquids and in sulfolane
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The nucleophilic substitution of PhCCl3 by KF in imidazolium-type RTILs is faster than in classical organic solvents but it is strongly dependent upon the nature of the counteranion. The addition of bromide salts in substoichoimetric amounts to the [bmim][PF6] solvent strongly accelerates this reaction. Furthermore, it has been discovered that addition of KPF6 to the reaction mixtures strongly activates the nucleophilic fluorination by KF, not only in the [bmim][NTf2] or [bmim][PF6] ionic liquids but also for the reactions performed in sulfolane.
- Anguille, Stephane,Garayt, Maxime,Schanen, Vincent,Gree, Rene
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- The photochemical synthesis of α,α,α-bromodifluorotoluene and α,α,α-chlorodifluorotoluene
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The syntheses of α,α,α-chlorodifluorotoluene and α,α,α- bromodifluorotoluene from α,α-difluorotoluene and N-chlorosuccinimide and N-bromosuccinimide, respectively, were achieved photochemically using sunlight and/or sunlamp irradiation. These methods gave
- He, Jinbao,Pittman Jr., Charles U.
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- Iron-Catalyzed Halogen Exchange of Trifluoromethyl Arenes**
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The facile production of ArCF2X and ArCX3 from ArCF3 using catalytic iron(III)halides is reported, which constitutes the first iron-catalyzed halogen exchange for non-aromatic C?F bonds. Theoretical calculations suggest direct activation of C?F bonds by iron coordination. ArCX3 and ArCF2X products of the reaction are synthetically valuable due to their diversification potential. In particular, chloro- and bromodifluoromethyl arenes (ArCF2Cl, ArCF2Br respectively) provide access to a myriad of difluoromethyl arene derivatives (ArCF2R). To optimize for mono-halogen exchange, a statistical method called Design of Experiments was used. Optimized parameters were successfully applied to electron rich and electron deficient aromatic substrates, and to the late stage diversification of flufenoxuron, a commercial insecticide. These methods are highly practical, being run at convenient temperatures and using inexpensive common reagents.
- Dorian, Andreas,Landgreen, Emily J.,Petras, Hayley R.,Shepherd, James J.,Williams, Florence J.
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supporting information
p. 10839 - 10843
(2021/06/21)
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- Radical Chlorodifluoromethylation: Providing a Motif for (Hetero)arene Diversification
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A method for the radical chlorodifluoromethylation of (hetero)arenes using chlorodifluoroacetic anhydride is reported. This operationally simple protocol proceeds under mild photochemical conditions with high functional group compatibility and complements the large body of literature for the trifluoromethylation of (hetero)arenes. Introduction of the chlorodifluoromethyl motif enables rapid diversification to a wide array of aromatic scaffolds. This work showcases the chlorodifluoromethyl group as an attractive entryway to otherwise synthetically challenging electron-rich difluoromethyl(hetero)arenes. Furthermore, facile conversion of the CF2Cl moiety into the corresponding aryl esters, gem-difluoroenones, and β-keto-esters is demonstrated.
- McAtee, Rory C.,Beatty, Joel W.,McAtee, Christopher C.,Stephenson, Corey R. J.
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supporting information
p. 3491 - 3495
(2018/06/26)
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- (Re)Investigation of the reactivity of uranium hexafluoride toward several organic functions at room temperature
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The annual worldwide production of UF6 is very large and this compound is not used. Consequently, it could be interesting to find some applications as organic reagent. UF6 could be considered as an oxidizer of various functions. However, it seems also present some possibilities as a fluorinating reagent in mild conditions.
- Roy, Olivier,Marquet, Bernard,Alric, Jean-Paul,Jourdan, Alex,Morel, Bertrand,Langlois, Bernard R.,Billard, Thierry
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- Selective fluorination of substituted trichloromethyl benzenes by HF in liquid phase: Preparation of fluorinated building blocks
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The selective fluorination by successive Cl/F exchanges of α,α,α-trichlorotoluene, substituted or not by a chlorine atom, was studied in the presence of HF as the fluorinating agent. The influence of the presence of a catalyst or a basic solvent (such as dioxane, pyridine, tributylphosphate) in order to control the fluorination was also investigated. In mild conditions (50 °C and after 1 h of reaction), HF in excess was required in order to obtained the trifluoromethylation by Cl/F exchanges. The presence of SbCl5 in small amount activated the Cl/F exchanges and only a stoichiometric amount of HF was required whatever the chlorinated molecules. Selective mono and difluorination could be obtained by using basic solvents.
- Piou, Alexandre,Celerier, Stephane,Brunet, Sylvette
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experimental part
p. 1241 - 1246
(2011/01/12)
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- Selective aliphatic fluorination by halogen exchange in mild conditions
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HF-Base media, in particular (HF)10-pyridine or (HF) 3-triethylamine, allow aliphatic chlorine-fluorine exchanges on acid-sensitive molecules. Depending on the nature (pyridine or triethylamine), stoichiometry of the base and temperature, selective mono-, di-, or tri-chlorine-fluorine exchanges on trichloromethyl groups alpha to sulfur, oxygen and carbon atoms can be obtained.
- Saint-Jalmes, Laurent
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- Fluorination agent and preparation and use of same
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The invention disclose a hydrogen fluoride containing composition comprising hydrogen fluoride and a compound which is liquid in the standard state (25° C., 1 atmosphere) and has a boiling point of 120° C. or more and pka of 12 or more at 25° C., and use of the composition for a fluorination agent. The compound which can be preferably used is represented by the formula (1): wherein R1 to R4 are a substituted or unsubstituted alkyl or aryl group and can be the same or different, and R1 or R2 or R3 and R4 can bond to form a ring having a nitrogen atom or a nitrogen atom and other hetero atom, or R1 and R3 can bond to form a ring having a nitrogen atom or a nitrogen atom and other hetero atom. The fluorination agent of the invention exerts effect with a similar reaction mechanism to hydrogen fluoride, can be applied to the halogen exchange reaction of a halogen containing organic compound, and can produce a fluorine containing compound with safety and ease without specific equipment or technique.
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- Convenient preparation of difluoromethylene-functionalized compounds from chlorodifluoroacetic acid
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A convenient route for the synthesis of difluoromethylene-functionalized compounds from chlorodifluoroacetic acid has been investigated.Bis(chlorodifluoroacetyl) peroxide, which was synthesized from chlorodifluoroacetic acid via its acid anhydride, was fo
- Yoshida, Masato,Morinaga, Yoshihiro,Iyoda, Masahiko
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- Convenient Preparation of (Chlorodifluoromethyl)arenes. Useful Precursors for Aryldifluoromethyl Radicals
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Chlorodifluoromethyl group was introduced into aromatic rings using bis(chlorodifluoroacetyl) peroxide which was readily prepared from corresponding acid anhydride with 30percent hydrogen peroxide, and the chlorine was successively replaced by hydrogen or
- Yoshida, Masato,Morinaga, Yoshihiro,Ueda, Masaaki,Kamigata, Nobumasa,Iyoda, Masahiko
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p. 227 - 230
(2007/10/02)
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