- The Conversion of Diaryl-1,3-Dithiolanes into gem-Difluoromethylene Compounds by a Combination of Elemental Fluorine and Iodine
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Diaryl-1,3-dithiolanes are converted to gem-difluorides in good yield by reaction with a mixture of elemental fluorine and iodine in acetonitrile at room temperature.
- Chambers, Richard D.,Sandford, Graham,Atherton, Malcolm
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- Desulfurative fluorination using nitrosonium tetrafluoroborate and pyridinium poly(hydrogen fluoride)
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Nitrosonium tetrafluoroborate in conjunction with pyridinium poly(hydrogen fluoride) has been found to be excellent desulfurative fluorination reagent. In NO+BF4-/PPHF system, mono-fluorides and gem-difluordes have been obtained in high yields from the corresponding phenylsulfides and dithiolane derivatives, respectively. Copyright
- York, Chentao,Prakash, G. K. Surya,Olah, George A.
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- Visible-light photoredox-catalyzed selective carboxylation of C(sp3)?F bonds with CO2
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It is highly attractive and challenging to utilize carbon dioxide (CO2), because of its inertness, as a nontoxic and sustainable C1 source in the synthesis of valuable compounds. Here, we report a novel selective carboxylation of C(sp3)?F bonds with CO2 via visible-light photoredox catalysis. A variety of mono-, di-, and trifluoroalkylarenes as well as α,α-difluorocarboxylic esters and amides undergo such reactions to give important aryl acetic acids and α-fluorocarboxylic acids, including several drugs and analogs, under mild conditions. Notably, mechanistic studies and DFT calculations demonstrate the dual role of CO2 as an electron carrier and electrophile during this transformation. The fluorinated substrates would undergo single-electron reduction by electron-rich CO2 radical anions, which are generated in situ from CO2 via sequential hydride-transfer reduction and hydrogen-atom-transfer processes. We anticipate our finding to be a starting point for more challenging CO2 utilization with inert substrates, including lignin and other biomass.
- Bo, Zhi-Yu,Chen, Lin,Gao, Tian-Yu,Jing, Ke,Lan, Yu,Liu, Shi-Han,Luo, Shu-Ping,Yan, Si-Shun,Yu, Bo,Yu, Da-Gang
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supporting information
p. 3099 - 3113
(2021/11/16)
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- Electrochemical fluorination using halogen mediators in ionic liquid hydrogen fluoride salt
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In order to utilize ammomium halides (Et4NX, X=Cl, Br, I) as halogenmediator for electrocatalytic fluorination, cyclic voltammetry measurements of the halides were investigated. The catalytic current of the halides in the presence of a dithioacatal compound was observed and the macro-scale electrolysis of dithioacetals using the halogen mediator was also carried out in ionic liquid hydrogen fluoride (HF) salt to give the corresponding fluorinated products in excellent yields. The recycle use of the halogen mediator in the electrochemical fluorination was successfully demonstrated. More inexpensive halides such as potassium bromide and potassium iodide could be soluble in HF salt and worked well as halogen mediator for the electrocatalytic fluorination.
- Takahashi, Kohta,Inagi, Shinsuke,Fuchigami, Toshio
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p. G3046-G3052
(2013/07/05)
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- Development of triarylamine mediator having ionic-tag and its application to electrocatalytic reaction in ionic liquid
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Novel triarylamine (Ar3N) mediators bearing an ionic-tag moiety were synthesized from 4,4′-dibromotriphenylamine. Their electrochemical properties were investigated by cyclic voltammetry both in organic solvent and ionic liquid HF salt. The electrocatalytic reactions such as deprotection and fluorodesulfurization of dithioacetals were successfully carried out using these Ar3N mediators in an undivided cell at room temperature.
- Takahashi, Kohta,Furusawa, Takashi,Sawamura, Takahiro,Kuribayashi, Shunsuke,Inagi, Shinsuke,Fuchigami, Toshio
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experimental part
p. 47 - 53
(2012/10/18)
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- Use of Task-Specific Ionic liquid for selective electrocatalytic fluorination
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[Chemical equation presented] Highly selective indirect anodic fluorination of organic compounds was successfully carried out for the first time by using a task-specific ionic liquid of iodoarene as a mediator in ionic liquid hydrogen fluoride salts.
- Sawamura, Takahiro,Kuribayashi, Shunsuke,Lnagi, Shinsuke,Fuchigami, Toshio
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supporting information; experimental part
p. 644 - 646
(2010/07/03)
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- Recyclable polymer-supported iodobenzene-mediated electrocatalytic fluorination in ionic liquid
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The electrochemical fluorination of organosulfur compounds in triethylamine/hydrofluoric acid (Et3N-5HF) with polystyrene-supported iodobenzene (PSIB) and tetraethylammonium chloride (Et4NCl) was performed successfully in an undivided cell under constant current conditions to afford the corresponding fluorinated compounds in moderate to good yields. Recycle use of the PSIB could be achieved due to its easy separation. Notably, the mediatory activity of the iodobenzene derivative was not appreciably changed even after 10 recycle uses.
- Sawamura, Takahiro,Kuribayashi, Shunsuke,Inagi, Shinsuke,Fuchigami, Toshio
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experimental part
p. 2757 - 2760
(2010/12/25)
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- Direct nucleophilic fluorination of carbonyl groups of benzophenones and benzils with Deoxofluor
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The carbonyl groups of diaryl ketones and diaryl diketones were directly fluorinated with bis(2-methoxyethyl)aminosulfur trifluoride (Deoxofluor) under neat conditions to give the corresponding gem-difluorides and tetrafluorinated derivatives in moderate
- Chang, Ying,Tewari, Amit,Adi, Avi-Izak,Bae, Chulsung
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p. 9837 - 9842
(2008/12/22)
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- gem-Difluorination of 2,2-diaryl-1,3-dithiolanes by Selectfluor and pyridinium polyhydrogen fluoride
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2,2-Diaryl-1,3-dithiolanes, readily obtainable from diaryl ketones, were transformed into the corresponding gem-difluoro compounds using a novel reagent combination involving Selectfluor and pyridinium polyhydrogen fluoride (PPHF) under mild conditions in moderate to good yields. The Royal Society of Chemistry 2005.
- Reddy, V. Prakash,Alleti, Ramesh,Perambuduru, Meher K.,Welz-Biermann, Urs,Buchholz, Herwig,Prakash, G. K. Surya
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p. 654 - 656
(2007/10/03)
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- Selectively fluorinated organic compounds
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A process for the preparation of a selectively fluorinated organic compound, which process includes reaction of a precursor of said organic compound, the precursor containing at least one Group VI element selected from sulfur, selenium and tellurium, with a fluorinating agent and another halogenating agent and characterized in that the fluorinating agent is elemental fluorine.
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- Electrolytic partial fluorination of organic compounds. 20. Electrosynthesis of novel hypervalent iodobenzene chlorofluoride derivatives and its application to indirect anodic gem-difluorination
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Electrosynthesis of novel hypervalent iodobenzene chlorofluorides was successfully performed for the first time and it was demonstrated that p-methoxyiodobenzene chlorofluoride could be used as a mediator for indirect anodic gem-difluorination of dithioacetals.
- Fujita, Toshiyasu,Fuchigami, Toshio
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p. 4725 - 4728
(2007/10/03)
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- Elemental fluorine. Part 5. Reactions of 1,3-dithiolanes and thioglycosides with fluorine-iodine mixtures
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1,3-Dithiolanes, prepared from diaryl ketones, react with elemental fluorine-iodine mixtures to give the corresponding difluoromethylene derivatives. Under the same conditions, thioglycosides give glycosyl fluorides in good yields. Reaction of 1,3-dithiolanes with fluorine in aqueous acetonitrile provides a remarkably mild method for efficient deprotection to the parent ketone.
- Chambers, Richard D.,Sandford, Graham,Sparrowhawk, Matthew E.,Atherton, Malcolm J.
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p. 1941 - 1944
(2007/10/03)
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- Electrolytic Partial Fluorination of Organic Compounds. 14. The First Electrosynthesis of Hypervalent Iodobenzene Difluoride Derivatives and Its Application to Indirect Anodic gem-Difluorination
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The electrosynthesis of hypervalent iodobenzene difluorides was accomplished by anodic oxidation of p-nitro- and p-methoxyiodobenzenes with Et3N*3HF in anhydrous acetonitrile, and p-methoxyiodobenzene difluoride was used as a mediator for indirect anodic
- Fuchigami, Toshio,Fujita, Toshiyasu
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p. 7190 - 7192
(2007/10/02)
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- Anodic gem-Difluorination of Dithioacetals
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Anodic desulfurization of dithioacetals of ketones in the presence of Et3N*3HF provided the corresponding gem-difluorocompounds while dithioacetals of aromatic and aliphatic aldehydes gave gem-difluorothioethers and monofluoro thioether, respectively.
- Yoshiyama, Tomonori,Fuchigami, Toshio
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p. 1995 - 1998
(2007/10/02)
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- Process for the preparation of compounds containing a difluoromethylene or trifluoromethyl group
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A process for the preparation of compounds containing a difluoromethylene or trifluoromethyl group. A compound containing a carbonyl group, preferbly an acid, acid halide, amide, ketone or any compound containing a perhaloalkylcarbonyl moiety is placed, in anhydrous liquid hydrofluoric acid, in contact with boron trifluoride in a quantity such that the absolute pressure of boron trifluoride in the reaction system is at least one bar for a time sufficient to convert the carbonyl group to a difluormethylene or trifluoromethyl group. The compounds obtained are useful as synthesis intermediates in the pharmaceutical, plant-protection and dye industries, as anesthetics or as heat-transfer and lubricating fluids.
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