- A HF Loaded Lewis-Acidic Aluminium Chlorofluoride for Hydrofluorination Reactions
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The very strong Lewis acid aluminium chlorofluoride (ACF) was loaded with anhydrous HF. The interaction between the surface of the catalyst and HF was investigated using a variety of characterization methods, which revealed the formation of polyfluorides. Moreover, the reactivity of the HF-loaded ACF towards the hydrofluorination of alkynes was studied.
- Kervarec, Ma?va-Charlotte,Kemnitz, Erhard,Scholz, Gudrun,Rudi?, Svemir,Braun, Thomas,J?ger, Christian,Michalchuk, Adam A. L.,Emmerling, Franziska
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Read Online
- Copper-Catalyzed Functionalization of Benzylic C-H Bonds with N-Fluorobenzenesulfonimide: Switch from C-N to C-F Bond Formation Promoted by a Redox Buffer and Br?nsted Base
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A copper catalyst in combination with N-fluorobenzenesulfonimide (NFSI) has been reported to functionalize benzylic C-H bonds to the corresponding benzylic sulfonimides via C-N coupling. Here, we reported a closely related Cu-catalyzed method with NFSI that instead leads to C-F coupling. This switch in selectivity arises from changes to the reaction conditions (Cu/ligand ratio, temperature, addition of base) and further benefits from inclusion of MeB(OH)2 in the reaction. MeB(OH)2 is shown to serve as a "redox buffer"in the reaction, responsible for rescuing inactive Cu(II) for continued promotion of fluorination reactivity.
- Buss, Joshua A.,Golden, Dung L.,Stahl, Shannon S.,Vasilopoulos, Aristidis
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supporting information
p. 5749 - 5752
(2020/10/02)
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- METHOD FOR PRODUCING (FLUOROALKYL) ARENE
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PROBLEM TO BE SOLVED: To provide a method for efficiently producing fluoroalkyl arene, which is important as synthetic raw materials for medicines and functional materials. SOLUTION: A fluoroalkyl arene is produced by the reaction between an aryl metal species represented by formula (2) and a fluoroalkyl halide represented by formula (3) in the presence of a cobalt compound and an ethylenediamine derivative. In the formula (2) shown in the following figure, R11-R15 independently represent H, a C1-C4 alkyl group or the like. In the formula (3): Y-Rf, Y is Cl or the like; Rf is a C2-C3 fluoroalkyl group. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0135-0137
(2018/08/28)
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- Copper-Mediated Aromatic 1,1-Difluoroethylation with (1,1-Difluoroethyl)trimethylsilane (TMSCF2CH3)
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A new method for the formation of 1,1-difluoroethyl copper species (“CuCF2CH3”) with 1,1-difluoroethylsilane (TMSCF2CH3) has been developed. The “CuCF2CH3” species can be applied to the efficient 1,1-difluoroethylation of diaryliodonium salts under mild conditions, affording (1,1-difluoroethyl)arenes in good to excellent yields. This convenient procedure tolerates a wide range of functional groups and thus serves as a practical synthetic tool for the introduction of CF2CH3 group(s) into complex molecules.
- Li, Xinjin,Zhao, Jingwei,Wang, Yunze,Rong, Jian,Hu, Mingyou,Chen, Dingben,Xiao, Pan,Ni, Chuanfa,Wang, Limin,Hu, Jinbo
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p. 1789 - 1792
(2016/07/07)
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- Cobalt/diamine-catalyzed 1,1-difluoroethylation and 2,2,2-trifluoroethylation of aryl Grignard reagents with corresponding fluoroalkyl halides
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Cobalt/diamine-catalyzed 1,1-difluoroethylation and 2,2,2-trifluoroethylation of aryl Grignard reagents with 1,1-difluoroethyl and 2,2,2-trifluoroethyl halides were investigated. With regard to the 1,1-difluoroethylation, 1,2-bis(dimethylamino)-2-methylpropane, which has been rarely used in the cross-coupling reactions, gave the highest yield among the diamine ligands tested. In the 2,2,2-trifluoroethylation, trans-1,2-bis(dimethylamino)cyclohexane provided the desired products in satisfactory yields with not only 2,2,2-trifluoroethyl iodide but also chloride. This Co/diamine catalyst was also effective for the coupling with other partially fluorinated alkyl halides in the presence of appropriate diamine ligands.
- Ohtsuka, Yuhki,Yamakawa, Tetsu
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- Designer HF-Based fluorination reagent: Highly regioselective synthesis of fluoroalkenes and gem -difluoromethylene compounds from alkynes
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Hydrogen fluoride (HF) and selected nonbasic and weakly coordinating (toward cationic metal) hydrogen-bond acceptors (e.g., DMPU) can form stable complexes through hydrogen bonding. The DMPU/HF complex is a new nucleophilic fluorination reagent that has high acidity and is compatible with cationic metal catalysts. The gold-catalyzed mono- and dihydrofluorination of alkynes using the DMPU/HF complex yields synthetically important fluoroalkenes and gem-difluoromethlylene compounds regioselectively.
- Okoromoba, Otome E.,Han, Junbin,Hammond, Gerald B.,Xu, Bo
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supporting information
p. 14381 - 14384
(2015/01/09)
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- Visible light-promoted metal-free C-H activation: Diarylketone-catalyzed selective benzylic mono- and difluorination
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We report herein an operationally simple method for the direct conversion of benzylic C-H groups to C-F. We show that visible light can activate diarylketones to abstract a benzylic hydrogen atom selectively. Adding a fluorine radical donor yields the benzylic fluoride and regenerates the catalyst. The selective formation of mono- and difluorination products can be achieved by catalyst control. 9-Fluorenone catalyzes benzylic C-H monofluorination, while xanthone catalyzes benzylic C-H difluorination. The scope and efficiency of this new C-H fluorination method are significantly better than those of the existing methods. This is also the first report of selective C-H gem-difluorination.
- Xia, Ji-Bao,Zhu, Chen,Chen, Chuo
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supporting information
p. 17494 - 17500
(2014/01/06)
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- Arylsulfur chlorotetrafluorides as useful fluorinating agents: Deoxo- and dethioxo-fluorinations
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Usage of arylsulfur chlorotetrafluorides 1 as versatile deoxo- and dethioxo-fluorinating agents is described. There have been developed two convenient methods for the in situ preparation of reactive arylsulfur trifluorides 2 from 1. The one is reduction of 1 with a reducer such as pyridine to 2, and the other is disproportionation of 1 with a diaryl disulfide to 2 with evolution of chlorine gas. The latter method is a convenient way to get neat 2 from 1. The in situ prepared 2 fluorinates many kinds of substrates such as alcohols, aldehydes, ketones, diketones, and carboxylic acids to give the corresponding CF, CF2, CF2CF2, and CF 3 compounds in high yields. 2 also fluorinates various sulfur compounds including CS groups to give CF2, OCF2, CF 3, and OCF3 compounds in high yields. Reactions of 2 with diols or bis(trimethylsilyl) derivatives of diols or amino alcohols provided the corresponding deoxofluoro-arylsulfinylation products in high yields. In addition, it has been found that chlorotetrafluorides 1 directly and effectively react with the sulfur compounds to give the corresponding fluoro compounds in high yields. Since they are the intermediates for the production of industrially useful arylsulfur pentafluorides, arylsulfur chlorotetrafluorides 1, in particular, phenylsulfur chlorotetrafluoride (1a) are expected to find use as inexpensive and versatile deoxo- and dethioxo-fluorinating agents for the preparation of many organofluoro compounds.
- Umemoto, Teruo,Singh, Rajendra P.
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experimental part
p. 17 - 27
(2012/09/07)
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- Method of Synthesis of Arylsulfur Trifluorides and Use as in situ Deoxofluorination Reagent
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The invention is a method of synthesizing Arylsulfur Trifluorides, such as Fluolead, by reacting BR2 and KF (or suitable alkali metal fluoride) in acetonitrile (or other suitable solvent). The invention also comprises using the Fluolead (or its
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Page/Page column 2; 3
(2012/04/11)
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- Arylsulfur trifluorides: Improved method of synthesis and use as in situ deoxofluorination reagents
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Building on recent results of Umemoto and Winter, an improved method of synthesis of arylsulfur trifluorides, including the excellent, new deoxofluorination reagent Fluolead, is hereby reported. The method utilizes Br2 and KF as oxidizing and fluorinating reagents for efficient, high yield conversion of aryl disulfides and mercaptans to arylsulfur trifluorides. It has also been shown that both Fluolead and mesitylsulfur trifluoride may be generated in acetonitrile and used as in situ deoxofluorination reagents for conversion of either aldehydes or ketones to their respective gem-difluoro compounds. An analysis of the probable mechanism of action, including computational efforts, allows postulation of a rationale for the highly variable reactivities of different arylsulfur trifluorides as deoxofluorination reagents.
- Xu, Wei,Martinez, Henry,Dolbier Jr., William R.
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experimental part
p. 482 - 488
(2011/08/03)
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- FLUORINATION PROCESSES WITH ARYLSULFUR HALOTETRAFLUORIDES
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New fluorination processes for introducing one or more fluorine atoms into target substrate compounds with arylsulfur halotetrafluorides are disclosed. Also disclosed are methods for preparation of arylsulfur trifluorides.
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Page/Page column 47
(2009/10/22)
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- Ionic liquids as recyclable solvents for diethylaminosulfur trifluoride (DAST) mediated fluorination of alcohols and carbonyl compounds
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The first simple and efficient method for the synthesis of mono and gem-difluorinated molecules using [C8mim][PF6] ionic liquid as a recyclable solvent medium with diethylaminosulfur trifluoride (DAST) as the fluorinating reagent, is reported.
- Das, Saibal,Chandrasekhar, Srivari,Yadav, Jhillu Singh,Grée, René
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p. 5305 - 5307
(2008/02/10)
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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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- Bis(2-methoxyethyl)aminosulfur trifluoride: A new broad-spectrum deoxofluorinating agent with enhanced thermal stability
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Bis(2-methoxyethyl)aminosulfur trifluoride (Deoxo-Fluor) is effective for the conversion of alcohols to alkyl fluorides, aldehydes/ketones to the corresponding gem-difluorides and also for the transformation of carboxylic acids to their trifluoromethyl derivatives; it is a less thermally sensitive, broader-spectrum alternative to the traditional dialkylaminosulfur trifluoride (DAST) deoxofluorination reagents.
- Lal, Gauri S.,Fez, Guido P.,Pesaresi, Reno J.,Prozonic, Frank M.
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p. 215 - 216
(2007/10/03)
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- Bis(2-methoxyethyl)aminosulfur trifluoride: A new broad-spectrum deoxofluorinating agent with enhanced thermal stability
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Bis(2-methoxyethyl)aminosulfur trifluoride, (CH3OCH2CH2)2NSF3 (Deoxo-Fluor reagent), is a new deoxofluorinating agent that is much more thermally stable than DAST (C2H5)2NSF3 and its congeners. It is effective for the conversion of alcohols to alkyl fluorides, aldehydes/ketones to the corresponding gem-difluorides, and carboxylic acids to the trifluoromethyl derivatives with, in some cases, superior performance compared to DAST. The enhanced stability is rationalized on the basis of conformational rigidity imposed by a coordination of the alkoxy groups with the electron-deficient sulfur atom of the trifluoride.
- Lal, Gauri S.,Pez, Guido P.,Pesaresi, Reno J.,Prozonic, Frank M.,Cheng, Hansong
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p. 7048 - 7054
(2007/10/03)
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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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- Transformation of Carbonyl Compounds into gem-Difluoro Compounds with Dibromodifluoromethane/Zinc Reagent
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Reaction of carbonyl compounds with dibromodifluoromethane/zinc gives the gem-difluoro compounds (12 examples).It seems to be that the reaction involves the generation of difluorocarbene by reaction of dibromodifluoromethane with zinc, followed by product
- Hu, Chang-Ming,Qing, Feng-Ling,Shen, Cun-Xi
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p. 335 - 338
(2007/10/02)
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- Conversion of the Carbonyl Group to CF2 Using IF
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A novel method for the transformation of CO -> CF2 is described.The easily made hydrazone derivatives of the carbonyl moiety are reacted under mild conditions with IF prepared directly from the corresponding elements.Various hydrazones have been examined and compared with each other.Unsubstituted ones are usually the most suitable although they are not always easy to purify and store.N-Methyl- and N,N-dimethylhydrazones also give quite satisfactory results.The more easily made dinitrophenyl hydrazones (DNPs), semicarbazones, and tosylhydrazones also react, but the yields of the desired CF2 compounds are usually lower.Oximes could also be successfully reacted.The two main byproducts of the reaction are the parent carbonyl compounds, which can be recycled, and the α-iododifluoro derivatives.The latter upon treatment with LiAlH4 or Bu3SnH were reduced to the desired product, thus increasing the overall yields.
- Rozen, Shlomo,Zamir, Dov
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p. 4695 - 4700
(2007/10/02)
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- Vicinal bromofluoroalkanes: Their regioselective formation and their conversion to fluoroolefins
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The reaction of alkenes with N-bromosuccinimide and triethylamine tris(hydrofluoride) produces vic-bromofluoroalkanes (1) with high yields. As long as the addition to the double bond is sterically unhindered, bromine and fluorine get attached with very high regioselectivity, the latter halogen occupying the more substituted, carbocation stabilizing position. 2-Fluoro-1-alkenes give 1-bromo-2,2-di-fluoroalkanes (4). The heavier halogen may be removed by base promoted dehydro-fluorination, to afford fluoroolefins (2), or by reduction with tributyltin hydride, leading to mono- or difluoroalkanes (e.g., 5).
- Suga, Hiroaki,Hamatani, Takeshi,Guggisberg, Yves,Schlosser, Manfred
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p. 4255 - 4260
(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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- Dialkylaminosulfur trifluorides as fluorinating agents
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Dialkylaminosulfur trifluorides such as diethylaminosulfur trifluoride are useful in replacing hydroxyl group and carbonyl oxygen with fluorine in various organic compounds.
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