- Metal-free reduction of the greenhouse gas sulfur hexafluoride, formation of SF5 containing ion pairs and the application in fluorinations
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A protocol for the fast and selective two-electron reduction of the potent greenhouse gas sulfur hexafluoride (SF6) by organic electron donors at ambient temperature has been developed. The reaction yields solid ion pairs consisting of donor di
- Rueping, Magnus,Nikolaienko, Pavlo,Lebedev, Yury,Adams, Alina
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Read Online
- Solvent free nucleophilic introduction of fluorine with [bmim][F]
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1-n-Butyl-3-methylimidazolium fluoride ([bmim][F]) proved very efficient fluorinated reagent for nucleophilic substitution over sulfonate esters and alkyl halides. Preparation of the ionic liquid as well as its use as the reagent has been performed to be the more eco-friendly as possible. No organic solvent is needed for the fluoride introduction, reaction times are reduced by using microwave as the heating source, and the ionic liquids carefully recycled. Furthermore, no special care has to be taken as the presence of water in [bmim][F] was not deleterious to the transformation yield.
- Bouvet, Sébastien,Pégot, Bruce,Marrot, Jérome,Magnier, Emmanuel
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Read Online
- METHOD AND REAGENT FOR DEOXYFLUORINATION
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A safe, simple, and selective method and reagent for deoxyfluorination is disclosed. With the method and reagent disclosed herein, organic compounds such as carboxylic acids, carboxylates, carboxylic acid anhydrides, aldehydes, and alcohols can be fluorinated by using the most common nucleophilic fluorinating reagents and electron deficient fluoroarenes as mediators under mild conditions, giving corresponding fluoroorganic compounds in excellent yield with a wide range of functional group compatibility and easy product purification. For example, directly utilizing KF for deoxyfluorination of carboxylic acids provides the most economical and the safest pathway to access acyl fluorides, key intermediates for syntheses of peptide, amide, ester, and dry fluoride salts.
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Paragraph 0148-0150; 0152; 0166
(2021/05/29)
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- A Series of Deoxyfluorination Reagents Featuring OCF2Functional Groups
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Research on perfluoroalkyl ether carboxylic acids (PFECAs) as alternatives for perfluoroalkyl substances continues with the goal of protecting the environment. However, very little is known about the utilization of decomposition products of PFECAs. We report herein a new series of deoxyfluorination reagents featuring OCF2 functional groups derived from certain PFECAs. Alkyl fluorides were generated from various alcohols in ≤97% yield by these novel reagents. The mechanistic experiment verified in situ generation of carbonic difluoride (COF2).
- Cao, Wei,Chen, Qing-Yun,Guo, Yong,Su, Zhaoben,Wu, Chengying,Zhao, Shiyu
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supporting information
(2020/11/03)
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- Fluorination reagent and deoxygenation fluorination method
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In order to overcome the problems of high cost and poor stability of the existing deoxidation fluorination reagent, the invention provides a fluorination reagent. The fluorination reagent comprises acation M and an anion, and the anion is selected from one or more of the following perfluoropolyether chain carboxylic acid anions: CF3 (OCF2) nCO2, and n is selected from 1-10. Meanwhile, the invention further discloses a deoxidation fluorination method. The fluorination reagent provided by the invention has the advantages that the materials are easy to obtain, the fluorination products can beobtained at higher yield for various alcohol substrates, and the universality for different alcohol substrates is better.
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Paragraph 0066-0116; 0127-0138; 0147-0148
(2020/12/30)
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- Palladium-Catalyzed Monofluoromethylation of Arylboronic Esters with Fluoromethyl Iodide
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The first palladium-catalyzed direct monofluoromethylation of arylboronic esters to produce monofluoromethyl arenes is reported. The reaction is typically carried out at room temperature within 4 h and has a good functional group tolerance. The monofluoromethylating agent, CH2FI, was readily prepared via a halogen-exchange process.
- Hu, Jingyu,Gao, Bing,Li, Lingchun,Ni, Chuanfa,Hu, Jinbo
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supporting information
p. 3086 - 3089
(2015/06/30)
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- Nickel-catalyzed monofluoromethylation of aryl boronic acids
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Aryl boronic acids can be monofluoromethylated under nickel catalysis. The utility of this method is demonstrated by the monofluoromethylation of a borylated and acyl-protected derivative of the statin drug ezetimibe. Mechanistic investigations indicate that a fluoromethyl radical is involved in the NiI/NiIII catalytic cycle.
- Su, Yi-Ming,Feng, Guang-Shou,Wang, Zhen-Yu,Lan, Quan,Wang, Xi-Sheng
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p. 6003 - 6007
(2015/05/13)
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- Friedel-crafts reaction of benzyl fluorides: Selective activation of C-f bonds as enabled by hydrogen bonding
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A Friedel-Crafts benzylation of arenes with benzyl fluorides has been developed. The reaction produces 1,1-diaryl alkanes in good yield under mild conditions without the need for a transition metal or a strong Lewis acid. A mechanism involving activation of the C-F bond through hydrogen bonding is proposed. This mode of activation enables the selective reaction of benzylic C-F bonds in the presence of other benzylic leaving groups.
- Champagne, Pier Alexandre,Benhassine, Yasmine,Desroches, Justine,Paquin, Jean-Franois
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p. 13835 - 13839
(2015/02/05)
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- Copper-catalyzed debenzoylative monofluoromethylation of aryl iodides assisted by the removable (2-Pyridyl)sulfonyl group
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A new method for aromatic monofluoromethylation was developed. Aryl iodides can be efficiently transformed into the corresponding monofluoromethylated products by a copper-catalyzed debenzoylative fluoroalkylation with 2-PySO 2CHFCOR and subsequent reductive desulfonylation. The (2-pyridyl)sulfonyl moiety plays an important role in the copper-catalyzed cross-coupling, and it can be removed easily through Bu3SnH-mediated desulfonylation.
- Zhao, Yanchuan,Ni, Chuanfa,Jiang, Fanzhou,Gao, Bing,Shen, Xiao,Hu, Jinbo
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p. 631 - 634
(2013/05/09)
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- Fluorination reactions in microreactors
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The DAST-mediated conversion of a range of alcohols to the corresponding fluorides in a microstructured device is described. This safe, practical fluorination method will facilitate reactions currently challenging on large scale. The Royal Society of Chem
- Gustafsson, Tomas,Gilmour, Ryan,Seeberger, Peter H.
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scheme or table
p. 3022 - 3024
(2009/02/04)
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- Practical and general method for direct synthesis of alkyl fluorides from alcohols under mild conditions
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A variety of alcohols were treated with Ph 3P and KF in CCl 4-DMF at room temperature to afford the corresponding fluorides in very good yields. Springer-Verlag 2005.
- Bandgar, Babasaheb P.,Kamble, Vinod T.,Biradar, Ankush V.
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p. 1579 - 1582
(2007/10/03)
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- Efficient and selective halogenation of allylic and benzylic alcohols under mild conditions
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A simple, mild, and high yielding procedure for the halogenation of allylic and benzylic alcohols using a combination of SOCl2, benzotriazole, and potassium halides in DMF is described. The effectiveness of the protocol is manifested in its selectivity towards allylic and benzylic alcohols whereas other simple alcohols such as primary, secondary, and tertiary are found to be unreactive. Springer-Verlag 2004.
- Bandgar, Babasaheb P.,Bettigeri, Sampada V.
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p. 1251 - 1255
(2007/10/03)
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- Hydrogen bonding and catalysis of solvolysis of 4-methoxybenzyl fluoride
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Values of ko = 8.0 × 10-3 s-1 and kH = 2.5 × 10-2 M-1 s-1, respectively, were determined for the spontaneous and the acid-catalyzed cleavage of 4-methoxybenzyl fluoride (1-F) to form the 4-methoxybenzyl carbocation (1+). Values of kF = 1.8 × 107 M-1 s-1 and kHF = 7.2 × 104 M-1 s-1 were determined for addition of F- and HF to 1+ for reaction in the microscopic reverse direction. Evidence is presented that the reversible addition of HF to 1+ to give 1-F + H+ proceeds by a concerted reaction mechanism. The relatively small 250-fold difference between the reactivities of fluoride ion and neutral HF toward 1+ is attributed to the tendency of the strong aqueous solvation of F- to decrease its nucleophilic reactivity and to the advantage for the concerted compared with the usual stepwise pathway for addition of HF. There is no significant stabilization of the transition state for cleavage of 1-F from general acid catalysis by 0.80 M cyanoacetate buffer at pH 1.7. The estimated 3 kcal/mol larger Marcus intrinsic barrier for heterolytic cleavage of 1-F than for cleavage of 1-Cl is attributed to a lag in the development at the transition state of the ca. 30 kcal/mol greater stabilizing solvation of the product ion F- compared with Cl-. The decrease in the electronegativity of X along the series X = F, OH, Cl is accompanied by a ca. 1010-fold increase in the carbon basicity compared with the proton basicity of X-.
- Toteva, Maria M.,Richard, John P.
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p. 9798 - 9805
(2007/10/03)
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- MONO ET DIFLUORATION ELECTROCHIMIQUES DE GROUPES BENZYLIQUES
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Anodic oxidation of benzylic compounds 1 using CH3CN as a solvent and Et3N,3HF as a fluorinating reagent allowed to introduce a fluorine atom in α position of electron withdrawing group via carbocation 1+ (ECBECN mechanism).Whatever the E group, monofluorides 2 are obtained in good yields from paramethoxy derivatives 1 (R=p-OCH3).In this case, by raising the potential of working electrode after the monofluorination step, gem difluorides 3 can be directly prepared from 1.When the substituent of the phenyl ring is different of a methoxy group, a mixture of fluoride 2 and acetamide 4 is generally obtained and the ratio of these two compounds is related to cation stability.
- Laurent, Eliane,Marquet, Bernard,Tardivel, Robert
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p. 4431 - 4444
(2007/10/02)
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- Selective Fluorination of Substituted Methanols with Methanesulfonyl Fluoride and Cesium Fluoride as Modified with Crown Ethers
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A new combination of methanesulfonyl fluoride and cesium fluoride as modified with 18-crown-6 was demonstrated to be the best for selective fluorination of various benzyl alcohols via nucleophilic substitution.As extended applications of this procedure, ethyl 1-fluoromethylpyrazole-4-carboxylate (6) and N-fluoromethylphthalimide (12) have been synthesized in high yields from the corresponding alcohol (4) and chloride (11) respectively.
- Makio, K.,Yoshioka, H.
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p. 677 - 684
(2007/10/02)
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- CHEMOSELECTIVE FLUORINATION FOR PRIMARY ALCOHOLS
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Primary alcohols and their silylated derivatives are selectively fluorinated by tetraalkylammonium fluoride and aryl (or alkyl) sulfonyl fluoride.
- Shimizu, Makoto,Nakahara, Yuko,Yoshioka, Hirosuke
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p. 4207 - 4210
(2007/10/02)
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- The Preparation of Primary Alkyl and Benzyl Fluorides from the Corresponding Primary Amines
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N-substituted 2,4,6-triphenylpyridinium fluorides (in contrast to these and other tetrafluoroborates) thermolyse to the corresponding primary alkyl and benzyl fluorides.The pyridinium fluorides are made from 2,4,6-triphenylpyrylium fluoride and the relevant amine.
- Katritzky, Alan R.,Patel, Ranjan C.
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p. 2901 - 2903
(2007/10/02)
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