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Richard D. Chambers - One of the best experts on this subject based on the ideXlab platform.
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Elemental Fluorine part 24 fluorination of ethers by Fluorine and selectfluor
ChemInform, 2010Co-Authors: Richard D. Chambers, Graham Sandford, Takashi Okazoe, Emmanuelle Thomas, Jelena TrmcicAbstract:Reaction of dialkyl ethers with either Fluorine or Selectfluor® leads to the formation of unusual difluorinated polyether products in modest yields.
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Elemental Fluorine. Part 24.[1]: Fluorination of ethers by Fluorine and Selectfluor
Journal of Fluorine Chemistry, 2010Co-Authors: Richard D. Chambers, Graham Sandford, Takashi Okazoe, Emmanuelle Thomas, Jelena TrmcicAbstract:Abstract Reactions of dialkyl ethers with either Fluorine or Selectfluor™ led to the formation of unusual difluorinated polyether products in modest yields. A mechanism involving initial fluorination of the site adjacent to ether oxygen followed by elimination of hydrogen fluoride, reaction of the generated enol system with a further equivalent of fluorinating agent giving an oxonium system which reacts with water during aqueous work-up to lead eventually to the products observed, is suggested.
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Elemental Fluorine part 23 direct fluorination of β ketoesters as an approach to enantioselective fluorination
Journal of Fluorine Chemistry, 2009Co-Authors: Richard D. Chambers, Takashi Nakano, Takashi Okazoe, Graham SandfordAbstract:Attempts to develop a direct enantioselective fluorination protocol using Elemental Fluorine and an appropriate Lewis acid and chiral ligand system are described.
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Elemental Fluorine: Part 22. Fluorination of 3β-acetoxy-5α-androstan-17-one using Fluorine and Selectfluor®
Journal of Fluorine Chemistry, 2008Co-Authors: Richard D. Chambers, Mandy Parsons, Graham Sandford, Takashi Nakano, Andrei S. Batsanov, Judith A. K. HowardAbstract:Reactions of 3β-acetoxy-5α-androstan-17-one with Elemental Fluorine and Selectfluor® are reported and give contrasting results. Fluorine gives a mixture of mono-fluorinated steroids in which Fluorine atoms are attached to tertiary carbon sites whereas Selectfluor® gives fluoro-steroid systems arising from electrophilic aliphatic substitution of the most sterically accessible secondary saturated positions. The identities of the fluoro-steroid products were determined by NMR analysis and X-ray crystallography.
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Elemental Fluorine. Part 21.1 Direct Fluorination of Benzaldehyde Derivatives
Organic Process Research & Development, 2008Co-Authors: Richard D. Chambers, Graham Sandford, Jelena Trmcic, Takashi OkazoeAbstract:Direct fluorination of a range of benzaldehyde derivatives gives mixtures of fluorobenzaldehyde and benzoyl fluoride products in ratios that depend upon the nature of the ring substituent. Electron-withdrawing substituents give predominantly benzoyl fluoride derivatives, whereas electron-donating substituents lead to fluoroarene systems. Separation of ring-fluorinated products can be easily accomplished by esterification of the benzoyl fluoride side products. Scale-up of these processes to provide significant quantities of appropriate fluorobenzaldehyde systems has also been achieved using continuous flow techniques.
Graham Sandford - One of the best experts on this subject based on the ideXlab platform.
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Elemental Fluorine part 24 fluorination of ethers by Fluorine and selectfluor
ChemInform, 2010Co-Authors: Richard D. Chambers, Graham Sandford, Takashi Okazoe, Emmanuelle Thomas, Jelena TrmcicAbstract:Reaction of dialkyl ethers with either Fluorine or Selectfluor® leads to the formation of unusual difluorinated polyether products in modest yields.
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Elemental Fluorine. Part 24.[1]: Fluorination of ethers by Fluorine and Selectfluor
Journal of Fluorine Chemistry, 2010Co-Authors: Richard D. Chambers, Graham Sandford, Takashi Okazoe, Emmanuelle Thomas, Jelena TrmcicAbstract:Abstract Reactions of dialkyl ethers with either Fluorine or Selectfluor™ led to the formation of unusual difluorinated polyether products in modest yields. A mechanism involving initial fluorination of the site adjacent to ether oxygen followed by elimination of hydrogen fluoride, reaction of the generated enol system with a further equivalent of fluorinating agent giving an oxonium system which reacts with water during aqueous work-up to lead eventually to the products observed, is suggested.
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Elemental Fluorine part 23 direct fluorination of β ketoesters as an approach to enantioselective fluorination
Journal of Fluorine Chemistry, 2009Co-Authors: Richard D. Chambers, Takashi Nakano, Takashi Okazoe, Graham SandfordAbstract:Attempts to develop a direct enantioselective fluorination protocol using Elemental Fluorine and an appropriate Lewis acid and chiral ligand system are described.
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Elemental Fluorine. Part 21.1 Direct Fluorination of Benzaldehyde Derivatives
Organic Process Research & Development, 2008Co-Authors: Richard D. Chambers, Graham Sandford, Jelena Trmcic, Takashi OkazoeAbstract:Direct fluorination of a range of benzaldehyde derivatives gives mixtures of fluorobenzaldehyde and benzoyl fluoride products in ratios that depend upon the nature of the ring substituent. Electron-withdrawing substituents give predominantly benzoyl fluoride derivatives, whereas electron-donating substituents lead to fluoroarene systems. Separation of ring-fluorinated products can be easily accomplished by esterification of the benzoyl fluoride side products. Scale-up of these processes to provide significant quantities of appropriate fluorobenzaldehyde systems has also been achieved using continuous flow techniques.
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Elemental Fluorine: Part 22. Fluorination of 3β-acetoxy-5α-androstan-17-one using Fluorine and Selectfluor®
Journal of Fluorine Chemistry, 2008Co-Authors: Richard D. Chambers, Mandy Parsons, Graham Sandford, Takashi Nakano, Andrei S. Batsanov, Judith A. K. HowardAbstract:Reactions of 3β-acetoxy-5α-androstan-17-one with Elemental Fluorine and Selectfluor® are reported and give contrasting results. Fluorine gives a mixture of mono-fluorinated steroids in which Fluorine atoms are attached to tertiary carbon sites whereas Selectfluor® gives fluoro-steroid systems arising from electrophilic aliphatic substitution of the most sterically accessible secondary saturated positions. The identities of the fluoro-steroid products were determined by NMR analysis and X-ray crystallography.
Shlomo Rozen - One of the best experts on this subject based on the ideXlab platform.
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fluorination of α β unsaturated carbonyl compounds using Elemental Fluorine
Tetrahedron, 2016Co-Authors: Inna Vints, Shlomo RozenAbstract:Abstract Elemental Fluorine was successfully added across the double bond of various α,β-unsaturated carbonyl compounds. A necessary ingredient is a presence of alcohol in the solvent mixture. Unlike all other halogen's addition to olefins, Fluorine adds itself in a syn mode specificity. The vic difluoro products were easily dehydrofluorinated to form the corresponding α-fluoro carbonyl derivatives.
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fluorination of flavones and chromones using Elemental Fluorine
Journal of Organic Chemistry, 2014Co-Authors: Inna Vints, Shlomo RozenAbstract:Flavonoids are abundant micronutrients in our diet, possessing various biological activities. Fluorine was successfully added across the double bond of various flavones and chromones. The difluoro derivative products were easily dehydrofluorinated to form the corresponding 3-fluoroflavones and 3-fluorochromones.
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attaching the Fluorine atom to organic molecules using brf3 and other reagents directly derived from f2
Accounts of Chemical Research, 2005Co-Authors: Shlomo RozenAbstract:Elemental Fluorine is a starting point for nucleophilic fluorinations (e.g., BrF3), radical fluorinations (e.g., F2 under irradiation), and electrophilic fluorinations (e.g., AcOF). All three categories are represented in this Account. Bromine trifluoride, although commercially available, can be readily made from the elements and is a very good source for naked nucleophilic fluoride ions. To minimize radical reactions, an anchor has to be installed in the molecules with which it reacts. Such an anchor is constituted of a soft base such as nitrogen and especially sulfur atoms. This reagent was used for constructing compounds with a CF2, CF3, CHF2, or CF2COOH group in specific sites. F2 itself was used for completing perfluorination of various polyfluoroethers, while the electrophilic acetyl hypofluorite is an excellent tool for introducing a single Fluorine atom into organic molecules such as carboxylic acids and nitro compounds.
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cover picture Elemental Fluorine and hof ch3cn in service of general organic chemistry eur j org chem 12 2005
European Journal of Organic Chemistry, 2005Co-Authors: Shlomo RozenAbstract:The cover picture shows part of the synthetic possibilities opened now by using Elemental Fluorine as a starting material. Mixtures of F2 with inert gases such as N2 are commercially available or easily prepared from commercial 95% Fluorine. During the last 15 years, chemists started to accept the notion that F2 could be used for fluorination purposes. More recently, they slowly started to get acquainted with yet another side of this element − its ability to perform difficult reactions leading to Fluorine-free derivatives. Thus, the most reactive element of the periodic table is an excellent tool for versatile regio- and stereospecific reactions which can not be performed without its “help”. Representative examples are presented in the Microreview by S. Rozen on p. 2433 ff.
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Elemental Fluorine and hof ch3cn in service of general organic chemistry
European Journal of Organic Chemistry, 2005Co-Authors: Shlomo RozenAbstract:At present, HOF·CH3CN complex is the best oxygen transfer agent that chemistry has to offer. It is readily made by passing dilute Fluorine through aqueous acetonitrile and does not require any isolation or purification. It is stable in aqueous acetonitrile solution for a few hours at room temperature, providing ample opportunities for various reactions. Epoxidation of regular olefins as well as of very electron-depleted ones proceeds smoothly. HOF·CH3CN transfer oxygen also to heteroatoms, especially sulfur and nitrogen. Even very electron-depleted sulfides such as RfSAr that are very difficult to oxidize, are converted into the respective sulfones in a matter of minutes. On the other hand, since the reaction conditions are very mild, the reagent can oxidize various thiophenes and amino acids to the corresponding S,S-dioxides and α-nitro acid derivatives. HOF·CH3CN was also instrumental in ending the 50 years quest for making the elusive 1,10-phenanthroline N,N-dioxide and for the novel transformation of azides to nitro derivatives. The use of BrF3 for making symmetric esters and of tBuOF as an electrophilic tert-butoxylation agent is also mentioned. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Kirby V Scherer - One of the best experts on this subject based on the ideXlab platform.
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liquid phase photofluorination with Elemental Fluorine part iii synthesis of perfluorocycloalkyl ethers with without a chlorine substituent
Journal of Fluorine Chemistry, 1995Co-Authors: Taizo Ono, Kouichi Yamanouchi, Richard E Fernandez, Kirby V SchererAbstract:Abstract Liquid-phase photofluorination (LPPF) of 2-phenyl-2-methoxyhexafluoropropane 1 gave the desired F -2-cyclohexyl-2-methoxypropane, 2 , in 21% yield. An unusual rearranged product, F -2-cyclohexylmethyl isopropyl ether, 4 , and a degradation product, F -2-cyclohexylpropane, 3 , were also produced in 10 and 20% yields, respectively. A plausible reaction mechanism for the formation of the rearranged product 4 was presented. The Cl-containing ethers with cyclic structures, 2-chlorohexafluorocyclopentenyl cyclopentyl ether, and 2-chlorohexafluorocyclopentenyl 2,2,3,3,4,4,5,5-octafluoro- n -pentyl ether were also perfluorinated by the LPPF method to give the corresponding Cl-containing F -ethers in fair yields. The total retention of the chlorine atom through perfluorination and the ability to have a benzene substituent on the substrate are benificial features of this novel perfluorinating method.
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liquid phase photofluorination with Elemental Fluorine part ii synthesis of perfluorotertiary amines
Journal of Fluorine Chemistry, 1995Co-Authors: Taizo Ono, Kouichi Yamanouchi, Kirby V SchererAbstract:Abstract The tertiary amines derived from hexafluoropropene dimers were subjected to liquid-phase photofluorination (LPPF). The corresponding perfluorotertiary amines, which were difficult to synthesize by the conventional fluorination methods such as electrochemical fluorination and indirect fluorination using high-valency metal fluorides, were obtained in good yields. Prepared by this method were F -( N,N -dimethyl-2- methylpentyl) amine 3 , F -( N,N -diethyl-2-methylpentyl) amine 4 , F -3-(1-pyrrolidino)-2-methylpentane 11 , F - ( N,N -dimethyl-1,1-dimethyl-butyl) amine 13 . Discussion on the regioselectivity in the reaction of F -2-methyl-2-pentene (D-II) with secondary amines is also included in connection with the necessity of preparing a regioselective adduct,3-(1-pyrrolidino)- F -2-methyl-2- pentene, for the synthesis of 11 .
Gabriel M. Veith - One of the best experts on this subject based on the ideXlab platform.
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low temperature fluorination of soft templated mesoporous carbons for a high power lithium carbon fluoride battery
Chemistry of Materials, 2011Co-Authors: Pasquale F Fulvio, Suree Brown, Jacqui L. Adcock, Richard T. Mayes, Shannon M Mahurin, Gabriel M. VeithAbstract:Soft-templated mesoporous carbons and activated mesoporous carbons were fluorinated using Elemental Fluorine between room temperature and 235 °C. The mesoporous carbons were prepared via self-assembly synthesis of phloroglucinol–formaldehyde as a carbon precursor in the presence of triblock ethylene oxide–propylene oxide–ethylene oxide copolymer BASF Pluronic F127 as the template. The F/C ratios ranged from ∼0.15 to 0.75 according to gravimetric, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy analysis. Materials have mesopore diameters up to 11 nm and specific surface areas as high as 850 m2 g–1 after fluorination as calculated from nitrogen adsorption isotherms at −196 °C. Furthermore, the materials exhibit higher discharge potentials and energy and power densities as well as faster reaction kinetics under high current densities than commercial carbon fluorides with similar Fluorine contents when tested as cathodes for Li/CFx batteries.