- A clean and selective radical homocoupling employing carboxylic acids with titania photoredox catalysis
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A titania photoredox catalysis protocol was developed for the homocoupling of C-centered radicals derived from carboxylic acids. Intermolecular reactions were generally efficient and selective, furnishing the desired dimers in good yields under mild neutral conditions. Selective cross-coupling with two acids proved unsuccessful. An intra-molecular adaptation enabled macrocycles to be prepared, albeit in modest yields. (Chemical Equation Presented).
- Manley, David W.,Walton, John C.
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supporting information
p. 5394 - 5397
(2015/02/19)
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- The vicinal F-C-C-F moiety as a tool for influencing peptide conformation
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Diastereoisomers of bis(amino acid amides) of 2,3-difluorosuccinic acid have been prepared and the erythro- and threoisomers display very different conformations. The Royal Society of Chemistry 2005.
- Schueler, Martin,O'Hagan, David,Slawin, Alexandra M. Z.
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p. 4324 - 4326
(2007/10/03)
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- Rearrangements accompanying fluorination of 2-amino alcohols and 1,2-diols with Deoxo-Fluor
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2-Amino alcohols and 1,2-diols treated with Deoxo-Fluor in methylene chloride resulted in the formation of rearranged major products concomitantly with minor amounts of the straightforward fluorinated replacement products in good yields.
- Ye, Chengfeng,Shreeve, Jean'ne M.
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p. 1869 - 1872
(2007/10/03)
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- Rearrangement of phenylethenes on reaction with iodine-xenon difluoride
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(matrix presented) Phenyl-substituted ethenes react with iodine and xenon difluoride to provide difluorinated products. Iodofluoro intermediates react with xenon difluoride to produce transient iodine difluoride species that lose IF and F- and produce carbocations.
- Patrick, Timothy B.,Qian, Suntian
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p. 3359 - 3360
(2007/10/03)
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- Utility of silicon tetrafluoride as a catalyst of reactions with xenon difluoride: Fluorinations of phenyl alkenes and benzaldehydes
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Application of silicon tetrafluoride to fluorinations with xenon difluoride as a catalyst is investigated. It was found that vic-difluorination of phenyl alkenes and transformation of benzaldehydes to difluoromethoxybenzenes using xenon difluoride are enhanced by silicon tetrafluoride.
- Tamura, Masanori,Takagi, Toshiyuki,Quan, Heng-Dao,Sekiya, Akira
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p. 163 - 166
(2007/10/03)
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- Hexafluoropropene oxide - a fluorinating reagent for the formation of element-fluorine bonds
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Hexafluoropropene oxide (HFPO) is shown to be a good reagent for the nucleophilic formation of the element-fluorine bond in organoelement compounds. Fluorides of Bi, Sb, Se, Te and I were prepared from appropriate oxygen compounds.
- Lermontov,Rakov,Zefirov,Stang
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p. 103 - 105
(2007/10/03)
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- Fluorination of olefins with PhSeF3, PhSeF5 and PhTeF5
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Phenyselenium trifluoride, PhSeF3 (PSTF) either oxidatively difluorinates or selenofluorinates olefins, depending on their structures. The pentafluorides PhSeF5 and PhTeF5 appear to be effective difluorinating reagents, af
- Lermontov, Sergei A.,Zavorin, Sergei I.,Bakhtin, Ilya V.,Pushin, Alexei N.,Zefirov, Nikolai S.,Stang, Peter J.
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- Phenyltetrafluorotelluromethoxide - A new fluorinating reagent for olefins
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Phenyltetrafluorotelluromethoxide fluorinates olefins to form 1,2-difluorides. The reaction with styrene afforded 1-fluoro-4-phenyl-1,2-dihydronaphthalene as the main product.
- Lermontov,Bahtin
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p. 722 - 723
(2007/10/03)
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- FLUORINATING PROPERTIES OF PhTeF5 AND PhSeF5 TOWARDS C=C BOND
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Phenylselenium pentafluoride and phenyltellurium pentafluoride react with olefins affording appropriate 1,2-difluorides under mild conditions.Key words: Phenylselenium pentafluoride, phenyltellurium pentafluoride, xenon difluoride, olefins, difluorination, electrophilic addition.
- Lermontov, Sergei A.,Zavorin, Sergei I.,Bakhtin, Ilya V.,Zefirov, Nikolai S.,Stang, Peter J.
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p. 283 - 286
(2007/10/02)
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- Site-Selective Fluorination of Organic Compounds Using 1-Alkyl-4-fluoro-1,4-diazabicyclooctane Salts (Selectfluor Reagents)
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The new "N-F"-type electrophilic reagent family of 1-alkyl-4-fluoro-1,4-diazabicyclooctane salts (derived from elemental fluorine (F2) and 1-alkyl-1,4-diazabicyclooctane salts) has been found to be very effective for the fluorination of a wide variety of organic substrates.These include steroidal enol acetates and silyl enol ethers, phenyl-substituted olefins, sulfides bearing α-H atoms, certain carbanions, and mildly activated aromatic compounds.The products were obtained with good yields and regioselectivity under very mild reaction conditions.
- Lal, G. Sankar
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p. 2791 - 2796
(2007/10/02)
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- Oxidative fluorination in amine-HF mixtures
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The selective electrochemical fluorination of alkenes, phenanthroline, naphthalene and chlorobenzene in neat amine-HF mixtures is described, together with the chemistry of 4,4-difluorocyclohexadienone.
- Meurs,Eilenberg
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p. 705 - 714
(2007/10/02)
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- Reaction of epoxides with diethylaminosulfur triflouride
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Diethylaminosulfur triflouride (DAST) reacts with epoxides (oxiranes) to form geminal diflourides, vicinal diflourides, and bis(2-fluoroalkyl) ethers. Thus cyclopentene oxide gave cis-1,2-difluorocyclopentane and bis(2-fluorocyclopentyl) ether; cyclohexene oxide gave cis-1,1-difluorocyclohexane and bis(2-fluorocylohexyl) ether; styrene oxide gave 1,1-difluoroethylbenzene and 1,2-difluoroethylbenzene; and cis- and trans-stilbene oxides gave mixtures of meso- and racemic 1,2-difluoro-1,2-diphenylethanes together with 1,1-difluoro-2,2-diphenylethane resulting from a rearrangement. Cyclooctene oxide and cyclohexene sulfide do not react appreciably under the same conditions.
- Hudlicky, Milos
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p. 373 - 384
(2007/10/02)
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- Facile, Temperature-Dependent Formation of Gaseous C1 and C2 Perfluoroalkyl Hypofluorites. Applications as Electrophilic Fluorinating Agents.
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A convenient method for continuous-flow production of gaseous C1 and C2 fluoroxyperfluoroalkanes (RfOF) was developed.Passage of 10percent F2 through short columns of CF3CO2Na resulted in the formation of the following hypofluorites: CF3CF2OF, CF3OF, CF3CF(OF)2, and CF2(OF)2.No other significant oxidizing side products or residual F2 were present in the column effluent under normal conditions.Identifications of the hypofluorites were made through direct 19F NMR measurements at -40 deg C of the -196 deg C condensate of the column effluent and also on the basis of stilbene trapping experiments.Hypofluorites were formed rapidly at temperatures at least as low as -110 deg C but no reaction occurred at -160 deg C.The ratios of hypofluorites formed strongly depended on the temperature of the salt column.Yields of CF3CF(OF)2 exceeding 90percent, based on input F2, were obtained at salt temperatures between -110 and -78 deg C.At moderate temperatures (-20 to +20 deg C) CF3CF2OF was the predominant products, accompanied by significant amounts of CF3OF and CF3CF(OF)2 and traces of CF2(OF)2.CF3OF was the major hypofluorite formed at high (60 to 100 deg C) temperatures.No hypofluorites were detected when the column temperature was above 135 deg C.A minimum of specialized equipment is required to produce hypofluorites by this method.It makes expensive or previously exotic, little-studied fluoroxy compounds readily available for synthetic applications.Fluorinations of anisole, 3,4,6-triacetyl-D-glucal, phenylmercuric acetate, and N,N-dimethylphenylacetamide tert-butyldimethylsilyl enolate were carried out to demonstrate the synthetic utility of RfOF and to compare its chemical reactivity with acetyl hypofluorite, an electrophilic fluorinating agent currently in wide use.RfOF, used as a homogeneous reagent, was comparable in fluorinating ability but was less regio- and stereoselective than acetyl hypofluorite in the cases examined.
- Mulholland, G. Keith,Ehrenkaufer, Richard E.
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p. 1482 - 1489
(2007/10/02)
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- FLUORATION ANODIQUE DANS LE CHLORURE DE METHYLENE (POLYMETHYL- et VINYLBENZENES)
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The anodic oxidation of polymethyl and of ethylenic derivatives of benzene in CH2Cl2/Et4NF, 3HF or Et3N, 3HF has been studied.The fluoro complounds are obtained in good yields.With the ethylenic compounds cis-addition products predominate.
- Bensadat, A.,Bodennec, G.,Laurent, E.,Tardivel, R.
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p. 333 - 340
(2007/10/02)
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- A NOVEL METHOD FOR PREPARATION OF VICINAL FLUORO-IODO COMPOUNDS USING ELEMENTAL FLUORINE
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Elemental fluorine reacts with iodine at -75 deg and the resulting IF is reacted, without any isolation or purification, with olefins thus producing fluoro-iodo compounds in an excellent regio- and stereospecific mode.
- Rozen, Shlomo,Brand, Michael
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p. 4543 - 4546
(2007/10/02)
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