- Cross-Coupling through Ag(I)/Ag(III) Redox Manifold
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In ample variety of transformations, the presence of silver as an additive or co-catalyst is believed to be innocuous for the efficiency of the operating metal catalyst. Even though Ag additives are required often as coupling partners, oxidants or halide scavengers, its role as a catalytically competent species is widely neglected in cross-coupling reactions. Most likely, this is due to the erroneously assumed incapacity of Ag to undergo 2e? redox steps. Definite proof is herein provided for the required elementary steps to accomplish the oxidative trifluoromethylation of arenes through AgI/AgIII redox catalysis (i. e. CEL coupling), namely: i) easy AgI/AgIII 2e? oxidation mediated by air; ii) bpy/phen ligation to AgIII; iii) boron-to-AgIII aryl transfer; and iv) ulterior reductive elimination of benzotrifluorides from an [aryl-AgIII-CF3] fragment. More precisely, an ultimate entry and full characterization of organosilver(III) compounds [K]+[AgIII(CF3)4]? (K-1), [(bpy)AgIII(CF3)3] (2) and [(phen)AgIII(CF3)3] (3), is described. The utility of 3 in cross-coupling has been showcased unambiguously, and a large variety of arylboron compounds was trifluoromethylated via [AgIII(aryl)(CF3)3]? intermediates. This work breaks with old stereotypes and misconceptions regarding the inability of Ag to undergo cross-coupling by itself.
- Demonti, Luca,Mézailles, Nicolas,Nebra, Noel,Saffon-Merceron, Nathalie
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supporting information
p. 15396 - 15405
(2021/10/12)
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- Visible-Light photoredox decarboxylation of perfluoroarene iodine(III) Trifluoroacetates for C-H trifluoromethylation of (Hetero)arenes
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A scalable and operationally simple decarboxylative trifluoromethylation of (hetero)arenes with easily accessible C6F5I(OCOCF3)2 under photoredox catalysis has been developed. This method is tolerant of various (hetero)arenes and functional groups. Notably, C6F5I is recycled from the decarboxylation reaction and further used for the preparation of C6F5I(OCOCF3)2. The combination of photoredox catalysis and hypervalent iodine reagent provides a practical approach for the application of trifluoroacetic acid in trifluoromethylation reactions.
- Yang, Bin,Yu, Donghai,Xu, Xiu-Hua,Qing, Feng-Ling
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p. 2839 - 2843
(2018/04/14)
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- The first nucleophilic C-H perfluoroalkylation of aromatic compounds via (arene)tricarbonylchromium complexes
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The first nucleophilic perfluoroalkylation of arenes is based on the arene π-system activation via (η6-arene)tricarbonylchromium complexes. Perfluoroalkyl anions generated from Me3SiRF and a fluoride ion source [Me4N]F exclusively attack the arene ligand under mild conditions. The formed negatively charged analogs of Meisenheimer adducts readily undergo a one-pot oxidation to perfluoroalkyl arenes.
- Kirij, Natalia V.,Filatov, Andrey A.,Khrapach, Gleb Yu.,Yagupolskii, Yurii L.
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supporting information
p. 2146 - 2149
(2017/02/19)
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- Fluoroform-derived CuCF3 for low-cost, simple, efficient, and safe trifluoromethylation of aryl boronic acids in air
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Easy does it: Aryl boronic acids undergo smooth and selective trifluoromethylation with low-cost fluoroform-derived CuCF3 in DMF in non-dried air. The reaction occurs under mild conditions (1 atm, room temperature), exhibits unprecedented funct
- Novak, Petr,Lishchynskyi, Anton,Grushin, Vladimir V.
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supporting information; experimental part
p. 7767 - 7770
(2012/08/29)
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- Cooperative effect of silver in copper-catalyzed trifluoromethylation of aryl iodides using Me3SiCF3
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An effective model of cooperative effect of silver for the coppercatalyzed trifluoromethylation of activated and unactivated aryl iodides to trifluoromethylated arenes using Me3SiCF3 was achieved with a broad substrate scope.
- Weng, Zhiqiang,Lee, Richmond,Jia, Weiguo,Yuan, Yaofeng,Wang, Wenfeng,Feng, Xue,Huang, Kuo-Wei
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experimental part
p. 3229 - 3232
(2011/07/31)
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- Cycloadditions and nucleophilic attack on Z-2H-Heptafluorobut-2-ene
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Chemistry of Z-2H-Heptafluorobut-2-ene 1 is surveyed; cycloaddition reactions occur with a variety of benzenoid compounds, in some cases leading directly to aromatics. Addition to cyclopentadiene, followed by eliminations of hydrogen fluoride and ethyne, lead to isomeric bistrifluoromethylcyclopentadienes. Nucleophilic reactions occur readily with oxygen, nitrogen and sulphur nucleophiles and aniline provides a quinoline synthesis.
- Chambers, Richard D.,Edwards, Andrew R.
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p. 4949 - 4964
(2007/10/03)
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- The Reaction of 3,4,5,6-Tetrahydrophthalic Anhydride with Sulphur Tetrafluoride. A Discovery of Dehydrogenating Properties of SF4
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The reaction of 3,4,5,6-tetrahydrophthalic anhydride 1 with sulphur tetrafluoride and hydrogen fluoride was investigated under variable temperatures.At 80 deg C difluorolactone 2 was obtained in almost quantitative yield while at 120-150 deg C a mixture of compound 2, tetrafluoroether 3, acid fluoride 4 and bis(trifluoromethyl)cyclohexene 5 was formed.At higher reaction temperatures dehydrogenation of the cyclohexene ring occurred to give bis(trifluoromethyl)benzene 6 as the main product. sulphur tetrafluoride, fluorination of tetrahydrophthalic anhydride, fluorocyclisation, tetrafluoroethers, dehydrogenation of cyclohexene ring
- Dmowski, W.
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p. 2175 - 2180
(2007/10/02)
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- TRIFLUORMETHYLIERUNGSREAKTIONEN VON Te(CF3)2 MIT HALOGENBENZOLEN UND METHYLBENZOLEN
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Substituent effects on yields and regioselectivity of photochemical and thermal trifluoromethylation reactions of Te(CF3)2 with halogen benzenes and methyl benzenes are investigated under comparable conditions.All reactions lead to trifluoromethylated products.The yields of the thermal are always higher than those of the corresponding photochemical reactions.The reactivity of the halobenzenes increases in the series C6H5-F a sidereaction, but H-substitution is the primary reaction pathway.During the reactions with iodobenzene tellurium containing compounds are also formed.The reactions with methyl benzenes show an increase in reactivity in the series hexamethylbenzene mesitylene toluene p-xylene.In all cases only ring substituted products are detected.Reactions with toluene and p-xylene yield tellurium containing compounds as well as addition products.The 19F-n.m.r spectra of the products are given.
- Naumann, Dieter,Kischkewitz, Jurgen
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p. 283 - 299
(2007/10/02)
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- Small Rings, 54. Cyclopentadienone
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Cyclopentadienone (1) can be generated by photolysis or pyrolysis of several precursors and isolated in an argon matrix.It dimerizes even on thawing of the matrix (38 K).The IR and UV spectroscopic properties of 1 are discussed.
- Maier, Guenther,Franz, Lothar Hermann,Hartan, Hans-Georg,Lanz, Klaus,Reisenauer, Hans Peter
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p. 3196 - 3204
(2007/10/02)
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- Hetero-?-Systems, 8. Silaethene
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By means of a combination of vacuum flash pyrolysis and matrix isolation silaethene (1a) and its simply substituted derivatives 1b-f can be prepared starting with precursors 9a-f of the silabicyclooctadiene type.Silaolefins 1a-f are stable in argon at 10 K and can be identified by their characteristic IR and UV spectra.
- Maier, Guenther,Mihm, Gerhard,Reisenauer, Hans Peter
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p. 2351 - 2368
(2007/10/02)
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- Direct Thermal and Photochemical Generation of Silanones
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2-Silapyrans (1,2-oxasilins) are synthesized by the pyrolysis of 1-disilanyl-4-methoxy-1,3-butadienes via initial 1,5-silyl migration to afford an intermediate 1-sila-1,3-butadiene.Diels-Alder reaction of the silapyrans and perfluoro-2-butyne does not lead to isolable adducts but rather leads to apparent extrusion of silanone (R2Si=O), which is trapped by a variety of reagents.Reaction of the silapyrans and maleic anhydride provides stable adducts that extrude silanones upon either thermolysis or photolysis.No evidence could not be found for rearrangement of a silylsilanone to a siloxysilylene.
- Hussmann, Gregory,Wulff, William D.,Barton, Thomas J.
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p. 1263 - 1269
(2007/10/02)
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- Synthesis and Photolysis of 1,2,3,8-Tetrakis(trifluoromethyl)cyclo-octatetraene
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The title compound was derived from tetrakis(trifluoromethyl)-5-thiabicyclopent-2-ene via Diels-Alder adduct formation with butadiene; its photolysis gave reaction products.
- Kobayashi, Yoshiro,Ando, Akiri,Kawada, Kosuke,Kumadaki, Itsumaro
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p. 1289 - 1291
(2007/10/02)
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