- 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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- Cathodic C-H Trifluoromethylation of Arenes and Heteroarenes Enabled by an in Situ-Generated Triflyltriethylammonium Complex
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While several trifluoromethylation reactions involving the electrochemical generation of CF3 radicals via anodic oxidation have been reported, the alternative cathodic, reductive radical generation has remained elusive. Herein, the first cathodic trifluoromethylation of arenes and heteroarenes is reported. The method is based on the electrochemical reduction of an unstable triflyltriethylammonium complex generated in situ from inexpensive triflyl chloride and triethylamine, which produces CF3 radicals that are trapped by the arenes on the cathode surface.
- Cantillo, David,Jud, Wolfgang,Kappe, C. Oliver,Maljuric, Snjezana
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supporting information
(2019/10/08)
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- Trifluoroacetic acid copper (I) reagent and its application in the trifluoromethylation reaction
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The invention discloses a copper trifluoroacetate (I) reagent and application thereof in trifluoromethylate reaction. The structural formula is disclosed in the specification. The copper trifluoroacetate (I) reagent is prepared by the following steps: reacting cuprous chloride, sodium tert-butyl alcoholate and bidentate nitrogen ligand in a tetrahydrofuran solvent, adding trifluoroacetic acid to react, and finally, carrying out separation purification to obtain the copper trifluoroacetate (I) reagent. The reagent can perform trifluoromethylation reaction with halogenated aromatic hydrocarbons or halogenated heterocyclic compounds in a decarboxylation mode to form the corresponding trifluoromethylation derivates. The method has the advantages of simple preparation technique and cheap and accessible raw materials; and the obtained copper trifluoroacetate (I) reagent has favorable selectivity, can promote the trifluoromethylation reaction to proceed quickly and efficiently, and has favorable industrial application prospects.
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Paragraph 0035; 0036
(2017/03/25)
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- Copper-catalysed synthesis of trifluoromethyl(hetero)arenes from di(hetero)aryl-λ3-iodanes
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An efficient synthesis of trifluoromethylated (hetero)arenes has been achieved through the regioselective copper-catalyzed trifluoromethylation of di(hetero)aryl-λ3-iodanes, employing readily available trifluoromethyltrimethylsilane. The reaction works well for both symmetrical and unsymmetrical di(hetero)aryl-λ3-iodanes with good regioselectivity and also tolerates diverse functional groups such as bromo, iodo, cyano, nitro, ester, ketone and enolizable ketone.
- Pandey, Vinay Kumar,Anbarasan, Pazhamalai
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p. 18525 - 18529
(2016/02/27)
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- Decarboxylative Trifluoromethylating Reagent [Cu(O2CCF3)(phen)] and Difluorocarbene Precursor [Cu(phen)2][O2CCF2Cl]
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This article describes the new economic decarboxylative trifluoromethylating reagent [Cu(phen)(O2CCF3)] (1; phen=1,10-phenanthroline) and the efficient difluorocarbene precursor [Cu(phen)2][O2CCF2Cl] (2). Treatment of copper tert-butoxide with phen and subsequent addition of trifluoroacetic acid or chlorodifluoroacetic acid afforded air-stable complexes 1 and 2, respectively, which were characterized by X-ray crystallography. The copper(I) ion in 1 is coordinated by a bidentate phen ligand, a monodentate trifluoroacetate group, and a molecule of CH3CN in a distorted tetrahedral coordination geometry. The molecular structure of 2 adopts an ionic form that consists of a [Cu(phen)2]+ cation and a chlorodifluoroacetate anion. Complex 1 reacted with a variety of aryl and heteroaryl halides to form trifluoromethyl (hetero)arenes in good yields. The corresponding Hammett plot exhibited a linear relationship and a reaction parameter (ρ)=+0.56±0.02, which indicated that the trifluoromethylation reaction proceeded via a nucleophilic reactive species. Complex 2 reacts with phenols to produce aryl difluoromethyl ethers in modest-to-excellent yields. Mechanistic investigations revealed that the difluoromethylation reaction proceeds by initial copper-mediated formation of difluorocarbene and subsequent concerted addition of difluorocarbene to the phenol to form a three-center transition state.
- Lin, Xiaoxi,Hou, Chuanqi,Li, Haohong,Weng, Zhiqiang
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supporting information
p. 2075 - 2084
(2016/02/12)
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- Introducing a new radical trifluoromethylation reagent
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Perfluoro-3-ethyl-2,4-dimethyl-3-pentyl radical (PPFR) is a persistent radical stable at room temperature, but easily decomposes at 90 °C to produce a CF3 radical which is able to react with a variety of aromatic compounds to afford the corresponding trifluoromethyl derivatives, usually as mixtures of regioisomers in good to excellent overall yields.
- Sato, Azusa,Han, Jianlin,Ono, Taizo,Wzorek, Alicja,Ace?a, José Luis,Soloshonok, Vadim A.
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supporting information
p. 5967 - 5970
(2015/03/30)
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- Silver-mediated trifluoromethylation of arenes using TMSCF3
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The silver-mediated C-H trifluoromethylation of aromatic substrates using TMSCF3 is described. The development, optimization, and scope of these transformations are reported. AgCF3 intermediates are proposed.
- Ye, Yingda,Lee, Shin Hee,Sanford, Melanie S.
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supporting information; experimental part
p. 5464 - 5467
(2011/12/05)
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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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- Phototransposition reactions of methyl-substituted benzotrifluorides: Proof of the role of trifluoromethyl-substituted carbon
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Irradiation in acetonitrile of any one of the six isomers of dimethylbenzotrifluoride 8 resulted in efficient photoisomerization to the others. The dominant processes in these phototransposition reactions divides the isomers into two triads. The first consists of 8-2,6 (2,6-dimethylbenzotrifluoride), 8-2,3, and 8-3,4; the second consists of 8-3,5, 8-2,4, and 8-2,5. Moreover, irradiation of 2,6-dideuterio-4-methylbenzotrifluoride 5-d2 resulted in formation of 5,6-dideuterio-3-methylbenzotrifluoride 6-d2. These observations demonstrate that it is the trifluoromethyl-substituted carbon that is the migratory one in these reactions.
- DeCosta, Dayal,Pincock, James
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p. 9484 - 9487
(2007/10/03)
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- 5-amino or substituted amino 1,2,3-triazoles
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Novel 5-amino or substituted amino 1,2,3-triazoles are disclosed as having anticoccidial activity. The compounds are useful for controlling coccidiosis when administered in minor quantities to animals, in particular to poultry, usually in admixture with animal sustenance.
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