- A radical approach to the copper oxidative addition problem: Trifluoromethylation of bromoarenes
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Transition metal–catalyzed arene functionalization has been widely used for molecular synthesis over the past century. In this arena, copper catalysis has long been considered a privileged platform due to the propensity of high-valent copper to undergo reductive elimination with a wide variety of coupling fragments. However, the sluggish nature of oxidative addition has limited copper’s capacity to broadly facilitate haloarene coupling protocols. Here, we demonstrate that this copper oxidative addition problem can be overcome with an aryl radical–capture mechanism, wherein the aryl radical is generated through a silyl radical halogen abstraction. This strategy was applied to a general trifluoromethylation of aryl bromides through dual copper-photoredox catalysis. Mechanistic studies support the formation of an open-shell aryl species.
- Le, Chip,Chen, Tiffany Q.,Liang, Tao,Zhang, Patricia,MacMillan, David W. C.
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p. 1010 - 1014
(2018/06/12)
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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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- Copper-mediated trifluoromethylation of aryl-, heteroaryl-, and vinyltrifluoroborates with Langlois' reagent
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An effortless and realistic procedure for the copper-mediated trifluoromethylation of aryl-, heteroaryl- and vinyltrifluoroborates with CF3 radicals generated from NaSO2CF3 and tert-butyl hydroperoxide (TBHP) is presented. The developed method produces trifluoromethyl arenes and -alkenes in good to excellent yields and a wide range of electronically and structurally diverse substrates are tolerated.
- Dubbaka, Srinivas Reddy,Salla, Manohar,Bolisetti, Raghu,Nizalapur, Shashidhar
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p. 6496 - 6499
(2014/02/14)
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- Trifluoromethylation of aryl and heteroaryl halides with fluoroform-derived CuCF3: Scope, limitations, and mechanistic features
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Fluoroform-derived CuCF3 recently discovered in our group exhibits remarkably high reactivity toward aryl and heteroaryl halides, performing best in the absence of extra ligands. A broad variety of iodoarenes undergo smooth trifluoromethylation with the ligandless CuCF3 at 23-50 C to give the corresponding benzotrifluorides in nearly quantitative yield. A number of much less reactive aromatic bromides also have been trifluoromethylated, including pyridine, pyrimidine, pyrazine, and thiazole derivatives as well as aryl bromides bearing electron-withdrawing groups and/or ortho substituents. Only the most electrophilic chloroarenes can be trifluoromethylated, e.g., 2-chloronicotinic acid. Exceptionally high chemoselectivity of the reactions (no side-formation of arenes, biaryls, and C2F5 derivatives) has allowed for the isolation of a large number of trifluoromethylated products in high yield on a gram scale (up to 20 mmol). The CuCF3 reagent is destabilized by CuX coproduced in the reaction, the magnitude of the effect paralleling the Lewis acidity of CuX: CuCl > CuBr > CuI. While SNAr and SRN1 mechanisms are not operational, there is a well-pronounced ortho effect, i.e., the enhanced reactivity of ortho-substituted aryl halides 2-RC6H4X toward CuCF3. Intriguingly, this ortho-effect is observed for R = NO2, COOH, CHO, COOEt, COCH3, OCH3, and even CH3, but not for R = CN. The fluoroform-derived CuCF3 reagent and its reactions with haloarenes provide an unmatched combination of reactivity, selectivity, and low cost.
- Lishchynskyi, Anton,Novikov, Maxim A.,Martin, Eddy,Escudero-Adan, Eduardo C.,Novak, Petr,Grushin, Vladimir V.
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p. 11126 - 11146
(2013/12/04)
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- Me3SiCF3/AgF/Cu - A new reagents combination for selective trifluoromethylation of various organic halides by trifluoromethylcopper, CuCF3
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An alternative copper halide-free route to obtain highly reactive trifluoromethylcopper species has been developed via the reaction of silver fluoride and trimethyl(trifluoromethyl)silane followed by a redox transmetallation with elemental copper. The composition of the reactive intermediate was investigated by means of UV/Vis/NIR, ESR, 19F NMR spectroscopy and ESI mass spectrometry. "Trifluoromethylcopper" prepared by the oxidative transmetallation route exhibits excellent reactivity and selectivity in substitutions of iodine or bromine bond to aromatic or heterocyclic compounds for trifluoromethyl groups without any additional catalyst.
- Kremlev, Mikhail M.,Mushta, Aleksej I.,Tyrra, Wieland,Yagupolskii, Yurii L.,Naumann, Dieter,M?ller, Angela
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scheme or table
p. 67 - 71
(2012/03/10)
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- IMIDAZOPYRIDINE DERIVATIVES AS INHIBITORS OF RECEPTOR TYROSINE KINASES
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The invention relates to new bicyclic heterocyclic derivative compounds, to pharmaceutical compositions comprising said compounds and to the use of said compounds in the treatment of diseases, e.g. cancer.
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Page/Page column 132
(2010/01/07)
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- Aryl sulfonamide and sulfonyl compounds as modulators of PPAR and methods of treating metabolic disorders
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Aryl sulfonamide and sulfonyl compounds as modulators of peroxisome proliferator activated receptors, pharmaceutical compositions comprising the same, and methods of treating disease using the same are disclosed.
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Page/Page column 63
(2010/02/14)
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- Preparation of novel β-trifluoromethyl vinamidinium salt and its synthetic application to trifluoromethylated heterocycles
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β-Trifluoromethylated vinamidinium salt (1) was prepared in high yield by the reaction between 3,3,3-trifluoropropanoic acid and phosphorus oxychloride in N,N,-dimethylformamide at 70°C for 1h. This salt 1 reacted readily with bifunctional nitrogen nucleophiles, such as amidine and hydrazine derivatives, in acetonitrile or dimethyl sulfoxide to furnish the corresponding trifluoromethylated azaheterocycles in good yields.
- Yamanaka, Hiroki,Takekawa, Tadashi,Morita, Kenji,Ishihara, Takashi,Gupton, John T.
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p. 1829 - 1832
(2007/10/03)
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- Synthesis of Some 5-Trifluoromethylpyrimidines
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5-Trifluoromethyl-2-pyrimidinones have been prepared by selective substitution reactions from 2-chloro-5-methylpyrimidine.
- Benneche, Tore,Undheim, Kjell
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p. 505 - 508
(2007/10/02)
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- Derivatives of (pyrimidyloxy)phenoxy-alkanecarboxylic acid and herbicidal compositions thereof
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A compound of general formula I: STR1 wherein A, B, D, E, and V are independently chosen from hydrogen, halogen, nitro, cyano, thiocyano, amino, alkyl, alkoxy, alkylthio, alkenyl, cycloalkyl, carbalkoxy, phenyl, phenoxy or phenylthio; R1 and R2 are independently hydrogen, alkyl, alkenyl, alkanoyl, or R1 and R2 together are alkylidene; W is carboxy or a functional derivative thereof or CH2 Z wherein Z is halogen, hydroxy, alkoxy, alkylthio, formyl or amino; and X and Y are oxygen or sulfur.
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