- Transition-Metal-Free Catalytic Hydrodefluorination of Polyfluoroarenes by Concerted Nucleophilic Aromatic Substitution with a Hydrosilicate
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A transition-metal-free catalytic hydrodefluorination (HDF) reaction of polyfluoroarenes is described. The reaction involves direct hydride transfer from a hydrosilicate as the key intermediate, which is generated from a hydrosilane and a fluoride salt. The eliminated fluoride regenerates the hydrosilicate to complete the catalytic cycle. Dispersion-corrected DFT calculations indicated that the HDF reaction proceeds through a concerted nucleophilic aromatic substitution (CSNAr) process.
- Kikushima, Kotaro,Grellier, Mary,Ohashi, Masato,Ogoshi, Sensuke
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supporting information
p. 16191 - 16196
(2017/11/27)
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- Copper-catalyzed hydrodefluorination of fluoroarenes by copper hydride intermediates
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Breaking bad: Efficient copper-catalyzed C-F bond activation has been achieved by replacing fluorine with hydrogen. A copper hydride is proposed as the active intermediate, which proceeds through a nucleophilic attack on the fluorocarbon, as determined by experimental and theoretical results (see structure; C gray, H white, Cu light red, F light blue; distances in ?).
- Lv, Hongbin,Cai, Yuan-Bo,Zhang, Jun-Long
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supporting information
p. 3203 - 3207
(2013/04/23)
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- Catalytic C-F bond activation of perfluoroarenes by tricoordinated gold(I) complexes
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We report the first example of gold catalyzing C-F bond activation for perfluoroarenes in the presence of silanes. Tricoordinated gold(I) complexes supported by Xantphos-type ligands, such as Xantphos and tBuXantphos ligands, exhibit efficacy in the hydrodefluorination (HDF) of various types of perfluoroarenes. For [tBuXantphosAu(AuCl2)], the highest turnover number is up to 1000 in the HDF of pentafluoronitrobenzene with diphenylsilane. An examination of functional group tolerance shows the orthogonality of this gold(I) catalytic protocol to ketone, ester, carboxylate, alkynyl, alkenyl and amide groups, suggesting its potential application in chemoselective C-F activations. Mechanistic studies show that the equilibrium between tetracoordinated [L2Au]+ and [LAu]+ is important for the reactivity of gold catalysts, which is dependent on the sterically bulky group of Xantphos-type ligands. Furthermore, computational studies for the possible reaction pathways suggest that direct oxidative addition of C-F bonds by gold(I) cation might be the key step during these catalytic reactions. Copyright
- Zhan, Jin-Hui,Lv, Hongbin,Yu, Yi,Zhang, Jun-Long
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experimental part
p. 1529 - 1541
(2012/07/14)
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- Process for production of benzonitrile and benzyl alcohol
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PCT No. PCT/JP97/03037 Sec. 371 Date Apr. 27, 1998 Sec. 102(e) Date Apr. 27, 1998 PCT Filed Aug. 29, 1997 PCT Pub. No. WO98/08795 PCT Pub. Date Mar. 5, 1998A process for producing a fluorinated benzonitrile comprising hydrogenolyzing a fluorinated dicyanobenzene substituted with 1 to 4 fluorine atoms and having the remainder which may be substituted with a chlorine atom in the presence of a catalyst to cause hydrodecyanation of only the cyano group of one side and a process for producing a fluorinated benzyl alcohol comprising reducing the fluorinated benzonitrile and hydrolyzing the fluorinated benzonitrile and reducing the resultant corresponding fluorinated benzoic acid to convert the cyano group to a hydroxymethyl group.
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- Quinolone Antibacterial Agents. Synthesis and Structure-Activity Relationships of 8-Substituted Quinoline-3-carboxylic Acids and 1,8-Naphthyridine-3-carboxylic Acids
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A series of 7,8-disubstituted 1-cyclopropyl-6-fluoroquinoline-3-carboxylic acids, 7-substituted 1-cyclopropyl-6-fluoro-1,8-naphthyridine-3-carboxylic acids, and 10-substituted 9-fluoropyridobenzoxazine-6-carboxylic acids has been prepared and evaluated for antibacterial activity.The side chains examined at the 7-position (benzoxazine 10-position) included piperazinyl (g), 3-aminopyrrolidinyl (a), 3-(aminomethyl)pyrrolidinyl (b), and alkylated 3-(aminomethyl)pyrrolidinyl (c-f).Variations ta C-8 of the quinolone ring system included hydrogen, nitro, amino, fluorine and chlorine.The relative enhancement of in vitro activities by the side chains on the 8-hydrogen quinolone and 1,8-naphthyridine against Gram-negative organisms was a > b > g > c-f.The activity imparted to the substituted quinolone nucleus by the 8-substituent was in the order F > Cl > naphthyridine > H > benzoxazine > NH2 > NO2.These trends were retained in vivo.
- Sanchez, Joseph P.,Domagala, John M.,Hagen, Susan E.,Heifetz, Carl L.,Hutt, Marland P.,et al.
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p. 983 - 991
(2007/10/02)
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- Aromatic radical-anions. XII. A cyclic amperometric and ESR study of the transformations of polyfluorinated benzonitrile radical-anions
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Cyclic voltamperometry and ESR spectrometry were used to study the chemical transformations of radical-anions of benzonitrile derivatives containing from two to five fluorine atoms.Two types of transformations were found to be characteristic for such species, namely, the elimination of a fluoride anion and subsequent formation of defluorination products and dimerization with the subsequent formation of fluorinated derivatives of 4,4'-dicyanodiphenyl.The facility of these processes depends significantly on the number and arrangement of the fluorine atoms in the benzene ring.The relationship between the electronic structure and reactivity of fluorinated benzonitrile radical-anions was examined.
- Efremova, N. V.,Starichenko, V. F.,Shteingarts, V. D.
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