- Diazaphospholene-Catalyzed Hydrodefluorination of Polyfluoroarenes with Phenylsilane via Concerted Nucleophilic Aromatic Substitution
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The metal-free catalytic C-F bond activation of polyfluoroarenes was achieved with diazaphospholene as the catalyst and phenylsilane as the terminal reductant. Density functional theory calculations suggested a concerted nucleophilic aromatic substitution mechanism.
- Cheng, Jin-Pei,Yang, Jin-Dong,Zhang, Jingjing,Zhao, Xiao
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supporting information
(2022/01/03)
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- Method for efficiently synthesizing fluorine-containing compound
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The invention discloses a method for efficiently synthesizing a fluorine-containing compound, and relates to the field of fluorine-containing compound synthesis. The method is a method for generating a corresponding fluorine atom substituted fluorine-containing compound by reacting aromatic chloride or activated chloride serving as a raw material with potassium fluoride under the action of a novel catalyst. The method disclosed by the invention has the advantages of good product selectivity, high efficiency, mild reaction conditions, simplicity and convenience in operation, convenience in application and the like.
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Paragraph 0064-0066
(2021/06/26)
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- Palladium-Catalyzed Cyanation under Mild Conditions: A Case Study to Discover Appropriate Substrates among Halides and Pseudohalides
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A case study has been effectively carried out to identify a suitable substrate among halides and pseudohalides for the palladium-catalyzed cyanation reactions under mild conditions. Among the various substrates considered for evaluation, aryl pentafluorobenzenesulfonates and nonaflates were identified to be the best substrates when compared to corresponding halides and pseudohalides. The substoichiometric use of nontoxic, environmentally benign potassium hexacyanoferrate as a cyanide source and exceptionally milder conditions further highlights the significance of the protocol developed. A wide range of electronically biased and sterically challenging substrates provided the corresponding the nitriles in good to excellent yields.
- Rajendra, Merla Arjuna,Sunil,Sajith, Ayyiliath Meleveetil,Joy, Muthipeedika Nibin,Bakulev, Vasiliy A.,Haridas, Karickal Raman
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supporting information
p. 1629 - 1633
(2020/09/15)
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- Photoinduced Copper(I)-Catalyzed Cyanation of Aromatic Halides at Room Temperature
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The first photoinduced copper(I)-catalyzed cyanation of aromatic halides at room temperature has been developed. The sp2 cyanation reaction exhibits outstanding tolerance to functional groups including primary amines and carboxylic acids, and chemoselectivity to SN2-reactive alkyl chlorides. Mechanistic investigations indicate that the reaction occurs via a single-electron transfer (SET) between the aryl halide and an excited copper(I) cyanide catalytic intermediate. (Figure presented.).
- Kim, Kicheol,Hong, Soon Hyeok
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supporting information
p. 2345 - 2351
(2017/07/22)
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- Solvent-Free Aerobic Oxidation of Alcohols to Nitriles Catalyzed by Copper Iodide in Combination with a Quaternary Ammonium Modified TEMPO
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A catalytic system consisting of N,N-dimethyl-(4-(2,2,6,6-tetramethyl-1-oxyl-4-piperidoxyl)butyl)dodecyl ammonium bromide (TEMPO-Q), CuI and 2,2′-bipyridine was established. This catalytic system (CuI/bpy/TEMPO-Q) showed high activity and good to excellent selectivity in the oxidative conversion of various alcohols to the corresponding nitriles with molecular oxygen as terminal oxidant and aqueous ammonia as nitrogen source under solvent-free conditions. Besides, the catalytic system also offers the advantages of simplified workup procedure. This protocol thus represents a greener pathway for the synthesis of nitriles from alcohols. Graphical Abstract: TEMPO-Q, a compound with both a TEMPO and a quaternary ammonium moieties, in combination with copper iodide and 2,2′-bipyridine as a catalytic system performed well in the oxidation of alcohols to nitriles with molecular oxygen as terminal oxidant in aqueous ammonia under solvent-free conditions. The catalytic system not only offers the advantages of simplified workup procedure, but also has high activity and selectivity due to the phase transfer catalysis of TEMPO-Q[Figure not available: see fulltext.]
- Zhang, Yuecheng,Huang, Rong,Gao, Baosheng,Zhao, Jiquan
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p. 220 - 228
(2016/02/23)
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- Transnitrilation from Dimethylmalononitrile to Aryl Grignard and Lithium Reagents: A Practical Method for Aryl Nitrile Synthesis
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An electrophilic cyanation of aryl Grignard or lithium reagents, generated in situ from the corresponding aryl bromides or iodides, by a transnitrilation with dimethylmalononitrile (DMMN) was developed. DMMN is a commercially available, bench-stable solid. The transnitrilation with DMMN avoids the use of toxic reagents and transition metals and occurs under mild reaction conditions, even for extremely sterically hindered substrates. The transnitrilation of aryllithium species generated by directed ortho-lithiation enabled a net C-H cyanation. The intermediacy of a Thorpe-type imine adduct in the reaction was supported by isolation of the corresponding ketone from the quenched reaction. Computational studies supported the energetic favorability of retro-Thorpe fragmentation of the imine adduct. (Chemical Equation Presented).
- Reeves, Jonathan T.,Malapit, Christian A.,Buono, Frederic G.,Sidhu, Kanwar P.,Marsini, Maurice A.,Sader, C. Avery,Fandrick, Keith R.,Busacca, Carl A.,Senanayake, Chris H.
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supporting information
p. 9481 - 9488
(2015/08/11)
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- Synthesis of aryl nitriles by palladium-assisted cyanation of aryl iodides using tert-butyl isocyanide as cyano source
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Abstract A palladium-catalyzed synthesis of aryl nitriles by the cyanation of aryl iodides with tert-butyl isocyanide as cyano source has been developed. This novel and efficient method avoids the use of toxic cyanides. The reaction is easy-to-handle and shows good functional group compatibility.
- Jiang, Xiao,Wang, Jin-Mei,Zhang, Ying,Chen, Zhong,Zhu, Yong-Ming,Ji, Shun-Jun
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p. 4883 - 4887
(2015/08/03)
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- Practical one-pot conversion of aryl bromides and β-bromostyrenes into aromatic nitriles and cinnamonitriles
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Various aryl bromides were efficiently converted into the corresponding aromatic nitriles in good yields by the treatment with Mg turnings and subsequently DMF, followed by treatment with molecular iodine and aq NH 3. The same treatment of aryl bromides, which are weakly reactive to Mg turnings, with iPrMgCl·LiCl and subsequently DMF, followed by the treatment with molecular iodine and aq NH3 also afforded the corresponding aromatic nitriles in good yields. On the other hand, when N-formylpiperidine was used instead of DMF, p-substituted β-bromostyrenes were converted into the corresponding p-substituted cinnamonitriles, i.e., α,β-unsaturated nitriles, in good to moderate yields by the same procedure. The reactions were carried out by means of a simple experimental procedure and did not require any toxic metal cyanides or expensive rare metals. Therefore, the present reactions are practical and environmentally benign one-pot methods for the preparation of aromatic nitriles, cinnamonitriles, and aliphatic nitriles from aryl bromides, β-bromostyrenes, and alkyl bromides, respectively, through the formation of Grignard reagents and their DMF or N-formylpiperidine adducts.
- Ishii, Genki,Harigae, Ryo,Moriyama, Katsuhiko,Togo, Hideo
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p. 1462 - 1469
(2013/02/25)
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- The first example for cyanation of arylboronic acids with nontoxic and inexpensive K4[Fe(CN)6]
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Nontoxic and inexpensive K4[Fe(CN)6] is first introduced as a cyanating agent to cyanation of arylboronic acids. The present method is simple, practical, and allowed a wide range of substrates including functionalized phenylboronic acids, 1-naphthylboronic acid as well as heterocyclic boronic acids to be smoothly converted into the corresponding products in moderate to high yields.
- Tian, Xinzhe,Sun, Yanpei,Dong, Chuanhua,Zhang, Kaixuan,Liang, Tengfei,Zhang, Yu,Hou, Chaodong
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supporting information; experimental part
p. 719 - 721
(2012/09/22)
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- Generation of iminyl copper species from α-azido carbonyl compounds and their catalytic C-C bond cleavage under an oxygen atmosphere
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Figure presented A copper-catalyzed reaction of α-azidocarbonyl compounds under an oxygen atmosphere is reported where nitriles are formed via C-C bond cleavage of a transient iminyl copper intermediate. The transformation is carried out by a sequence of denitrogenative formation of iminyl copper species from α-azidocarbonyl compounds and their C-C bond cleavage, where molecular oxygen (1 atm) is a prerequisite to achieve the catalytic process and one of the oxygen atoms of O2 was found to be incorporated into the β-carbon fragment as a carboxylic acid.
- Chiba, Shunsuke,Zhang, Line,Ang, Gim Yean,Hui, Benjamin Wei-Qiang
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supporting information; experimental part
p. 2052 - 2055
(2010/07/04)
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- Mild and efficient copper-catalyzed cyanation of aryl iodides and bromides
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An efficient copper-catalyzed cyanation of aryl iodides and bromides is reported. Our system combines catalytic amounts of both copper salts and chelating ligands. The latter, which have potential nitrogen- and/or oxygen-binding sites, have never previously been used in this type of reaction. A protocol has been developed that enables the cyanation of aryl bromides through the copper-catalyzed in situ production of the corresponding aryl iodides using catalytic amounts of potassium iodide. Aryl nitriles are obtained in good yields and excellent selectivities in relatively mild conditions (110°C) compared with the Rose-nmund-von Braun cyanation reaction. Furthermore, the reaction is compatible with a wide range of functional groups including nitro and amino substituents. The protocol reported herein involves two main innovations: the use of catalytic amounts of ligands and the use of acetone cyanohydrin as the cyanating agent in copper-mediated cyanation reactions.
- Cristau, Henri-Jean,Ouali, Armelle,Spindler, Jean-Francis,Taillefer, Marc
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p. 2483 - 2492
(2007/10/03)
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- Reductive dehalogenation of polyfluoroarenes by zinc in aqueous ammonia
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Aqueous ammonia has been found to be a good and versatile medium for the highly selective hydrodehalogenation of polyfluoroarenes by zinc under unprecedentedly mild conditions. The reduction of pentafluorobenzoic acid, 2,3,4,5,6-pentafluorobenzyl alcohol, pentafluorobenzamide, pentafluoropyridine, heptafluoro-2-naphthoic acid, 1,3,4,5,7,8-hexafluoro-2-naphthoic acid, octafluoronaphthalene, octafluorotoluene, decafluorobiphenyl, chloropentafluorobenzene and 4-chlorotetrafluorobenzoic acid give products derived from the removal of one or two halogen atoms. A reduction mechanism, proceeding through electron capture to give a radical anion and then fragmentation of the latter, has been suggested. The observed high selectivity of the process suggests a radical anion formed by direct electron transfer from zinc to substrate. The dehalogenation regioselectivity is basically in accordance with that expected for radical anion fragmentation.
- Laev, Sergey S.,Shteingarts, Vitalii D.
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p. 175 - 185
(2007/10/03)
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- Method for the dehydration of amides to nitriles
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The present invention relates to a process for the dehydration of amides to nitrites which comprises carrying out the dehydration in the presence of an adduct of sulphur trioxide and an amine as the dehydrating reagent in a basic reaction mixture. Thereby, for example, aliphatic, aromatic and heteroaromatic amides are dehydrated to the corresponding nitrites, such as 5-carbamoyl-4-methyl-oxazole to 5-cyano-4-methyl-oxazole, a valuable intermediate in the synthesis of pyridoxine.
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- Tetramethylammonium hydrogendifluoride: A convenient source of nucleophilic fluoride
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Tetramethylammonium hydrogendifluoride (TMAHF2) acts as an effective fluoride source for the selective fluorination in high yields of various chloro and nitroaromatics via halogen exchange (halex) and fluorodenitration.
- Adams, David J.,Clark, James H.,Nightingale, David J.
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p. 4295 - 4301
(2007/10/03)
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- C-Azidodiazirines in the SRN1 Reaction of Azide Ion with Arylchlorodiazirines. Further Insights into Reaction Mechanism
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Mixtures of arylchlorodiazirines and sodium azide in DMSO form visible charge transfer complexes.Irradiation of these solutions with fluorescent room light leads to SRN1 displacement of chloride and the transient formation of C-azidodiazirines.Relative reactivity studies (using competition experiments) show that nitro-substituted arylchlorodiazirines are substantially more reactive than other arylchlorodiazirines.This is attributed to facile electron transfer in the propagation cycle, involving the nitro-substituted aromatic ring.C-Azidodiazirines can be isolatedin solution and spectroscopically characterized when the SRN1 reaction is initiated by addition of catalytic amounts of the sodium salt of 2-nitropropane.These azidodiazirines readily decompose at room temperature by first order processes to give molecular nitrogen and benzonitriles.Solvent and substituent effects on decomposition rates are minimal.Computational studies on potential intermediate carbenes in the decomposition of azidodiazirines have been carried out at the HF/6-31-G* level.Singlet α-azidocarbenes RCN3, where R = NH2, OH, F, vinyl, phenyl, and CH3, are energy minima at this computational level.Isodesmic calculations show that the azido group is comparable to OH in its carbene stabilizing ability.Subsequent loss of N2 from α-azidocarbenes, leading to nitriles, is a highly exothermic process (126 kcal when R = vinyl and 128 kcal when R = phenyl).
- Creary, Xavier
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p. 7700 - 7708
(2007/10/02)
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- Reaction of arylhalodiazirines with thiophenoxide: A redox process
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Phenylbromodiazirine reacts with thiophenoxide ion in methanol to give benzonitrile, benzamidine, ammonia, and diphenyl disulfide. The reaction is general for arylhalodiazirines, with electron-withdrawing groups on the aromatic ring exerting a small rate-enhancing effect. Three potential mechanisms are suggested for this redox process. These mechanisms include an N-sulfenylated diazirine, a diazirinyl radical, and a diazirinyl anion. Ring opening of these intermediates and subsequent transformations would lead to benzonitriles, benzamidine, and ammonia. A key intermediate in these transformations is PhSNH2, 32. This intermediate has been independently generated and found to rapidly convert to ammonia and diphenyl disulfide under the reaction conditions. Another proposed intermediate, N-(phenylthio)benzamidine, 38, has also been independently generated and subjected to the reaction conditions, where benzamidine and more diphenyl disulfide result. Theoretical calculations suggest the existence of isomeric diazirinyl anions. In addition to a diazirinyl ion with charge essentially on carbon, there is also an allylic-type ion with charge on the two nitrogen atoms. Single-electron reduction of a diazirinyl radical necessarily leads to a nitrogen-centered diazirinyl anion. Conversion of this anion to the carbon-centered diazirinyl anion is a forbidden process. These theoretical studies suggest that the diazirinyl anion may be a viable intermediate in solution.
- Creary, Xavier,Sky, Anthony F.,Phillips, Gillian,Alonso, David E.
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p. 7584 - 7592
(2007/10/02)
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