- Synthesis of 2-trifluoromethyl-2-hydroxy-2H-chromenes via cyclization of (Z)-trifluoromethyl alkenyl triflates and salicylaldehydes
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A new and efficient method for the synthesis of 2-trifluoromethyl-2-hydroxy-2H-chromenes was developed via intermolecular cyclization of (Z)-trifluoromethyl alkenyl triflates and salicylaldehydes. A series of 2-trifluoromethyl-2-hydroxy-2H-chromenes with aryl or alkyl groups at 3-position have been obtained in moderate to excellent yields. And a key intermediate, 3-phenyl-4-(pyrrolidin-1-yl)-2-(trifluoromethyl)chroman-2-ol (6), was isolated and fully characterized, which suggests that the elimination of pyrrolidine from this intermediate is the last step during the formation of 2-trifluoromethyl-2-hydroxy-2H-chromenes.
- Li, Dong,Zhou, Yuhan,Zhao, Yilong,Zhang, Chunxia,Li, Jianzhe,Zhao, Jinfeng,Qu, Jingping
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Read Online
- Solvated Nickel Complexes as Stoichiometric and Catalytic Perfluoroalkylation Agents**
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The acetonitrile-solvated [(MeCN)Ni(C2F5)3]? was prepared in order to compare and contrast its reactivity with the known [(MeCN)Ni(CF3)3]? towards organic electrophiles. Both [(MeCN)Ni(CF3)3]? and [(MeCN)Ni(C2F5)3]? successfully react with aryl iodonium and diazonium salts as well as alkynyl iodonium salts to give fluoroalkylated organic products. Electrochemical analysis of [(MeCN)NiII(C2F5)3]? suggests that, upon electro-oxidation to [(MeCN)nNiIII(C2F5)3], reductive homolysis of a perfluoroethyl radical occurs, with the concomitant formation of [(MeCN)2NiII(C2F5)2]. Catalytic C?H trifluoromethylations of electron-rich arenes were successfully achieved using either [(MeCN)Ni(CF3)3]? or the related [Ni(CF3)4]2?. Stoichiometric reactions of the solvated nickel complexes reveal that “ligandless” nickel is exceptionally capable of serving as reservoir of CF3 groups under catalytically relevant conditions.
- Shreiber, Scott T.,Vicic, David A.
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supporting information
p. 18162 - 18167
(2021/07/14)
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- Synthesis of fluoroalkylated alkynes: Via visible-light photocatalysis
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Fluoroalkylated alkynes, which are versatile building blocks for the synthesis of various biologically active organofluorine compounds, were synthesized from easily available alkynyl halides and fluoroalkyl halides by visible-light photocatalysis. Addition of fluoroalkyl radicals to alkynes and subsequent dehalogenation selectively yielded fluoroalkylated alkynes.
- Iqbal, Naila,Iqbal, Naeem,Han, Sung Su,Cho, Eun Jin
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p. 1758 - 1762
(2019/02/20)
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- Regioselective Gold-Catalyzed Hydration of CF3- and SF5-alkynes
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The regioselective gold-catalyzed hydration of CF3- and SF5-alkynes is described. The corresponding trifluoromethylated and pentasulfanylated ketones are obtained in up to 91% yield as single regioisomers showcasing the use of CF3 and SF5 as highly efficient directing groups in this reaction. Notably, this transformation represents the first use of CF3- and SF5-alkynes in gold catalysis.
- Cloutier, Mélissa,Roudias, Majdouline,Paquin, Jean-Fran?ois
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supporting information
p. 3866 - 3870
(2019/05/24)
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- Catalyst-free room-temperature iClick reaction of molybdenum(II) and tungsten(II) azide complexes with electron-poor alkynes: Structural preferences and kinetic studies
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Two isostructural and isoelectronic group VI azide complexes of the general formula [M(η3-allyl)(N3)(bpy)(CO)2] with M = Mo, W and bpy = 2,2′-bipyridine were prepared and fully characterized, including X-ray structure analysis. Both reacted smoothly with electron-poor alkynes such as dimethyl acetylenedicarboxylate (DMAD) and 4,4,4-trifluoro-2-butynoic acid ethyl ester in a catalyst-free room-temperature iClick [3 + 2] cycloaddition reaction. Reaction with phenyl(trifluoromethyl)acetylene, on the other hand, did not lead to any product formation. X-ray structures of the four triazolate complexes isolated showed the monodentate ligand to be N2-coordinated in all cases, which requires a 1,2-shift of the nitrogen from the terminal azide to the triazolate cycloaddition product. On the other hand, a 19F NMR spectroscopic study of the reaction of the fluorinated alkyne with the tungsten azide complex at 27 °C allowed detection of the N1-coordinated intermediate. With this method, the second-order rate constant was determined as (7.3 ± 0.1) × 10-2 M-1 s-1, which compares favorably with that of first-generation compounds such as difluorocyclooctyne (DIFO) used in the strain-promoted azide-alkyne cycloaddition (SPAAC). In contrast, the reaction of the molybdenum analogue was too fast to be studied with NMR methods. Alternatively, solution IR studies revealed pseudo-first order rate constants of 0.4 to 6.5 × 10-3 s-1, which increased in the order of Mo > W and F3C-CC-COOEt > DMAD.
- Schmid, Paul,Maier, Matthias,Pfeiffer, Hendrik,Belz, Anja,Henry, Lucas,Friedrich, Alexandra,Sch?nfeld, Fabian,Edkins, Katharina,Schatzschneider, Ulrich
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supporting information
p. 13386 - 13396
(2017/10/17)
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- Copper(I)-Catalyzed Interrupted Click Reaction with TMSCF3: Synthesis of 5-Trifluoromethyl 1,2,3-Triazoles
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We herein describe a Cu(I)-catalyzed interrupted click reaction, using (trifluoromethyl)trimethylsilane (TMSCF3) as a nucleophilic CF3 source, to synthesize 5-trifluoromethyl 1,2,3-triazoles in one step from readily available terminal alkynes and azides. The reaction shows complete regioselectivity, broad substrate scope, and good functional group tolerability. The application of the reaction has been demonstrated in the synthesis of a trifluoromethylated analog of antiepileptic drug rufinamide.
- Cheung, Kelvin Pak Shing,Tsui, Gavin Chit
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supporting information
p. 2881 - 2884
(2017/06/07)
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- Cu(I)/Ag(I)-mediated decarboxylative trifluoromethylation of arylpropiolic acids with Me3SiCF3at room temperature
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A novel Cu(I)/Ag(I)-mediated decarboxylative trifluoromethylation of arylpropiolic acids with Me3SiCF3has been developed for the construction of Csp-CF3bond under mild conditions. This method proceeds smoothly at room temperature and shows a widely functional compatibility, providing a series of corresponding trifluoromethylated acetylenyl-containing aromatics in good yields.
- Yang, Lingling,Jiang, Linlin,Li, Yaming,Fu, Xinmei,Zhang, Rong,Jin, Kun,Duan, Chunying
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supporting information
p. 3858 - 3862
(2016/07/06)
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- Fluoroform-Derived CuCF3 for Trifluoromethylation of Terminal and TMS-Protected Alkynes
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An efficient trifluoromethylation reaction of alkynes using a fluoroform-derived CuCF3 reagent is described. The CF3 source is the inexpensive industrial waste fluoroform (CF3H). The air-stable CuCF3 reagent can be prepared in large quantities and is convenient to use. Synthetically useful trifluoromethylated alkynes containing a wide range of functional groups were successfully synthesized under mild conditions. Both terminal and TMS-protected alkynes gave the products in one step. The beneficial effect of a diamine ligand tetramethylethylenediamine (TMEDA) with the fluoroform-derived CuCF3 reagent was also demonstrated.
- He, Lisi,Tsui, Gavin Chit
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supporting information
p. 2800 - 2803
(2016/07/06)
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- Cyclic-Protected Hexafluoroacetone as an Air-Stable Liquid Reagent for Trifluoromethylations
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An air-stable liquid trifluoromethylating reagent is readily synthesized from gaseous hexafluoroacetone and 2-methylproline on a gram scale. The reaction of the trifluoromethylating reagent with tert-butoxy cuprate K[Cu(OtBu)2] leads to the CuCF3in high yield. This species is directly formed from the tetrahedral cuprate intermediate through intramolecular migration of the trifluoromethyl group to copper. The CuCF3reagent prepared in situ by our method can be used for the trifluoromethylation of aryl iodides, arylboronic acids, and terminal alkynes in good to excellent yields, even on a gram scale. Furthermore, the CuC2F5reagent can be prepared in the same way, and this can be used in the pentafluoroethylation of arylboronic acids or aryl bromides in good to excellent yields.
- Negishi, Kazuyuki,Aikawa, Kohsuke,Mikami, Koichi
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p. 4099 - 4104
(2016/08/24)
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- Gold(I)-catalysed tandem cyclization of propargyl acetals and alkynes
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To expand the understanding of the chemistry of propargyl acetals, their gold(I) catalysed cycloaddition reactions with alkynes have been investigated. We hereby report a novel tandem reaction that allows the construction of a new type of polysubstituted
- Siah, Huey-San Melanie,Hogsnes, Morten Christian,Iqbal, Naseem,Fiksdahl, Anne
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p. 1058 - 1068
(2016/07/06)
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- Copper-mediated trifluoromethylation using phenyl trifluoromethyl sulfoxide
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A new method for the generation of trifluoromethylcopper ( CuCF3 ) species from readily available phenyl trifluoromethyl sulfoxide has been developed. The CuCF3 reagent can be applied in efficient trifluoromethylations of aryl iodides and activated aryl bromides in the absence of additional ligands. Furthermore, the CuCF3 species can also undergo oxidative cross-coupling with terminal alkynes and arylboronic acids.
- Li, Xinjin,Zhao, Jingwei,Zhang, Liang,Hu, Mingyou,Wang, Limin,Hu, Jinbo
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supporting information
p. 298 - 301
(2015/03/04)
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- Practical methods for the synthesis of trifluoromethylated alkynes: Oxidative trifluoromethylation of copper acetylides and alkynes
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Two practical and complementary methods are reported for the synthesis of trifluoromethylated alkynes. The first one, a mix-and-stir process, is based on the oxidative trifluoromethylation of readily available and bench-stable copper acetylides while the second one, which displays a broad substrate scope and has several advantages over existing procedures, is based on the oxidative copper-catalyzed direct trifluoromethylation of terminal alkynes. Both reactions provide user-friendly processes for the synthesis of trifluoromethylated acetylenes which can be easily obtained from readily available starting materials.
- Tresse, Cedric,Guissart, Celine,Schweizer, Stephane,Bouhoute, Yassine,Chany, Anne-Caroline,Goddard, Mary-Lorene,Blanchard, Nicolas,Evano, Gwilherm
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supporting information
p. 2051 - 2060
(2014/07/07)
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- Controlled trifluoromethylation reactions of alkynes through visible-light photoredox catalysis
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The control of a reaction that can form multiple products is a highly attractive and challenging concept in synthetic chemistry. A set of valuable CF3-containing molecules, namely trifluoromethylated alkenyl iodides, alkenes, and alkynes, were selectively generated from alkynes and CF 3I by environmentally benign and efficient visible-light photoredox catalysis. Subtle differences in the combination of catalyst, base, and solvent enabled the control of reactivity and selectivity for the reaction between an alkyne and CF3I. Variety through selectivity: Highly valuable trifluoromethylated alkenyl iodides, alkenes, and alkynes were selectively generated from alkynes and CF3I by environmentally benign and efficient visible-light photoredox catalysis. A suitable choice of catalyst, base, and solvent was crucial for the reactivity and selectivity of these processes.
- Iqbal, Naeem,Jung, Jaehun,Park, Sehyun,Cho, Eun Jin
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supporting information
p. 539 - 542
(2014/01/23)
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- Copper-mediated trifluoromethylation of potassium alkynyltrifluoroborates with Langlois' reagent Dedicated to Professor Pierre Vogel on the occasion of his 70th birthday
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Synthesis of trifluoromethylated acetylenes by copper-mediated trifluoromethylation of potassium alkynyltrifluoroborates with CF3 radicals generated from NaSO2CF3 and tert-butyl hydroperoxide (TBHP) is communicated. The trifluoromethylated acetylenes were obtained in good to moderate yields. The presented method tolerates a wide range of aromatic, heteroaromatic, and aliphatic potassium alkynyltrifluoroborates.
- Dubbaka, Srinivas Reddy,Nizalapur, Shashidhar,Atthunuri, Azmi Reddy,Salla, Manohar,Mathew, Thresen
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p. 2118 - 2121
(2014/03/21)
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- Direct synthesis of a trifluoromethyl copper reagent from trifluoromethyl ketones: Application to trifluoromethylation
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Being economic with fluorine: The direct synthesis of CuCF3 from a cuprate reagent and trifluoromethyl ketones, as one of the most economical and efficient trifluoromethyl sources, was accomplished. The advantages of this method are all of reagents employed are low-cost, operation is simple, and the yield of CuCF3 is virtually quantitative (see scheme). Furthermore, three types of trifluoromethylations smoothly proceeded to provide the corresponding products in high yields. Copyright
- Serizawa, Hiroki,Aikawa, Kohsuke,Mikami, Koichi
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supporting information
p. 17692 - 17697
(2014/01/17)
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- Copper-mediated radical trifluoromethylation of unsaturated potassium organotrifluoroborates
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Copper-mediated trifluoromethylation of unsaturated organotrifluoroborates with the Langlois reagent (NaSO2CF3) and TBHP allows the introduction of trifluoromethyl groups into a variety of organic substructures. The reactions are easy to set up, the conditions are mild and general, and the process provides access to trifluoromethylated alkynes, alkenes, arenes, and heteroarenes in fair to good yields.
- Presset, Marc,Oehlrich, Daniel,Rombouts, Frederik,Molander, Gary A.
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p. 12837 - 12843
(2014/01/17)
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- Copper-mediated trifluoromethylation of terminal alkynes by S-(trifluoromethyl)diarylsulfonium salt
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The copper-mediated trifluoromethylation of terminal alkynes with S-(trifluoromethyl)diarylsulfonium salt has been carefully investigated. The reactions proceeded smoothly to afford trifluoromethylated acetylenes in moderate to good yields. This approach is a convenient method to synthesize a variety of functional trifluoromethylated acetylenes. A convenient method for the trifluoromethylation of a variety of terminal alkynes with S-(trifluoromethyl)diarylsulfoniumtriflate in the presence of copper iodide was described. The reactions proceeded smoothly under mild condition to give the desired product in moderate to good yields. Copyright
- Wang, Xiaoping,Lin, Jinhong,Zhang, Chengpan,Xiao, Jichang,Zheng, Xing
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p. 915 - 920
(2013/08/23)
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- Synthesis of trifluoromethylated acetylenes via copper-catalyzed trifluoromethylation of alkynyltrifluoroborates
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A new method for the synthesis of trifluoromethylated acetylenes is developed which involves the copper-catalyzed trifluoromethylation of alkynyltrifluoroborates with an electrophilic trifluoromethylating reagent. This method offers significant advantages such as efficiency and mild and base-free reaction conditions. A plausible mechanism is proposed.
- Zheng, Huidong,Huang, Yuanyuan,Wang, Zhiwei,Li, Huaifeng,Huang, Kuo-Wei,Yuan, Yaofeng,Weng, Zhiqiang
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supporting information
p. 6646 - 6649
(2013/01/15)
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- Metal-free oxidative trifluoromethylthiolation of terminal alkynes with CF3SiMe3 and elemental sulfur
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A metal-free oxidative trifluoromethyl-thiolation of terminal alkynes using readily available CF3SiMe3 and elemental sulfur at room temperature has been developed. This reaction provides an efficient and convenient method for the preparation of alkynyl trifluoromethyl sulfides bearing a wide range of functional groups. Preliminary investigation revealed that elemental sulfur instead of air acted as the oxidant.
- Chen, Chao,Chu, Lingling,Qing, Feng-Ling
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experimental part
p. 12454 - 12457
(2012/09/05)
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- Mild copper-catalyzed trifluoromethylation of terminal alkynes using an electrophilic trifluoromethylating reagent
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A catalytic process for trifluoromethylation of terminal alkynes with Togni's reagent has been developed, affording trifluoromethylated acetylenes in good to excellent yields. The reaction is conducted at room temperature and exhibits tolerance to a range
- Weng, Zhiqiang,Li, Huaifeng,He, Weiming,Yao, Liang-Feng,Tan, Jianwei,Chen, Jinfa,Yuan, Yaofeng,Huang, Kuo-Wei
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scheme or table
p. 2527 - 2531
(2012/04/23)
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- Copper-catalyzed oxidative trifluoromethylation of terminal alkynes and aryl boronic acids using (trifluoromethyl)trimethylsilane
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Trifluoromethylated acetylenes and arenes are widely applicable in the synthesis of pharmaceuticals and agrochemicals. In 2010, our group has reported the copper-mediated oxidative trifluomethylation of terminal alkynes and aryl boronic acids. This method allows a wide range of functional group tolerant trifluoromethylated acetylenes and arenes to be easily prepared. After the preliminary mechanistic studies of the oxidative trifluoromethylation of terminal alkyne, an efficient copper-catalyzed oxidative trifluoromethylation of terminal alkynes and aryl boronic acids has been developed. The catalytic protocol is successfully achieved by adding both the substrate and a portion of CF3TMS slowly using a syringe pump to the reaction mixture.
- Jiang, Xueliang,Chu, Lingling,Qing, Feng-Ling
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experimental part
p. 1251 - 1257
(2012/03/22)
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- Sulfoximines as a versatile scaffold for electrophilic fluoroalkylating reagents
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New electrophilic fluoroalkylating agents based on the sulfoximine skeleton as a common platform are described. We demonstrate the importance of the activating group, attached to the nitrogen, and its specificity for the fluorinated group to be delivered.
- Urban, Celine,Cadoret, Frederic,Blazejewski, Jean-Claude,Magnier, Emmanuel
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experimental part
p. 4862 - 4867
(2011/10/09)
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- Copper-mediated aerobic oxidative trifluoromethylation of terminal alkynes with Me3SiCF3
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An efficient copper-mediated trifluoromethylation of terminal alkynes with nucleophilic trifluoromethylating reagent (Me3SiCF3) was developed. Both aromatic alkynes and aliphatic alkynes were effective, and a variety of functionalities such as amino, -OMe, -CO2Et, -Br, and -NO2 were tolerated under the reaction conditions. This reaction provides a general, straightforward, and practically useful method to prepare trifluoromethylated acetylenes.
- Chu, Lingling,Qing, Feng-Ling
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scheme or table
p. 7262 - 7263
(2010/08/07)
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- Reaction of C-silylated α-diazophosphines as nucleophiles toward carbonyl compounds: A mechanistic study and application to the synthesis of alkynes and α-hydroxyphosphonamides
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Diversely substituted α-hydroxyphosphonamides and alkynes have been efficiently synthesized through the reaction of C-silylated α- diazophosphines with different types of aldehydes (2 equiv) in a neutral medium under very mild conditions. The reaction with some chiral aldehydes is highly diastereoselective leading to phosphonamides as single diastereomers. The novel reaction is influenced by electronic and steric effects being precluded for aromatic aldehydes containing electron-releasing substituents on the phenyl ring and for bulky aliphatic aldehydes. The mechanistic studies of these processes, which are highly exothermic, provide evidence for a nucleophilic attack of the diazophosphine to the aldehyde leading to a betaine that rapidly rearranges to a diazomethylenephosphorane, which has been detected or captured in some instances. The diazomethylenephosphorane reacts with a second molecule of aldehyde according to a Wittig-type condensation, and the rate-determining step of the whole process is believed to be the decomposition of the resultant oxaphosphetane to afford the hydroxyphosphonamide and a diazocumulene. Finally, this intermediate loses molecular nitrogen giving a transient carbene that rapidly evolves toward the alkyne.
- Illa, Ona,Bagan, Xavier,Cazorla, Anna M.,Lyon, Celine,Baceiredo, Antoine,Branchadell, Vicenc,Ortuno, Rosa M.
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p. 5320 - 5327
(2007/10/03)
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- Photochemical generation of highly destabilized vinyl cations: The effects of α- and β-trifluoromethyl versus α- and β-methyl substituents
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(Chemical Equation Presented). The photochemical reactions in methanol of the vinylic halides 1-4, halostyrenes with a methyl or a trifluoromethyl substituent at the α- or β-position, have been investigated quantitatively. Next to E/Z isomerization, the reactions are formation of vinyl radicals, leading to reductive dehalogenation products, and formation of vinyl cations, leading to elimination, nucleophilic substitution, and rearrangement products. The vinyl cations are parts of tight ion pairs with halide as the counterion. The elimination products are the result of β-proton loss from the primarily generated α-CH3 and α-CF3 vinyl cations, or from the α-CH3 vinyl cation formed from the β-CH3 vinyl cation via a 1,2-phenyl shift. The β-CF 3 vinyl cation reacts with methanol yielding nucleophilic substitution products, no migration of the phenyl ring producing the α-CF3 vinyl cation occurs. The α-CF3 vinyl cation, which is the most destabilized vinyl cation generated thus far, gives a 1,2-fluorine shift in competition with proton loss. The experimentally derived order of stabilization of the vinyl cations photogenerated in this study, α-CF3 3 3 3, is corroborated by quantum chemical calculations, provided the effect of solvent is taken into account.
- Van Alem, Kaj,Belder, Geerte,Lodder, Gerrit,Zuilhof, Han
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p. 179 - 190
(2007/10/03)
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- Reaction of benzohydroximinoyl chlorides and β -(Trifluoromethyl)-acetylenic esters: Synthesis of regioisomeric (Trifluoromethyl)-isoxazolecarboxylate esters and oxime addition products
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The triethylamine induced reaction of benzohydroximinoyl chlorides, precursors of nitrile oxides, with β-trifluoromethylacetylenic esters gives rise to three products: 5-trifluoromethyl-4-isoxozolecarboxylate esters, regioisomeric 4-trifluoromethyl-5-isox
- Hamper, Bruce C.,Leschinsky, Kindrick L.
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p. 575 - 583
(2007/10/03)
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- Facile syntheses of various per- or polyfluoroalkylated internal acetylene derivatives
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Treatment of per- or polyfluoroalkylated vinyl iodides 5 with 2equiv. of n-BuLi in THF produced the corresponding lithium acetylides in situ, which were transformed into zinc acetylides by the addition of ZnCl2· TMEDA complex into the reaction mixture. The in situ generated zinc acetylides were exposed to the cross-coupling conditions such as ArI/cat. Pd(PPh 3)4, reflux, 6-12 h, giving rise to the desired per- or polyfluoroalkylated acetylenes in high yields. In the case of trifluoromethylated acetylene, commercially available 2-bromo-3,3,3-trifluoropropene 6 could also be used instead of 5 as the starting material. In the acetylenes having a fluoroalkyl group and an aliphatic side chain, vinyl iodides 7, prepared by radical addition of perfluoroalkyl iodide to terminal acetylenes, were treated with t-BuOK at room temperature or at the reflux temperature of benzene, affording the desired compounds in good yields.
- Konno, Tsutomu,Chae, Jungha,Kanda, Masashi,Nagai, Go,Tamura, Kazushige,Ishihara, Takashi,Yamanaka, Hiroki
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p. 7571 - 7580
(2007/10/03)
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- Advances in trifluoromethylating phosphorus compounds
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The System CF3IMe3P is re-investigated and Me2PCF3, Me4P+I-, (CF3)2PMe3, Me3PI2, [Me3(CF3)P]+I- are found as products. Using CF3Br/P(NEt2)3 the phosphines R12PCF3 and R1P(CF3)2 (e.g. R1 = Me, iPr, NEt2) can be obtained which are precursors either for phosphoranes (e.g. 1,2λ5σ5-oxaphosphetanes) or phosphonium salts (e.g. [R12(Me)PCF3]+X- or [R1(Me)P(CF3)2X-]. The latter are deprotonated to furnish methylene phosphoranes R12(CH2=)PCF3 or R1(CH2=)P(CF3)2, reactive synthons. From CF3Br/ P(NEt2)3/P(OPh)3 the phosphine P(CF3)3 is available, which turned out to be a potent electrophile. Amido phospites ROP(NEt2)2 and halides R2X (R2= CCl2CF3, X= Cl; R2= CF=CFCF3, X= F; R2= C6F5, X= Br, I; R2= C(CF3)3, X= Br; R2= SCF3, X= CF3) undergo an ARBUZOV reaction.
- Kolomeitsev, Alexander,Goerg, Michaela,Dieckbreder, Uwe,Lork, Enno,Roeschenthaler, Gerd-Volker
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p. 597 - 600
(2007/10/03)
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- Synthesis of trifluoromethylalkenes and alkynes. Trifluoromethyl captodative olefins
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β-ethylthio-β-trifluoromethylketones 3 and aldehydes 4 are easily prepared from β-chloroolefines 5 and 6. Trifluoromethylalkynes 7 and captodative alkenes 8 are obtained by reaction of KOH on aldehydes 6 or 4.
- Laurent,Le Drean,Selmi
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p. 3071 - 3074
(2007/10/02)
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- Power-variable trifluoromethylating agents, (trifluoromethyl)dibenzothio- and -selenophenium salt system
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(Trifluoromethyl)dibenzothio- and -selenophenium triflates and their nitro derivatives differing in trifluoromethylating power were developed as a new system of electrophilic trifluoromethylating agents.
- Umemoto,Ishihara
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p. 3579 - 3582
(2007/10/02)
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- ARYL TRIFLUOROMETHYL ACETYLENES
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A wide variety of aryl trifluoromethyl acetylenes may be prepared in high yield by allowing CF3CCZnCl, generated from CF3CCH, to react with aryl iodides and a catalytic amount of tetrakis(triphenylphosphine)palladium
- Bunch, J. E.,Bumgardner, C. L.
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p. 313 - 318
(2007/10/02)
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- Studies on Organic Fluorine Compounds. XLII. Synthesis and Reactions of Phenyltrifluoromethylacetylenes
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Phenyltrifluoromethylacetylene (4a) was synthesized by the pyrolysis of triphenylphosphonium α-(trifluoroacetyl)benzylide (3a), which was easily derived from benzyl halide (1a).This method can be used for the synthesis of 4-substituted-phenyltrifluoromethylacetylenes (4).The 1,3-dipolar reaction of 4 with diazomethane and phenyl azide proceeds readily to give trifluoromethylated pyrazoles and triazoles.Keywords - trifluoromethyl; acetylene; 1,3-dipolar reaction; intramolecular Wittig reaction; trifluoroacetylphosphonium ylide; pyrazole; diazomethane; phenyl azide
- Kobayashi, Yoshiro,Yamashita, Toshinori,Takahashi, Katsuhiro,Kuroda, Hisashi,Kumadaki, Itsumaro
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p. 4402 - 4409
(2007/10/02)
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- Preparation of α-Trifluoromethyl Esters from Malonic Esters
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A wide variety of α-trifluoromethyl esters can be synthesized in two steps starting from monosubstituted malonic esters and dibromodifluoromethane.The product of the first step, a bromodifluoromethyl-substituted malonate, is transformed to the desired fin
- Everett, Stephen T.,Purrington, Suzanne T.,Bumgardner, Carl L.
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p. 3702 - 3706
(2007/10/02)
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- SYNTHESIS OF ARYLTRIFLUOROMETHYLACETYLENES
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Aryltrifluoromethylacetylenes were synthesized by an intramolecular Wittig reaction of trifluoroacetylarylidenephosphoranes, which were synthesized from arylmethyl halides.
- Kobayashi, Yoshiro,Yamashita, Toshinori,Takahashi, Katsuhiro,Kuroda, Hisashi,Kumadaki, Itsumaro
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p. 343 - 344
(2007/10/02)
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