- 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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Read Online
- Cobalt-Catalyzed Aerobic Oxidative Cleavage of Alkyl Aldehydes: Synthesis of Ketones, Esters, Amides, and α-Ketoamides
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A widely applicable approach was developed to synthesize ketones, esters, amides via the oxidative C?C bond cleavage of readily available alkyl aldehydes. Green and abundant molecular oxygen (O2) was used as the oxidant, and base metals (cobalt and copper) were used as the catalysts. This strategy can be extended to the one-pot synthesis of ketones from primary alcohols and α-ketoamides from aldehydes.
- Li, Tingting,Hammond, Gerald B.,Xu, Bo
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p. 9737 - 9741
(2021/05/31)
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- One-Pot Chemoenzymatic Conversion of Alkynes to Chiral Amines
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A one-pot chemoenzymatic sequential cascade for the synthesis of chiral amines from alkynes was developed. In this integrated approach, just ppm amounts of gold catalysts enabled the conversion of alkynes to ketones (>99%) after which a transaminase was used to catalyze the production of biologically valuable chiral amines in a good yield (up to 99%) and enantiomeric excess (>99%). A preparative scale synthesis of (S)-methylbenzylamine and (S)-4-methoxy-methylbenzylamine from its alkyne form gave a yield of 59 and 92%, respectively, withee> 99%.
- Mathew, Sam,Renn, Dominik,Rueping, Magnus,Sagadevan, Arunachalam
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p. 12565 - 12569
(2021/10/21)
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- Towards a practical perfluoroalkylation of (hetero)arenes with perfluoroalkyl bromides using cobalt nanocatalysts
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A convenient methodology for perfluoroalkylation including trifluoromethylation of (hetero)arenes with perfluoroalkyl bromides was developed. Key for the success is the use of a specific cobalt-based nanocatalyst, which can be recycled at least up to 4 times. The scope of this first cobalt-catalyzed perfluoroalkylation is presented and detailed catalyst characterization (e.g. analytical STEM, XPS, and XRD) has been carried out.
- Bartling, Stephan,Beller, Matthias,Ellinger, Stefan,Kreyenschulte, Carsten Robert,Lund, Henrik,Neumann, Helfried,Taeschler, Christoph,Weniger, Florian,Zhang, Shaoke
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p. 1731 - 1738
(2020/04/09)
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- Efficient Palladium(0) supported on reduced graphene oxide for selective oxidation of olefins using graphene oxide as a ‘solid weak acid’
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Selective oxidation of olefin derivatives to ketones has made innovative development over palladium(0) supported on reduced graphene oxide. Compared to traditional Wacker oxidation, the novel method offers an economical and environment-friendly option by using graphene oxide (GO) as a ‘solid weak acid’ instead of classical homogeneous catalysts like H2SO4 and CF3COOH. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscopy images of Pd0/RGO showed that the nanoscaled Pd particles generated at the flake structure of reduced graphene oxide. Under optimized condition, up to 44 kinds of ketones with different structures can be prepared with excellent yields.
- Gao, Xi,Zhou, Jianhao,Peng, Xinhua
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- METHOD OF PRODUCING HIGH-PURITY TRIFLUOROMETHYL GROUP-SUBSTITUTED AROMATIC KETONE
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PROBLEM TO BE SOLVED: To provide a method of producing high-purity trifluoromethyl group-substituted aromatic ketone with a high yield. SOLUTION: The trifluoromethyl group-substituted aromatic ketone is improved in a distillation yield to attain high purity by the steps of: reacting a halogen-substituted benzotrifluoride compound with a magnesium metal to convert to a Grignard reagent; reacting the Grignard reagent with an acid anhydride; thereafter subjecting to hydrolysis treatment with an aqueous solution containing an acid to produce trifluoromethyl-substituted aromatic ketone; and thereafter subjecting to hydrolysis treatment under a basic condition using an aqueous solution containing a base to decompose and remove aliphatic fatty acid halogenated butyl ester, and aliphatic fatty acid trifluoromethyl phenyl ester which are hard to be distilled and removed from trifluoromethyl group-substituted aromatic ketone. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPO&INPIT
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Paragraph 0051; 0052; 0053; 0055; 0058; 0060
(2019/06/12)
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- Regio- and chemoselective rearrangement of terminal epoxides into methyl alkyl and aryl ketones
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The development of the highly active pincer-type rhodium catalyst 2 for the nucleophilic Meinwald rearrangement of functionalised terminal epoxides into methyl ketones under mild conditions is presented. An excellent regio- and chemoselectivity is obtained for the first time for aryl oxiranes.
- Tian, Yingying,Jürgens, Eva,Kunz, Doris
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p. 11340 - 11343
(2018/10/31)
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- Visible-Light photoredox decarboxylation of perfluoroarene iodine(III) Trifluoroacetates for C-H trifluoromethylation of (Hetero)arenes
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A scalable and operationally simple decarboxylative trifluoromethylation of (hetero)arenes with easily accessible C6F5I(OCOCF3)2 under photoredox catalysis has been developed. This method is tolerant of various (hetero)arenes and functional groups. Notably, C6F5I is recycled from the decarboxylation reaction and further used for the preparation of C6F5I(OCOCF3)2. The combination of photoredox catalysis and hypervalent iodine reagent provides a practical approach for the application of trifluoroacetic acid in trifluoromethylation reactions.
- Yang, Bin,Yu, Donghai,Xu, Xiu-Hua,Qing, Feng-Ling
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p. 2839 - 2843
(2018/04/14)
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- METHOD OF PRODUCING 2'-TRIFLUOROMETHYL GROUP-SUBSTITUTED AROMATIC KETONE
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A method produces a 2′-trifluoromethyl-substituted aromatic ketone and includes reacting a 2-halogen-substituted benzotrifluoride compound with magnesium metal to convert the compound to a Grignard reagent; and reacting the Grignard reagent with an acid anhydride; and then hydrolyzing the resultant to produce a 2′-trifluoromethyl-substituted aromatic ketone. The method of producing a 2′-trifluoromethyl-substituted aromatic ketone enables 2′-trifluoromethyl-substituted aromatic ketone to be produced without using expensive raw materials by generating a Grignard reagent as an intermediate and reacting this Grignard reagent with an acid anhydride in an efficient productivity. The 2′-trifluoromethyl-substituted aromatic ketone that is produced by the method of producing a 2′-trifluoromethyl-substituted aromatic ketone can be used as fine chemicals, raw materials for pharmaceuticals and agrochemicals, raw materials for resins and plastics, electronics and information related materials, optical materials, and the like.
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Paragraph 0042; 0043; 0044; 0045; 0051
(2017/04/18)
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- Stereoselective amination of racemic sec-alcohols through sequential application of laccases and transaminases
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A one-pot/two-step bienzymatic asymmetric amination of secondary alcohols is disclosed. The approach is based on a sequential strategy involving the use of a laccase/TEMPO catalytic system for the oxidation of alcohols into ketone intermediates, and their following transformation into optically enriched amines by using transaminases. Individual optimizations of the oxidation and biotransamination reactions have been carried out, studying later their applicability in a concurrent process. Therefore, 17 racemic (hetero) aromatic sec-alcohols with different substitutions in the aromatic ring have been converted into enantioenriched amines with good to excellent selectivities (90-99% ee) and conversion values (67-99%). The scalability of the process was also demonstrated when two different amine donors were used in the transamination step, such as isopropylamine and cis-2-buten-1,4-diamine. Satisfyingly, both sacrificial amine donors can shift the equilibrium toward the amine formation, leading to the corresponding isolated enantioenriched amines with good to excellent results.
- Martínez-Montero, Lía,Gotor, Vicente,Gotor-Fernández, Vicente,Lavandera, Iván
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supporting information
p. 474 - 480
(2017/06/23)
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- Preparation of Trifluoromethylphenyl Magnesium Halides in the Presence of LiCl and Synthesis of 2′-Trifluoromethyl-Aromatic Ketones
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The effect of LiCl-promoted insertion of magnesium turnings into halogenated-trifluoromethylbenzenes for Grignard reagent synthesis was investigated. In the presence of less than 1.0 equiv of LiCl, chloro(trifluoromethyl)benzene Grignard reagents were easily generated. The 2-trifluoromethylphenyl magnesium chloride Grignard reagent was obtained in high yield and 2′-trifluoromethyl-substituted aromatic ketone was synthesized through reaction of the obtained Grignard reagent with a carboxylic anhydride in an 83% yield.
- Nakatani, Jiro,Nozoe, Tatsuhiro
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p. 1633 - 1636
(2016/09/23)
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- Trifluoromethylation of haloarenes with a new trifluoro-methylating reagent Cu(O2CCF2SO2F)2
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A new trifluoromethylating reagent Cu(O2CCF2SO2F)2, which easily decomposes to generate active CuCF3 species in DMF at room temperature, has been conveniently prepared from inexpensive starting materials on a large scale. This new reagent can be applied to efficiently trifluoromethylate a variety of haloarenes under mild conditions, providing good-to-excellent yields of the desired products.
- Zhao, Gang,Wu, Hao,Xiao, Zhiwei,Chen, Qing-Yun,Liu, Chao
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p. 50250 - 50254
(2016/06/15)
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- Visible light mediated chemo-selective oxidation of benzylic alcohols
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A highly chemoselective visible light mediated strategy has been developed for oxidation of benzylic alcohols. The method circumvents the use of toxic metal catalysts, high energy light source, and operates at room temperature. Furthermore reaction is easily scalable to gram levels.
- Devari, Shekaraiah,Rizvi, Masood Ahmad,Shah, Bhahwal Ali
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supporting information
p. 3294 - 3297
(2016/07/11)
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- 4-CH3CONH-TEMPO/Peracetic Acid System for a Shortened Electron-Transfer-Cycle-Controlled Oxidation of Secondary Alcohols
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We have developed a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) derivative catalyzed oxidation of secondary alcohols with peracetic acid as the oxidant, which was generated from H2O2 and acetic acid catalyzed by strongly acidic resins. The oxidation of alcohols proceeded well through a shortened electron-transfer cycle under metal-free conditions, avoiding the use of any other electron-transfer mediators such as halides. In addition, we demonstrated that the present system exhibited excellent efficiency under mild conditions for the oxidation of aromatic, aliphatic, and allylic secondary alcohols. Shortcut to ketones: The 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-derivative-catalyzed oxidation of secondary alcohols employing peracetic acid generated from H2O2 and acetic acid with strongly acidic resins proceeds through a shortened electron-transfer cycle without halide additives. The system not only exhibits excellent efficiency at room temperature but also has a wide substrate scope.
- Zhang, Shufang,Miao, Chengxia,Xia, Chungu,Sun, Wei
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p. 1865 - 1870
(2015/06/23)
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- Stable but reactive perfluoroalkylzinc reagents: Application in ligand-free copper-catalyzed perfluoroalkylation of aryl iodides
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The aromatic perfluoroalkylation catalyzed by a copper(I) salt with bis(perfluoroalkyl)zinc reagents Zn(RF)2(DMPU)2, which were prepared and then isolated as a stable white powder from perfluoroalkyl iodide and diethylzinc, was accomplished to provide the perfluoroalkylated products in good-to-excellent yields. The advantages of this reliable and practical catalytic reaction are 1) airstable and easy-to-handle bis(perfluoroalkyl)zinc reagents can be utilized, 2) the reagent is reactive and hence the operation without activators and ligands is simple, and 3) not only trifluoromethylation but also perfluoroalkylation can be attained.
- Aikawa, Kohsuke,Nakamura, Yuzo,Yokota, Yuki,Toya, Wataru,Mikami, Koichi
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supporting information
p. 96 - 100
(2015/02/05)
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- Mechanism of trifluoromethylation of aryl halides with CuCF3and the ortho effect
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A combined experimental (radical clock, kinetic, Hammett) and computational (DFT, MM) study of the trifluoromethylation reaction of aryl halides with CuCF3 reveals a nonradical mechanism involving Ar-X oxidative addition to the Cu(I) center as the rate determining step. The reaction is second order, first order in each reactant with ΔG? ≈ 24 kcal/mol for PhI (computed ΔG? = 21.9 kcal/ mol). An abrupt change in the gradient on the Hammett plot of log(kR/ kH) versus σp for 11 p-RC6H4I substrates produces two correlations (ρ = +0.69 and +1.83), which is temptingly suggestive of two different reaction pathways. Only one mechanism is operational, however, as advocated by a single linear correlation with σp- (ρ = +0.91), analysis of the experimental ρ values, close similarity of the transition states varying in R and displaying clear signs of -M interactions, and excellent reproduction of the plot by DFT. The long-known yet previously uncomprehended ortho effect has been quantified, for the first time, using the reaction of CuCF3 with a series of o-RC6H4Br: R(kR/kH) = H (1) 2Me (850) 2 (4300) 2H (150 000). With minor contributions from electronic factors, the ortho effect is largely determined by (i) the stabilizing coordination of the o-substituent to Cu in the transition state with the Cu?O distance varying directly with the barrier and (ii) the steric bulk of the o-substituent that raises the ground state free energy of the haloarene (Go ortho - Go H or Go ortho - Go para) by inflicting molecular strain and consequently weakening the Ar-X bond.
- Konovalov, Andrey I.,Lishchynskyi, Anton,Grushin, Vladimir V.
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supporting information
p. 13410 - 13425
(2015/03/30)
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- Trifluoromethylation of arenediazonium salts with fluoroform-derived CuCF3 in aqueous media
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A new protocol has been developed for trifluoromethylation of arenediazonium salts with moisture-sensitive CuCF3 (from fluoroform) in aqueous media. The reaction is governed by a radical mechanism, tolerates a broad variety of functional groups, and is applicable to the synthesis of complex, polyfunctionalized molecules. This journal is the Partner Organisations 2014.
- Lishchynskyi, Anton,Berthon, Guillaume,Grushin, Vladimir V.
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supporting information
p. 10237 - 10240
(2014/08/18)
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- In Situ Preparation of Au-SH@SO3H-SBA-15 Catalyst with Enhanced Activity and Durability in Alkyne Hydration
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A facile approach was developed for synthesizing Au-SH@SO3H-SBA-15 with ordered mesoporous channels by reducing Au3+ to Au nanoparticles with SH-group bonded to silica support, followed by in situ coordinating Au with the unreacted SH-groups. This catalyst exhibited high efficiency in alkyne hydration owing to the high activity of uniformly dispersed ultrasmall Au nanoparticles, the diminished diffusion limit due to the mesoporous structure, and the promoting effect of acidic SO3H-groups resulting from oxidation of the SH-group by Au3+. Meanwhile, the catalyst could be easily recycled and displayed strong durability owing to the strong hydrothermal stability of mesoporous structure and the enhanced stability against Au leaching due to the Au-SH coordination bond.
- Zhu, Fengxia,Li, Hexing
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p. 1072 - 1076
(2016/02/18)
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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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- AgOTf catalyzed hydration of terminal alkynes
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The silver catalysis towards the hydration of terminal alkynes is explored using Silver(I) triflate (AgOTf). The reaction leads to the formation of only Markovnikov addition product with excellent yield. Copyright
- Das, Rima,Chakraborty, Debashis
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p. 722 - 726
(2013/02/22)
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- Water-medium and solvent-free organic reactions over a bifunctional catalyst with Au nanoparticles covalently bonded to HS/SO3H functionalized periodic mesoporous organosilica
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An operationally simple approach for the preparation of a new class of bifunctional Au nanoparticle-acid catalysts has been developed. In situ reduction of Au3+ with HS-functionalized periodic mesoporous organosilicas (PMOs) creates robust, fine Au nanoparticles and concomitantly produces a sulfonic acid moiety strongly bonded to PMOs. Characterizations of the nanostructures reveal that Au nanoparticles are formed with uniformed, narrow size distribution around 1-2 nm, which is very critical for essential catalytic activities. Moreover, the Au nanoparticles are mainly attached onto the pore surface rather than onto the outer surface with ordered mesoporous channels, allowing for maximal exposure to reaction substrates while minimizing Au nanoparticle leaching. Their higher SBET, VP, and DP than either the Au-HS-PMO(Et) or the Au/SO3H-PMO(Et) render the catalyst with comparably even higher catalytic efficiency than its homogeneous counterparts. Furthermore, the unique amphiphilic compartment of the Au-HS/SO3H-PMO(Et) nanostructures enables organic reactions to proceed efficiently in a pure aqueous solution without using any organic solvents or even without water. As demonstrated experimentally, remarkably, the unique bifunctional Au-HS/SO3H-PMO(Et) catalyst displays higher efficiencies in promoting water-medium alkyne hydration, intramolecular hydroamination, styrene oxidation, and three-component coupling reactions and even the solvent-free alkyne hydration process than its homogeneous catalysts. The robust catalyst can be easily recycled and used repetitively at least 10 times without loss of catalytic efficiency. These features render the catalyst particularly attractive in the practice of organic synthesis in an environmentally friendly manner.
- Zhu, Feng-Xia,Wang, Wei,Li, He-Xing
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experimental part
p. 11632 - 11640
(2011/09/16)
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- Periodic mesoporous organogold(I)silica as an active and reusable catalyst for alkyne hydration
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A periodic mesoporous organogold(I)silica catalyst was synthesized by surfactant-directed co-condensation of Au[PPh2(CH2) 2Si(OCH2CH3)3]2Cl and (CH3CH2O)3SiPhSi(OCH2CH 3)3. The as-prepared Au-PPh2-PMO(Ph) contained ordered mesopore channels with both phenyl (Ph) group and Au(I) organometal homogeneously embedded in silica walls. Such catalyst exhibited higher activity than free Au(PPh3)Cl in hydration reactions of various terminal alkynes. This could be mainly attributed to the high surface area, the ordered mesoporous channels and the enhanced surface hydrophobility, which facilitated the diffusion and adsorption of reactants. Meanwhile, the unique coordination model between Au(I) and (PPh2) was also favorable for the alkyne hydration. Besides the high activity, the catalyst could be easily recycled and used repetitively owing to the high hydrothermal stability and the stabilized Au(I) active sites against leaching.
- Zhu, Fengxia,Zhang, Fang,Yang, Xushi,Huang, Jianlin,Li, Hexing
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scheme or table
p. 1 - 7
(2011/06/16)
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- METHOD FOR PURIFYING OPTICALLY ACTIVE 1-(2-TRIFLUOROMETHYLPHENYL)ETHANOL
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There is disclosed a purification method of an optically active 1-(2-trifluoromethylphenyl)ethanol represented by the formula [1], which includes recrystallizing the optically active 1-(2-trifluoromethylphenyl)ethanol from an aliphatic hydrocarbon solvent where * denotes an asymmetric carbon. This method makes it possible to improve the optical purity of the ethanol significantly.
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Page/Page column 5-6
(2010/11/19)
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- Low-valent niobium-mediated synthesis of indenes: Intramolecular coupling reaction of CF3 group with alkene C-H bond
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CF3 group of o-alkenyl-α,α,α-trifluorotoluenes underwent intramolecular coupling reaction with the alkene C-H bond under NbCl5/LiAlH4 system. Substituted indenes were obtained in good yields. Copyright
- Fuchibe, Kohei,Mitomi, Ken,Akiyama, Takahiko
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- Electrosynthesis of (trifluoromethyl)copper complexes from bromotrifluoromethane: reactivities with various organic halides
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The synthesis of (trifluoromethyl)copper complexes is achieved easily by electroreduction of bromotrifluoromethane in N,N-dimethylformamide, in the presence of a sacrificial copper anode and various potential ligands.Three (trifluoromethyl)copper species are considered; two copper(II) and one copper(I).The mechanism of formation of the (trifluoromethyl)copper species is discussed and a study of their reactivities towards various organic halides is reported. Keywords: Copper; Trifluoromethyl derivatives; Electroreduction; Mechanism; Bromotrifluoromethane; (Trifluoromethyl)copper complexes
- Paratian, J. M.,Labbe, E.,Sibille, S.,Perichon, J.
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p. 137 - 144
(2007/10/02)
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- THE TRIFLUOROMETHYLATION OF CHLOROAROMATICS USING THE COPPER-CF2Br2-DIALKYLAMIDE REACTION SYSTEM
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The in situ generation of CuCF3 from the reaction of copper, dibromodifluoromethane and either N,N-dimethylformamide or N,N-dimethylacetamide (Burton's reagent) has been used for the direct substitution of chlorine by CF3 in a number of aromatic substrates.Particular attention has been paid to the effects of ring substituents on the efficiency of reaction.
- Clark, James H.,Denness, James E.,McClinton, Martin A.,Wynd, Andrew J.
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p. 411 - 426
(2007/10/02)
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- Deactivation of Triplet Phenyl Alkyl Ketones by Conjugatively Electron-Withdrawing Substituents
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Para-cyano, -carbomethoxy, and -acyl substituents decrease the triplet reactivity of valerophenone (γ-hydrogen abstraction), whereas comparable meta substituents increase reactivity.Spectroscopic results are presented which indicate that para-(-R) substituents lower ?,?* triplet energies so much more than n,?* energies that the lowest triplets become largely ?,?* in nature.Meta-(-R) substituents do not stabilize ?,?* triplets enough to invert triplet levels.Both substitution patterns support a largely 1,4-biradical structure for the lowest ?,?* triplet of acylbenzenes.Ortho substituents show the usual steric anomalies: ortho cyano enhances valerophenone triplet reactivity by stabilizing the n,?* triplet; ortho carbomethoxy deactivates valerophenone by stabilizing the ?,?* triplet but not the n,?.*
- Wagner, Peter J.,Siebert, Elizabeth J.
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p. 7329 - 7335
(2007/10/02)
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