- Copper-Catalyzed and Proton-Directed Selective Hydroxymethylation of Alkynes with CO2
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An intriguing strategy for copper-catalyzed hydroxymethylation of alkynes with CO2 and hydrosilane was developed. Switched on/off a proton source, for example, tBuOH, direct hydroxymethylation and reductive hydroxymethylation could be triggered selectively, delivering a series of allylic alcohols and homobenzylic alcohols, respectively, with high levels of Z/E, regio- and enantioselectivity. Such a selective synthesis is attributed to the differences in response of vinylcopper intermediate to proton and CO2. The protonation of vinylcopper species is demonstrated to be prior to hydroxymethylation, thus allowing a diversion from direct alkyne hydroxymethylation to reductive hydroxymethylation in the presence of suitable proton.
- Wang, Mei-Yan,Jin, Xin,Wang, Xiaofei,Xia, Shumei,Wang, Yue,Huang, Shouying,Li, Ying,He, Liang-Nian,Ma, Xinbin
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supporting information
p. 3984 - 3988
(2020/12/25)
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- Mild and efficient rhodium-catalyzed deoxygenation of ketones to alkanes
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A new and simple method for the deoxygenation of ketones to alkanes is presented. Most substrates are reduced under mild conditions by triethylsilane in the presence of catalytic amounts of [Rh(μ-Cl)(CO)2]2. This system selectively provides the methylene hydrocarbons in good to excellent yields starting from acetophenones and diaryl ketones. A rapid examination of the reaction pathway suggests that the ketone is first converted into an alcohol, which then undergoes hydrogenolysis to give the alkane.
- Argouarch, Gilles
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supporting information
p. 11041 - 11044
(2019/07/31)
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- Pd-PEPPSI complexes based on 1,2,4-triazol-3-ylidene ligands as efficient catalysts in the Suzuki—Miyaura reaction
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The palladium complexes of the Pd-PEPPSI type with N-heterocyclic carbenes of the 1,2,4-triazole series were synthesized in 76—99% yields by the reactions of PdCl2 with 1,4-di- alkyl-1,2,4-triazolium salts in pyridine in the presence of KBr or KI as sources of halide ions and tetrabutylammonium salts as phase-transfer catalysts. The obtained complexes can be used as efficient catalysts for the Suzuki—Miyaura cross-coupling and are not inferior to the commercially available Pd-PEPPSI catalysts in activity.
- Chernenko, A. Yu.,Astakhov,Pasyukov,Dorovatovskii,Zubavichus, Ya. V.,Khrustalev,Chernyshev
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- Amide-ligand-controlled highly para-selective arylation of monosubstituted simple arenes with arylboronic acids
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Pd-catalyzed highly para-selective arylations of monosubstituted simple arenes with arylboronic acids to widely existed biaryls have been developed. Inspired by requisite amide-directing groups in reported selective oxidative couplings, amide ligands, especially DMF, are designed and found to be critical for the selectivity control in current arylations.
- Luan, Yu-Xin,Zhang, Tao,Yao, Wei-Wei,Lu, Ke,Kong, Lu-Yao,Lin, Yu-Tong,Ye, Mengchun
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supporting information
p. 1786 - 1789
(2017/02/15)
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- Controlling selectivity in the Ullmann reaction on Cu(111)
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Using a surface science approach, the selectivity in the Ullmann cross-coupling of aryl halides on Cu(111) has been understood and controlled. The binding strength of the reactants and repulsion between them dictates which organometallic intermediates form, and hence the product distribution. Cross coupling can be maximized at low reactant concentrations.
- Lewis,Marcinkowski,Murphy,Liriano,Therrien,Pronschinske,Sykes
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supporting information
p. 7816 - 7819
(2017/07/13)
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- Nickel-catalyzed C-N bond reduction of aromatic and benzylic quaternary ammonium triflates
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A nickel-catalyzed, efficient C-N bond reduction of aromatic and benzylic ammonium triflates has been developed using sodium isopropoxide as a reducing agent. The high efficiency, mild conditions, and good compatibility with various substituents made this method an effective supplement to the current catalytic hydrogenation reactions. Combining this reductive deamination reaction with directed aromatic functionalization reactions, a powerful strategy for regioselective functionalization of arenes was demonstrated using dialkylamine groups as traceless directing groups.
- Yi, Yuan-Qiu-Qiang,Yang, Wen-Cheng,Zhai, Dan-Dan,Zhang, Xiang-Yu,Li, Shuai-Qi,Guan, Bing-Tao
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p. 10894 - 10897
(2016/09/09)
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- Cis-specific hydrofluorination of alkenylarenes under palladium catalysis through an ionic pathway
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This paper describes the hydrofluorination of alkenes through sequential H- and F+ addition under palladium catalysis. The reaction is cis specific, thus providing access to benzylic fluorides. The mechanism of this reaction involves an ionic pathway and is distinct from known hydrofluorinations involving radical intermediates. The first catalytic enantioselective hydrofluorination is also disclosed. See attached PdF: A series of benzylic fluorides was prepared by hydrofluorination which proceeds through a PdII/IV catalytic manifold. The method is mechanistically distinct from previously reported radical hydrofluorination, and is characterized by its clean regioselectivity and unique cis stereospecificity. The first example of enantioselective net HF addition onto 2-vinylnaphthalene is also disclosed.
- Emer, Enrico,Pfeifer, Lukas,Brown, John M.,Gouverneur, Veronique
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supporting information
p. 4181 - 4185
(2014/05/06)
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- Palladium-catalyzed arylation of simple arenes with iodonium salts
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The development of an arylation protocol for simple arenes with diaryliodonium salts using the Herrmann-Beller palladacycle catalyst is reported. The reaction takes simple aromatic feedstocks and creates valuable biaryls for use in all sectors of the chem
- Storr, Thomas E.,Greaney, Michael F.
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supporting information
p. 1410 - 1413
(2013/05/09)
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- Silver catalyzed C-C and C-S coupling of aryl halides and thiols with boronic acids
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An efficient Ag(I) catalyzed carbon-carbon and carbon-sulfur bond formation reaction of aryl halides and thiols with boronic acids has been demonstrated. Using this protocol, substrates with a wide range of functional group including electron-rich, and electron deficient substituents have been explored. These reactions are particularly useful to prepare symmetrical and unsymmetrical biphenyls and thioethers. These products were isolated in high yield.
- Das, Rima,Chakraborty, Debashis
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p. 7023 - 7027
(2013/01/15)
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- Practical iron-catalyzed dehalogenation of aryl halides
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An operationally simple iron-catalyzed hydrodehalogenation of aryl halides has been developed with 1 mol% Fe(acac)3 and commercial t-BuMgCl as reductant. The mild reaction conditions (THF, 0 °C, 1.5 h) effect rapid chemoselective dehalogenation of (hetero)aryl halides (I, Br, Cl) and tolerate F, Cl, OR, SR, CN, CO2R, and vinyl groups.
- Czaplik, Waldemar Maximilian,Grupe, Sabine,Mayer, Matthias,Wangelin, Axel Jacobi Von
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supporting information; scheme or table
p. 6350 - 6352
(2010/10/03)
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- Thermal transformations of 4-tert-butylbiphenyl
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The thermal stability of 4-tert-butylbiphenyl was studied in the range of 703-763 K. The competition of the cracking and isomerization reactions of alkyl substituents on the aromatic ring of the reactant and its products has been revealed. The kinetic characteristics of the complex of transformations occurring in the system have been determined. Recommendations are provided regarding the conditions for the determination of the critical parameters of 4-tert-butylbiphenyl and for the processing and use of compounds with a tert-butyl moiety in the molecule.
- Repkin,Nesterova,Nesterov,Golovin
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experimental part
p. 149 - 153
(2011/08/05)
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- METHOD FOR PRODUCING COMPOUND THROUGH COUPLING
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Disclosed is a method for producing a compound (D) through coupling by subjecting an organic compound (A) having a leaving group and an organic metal compound or metal hydride compound (B) to a coupling reaction. This method is characterized in that the organic compound (A) having a leaving group and the organic metal compound or metal hydride compound (B) are reacted with each other in the presence of a catalyst composition (C) containing a transition metal compound (C-1) and a ligand (C-2) which has a coordinating group and a protic group in such a manner that the coordinating group and the protic group are next to each other. This method is useful for efficiently producing a compound through coupling.
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Page/Page column 35-36
(2008/06/13)
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- Nickel(0)-catalyzed cross-coupling of alkyl arenesulfonates with aryl Grignard reagents
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The nickel-catalyzed cross-coupling reactions of neopentyl arenesulfonates with arylmagnesium bromides, involving nucleophilic aromatic substitution of alkyloxysulfonyl groups by aryl nucleophiles, take place in high yields. Optimal efficiencies are obtained by adding 3 + 2 equiv of the Grignard reagent to a mixture of dppfNiCl2 and the sulfonate in refluxing THF. Neopentyl arenesulfonates are useful sources of the electrophilic aryl groups in these transition metal-catalyzed cross-coupling reactions. Aryl sulfonates are inappropriate due to their ambident reactivity under the reaction conditions. This new cross-coupling reaction can be used for the creative elimination of alkyloxysulfonyl groups from aromatic compounds and for the preparation of unsymmetric terphenyls and oligophenyls.
- Cho, Chul-Hee,Yun, Hee-Sung,Park, Kwangyong
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p. 3017 - 3025
(2007/10/03)
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- Versatile catalysts for the Suzuki cross-coupling of arylboronic acids with aryl and vinyl halides and triflates under mild conditions
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Through the use of Pd2(dba)3/P(t-Bu)3 as a catalyst, a wide range of aryl and vinyl halides, including chlorides, undergo Suzuki cross-coupling with arylboronic acids in very good yield, typically at room temperature; through use of Pd(OAc)2/PCy3, a diverse array of aryl and vinyl triflates react cleanly at room temperature. Together, these two catalyst systems cover a broad spectrum of commonly encountered substrates for Suzuki couplings. Furthermore, they display novel reactivity patterns, such as the selective cross-coupling by Pd2(dba)3/P(t-Bu)3 of an aryl chloride in preference to an aryl triflate, and they can be used at low loading, even for reactions of aryl chlorides. Preliminary mechanistic work indicates that a palladium monophosphine complex is the active catalyst in the cross-coupling of aryl halides.
- Littke, Adam F.,Dai, Chaoyang,Fu, Gregory C.
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p. 4020 - 4028
(2007/10/03)
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