- Synthesis and catalytic properties of large-pore Sn-β and Al-free Sn-β molecular sieves
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Sn-β and Al-free Sn-β (large pore, 12-membered ring channels) molecular sieves prepared by hydrothermal synthesis and characterised by XRD, FTIR and sorption techniques are distinguished by their acidic and oxidation properties, in the acetylation of 1,3,5-trimethylbenzene (1,3,5-TMB) with acetyl chloride and in the oxidation of m-cresol and 1,3,5-TMB with aqueous H2O2, respectively.
- Mal,Ramaswamy
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- A Novel Friedel-Crafts Reaction of Hindered Ketones
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Mesitylene has been shown to react with acetyl chloride in the presence of aluminium chloride to form 1,1-dimesitylethene.Acetomesitylene has been demonstrated to be an intermediate in the reaction, which proceeds in the second step by nucleophilic attack by the arene on the carbonyl group of acetomesitylene, which is activated by the formation of a polarized complex with aluminum chloride.Mesitylene reacts similarly with propionyl chloride, forming 1,1-dimesitylpropene; propiomesitylene is an intermediate.Steric and electronic factors responsible for this unique Friedel-Crafts reaction are discussed.
- Roberts, Royston M.,El-Khawaga, Ahmed M.,Roengsumran, Sophon
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- Studies on the Mechanism of Acid-Catalyzed Bromination of a Hindered Alkyl Aryl Ketone: 2,4,6-trimethylacetophenone. Rate Dependence on Bromine Concentration
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According to the generally accepted Lapworth mechanism for halogenation of ketones, where the rate of reaction is independent of halogen concentration, the slow, rate-determining step is the formation of enol or enolate.The rate of reaction of bromine with 2,4,6-trimethylacetophenone (1) was found to depend on bromine concentration at moderately high concentrations.In the proposed mechanism, reaction of bromine with enol is rate determining - the enolization step being faster.A carbocation (4) instead of a bromonium ion is proposed as the intermediate from reaction of enol with bromine.Rates were determined by following the decrease in bromine concentration at 449 nm under these conditions: 50percent acetic acid (v/v), HBr catalysis, and ionic strength adjusted with sodium perchlorate at 25 deg C.With excess ketone, the average pseudo-first-order rate constant was 1.82x10-3 s-1.At a fixed bromine concentration and at varying equal concentrations of both ketone and bromine, k2 values were 4.34x10-2 and 4.39x10-2 L mol-1 s-1, respectively.In studies on the effect of bromide ion on the rate, molecular bromine was found to be the active brominating agent with Br3- contributing to only 0.6percent of the rate constant.Added chloride ion increased the rate; this was explained by Br2/Cl- interchange to form Br-Cl, a more effective brominating agent.Only bromo ketone was isolated in a preparative-scale reaction containing chloride ions.Added acetate ions decreased the rate as a result of a decrease in proton concentration by formation of acetic acid.Perchloric acid increased the rate.From variable-temperature studies, Ea=61.5 kJ mol-1 and ΔH(excit.)=59.0 kJ mol-1.The rate of reaction of bromine with hindered ketone, 1, was nearly 900 times as fast as that with the unhindered analogue, acetophenone, under comparable conditions.
- Pinkus, A. G.,Gopalan, R.
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- Development of Trifluoromethanesulfonic Acid-Immobilized Nitrogen-Doped Carbon-Incarcerated Niobia Nanoparticle Catalysts for Friedel-Crafts Acylation
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Heterogeneous trifluoromethanesulfonic acid-immobilized nitrogen-doped carbon-incarcerated niobia nanoparticle catalysts (NCI-Nb-TfOH) that show excellent catalytic performance with low niobium loading (1 mol %) in Friedel-Crafts acylation have been developed. These catalysts exhibit higher activity and higher tolerance to catalytic poisons compared with the previously reported TfOH-treated NCI-Ti catalysts, leading to a broader substrate scope. The catalysts were characterized via spectroscopic and microscopic studies.
- Yang, Xi,Yasukawa, Tomohiro,Yamashita, Yasuhiro,Kobayashi, Shū
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p. 15800 - 15806
(2021/10/25)
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- Well-Dispersed Trifluoromethanesulfonic Acid-Treated Metal Oxide Nanoparticles Immobilized on Nitrogen-Doped Carbon as Catalysts for Friedel–Crafts Acylation
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Although strong acid-treated metal oxides are useful heterogeneous superacid catalysts for various organic transformations, they usually have a limited density of acidic sites due to their low surface areas. Herein, heterogeneous trifluoromethanesulfonic acid immobilized nitrogen-doped carbon-incarcerated titanium nanoparticle (NP) catalysts have been developed that are composed of well-dispersed, small Ti NPs (ca 7 nm) that are otherwise difficult to achieve using acid-treated metal oxides. The catalysts showed high activity for Friedel–Crafts acylation with low titanium loading (2 mol%, 1 mg of metal for 1 mmol of substrate). A range of microscopic, spectroscopic and physicochemical studies revealed that the nitrogen-doped carbon immobilized the trifluoromethanesulfonic acid and that the addition of metals further changed the nature of the acidic species and enhanced catalytic activity.
- Yang, Xi,Yasukawa, Tomohiro,Maki, Tei,Yamashita, Yasuhiro,Kobayashi, Shū
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supporting information
p. 232 - 236
(2020/12/30)
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- Synthesis and Catalytic Applications of Multinuclear Gold(I)-1,2,3-Triazolylidene Complexes
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A series of mono- to trinuclear gold(I) complexes (1–3) supported by oxo-functionalized 1,2,3-triazolylidenes have been prepared. All new compounds were fully characterized by means of 1H and 13C NMR spectroscopy, elemental analyses, and in the case of complexes 1 and 2 by x-ray diffraction. The catalytic performance of the new triazolylidene gold complexes was tested in several hydroelementation and cyclization processes employing a variety of alkynes as starting materials. According to the overall results, the trinuclear complex 3 displayed the highest catalytic activity in all processes, providing good to excellent yields under mild reaction conditions.
- Rendón-Nava, David,álvarez-Hernández, Alejandro,Mendoza-Espinosa, Daniel
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supporting information
p. 840 - 847
(2021/02/26)
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- Selective monoacylation of mesitylene using hierarchical nanocrystalline ZSM-5 catalyst
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Monoacylated mesitylene is an important precursor used in fine chemical industries In the present work, acylation of mesitylene was carried out using hierarchical ZSM-5 catalyst to prepare 2′,4′,6′-trimethyl acetophenone (monoacylated Mesitylene). The catalyst hierarchical ZSM-5 possessing three generations of micro-, meso-, and macroporosities was fabricated through a dual-template approach using tetrapropylammonium hydroxide (TPAOH) and poly(methyl methacrylate) (PMMA) latex particles as micropore and macropore templates, respectively. The catalyst is well characterized by XRD, FTIR and SEM. The liquid phase reactions were carried out in the temperature range of 30-50 °C. The effect of various parameters such as mole ratio of reactants, catalyst loading, and temperature on the rates of reaction has been investigated. The result shows that the present process gives 100% selective towards the desired product, that is, 2′,4′,6′-trimethyl acetophenone, because hierarchical ZSM-5 allows faster diffusion of the products out of the catalyst provide an important increase in the activity and selectivity.
- Selva Roselin,Selvin, Rosilda
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p. 1315 - 1319
(2020/01/21)
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- Manganese complex-catalysed α-alkylation of ketones with secondary alcohols enables the synthesis of β-branched carbonyl compounds
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Herein, β-branched carbonyl compounds were synthesised via the α-alkylation of ketones with secondary alcohols under "borrowing hydrogen"catalysis. A wide range of secondary alcohols, including various cyclic, acyclic, symmetrical, and unsymmetrical alcohols, have been successfully applied under the developed reaction conditions. A manganese(i) complex bearing a phosphine-free multifunctional ligand catalysed the reaction and produced water as the sole byproduct.
- Waiba, Satyadeep,Jana, Sayan K.,Jati, Ayan,Jana, Akash,Maji, Biplab
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supporting information
p. 8376 - 8379
(2020/08/13)
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- MnO2as a terminal oxidant in Wacker oxidation of homoallyl alcohols and terminal olefins
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Efficient and mild reaction conditions for Wacker-type oxidation of terminal olefins of less explored homoallyl alcohols to β-hydroxy-methyl ketones have been developed by using a Pd(ii) catalyst and MnO2 as a co-oxidant. The method involves mild reaction conditions and shows good functional group compatibility along with high regio- and chemoselectivity. While our earlier system of PdCl2/CrO3/HCl produced α,β-unsaturated ketones from homoallyl alcohols, the present method provided orthogonally the β-hydroxy-methyl ketones. No overoxidation or elimination of benzylic and/or β-hydroxy groups was observed. The method could be extended to the oxidation of simple terminal olefins as well, to methyl ketones, displaying its versatility. An application to the regioselective synthesis of gingerol is demonstrated.
- Fernandes, Rodney A.,Ramakrishna, Gujjula V.,Bethi, Venkati
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p. 6115 - 6125
(2020/10/27)
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- Strongly Lewis Acidic Metal-Organic Frameworks for Continuous Flow Catalysis
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The synthesis of highly acidic metal-organic frameworks (MOFs) has attracted significant research interest in recent years. We report here the design of a strongly Lewis acidic MOF, ZrOTf-BTC, through two-step transformation of MOF-808 (Zr-BTC) secondary building units (SBUs). Zr-BTC was first treated with 1 M hydrochloric acid solution to afford ZrOH-BTC by replacing each bridging formate group with a pair of hydroxide and water groups. The resultant ZrOH-BTC was further treated with trimethylsilyl triflate (Me3SiOTf) to afford ZrOTf-BTC by taking advantage of the oxophilicity of the Me3Si group. Electron paramagnetic resonance spectra of Zr-bound superoxide and fluorescence spectra of Zr-bound N-methylacridone provided a quantitative measurement of Lewis acidity of ZrOTf-BTC with an energy splitting (?E) of 0.99 eV between the ?x? and ?y? orbitals, which is competitive to the homogeneous benchmark Sc(OTf)3. ZrOTf-BTC was shown to be a highly active solid Lewis acid catalyst for a broad range of important organic transformations under mild conditions, including Diels-Alder reaction, epoxide ring-opening reaction, Friedel-Crafts acylation, and alkene hydroalkoxylation reaction. The MOF catalyst outperformed Sc(OTf)3 in terms of both catalytic activity and catalyst lifetime. Moreover, we developed a ZrOTf-BTC?SiO2 composite as an efficient solid Lewis acid catalyst for continuous flow catalysis. The Zr centers in ZrOTf-BTC?SiO2 feature identical coordination environment to ZrOTf-BTC based on spectroscopic evidence. ZrOTf-BTC?SiO2 displayed exceptionally high turnover numbers (TONs) of 1700 for Diels-Alder reaction, 2700 for epoxide ring-opening reaction, and 326 for Friedel-Crafts acylation under flow conditions. We have thus created strongly Lewis acidic sites in MOFs via triflation and constructed the MOF?SiO2 composite for continuous flow catalysis of important organic transformations.
- Ji, Pengfei,Feng, Xuanyu,Oliveres, Pau,Li, Zhe,Murakami, Akiko,Wang, Cheng,Lin, Wenbin
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supporting information
p. 14878 - 14888
(2019/10/02)
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- The impact of cation structure upon the acidity of triazolium salts in dimethyl sulfoxide
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A series of triazolium salts, selected for their varying electronic and steric properties, were prepared and their pKa values were determined in DMSO at 25 °C using the bracketing indicator method. The effect of each systematic structural variation upon the acidity of the triazolium cation has been considered, in particular examining the effects of systematically altering electronic properties, quantified through the use of Hammett σ parameters. The first pKa value for an azolium salt that generates a mesionic carbene is also reported. These new data allow for the selection of appropriate bases for the deprotonation of such triazolium salts and the potential to correlate the pKa values determined herein with the nucleophilicity of the corresponding carbenes.
- Konstandaras, Nicholas,Dunn, Michelle H.,Guerry, Max S.,Barnett, Christopher D.,Cole, Marcus L.,Harper, Jason B.
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supporting information
p. 66 - 75
(2019/12/26)
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- Catalyst-Free Photodriven Reduction of α-Haloketones with Hantzsch Ester
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Catalyst-free dehalogenation of α-haloketones under visible light irradiation is studied. The reactions were carried out in common organic solvent. The outcomes of dechlorination are excellent in yields up to 92%, and it is also applicable to bromides, which give even higher yields. The reaction is tolerable to a broad spectrum of substrates, especially to aromatic ketones, including various aryl and hetaryl groups. There are two examples of aliphatic ketones presented in the paper, although their reactivities are not as high as that of the aromatic ketones.
- Lu, Zheng,Yang, Yong-Qing
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p. 508 - 515
(2019/01/10)
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- Bispentiptycenyl-N-Heterocyclic Carbene (NHC) Gold Complexes: Highly Active Catalysts for the Room Temperature Hydration of Alkynes
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The virtually quantitative, room temperature hydration of various terminal and internal alkynes in methanol/water requires between 0.01–0.05 molpercent of [AuCl(NHC)] activated with 1.5 equiv. of silver triflate and 45 equiv. of triflic acid (both relative to gold complex) with ton of up to 300.000. Iptycenyl-substituted NHC ligands play the key role and the most efficient NHC ligand is characterized by a hemispherical shape formed by two N-pentiptycenyl substituents. (Figure presented.).
- Bergmann, Marvin,Heidrich, Maximillian,Müller-Borges, Dorian,Plenio, Herbert
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p. 3572 - 3578
(2018/09/22)
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- Tropylium Ion Catalyzes Hydration Reactions of Alkynes
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The hydration of alkynes is one of the most atom-economic and versatile synthetic protocols to access carbonyl compounds. This fundamental reaction, however, often requires transition-metal catalysts or harsh reaction conditions to promote the addition of water to the carbon–carbon triple bond. In this work, it is demonstrated that the non-benzenoid aromatic tropylium ion can be used as an organic Lewis acid promoter for the hydration of alkynes under simple reaction conditions with excellent outcomes.
- Oss, Giulia,Ho, Junming,Nguyen, Thanh Vinh
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supporting information
p. 3974 - 3981
(2018/08/17)
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- Pd(II)-Catalyzed Denitrogenative and Desulfinative Addition of Arylsulfonyl Hydrazides with Nitriles
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A Pd(II)-catalyzed denitrogenative and desulfinative addition of arylsulfonyl hydrazides with nitriles has been successfully achieved under mild conditions. This transformation is a new method for the addition reaction to nitriles with arylsulfonyl hydrazides as arylating agent, thus providing an alternative synthesis of aryl ketones. The reported addition reaction is tolerant to many common functional groups, and works well in the presence of electron-donating and electron-withdrawing substituents. Notably, the reported denitrogenative and desulfinative addition was also appropriate for alkyl nitriles, making this newly developed transformation attractive.
- Meng, Mengting,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
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p. 3275 - 3284
(2018/03/25)
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- Preparation method of aromatic ketone
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The invention discloses a preparation method of aromatic ketone. Under the effects of a palladium catalyst and a nitrogen-containing ligand, nitrile compounds and arylsulfonylhydrazide take desulfurization addition reaction in an organic solvent; after the reaction is completed, post treatment is performed to obtain aromatic ketone. The reaction is applicable to aromatic nitrile compounds, and isalso applicable to aliphatic nitrile compounds; the reaction realizes the wide substrate applicability and functional group tolerance; the potential application value is realized in the aspect of aryl-carbonyl building.
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Paragraph 0056; 0057; 0058; 0060
(2018/09/11)
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- Visible light promoted copper-catalyzed Markovnikov hydration of alkynes at room temperature
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A new and efficient method for the hydration of alkynes to the corresponding ketones was successfully developed. The hydration process proceeds smoothly at room temperature with 1% mol of CuCl as catalyst under visible light irradiation. This protocol is applicable to various alkynes, including aromatic alkynes, polycyclic aromatic and heterocyclic aromatic excellent regioselectivity in good to excellent yields.
- Niu, Teng-fei,Jiang, Ding-yun,Li, Si-yuan,Shu, Xing-ge,Li, Huan,Zhang, Ai-ling,Xu, Jia-yu,Ni, Bang-qing
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supporting information
p. 1156 - 1159
(2017/03/02)
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- P -Selective (sp2)-C-H functionalization for an acylation/alkylation reaction using organic photoredox catalysis
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p-Selective (sp2)-C-H functionalization of electron rich arenes has been achieved for acylation and alkylation reactions, respectively, with acyl/alkylselenides by organic photoredox catalysis involving an interesting mechanistic pathway.
- Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Bhawana,Vanka, Kumar,Jain, Shailja
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supporting information
p. 12337 - 12340
(2017/11/20)
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- Wacker Oxidation of Terminal Alkenes Over ZrO2-Supported Pd Nanoparticles Under Acid- and Cocatalyst-Free Conditions
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Highly efficient Wacker oxidation of aromatic or aliphatic terminal alkenes into methyl ketones and benzofurans is developed by using reusable Pd0 nanoparticles (NPs) supported on ZrO2 under acid- and cocatalyst-free conditions. Molecular oxygen or air can be utilized as the terminal oxidant, which results in the formation of H2O as the only theoretical byproduct. The activation of the Pd NPs by O2 plays an important role in promoting this reaction. Interestingly, PdO supported on ZrO2 showed no activity. Additionally, the Pd particle size significantly affects the catalytic activity, with an apparent optimal diameter of 4–12 nm. In addition to the heterogeneous catalyst forms, the Pd NPs can be generated from a Pd0 complex during the reaction, and these particles are even recyclable.
- Zhang, Zhenzhong,Kumamoto, Yuhya,Hashiguchi, Taishin,Mamba, Tetsuya,Murayama, Haruno,Yamamoto, Eiji,Ishida, Tamao,Honma, Tetsuo,Tokunaga, Makoto
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p. 3482 - 3489
(2017/09/15)
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- Cationic Palladium(II) Complexes for Catalytic Wacker-Type Oxidation of Styrenes to Ketones Using O2 as the Sole Oxidant
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A series of new cationic palladium(II) complexes were prepared and studied for their ability to catalyze the Wacker-type oxidation of styrenes to their corresponding acetophenones using O2 as the sole oxidant. Catalysts are active at room temperature and the study highlights the importance of solvent choice and the need for ligand development in improving catalyst performance.
- Chai, Hongxin,Cao, Qun,Dornan, Laura M.,Hughes, N. Louise,Brown, Clare L.,Nockemann, Peter,Li, Jiarong,Muldoon, Mark J.
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p. 5604 - 5608
(2017/12/26)
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- Taming of superacids: PVP-triflic acid as an effective solid triflic acid equivalent for Friedel-Crafts hydroxyalkylation and acylation
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The application of poly(4-vinylpyridine) supported trifluoromethanesulfonic acid (PVP-TfOH, 1:10) as a convenient solid superacid catalyst system in Friedel-Crafts reactions is described. In the presence of PVP-TfOH, one pot solvent-free synthesis of a wide variety of diarylacetic acid derivatives was achieved by Friedel-Crafts hydroxyalkylation reaction of glyoxylic acid with arenes under mild conditions. Acylation of both activated and deactivated aromatic compounds with acetyl chloride was also achieved using PVP-TfOH complex under solvent-free conditions at room temperature. As the polymer supported triflic acid was found to be a very efficient and an easy-to-handle solid acid, it can be a useful addition to environmentally more adaptable strong acid catalyst systems.
- Prakash, G.K. Surya,Paknia, Farzaneh,Kulkarni, Aditya,Narayanan, Arjun,Wang, Fang,Rasul, Golam,Mathew, Thomas,Olah, George A.
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p. 102 - 112
(2015/03/04)
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- Cationic palladium(II) complexes as catalysts for the oxidation of terminal olefins to methyl ketones using hydrogen peroxide
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Ligated Pd(II) complexes have been studied for the catalytic oxidation of terminal olefins to their corresponding methyl ketones. The method uses aqueous hydrogen peroxide as the terminal oxidant; a sustainable and readily accessible oxidant. The choice of ligand, counterion and solvent all have a significant effect on catalytic performance and we were able to develop systems which perform well for these challenging oxidations.
- Cao, Qun,Bailie, David S.,Fu, Runzhong,Muldoon, Mark J.
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supporting information
p. 2750 - 2757
(2015/05/27)
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- Discovery of 4-aryl-N-arylcarbonyl-2-aminothiazoles as Hec1/Nek2 inhibitors. Part I: Optimization of in vitro potencies and pharmacokinetic properties
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A series of 4-aryl-N-arylcarbonyl-2-aminothiazoles of scaffold 4 was designed and synthesized as Hec1/Nek2 inhibitors. Structural optimization of 4 led to compound 32 bearing C-4′ 4-methoxyphenoxy and 4-(o-fluoropyridyl) carbonyl groups that showed low nanomolar in vitro antiproliferative activity (IC50: 16.3-42.7 nM), high intravenous AUC (64.9 μM·h, 2.0 mg/kg) in SD rats, and significant in vivo antitumor activity (T/C = 32%, 20 mg/kg, IV) in mice bearing human MDA-MB-231 xenografts. Cell responses resulting from Hec1/Nek2 inhibition were observed in cells treated with 32, including a reduced level of Hec1 coimmunoprecipitated with Nek2, degradation of Nek2, mitotic abnormalities, and apoptosis. Compound 32 showed selectivity toward cancer cells over normal phenotype cells and was inactive in a [ 3H]astemizole competitive binding assay for hERG liability screening. Therefore, 32 is as a good lead toward the discovery of a preclinical candidate targeting Hec1/Nek2 interaction.
- Lee, Ying-Shuan E.,Chuang, Shih-Hsien,Huang, Lynn Y. L.,Lai, Chun-Liang,Lin, Yu-Hsiang,Yang, Ju-Ying,Liu, Chia-Wei,Yang, Sheng-Chuan,Lin, Her-Sheng,Chang, Chia-Chi,Lai, Jun-Yu,Jian, Pei-Shiou,Lam, King,Chang, Jia-Ming,Lau, Johnson Y. N.,Huang, Jiann-Jyh
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p. 4098 - 4110
(2014/06/09)
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- Palladium(II)-catalyzed desulfitative synthesis of aryl ketones from sodium arylsulfinates and nitriles: Scope, limitations, and mechanistic studies
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A fast and efficient protocol for the palladium(II)-catalyzed production of aryl ketones from sodium arylsulfinates and various organic nitriles under controlled microwave irradiation has been developed. The wide scope of the reaction has been demonstrated by combining 14 sodium arylsulfinates and 21 nitriles to give 55 examples of aryl ketones. One additional example illustrated that, through the choice of the nitrile reactant, benzofurans are also accessible. The reaction mechanism was investigated by electrospray ionization mass spectrometry and DFT calculations. The desulfitative synthesis of aryl ketones from nitriles was also compared to the corresponding transformation starting from benzoic acids. Comparison of the energy profiles indicates that the free energy requirement for decarboxylation of 2,6-dimethoxybenzoic acid and especially benzoic acid is higher than the corresponding desulfitative process for generating the key aryl palladium intermediate. The palladium(II) intermediates detected by ESI-MS and the DFT calculations provide a detailed understanding of the catalytic cycle. (Figure Presented).
- Skillinghaug, Bobo,Sk?ld, Christian,Rydfjord, Jonas,Svensson, Fredrik,Behrends, Malte,S?vmarker, Jonas,Sj?berg, Per J. R.,Larhed, Mats
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p. 12018 - 12032
(2015/01/16)
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- Wacker-type oxidation and dehydrogenation of terminal olefins using molecular oxygen as the sole oxidant without adding ligand
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An efficient and economical palladium-catalyzed oxidation system has been identified. The oxidation system, characterized by not adding ligand and using molecular oxygen as the sole oxidant, can realize the Tsuji-Wacker oxidation of terminal olefins and especially styrenes to methyl ketones; in addition, this system can achieve tandem Wacker oxidation-dehydrogenation of terminal olefins to α,β-unsaturated ketones.
- Wang, Yu-Fei,Gao, Ya-Ru,Mao, Shuai,Zhang, Yan-Lei,Guo, Dong-Dong,Yan, Zhao-Lei,Guo, Shi-Huan,Wang, Yong-Qiang
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supporting information
p. 1610 - 1613
(2014/04/17)
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- Highly selective Wacker oxidation of terminal olefins using magnetically recyclable Pd-Fe3O4 heterodimer nanocrystals
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A new highly selective and environment-friendly Wacker oxidation process employing superparamagnetic Pd-Fe3O4 heterodimer nanocrystals in EtOH-H2O under 1 atm O2 has been developed. Consistently high yields of the desired Wacker product and excellent reaction selectivity were observed in almost all of the reactions examined. This operationally simple oxidation protocol allows recycling of the Pd-Fe 3O4 catalyst after the reaction through the use of an external magnet. The Royal Society of Chemistry 2013.
- Byun, Sangmoon,Chung, Jooyoung,Jang, Youngjin,Kwon, Jungmin,Hyeon, Taeghwan,Kim, B. Moon
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p. 16296 - 16299
(2013/09/23)
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- Observation of 1,3-diketones formation in the reaction of bulky acyl chlorides with methyllithium
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The formation of 1,3-diketones was observed in the reactions of bulky acyl chlorides with methyllithium. The reaction products depend on the steric hindrance around the carbonyl group of the acyl chloride and the electronic effect of the group(s) linked to the carbonyl. When the steric hindrance around the carbonyl group of the acyl chloride is big enough, the 1,3-diketone is the only product. In the case of the moderate hindrance around the carbonyl group of the acyl chloride, a moderate yield of 1,3-diketone is obtained and some tertiary alcohol is generated. When there is no steric hindrance around the carbonyl group of the acyl chloride, the tertiary alcohol is the only product. When the steric hindrance around the carbonyl group is moderate and an electron-donating group is connected to the carbonyl of the acyl chloride, all three products-ketone, 1,3-diketone and tertiary alcohol-can be isolated from the reaction mixture after long reaction times.
- Zhang, Jian,Yang, Nianfa,Yang, Liwen
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experimental part
p. 6415 - 6423
(2012/09/08)
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- Nano-sulfated titania (TiO2/SO2-4) as a new solid acid catalyst for Friedel-Crafts acylation and Beckman rearrangement in solvent-free conditions
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The present work describes a novel application of nano-sulfated titania (nano-ST) as a solid acid catalyst for Friedel-Crafts acylation and Beckmann rearrangement. A nano-ST catalyst has been synthesized and characterized using various techniques such as XRD, scanning electron morphology, transmission electron microscopy, FT-IR, measurement of the specific surface area by Brunauer-Emmett-Teller theory and thermal analysis. The influences of various reaction parameters such as reaction temperature, molar ratio of reactants, reaction time and solvent effects have been investigated. [image omitted].
- Hosseini-Sarvari, Mona,Safary, Ensieh
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experimental part
p. 463 - 473
(2012/06/16)
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- Friedel-crafts acylation of arenes with carboxylic acids using polystyrene-supported aluminum triflate
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Cross-linked polystyrene-supported aluminum triflate (Ps-Al(OTf) 3) has been shown to be a mild, efficient, and chemoselective heterogeneous Lewis acid catalyst for the acylation of aromatic compounds. The catalyst can be easily prepared from cheap starting materials, is stable (as a bench top catalyst) and is reusable.
- Boroujeni, Kaveh Parvanak,Parvanak, Kamran
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experimental part
p. 155 - 163
(2012/01/02)
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- Selective reductions of the carbonyl compounds and aryl halides with Ni-Al alloy in aqueous alkali medium
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The carbonyl compounds and the aryl halides are efficiently reduced by Ni-Al alloy powder, in aqueous alkali medium, with or without organic solvents. The relative reactivities in a series of structurally selected reducible compounds showed a sequence of reactivity in agreement with the mechanism involving a direct electron transfer from aluminum to the organic phase. In some cases an important change in reactivity with respect to conversion of the reducing reagent was notified. Most probably this complicated variability is the result of the changes in composition and morphology of the reacting Ni-Al alloy.
- Suceveanu, Mirela,Raicopol, Matei,Enache, Raluca,Finaru, Adriana,Rosca, Sorin I.
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experimental part
p. 690 - 695
(2012/06/04)
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- Friedel-Crafts acylation of arenes with carboxylic acids using silica gel supported AlCl3
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Aromatic compounds react smoothly with carboxylic acids in the presence of silica gel supported aluminium trichloride to afford the corresponding ketones with high regioselectivity in high to excellent yields. The catalyst is stable (as a bench top catalyst) and can be easily recovered and reused without appreciable change in its efficiency. tuebitak.
- Parvanak Boroujeni, Kaveh
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experimental part
p. 621 - 630
(2010/11/04)
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- Catalytic Friedel-Crafts acylation and benzoylation of aromatic compounds using activated hematite as a novel heterogeneous catalyst
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Catalytic Friedel-Crafts acylation of benzene and unactivated benzenes such as chlorobenzene and nitrobenzene have been successfully carried out using activated hematite (α-Fe2O3) as a new, heterogeneous and green catalyst. Sonication of neat α-Fe2O3 in a water bath under air atmosphere at room temperature followed by heating at 200°C, dramatically increase the activity of α-Fe2O 3. With the catalyst loading as low as 5.0mol%, a wide variety of benzene derivatives were easily converted into the corresponding acylated products in a clean and high-yielding acylation reaction. It was found that the activated α-Fe2O3 could be efficiently recycled and reused several times by simple washing with ethyl acetate, this cannot be attained with most of the traditional catalysts. Copyright
- Sharghi, Hashem,Jokar, Mahboubeh,Doroodmand, Mohammad Mahdi,Khalifeh, Reza
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experimental part
p. 3031 - 3044
(2011/02/21)
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- Synthesis of aryl ketones by palladium(II)-catalyzed decarboxylative addition of benzoic acids to nitriles
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An efficient, sustainable method for the preparation of aryl ketones from ortho-substituted benzoic acids proceeds through their decarboxylation to generate an aryl-palladium species, followed by addition to a nitrile and hydrolysis of the intermediate ketimine.
- Lindh, Jonas,Sjoeberg, Per J. R.,Larhed, Mats
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supporting information; experimental part
p. 7733 - 7737
(2011/01/05)
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- Chiral azabicyclo-N-oxyls mediated enantioselective electrooxidation of sec-alcohols
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Enantiomerically pure azabicyclo-N-oxyls were prepared from l-hydroxyproline. They mediated enantioselective electrooxidation of racemic sec-alcohols to afford optically active sec-alcohols with moderate to high s value (up to 21).
- Shiigi, Hirofumi,Mori, Hiroyuki,Tanaka, Tomoaki,Demizu, Yosuke,Onomura, Osamu
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p. 5247 - 5251
(2008/12/22)
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- An efficient method for aromatic Friedel-Crafts acylation reactions
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Friedel-Crafts acylation of aromatic compounds was carried out using FeCl3-based ionic liquid. This liquid serves as an efficient media as well as a Lewis acid catalyst. The significant advantages of this methodology are excellent yields, short reaction times, mild reaction conditions, environmentally friendly method, simple work-up procedure, low cost, and easy preparation and handling of the catalyst. Copyright
- Khodaei, Mohammad Mehdi,Bahrami, Kiumars,Shahbazi, Fomeida
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p. 844 - 845
(2008/12/22)
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- Electrochemically promoted Friedel-Crafts acylation of aromatic compounds
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Friedel-Crafts acylation is carried out with several aromatic substrates in the presence of an electrochemically active aluminium anode to minimize the inorganic reagents. Only a catalytic amount of AlCl3 (5 mol %) is required to enable the anodic polarization of the aluminium electrode to promote continuous acylation. This process typically gave products in good yields (70-96%).
- Karthik,Kulangiappar,Marken, Frank,Kulandainathan, M. Anbu
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p. 2625 - 2627
(2008/09/18)
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- Convenient synthesis of an enantiomerically pure bicyclic proline and its N-oxyl derivatives
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An enantiomerically pure bicyclic proline derivative was prepared by cis-selective allylation and diastereospecific intramolecular alkylation starting from d-pipecolinic acid. In addition, enantiomerically pure azabicyclo N-oxyls derived from the bicyclic proline worked well as catalysts for the enantioselective electrooxidation of racemic sec-alcohols to afford optically active sec-alcohols in moderate enantiomeric purity.
- Demizu, Yosuke,Shiigi, Hirofumi,Mori, Hiroyuki,Matsumoto, Kazuya,Onomura, Osamu
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experimental part
p. 2659 - 2665
(2009/04/06)
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- Tf2O as a rapid and efficient promoter for the dehydrative Friedel-Crafts acylation of aromatic compounds with carboxylic acids
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The Friedel-Crafts acylation of aromatic compounds with carboxylic acids was investigated in the presence of Tf2O. The reaction was carried out efficiently and very rapidly under mild reaction conditions without the need of any catalyst.
- Khodaei, Mohammd Mehdi,Alizadeh, Abdolhamid,Nazari, Ehsan
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p. 4199 - 4202
(2008/02/05)
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- Gallium-mediated allyl transfer from bulky homoallyl alcohol to aldehydes or alkynes: Control of dynamic σ-allylgalliums based on retro-allylation reaction
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A new method for the preparation and control of dynamic σ-allylgalliums is disclosed. Upon treatment with a Grignard reagent and gallium trichloride, bulky homoallyl alcohols undergo gallium-mediated retro-allylation reaction to provide σ-allylgallium reagents. The σ-allylgallium reagents generated were applied to carbonyl allylation. The retro-allylation reaction generates (Z)- and (E)-σ-crotylgalliums stereospecifically, starting from erythro- and threo-homoallyl alcohols, respectively. The stereochemically defined crotylgallium reagents effected stereoselective allylation of aldehydes. Allylgallation reaction of alkynes with the allylgallium reagents prepared by retro-allylation is also described.
- Hayashi, Sayuri,Hirano, Koji,Yorimitsu, Hideki,Oshima, Koichiro
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p. 505 - 513
(2008/02/06)
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- An efficient bismuth(III) chloride-catalyzed synthesis of 1,1-di-arylalkenes via Friedel-Crafts reaction of acyl chloride or vinyl chloride with arenes
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In the presence of catalytic amount of bismuth(III) chloride, the reactions of acyl chlorides or vinyl chlorides with arenes afforded 1,1-diarylalkenes in 25-82% isolated yield. In the case of the reaction of acyl chlorides with arenes, the procedure includes an initial Friedel-Crafts acylation, subsequent formation of vinyl chlorides and final Friedel-Crafts-type vinylation of another arene molecule with vinyl chloride. This paper reports the first Lewis acid-catalyzed cleavage of the C-Cl bond of vinyl chloride and its application in the synthesis of multiply subtituted alkenes.
- Sun, Hongbin,Hua, Ruimao,Chen, Songjie,Yin, Yingwu
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p. 1919 - 1925
(2007/10/03)
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- Synthesis of aryl ketones or ketimines by palladium-catalyzed arene C-H addition to nitriles
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The unprecedented palladium-catalyzed C-H addition of arenes to nitriles provides moderate to excellent yields of aryl ketones or the corresponding hindered imines. The addition of a small amount of DMSO increases the yields dramatically. Both intermolecular and intramolecular reactions are successful, although the intramolecular reactions tend to be more sluggish. This novel chemistry is believed to involve palladium-catalyzed C-H activation of the arene by electrophilic aromatic substitution, followed by the unusual carbopalladation of a nitrile. Similar reactions have been successfully developed employing arylboronic acids and nitriles. A concise route to xanthones starting from cheap starting materials has been developed employing this synthetic protocol.
- Zhou, Chengxiang,Larock, Richard C.
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p. 3551 - 3558
(2007/10/03)
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- Mild oxidation of alcohols with o-iodoxybenzoic acid (IBX) in a water/CH2CL2 mixture in the presence of phase-transfer catalyst
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A mild oxidation of alcohols to the respective carbonyl compounds with o-iodoxybenzoic acid (IBX) catalyzed by n-Bu4NBr in a water/dichloromethane (1:1) mixture is described. The method offers the advantage of a simple, inexpensive catalyst and the diminution of organic solvent employed in the reaction. Copyright Taylor & Francis Group, LLC.
- Kuhakarn, Chutima,Kittigowittana, Krisada,Ghabkham, Pattama,Pohmakotr, Manat,Reutrakul, Vichai
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p. 2887 - 2892
(2007/10/03)
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- Gallium-mediated allyl transfer from bulky homoallylic alcohol to aldehydes via retro-allylation: Stereoselective synthesis of both erythro- and threo-homoallylic alcohols
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(Chemical Equation Presented) Retro-allylation of bulky gallium homoallylic alkoxides occurs to generate (Z)- and (E)-crotylgallium reagents stereospecifically, starting from erythro- and threo-homoallylic alcohols, respectively. The (Z)- and (E)-crotylgallium reagents immediately reacted with aromatic aldehydes to afford the corresponding erythro and threo-homoallylic alcohols, respectively.
- Hayashi, Sayuri,Hirano, Koji,Yorimitsu, Hideki,Oshima, Koichiro
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p. 3577 - 3579
(2007/10/03)
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- Discovery of and mechanistic insight into a ligand-modulated palladium-catalyzed wacker oxidation of styrenes using TBHP
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We describe the discovery of a new N-heterocyclic carbene-modulated Pd catalyst for the Wacker oxidation that does not require molecular oxygen but instead uses TBHP as a reagent in this oxidation. The catalyst activity and selectivity for the oxidation of styrene derivatives to methyl ketones are among the best reported. Preliminary mechanistic studies of the catalytic system were performed and show that the origin of the carbonyl oxygen is TBHP and that the hydrogens in the product all originate from the starting olefin. Copyright
- Cornell, Candace N.,Sigman, Matthew S.
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p. 2796 - 2797
(2007/10/03)
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- Aluminum dodecatungstophosphate (AlPW12O40) as a non-hygroscopic Lewis acid catalyst for the efficient Friedel-Crafts acylation of aromatic compounds under solvent-less conditions
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Stable and non-hygroscopic aluminum dodecatungstophosphate (AlPW 12O40), which is prepared easily from cheap and commercially available compounds was found to be an effective catalyst for Friedel-Crafts acylation reactions using carboxylic acids, acetic anhydride and benzoyl chloride in the absence of solvent under mild reaction conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Nowrouzi, Farhad
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p. 10843 - 10850
(2007/10/03)
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- Lewis Acid Catalysis in Supercritical Carbon Dioxide. Use of Poly(ethylene glycol) Derivatives and Perfluoroalkylbenzenes As Surfactant Molecules Which Enable Efficient Catalysis in ScCO2
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Lewis acid catalysis in supercritical carbon dioxide (CO2) was investigated. While solubility of most organic materials is low in scCO 2, poly(ethylene glycol) derivatives or perfluoroalkylbenzenes were found to work as surfactants to dissolve organic materials in scCO2. In the presence of these molecules, Lewis acid catalyzed organic reactions such as aldol-, Mannich-, and Friedel-Crafts-type reactions proceeded smoothly in scCO2. Formation of emulsions was observed in these reactions, and the systems were studied in detail.
- Komoto, Ichiro,Kobayashi, Shu
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p. 680 - 688
(2007/10/03)
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- The Friedel-Crafts acylation of aromatic compounds with carboxylic acids by the combined use of perfluoroalkanoic anhydride and bismuth or scandium triflate
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Aromatic ketones were synthesized by solventless Friedel-Crafts acylation of anisole, mesitylene, xylenes, and toluene with acetic acid and benzoic acid in the presence of trifluoroacetic anhydride by use of bismuth or scandium triflate at 30°C. Toluene, benzene, and even deactivated substrate such as chlorobenzene were benzoylated by the combined use of heptafluorobutyric anhydride and bismuth triflate at 75-100°C. The catalyst could be easily recovered and reused repeatedly for the reaction.
- Matsushita, Yoh-Ichi,Sugamoto, Kazuhiro,Matsui, Takanao
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p. 4723 - 4727
(2007/10/03)
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- Synthesis of Aryl Ketones by the Pd-Catalyzed C-H Activation of Arenes and Intermolecular Carbopalladation of Nitriles
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The palladium-catalyzed reaction of simple arenes and nitriles provides good to excellent yields of aryl ketones or the corresponding hindered imines. The addition of a small amount of DMSO increases the yields dramatically. Both intermolecular and intramolecular examples of this process are successful. This novel chemistry is believed to involve palladium-catalyzed C?H activation, followed by carbopalladation of the nitrile. Copyright
- Zhou, Chengxiang,Larock, Richard C.
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p. 2302 - 2303
(2007/10/03)
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- Antimony(V) chloride-benzyltriethylammonium chloride complex as an efficient catalyst for friedel-crafts acylation reactions
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A novel catalytic system, the complex of antimony(V) chloride (SbCl 5) and benzyltriethylammonium chloride (TEBA), C6H 5CH2NEt3(SbCl5)2Cl complex, is described for Friedel-Crafts acylation reactions of aromatics with acyl and sulfonyl chlorides. The catalyst has a number of useful characteristics, such as ready access, minimal toxicity, reusability, insensitivity to atmosphere and moisture, rapid acylation with high yield, and ease of operation.
- Huang, An-Ping,Liu, Xue-Yuan,Li, Lian-Hua,Wu, Xiao-Li,Liu, Wei-Min,Liang, Yong-Min
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p. 599 - 602
(2007/10/03)
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- BiCl3-catalyzed Friedel-Crafts acylation reactions: Bismuth(III) oxychloride as a water insensitive and recyclable procatalyst
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The Friedel-Crafts acylation of activated and polycyclic aromatics is efficiently catalyzed by bismuth(III) chloride which is generated in situ from bismuth(III) oxychloride, a water insensitive and eco-friendly material. Bismuth(III) oxychloride is easily recovered in near quantitative yields after an aqueous work-up.
- Répichet, Sigrid,Le Roux, Christophe,Roques, Nicolas,Dubac, Jacques
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p. 2037 - 2040
(2007/10/03)
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- Efficient aromatic and heteroatom acylations using catalytic indium complexes with lithium perchlorate
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The combination of an indium complex with lithium perchlorate affords a potent system for the catalytic acylation of electron-rich aromatics and alcohols. The use of isopropenyl acetate as acyl donor results in cleaner methodology with acetone as the only by-product. The study has also revealed an indium-catalysed ketalisation reaction.
- Chapman, Christopher J.,Frost, Christopher G.,Hartley, Joseph P.,Whittle, Alan J.
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p. 773 - 775
(2007/10/03)
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- A "Hard/Soft" Mismatch Enables Catalytic Friedel-Crafts Acylations
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(Equation Presented) Cationic complexes of Pt(II) and other late transition metals efficiently catalyze Friedel-Crafts acylations of moderately activated arenes by carboxylic acid anhydrides. The nature of the catalytically relevant species formed from (PhCN)2PtCl2 and AgSbF6 and their interactions with the substrates are studied by NMR and ESI-MS.
- Fuerstner, Alois,Voigtlaender, David,Schrader, Wolfgang,Giebel, Dirk,Reetz, Manfred T.
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p. 417 - 420
(2007/10/03)
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