- The catalytic Friedel-Crafts alkylation reaction of aromatic compounds with benzyl or allyl silyl ethers using Cl2Si(OTf)2 or Hf(OTf)4
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The Friedel-Crafts alkylation reaction of various aromatic compounds with benzyl or allyl silyl ethers is effectively promoted under mild reaction conditions using Lewis acid catalysts. A mixture of the desired phenyltolylmethanes is obtained in 80% yield from toluene with benzyl dimethylsilyl or trimethylsilyl ether at 50°C in the presence of a catalytic amount of Cl2Si(OTf)2 or Hf(OTf)4.
- Shiina, Isamu,Suzuki, Masahiko
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Read Online
- Helical Al- and Ce-MCM-41 materials as novel catalyst for acid and redox processes
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Helical mesoporous silicas containing aluminium or cerium into their framework have been synthesized via hydrothermal method. The synthesized materials were extensively characterized to understand their physico-chemical properties in view of their future catalytic applications. Low-angle powder XRD patterns of calcined samples showed a hexagonally ordered mesopore structure. NMR spectra of aluminium materials exhibited two signals at 50 and 0 ppm assigned to tetracoordinated and octahedrally coordinated Al3+. DR-UV-vis and XPS spectrum of cerium content materials show that cerium was incorporated as Ce3+ and Ce4+ into the helical mesoporous material. Materials with molar ratios Si/Al = 95 and Si/Ce = 500 were found to be catalytically active in acid (oxathioacetalisations and alkylations) or redox (epoxidation of cyclohexene) catalyzed processes, respectively.
- Carrillo, Adela I.,Serrano, Elena,Serrano-Ruiz, Juan Carlos,Luque, Rafael,Garcia-Martinez, Javier
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Read Online
- Dihalogen-halogenomethyl complexes of indium(III) X2InCH2X (X = Br, I): Simultaneous coordination of soft and hard ligands
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Halogenomethyl-dihalogen-indium(III) compounds X2InCH2X (X = Br, I) obtained from indium monohalides and methylene dihalides were reacted with the soft donor ligands dialkylsulfides, R2S (R = CH3, CH2
- Peppe, Clovis,de Andrade, Fabiano Molinos,Vargas, Jaqueline Pinto,Mello, Melina de Azevedo,Barcellos, Railander Alves,Burrow, Robert A.,da Silva, Rubia Mara Siqueira
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Read Online
- Multifunctional oxygen vacancies in WO3–x for catalytic alkylation of C–H by alcohols under red-light
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Surface reaction kinetics and light absorption properties of a photocatalyst are essential demands for efficiently solar to chemical energy converting. In this study, plasmonic WO3–x was firstly applied to photocatalytic alkylation of arenes under red light irradiation. The oxygen vacancies, both on the surface and in the bulk of WO3–x, allow abundant free electrons to increase carrier densities and support its LSPR using low energy photons. The surface oxygen vacancies have more functions: they not only release surface tungsten sites which ensure the chemisorption of alcohols due to the coordianation ability but also promote the activation of alcohols via an efficient transport of the holes on the neighbouring O sites to chemisorption alcohol species. In brief, the bulk oxygen vacancies provide abundant charges and the surface vacancies promote the bond adsorption and activation abilities, which ensure the high efficiency of photocatalytic alkylation of C–H.
- Gu, Xianmo,Sun, Xichen,Wang, Yunwei,Zhang, Jin,Zheng, Zhanfeng,Zhu, Pengqi
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p. 208 - 217
(2021/09/06)
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- Development of highly efficient Friedel-Crafts alkylations with alcohols using heterogeneous catalysts under continuous-flow conditions
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The development of Friedel-Crafts alkylations with alcohols under continuous-flow conditions using heterogeneous catalysts is reported. The reactivities and durabilities of the examined catalysts were systematically investigated, which showed that montmorillonite clay is the best catalyst for these reactions. A high turnover frequency of 9.0 × 102h?1was recorded under continuous-flow conditions, and the continuous operation was successfully maintained over one week.
- Kobayashi, Shū,Koumura, Nagatoshi,Masuda, Koichiro,Okamoto, Yukiko,Onozawa, Shun-Ya
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p. 24424 - 24428
(2021/07/29)
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- Selective Conversion of Benzylic Phosphates into Diarylmethanes Through Al(OTf)3-Catalyzed Friedel–Crafts-Type Benzylation
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Al(OTf)3 was identified as a high-performance catalyst for Friedel–Crafts-type benzylation using benzylic phosphates as electrophiles. The reaction proceeded even with 0.2 mol-% of the catalyst. A series of diarylmethanes (21 examples) was obtained in moderate to high yield. The catalyst showed unique chemoselectivity, preferentially converting the benzylic phosphate motif, even with a benzylic acetate group existed in the same molecule.
- Yurino, Taiga,Hachiya, Asuka,Suzuki, Keisuke,Ohkuma, Takeshi
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p. 2225 - 2232
(2020/04/16)
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- Friedel–Crafts benzylation of toluene catalyzed by ZnCl2/SiO2 heterogeneous catalyst to para- and ortho-mono-benzylated toluene
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A series of catalysts was prepared for the liquid-phase Friedel–Crafts benzylation of toluene with benzyl chloride (BC) by impregnating rice husk ash silica with ZnCl2 (3?wt%, 6?wt%, 9?wt%, and 12?wt%) via a wet impregnation method. The XRD analysis indicates that the catalysts were amorphous with ill-defined pore systems. The XPS analysis detected the coexistence of ZnO nanoparticles together with ZnCl2 on the catalyst surface, whereas the 29Si NMR analysis indicates the formation of Si–O–Zn bond. Quantitative conversion of benzyl chloride (100%) was achieved within 3?h at 353?K when a catalyst with 9?wt% ZnCl2 was used due to its narrow pore size and high surface area (635?m2?g?1). Para- and ortho-mono-benzylated toluene was obtained as the products. The reaction is proposed to take place via weak attraction between benzyl chloride and the Zn through its chlorine atom. The catalyst was recycled four times with minimum loss (8%) in activity. The benzylation of benzene, toluene, p-xylene, and anisole followed the classical mechanism of Friedel–Craft-type acid-catalyzed benzylation reaction. The BC conversion increased in the order of toluene = p-xylene > anisole > benzene. The catalyst was also screened to be active in the benzoylation of toluene with benzoyl chloride (BOC). The conversion of BOC was 45% with selectivity toward 2-methylbenzophenone (50%) and 3-methylbenzophenone (50%).
- Iqbal, Anwar,Tan, Kok-Hou,Shaari,Ahmad,Adam, Farook,Lee, Hwei Voon,Yusop, Rahimi M.,Abu Bakar,Lee, Hooi Ling,Pauzi, Hariy,Malik, Muhammad Fadhirul Izwan Abd,Jusoh, Ahmad Fadly,Wilson, Lee D.,Ahmad,Hazwan Hussain,Ibrahim, Mohamad Nasir Mohamad
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p. 1615 - 1626
(2020/03/05)
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- Catalytic arene alkylation over H-Beta zeolite: Influence of zeolite shape selectivity and reactant nucleophilicity
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Renewable arenes and aromatic alcohols can be derived from lignocellulose by biorefineries, which has been considered as a sustainable alternative to replace petrochemical feedstocks in the synthesis of monobenzylation products, key industrial intermediates, via benzylation reactions. Zeolites with micropores are the most widely used catalysts in the benzylation of arenes, however, their performance suffers from diffusion limitations in converting large arenes. In this work, mesoporous and microporous H–Beta zeolites were prepared and applied in the systematic study of benzylation of arenes (benzene, toluene, p-xylene and mesitylene) with benzyl alcohol (BA). The porous structure of these zeolites has been confirmed by XRD, BET and TEM techniques. The catalytically active Br?nsted acid sites (BAS) were determined by quantitative 1H magic-angle spinning (MAS) nuclear magnetic resonance (NMR) experiments. The benzylation studies have shown that introducing mesopores into H–Beta zeolites can significantly increase the diffusion/access of arenes to surface sites, particularly for bulky arenes (e.g. mesitylene), while micropores are mainly selective for the conversion of small arenes (e.g. benzene). Increasing the nucleophilicity of arenes with more alkyl groups can enhance their catalytic performance in mesopores, however, the increase hinders their conversion in micropores because of the shape selectivity due to their increasing molecular size. Compared to mesopores, micropores promote the conversion of small arenes (e.g. benzene), which can be additionally enhanced by a high Br?nsted acidity. Therefore, introducing a suitable porosity balanced with acidity are keys in the tailoring of the catalytic performance of H-Beta zeolites for target benzylation reactions.
- Zeng, Xin,Wang, Zichun,Ding, Jia,Wang, Leizhi,Jiang, Yijiao,Stampfl, Catherine,Hunger, Michael,Huang, Jun
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- Benzylation of Arenes with Benzyl Halides under Promoter-Free and Additive-Free Conditions
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It was found that benzyl chlorides and bromides could directly react with electron-rich arenes, which provided an example of promoter-free and additive-free benzylation of arenes. A variety of benzyl chlorides and bromides were treated with benzene rings to give the targeted products in low to high yields. The present conditions tolerated the vinyl group of the substrates. Preliminary mechanistic investigation suggests that the present reactions possibly proceed via an autocatalytic mechanism pathway.
- Cheng, Xinqiang,Shan, Jiankai,Tian, Xinshe,Ren, Yun-Lai,Zhu, Yanyan
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supporting information
p. 4404 - 4410
(2019/07/03)
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- Bisulfate Salt-Catalyzed Friedel-Crafts Benzylation of Arenes with Benzylic Alcohols
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We report here a method of direct Friedel-Crafts benzylation of arenes with benzylic alcohols using cheap and readily available bisulfate salt as the catalyst in hexafluoroisopropanol. The catalytic system is powerful with a quite diverse group of functionalized arenes and benzylic alcohols. These mild conditions provide a straightforward synthesis of a variety of unsymmetrical diarylmethanes in high yield with good to high regioselectivity. An SN1 mechanism involving activation of the hydroxy group through a hydrogen bond is proposed.
- Tang, Ren-Jin,Milcent, Thierry,Crousse, Benoit
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p. 14001 - 14009
(2018/11/23)
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- Benzylation with Benzyl Alcohol Catalyzed By [ChCl][TfOH]2, a Br?nsted Acidic DES with Reaction Control Self-Separation Performance
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Abstract: A deep eutectic solvent with strong Br?nsted acidity was prepared easily by choline chloride and trifluoromethanesulfonic acid. The obtained [ChCl][TfOH]2 catalyst which was characterized by FT-IR, 1H NMR and TG, possessed greatly enhanced stability than trifluoromethanesulfonic acid, and exhibited excellent catalytic performance in benzylation with benzyl alcohol. Especially, the prepared [ChCl][TfOH]2 catalyst could dissolve into the reactants to realize homogeneous catalysis, and then self-separate from the organic phase after reaction due to the entire consumption of benzyl alcohol. As a result, the catalyst could be recovered and reused simply for six-runs without noticeable loss of catalytic performance. Graphical Abstract: [Figure not available: see fulltext.].
- Yuan, Bing,Li, Yinglian,Yu, Fengli,Li, Xiaoqiang,Xie, Congxia,Yu, Shitao
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p. 2133 - 2138
(2018/05/29)
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- MoO3 supported on ordered mesoporous zirconium oxophosphate: An efficient and reusability solid acid catalyst for alkylation and esterification
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A series of molybdenum oxide supported on ordered mesoporous zirconium oxophosphate (MoO3/M-ZrPO) materials with different MoO3 loadings (0–20 wt%) and calcination temperatures (500–900 °C) have been designed, synthesized and employed as solid acid catalysts in alkylation and esterification. The XRD, TG-DSC, H2-TPR, N2-physisorption and TEM characterizations were taken to investigate the structural properties and states of introduced MoO3 species. The influence of MoO3 loadings and calcination temperatures in catalytic performance was detailedly investigated and optimal catalytic activity was reached at 10 wt% MoO3 loadings and treated at 700 °C. Moreover, MoO3/M-ZrPO catalysts exhibited outstanding catalytic performance in Friedel-Crafts alkylation of different aromatic compounds and esterification of levulinic acid with 1-butanol. Furthermore, it was noteworthy that the catalyst had superior reusability and no noticeable declines were observed in catalytic performance even after seven runs.
- Miao, Zhichao,Li, Zhenbin,Zhao, Jinping,Si, Weijiang,Zhou, Jin,Zhuo, Shuping
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- Mild Friedel–Crafts Reactions inside a Hexameric Resorcinarene Capsule: C?Cl Bond Activation through Hydrogen Bonding to Bridging Water Molecules
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A novel catalytic feature of a hexameric resorcinarene capsule is highlighted. The self-assembled cage was exploited to promote the Friedel–Crafts benzylation of several arenes and heteroarenes with benzyl chloride under mild conditions. Calculations showed that there are catalytically relevant hydrogen-bonding interactions between the bridging water molecules of the capsule and benzyl chloride, which is fundamental for the activation of the C?Cl bond. The capsule controls the reaction outcome. Inside the inner cavity of the capsule, N-methylpyrrole is preferentially benzylated in the unusual β-position while mesitylene reacts faster than 1,3-dimethoxybenzene despite the greater π-nucleophilicity of the latter compound.
- La Manna, Pellegrino,Talotta, Carmen,Floresta, Giuseppe,De Rosa, Margherita,Soriente, Annunziata,Rescifina, Antonio,Gaeta, Carmine,Neri, Placido
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p. 5423 - 5428
(2018/04/09)
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- IONIC LIQUIDS HAVING ACIDIC CATALYTIC ACTIVITY, AND A CATALYST THEREOF
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This invention provides ionic liquids having acidic catalytic activity which having the structure as indicated in formula (I), wherein, the substitution group R is selected from hydrogen, alkyl group, alkoxy group or nitro group.
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Paragraph 0038
(2016/10/08)
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- Donor-Acceptor Fluorophores for Visible-Light-Promoted Organic Synthesis: Photoredox/Ni Dual Catalytic C(sp3)-C(sp2) Cross-Coupling
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We describe carbazolyl dicyanobenzene (CDCB)-based donor-acceptor (D-A) fluorophores as a class of cheap, easily accessible, and efficient metal-free photoredox catalysts for organic synthesis. By changing the number and position of carbazolyl and cyano groups on the center benzene ring, CDCBs with a wide range of photoredox potentials are obtained to effectively drive the energetically demanding C(sp3)-C(sp2) cross-coupling of carboxylic acids and alkyltrifluoroborates with aryl halides via a photoredox/Ni dual catalysis mechanism. This work validates the utility of D-A fluorophores in guiding the rational design of metal-free photoredox catalysts for visible-light-promoted organic synthesis.
- Luo, Jian,Zhang, Jian
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p. 873 - 877
(2016/02/18)
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- In situ activation of benzyl alcohols with XtalFluor-E: Formation of 1,1-diarylmethanes and 1,1,1-triarylmethanes through Friedel-Crafts benzylation
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The Friedel-Crafts benzylation of arenes using benzyl alcohols activated in situ with XtalFluor-E is described. A wide range of 1,1-diarylmethanes and 1,1,1-triarylmethanes were prepared under experimentally simple and mild conditions, without the need for a transition metal or a strong Lewis acid. Notably, the reactivity observed demonstrates the potential of XtalFluor-E to induce C-OH bond ionization and SN1 reactivity of benzylic alcohols. This journal is
- Desroches, Justine,Champagne, Pier Alexandre,Benhassine, Yasmine,Paquin, Jean-Franois
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supporting information
p. 2243 - 2246
(2015/03/04)
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- A surprising substituent effect provides a superior boronic acid catalyst for mild and metal-free direct Friedel-Crafts alkylations and prenylations of neutral arenes
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The development of more general and efficient catalytic processes for Friedel-Crafts alkylations is an important objective of interest toward the production of pharmaceuticals and commodity chemicals. Herein, 2,3,4,5-tetrafluorophenylboronic acid was identified as a potent air- and moisture-tolerant metal-free catalyst that significantly improves the scope of direct Friedel-Crafts alkylations of a variety of slightly activated and neutral arenes, including polyarenes, with allylic and benzylic alcohols. This method also provides a simple alternative for the direct installation of prenyl units commonly found in naturally occurring arenes. Alkylations with benzylic alcohols occur under exceptionally mild conditions.
- Ricardo, Carolynne L.,Mo, Xiaobin,McCubbin, J. Adam,Hall, Dennis G.
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supporting information
p. 4218 - 4223
(2015/03/14)
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- Use of metal-accumulating plants for implementing chemical reactions
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The use of metal-accumulating plants for implementing chemical reactions.
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Page/Page column 39-41
(2015/10/28)
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- Metal-organic framework based upon the synergy of a Br?nsted acid framework and Lewis acid centers as a highly efficient heterogeneous catalyst for fixed-bed reactions
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We report a strategy of combining a Br?nsted acid metal-organic framework (MOF) with Lewis acid centers to afford a Lewis acid@Br?nsted acid MOF with high catalytic activity, as exemplified in the context of MIL-101-Cr-SO3H·Al(III). Because of the synergy between the Br?nsted acid framework and the Al(III) Lewis acid centers, MIL-101-Cr-SO3H·Al(III) demonstrates excellent catalytic performance in a series of fixed-bed reactions, outperforming two benchmark zeolite catalysts (H-Beta and HMOR). Our work therefore not only provides a new approach to achieve high catalytic activity in MOFs but also paves a way to develop MOFs as a new type of highly efficient heterogeneous catalysts for fixed-bed reactions.
- Li, Baiyan,Leng, Kunyue,Zhang, Yiming,Dynes, James J.,Wang, Jian,Hu, Yongfeng,Ma, Dingxuan,Shi, Zhan,Zhu, Liangkui,Zhang, Daliang,Sun, Yinyong,Chrzanowski, Matthew,Ma, Shengqian
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supporting information
p. 4243 - 4248
(2015/04/14)
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- Microwave-specific acceleration of a friedel-crafts reaction: Evidence for selective heating in homogeneous solution
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Thermally promoted Friedel-Crafts benzylation of arene solvents has been examined under both conventional convective heating with an oil bath and heating using microwave (MW) energy. Bulk solution temperatures-as measured by internal and external temperature probes and as defined by solvent reflux-were comparable in both sets of experiments. MW-specific rate enhancements were documented under certain conditions and not others. The observed rate enhancements at a given temperature are proposed to arise from selective MW heating of polar solutes, perturbing thermal equilibrium between the solute and bulk solution. Central to MW-specific thermal phenomena is the difference between heat and temperature. Temperature is a measure of the ensemble average kinetic molecular energy of all solution components, but temperature does not provide information about solute-specific energy differences that may arise as a consequence of selective MW heating. Enhanced chemical reactivity of the MW-absorbing solute can be described as a MW-specific extra-temperature thermal effect , because the measurable solution temperature only captures a portion of the solute kinetic molecular energy. Experimental factors that favor MW-specific rate enhancements are discussed with an eye toward future development of MW-actuated organic reactions, in which the observed thermal reactivity exceeds what is predicted from temperature-based Arrhenius calculations.
- Rosana, Michael R.,Hunt, Jacob,Ferrari, Anthony,Southworth, Taylor A.,Tao, Yuchuan,Stiegman, Albert E.,Dudley, Gregory B.
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supporting information
p. 7437 - 7450
(2014/11/27)
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- Nanoporous hematite nanoparticles: Synthesis and applications for benzylation of benzene and aromatic compounds
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The catalytic benzylation of benzene and other aromatic compounds is one of the most important reactions in the synthesis of pharmaceutical compounds. In this study, we report the synthesis of nanoporous α-Fe2O 3 nanoparticles via a hydrothermal method and their application in the catalytic benzylation of benzene and benzyl chloride in the fabrication of diphenylmethane. Crystal structure and morphology characterization results demonstrated that the hydrothermal method enabled the fabrication of highly dispersed α-Fe2O3 nanoparticles with spherical shape and an average size of 100 nm. The α-Fe2O3 nanoparticles have nanopores of less than 10 nm that are randomly distributed inside the nanoparticles. The catalytic benzylation of benzene and benzyl chloride was conducted over the synthesized a-Fe2O3 nanoparticles. The results demonstrated that the synthesized a-Fe 2O3 nanoparticles are effective catalysts for the benzylation of benzene and benzyl chloride with high activity and selectivity.
- Cuong, Nguyen Duc,Hoa, Nguyen Duc,Hoa, Tran Thai,Khieu, Dinh Quang,Quang, Duong Tuan,Quang, Vu Van,Hieu, Nguyen Van
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- Benzylation of arenes with benzyl ethers promoted by the in situ prepared superacid BF3-H2O
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An efficient and environmentally friendly benzylation of arenes with benzyl ethers as benzyl donors using BF3-Et2O to generate in situ the superacid BF3-H2O as an efficient promotor has been described. A wide variety of functional groups have been investigated and found to be compatible to give the desired diarylmethanes in yields of up to 99%. The crucial role of the moisture content in this transformation has been demonstrated by detailed investigations. This journal is the Partner Organisations 2014.
- Li, Yu,Xiong, Yan,Li, Xueming,Ling, Xuege,Huang, Ruofeng,Zhang, Xiaohui,Yang, Jianchun
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p. 2976 - 2981
(2014/06/10)
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- Iron-catalyzed arylation of aromatic ketones and aldehydes mediated by organosilanes
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A simple and efficient iron-catalyzed method for arylation of aromatic carbonyl compounds is reported. The use of 4-% FeCl3 or Fe(acac) 3 as the catalyst, in combination with a slight excess of chlorotrimethylsilane and triethylsilane, chlorination of benzylic ketones and aldehydes with subsequent Friedel-Crafts alkylation of arenes is achieved. Although the method is limited by the general constraints associated with Friedel-Crafts alkylation reactions, robust applications for the synthesis of pharmaceutical intermediates and so on can be envisioned. A robust one-pot, iron-catalyzed chlorination Friedel-Crafts alkylation reaction of benzylic carbonyl compounds, mediated by chlorotrimethylsilane and triethylsilane, has been developed to yield substituted diaryl and triaryl building blocks. Copyright
- Savela, Risto,Majewski, Marcin,Leino, Reko
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p. 4137 - 4147
(2014/07/08)
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- Gold-catalyzed oxidative coupling of arylsilanes and arenes: Origin of selectivity and improved precatalyst
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The mechanism of gold-catalyzed coupling of arenes with aryltrimethylsilanes has been investigated, employing an improved precatalyst (thtAuBr3) to facilitate kinetic analysis. In combination with linear free-energy relationships, kinetic isotope effects, and stoichiometric experiments, the data support a mechanism involving an Au(I)/Au(III) redox cycle in which sequential electrophilic aromatic substitution of the arylsilane and the arene by Au(III) precedes product-forming reductive elimination and subsequent cycle-closing reoxidation of the metal. Despite the fundamental mechanistic similarities between the two auration events, high selectivity is observed for heterocoupling (C-Si then C-H auration) over homocoupling of either the arylsilane or the arene (C-Si then C-Si, or C-H then C-H auration); this chemoselectivity originates from differences in the product-determining elementary steps of each electrophilic substitution. The turnover-limiting step of the reaction involves associative substitution en route to an arene π-complex. The ramifications of this insight for implementation of the methodology are discussed.
- Ball, Liam T.,Lloyd-Jones, Guy C.,Russell, Christopher A.
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supporting information
p. 254 - 264
(2014/01/23)
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- Multimetallic Ir-Sn3-catalyzed substitution reaction of π-activated alcohols with carbon and heteroatom nucleophiles
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An atom economic and catalytic substitution reaction of π-activated alcohols by a multimetallic IreSn3 complex has been demonstrated. The multimetallic IreSn3 complex can be easily synthesized from the reaction between [Cp*IrCl2]2 and SnCl2. In presence of as little as 1 mol % of the catalyst three different types of π-activated alcohols, namely benzyl, allyl, and propargyl alcohols, have been successfully transformed into alkylated products using carbon (arenes, heteroarenes, allyltrimethylsilane, and 1,3-dicarbonyls), nitrogen (sulfonamides), oxygen (alcohols), and sulfur (thiols) nucleophiles in very high yields. An electrophilic mechanism is proposed from the Hammett correlation study.
- Maity, Arnab Kumar,Chatterjee, Paresh Nath,Roy, Sujit
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p. 942 - 956
(2013/07/25)
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- Benzylation of aromatic compounds catalyzed by 3-methyl-1-sulfonic acid imidazolium tetrachloroaluminate and silica sulfuric acid under mild conditions
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In this work, efficient procedures for benzylation of a range of aromatic compounds by benzyl acetate in the presence of catalytic amounts of 3-methyl-1-sulfonic acid imidazolium tetrachloroaluminate ([Msim]AlCl 4) or silica sulfuric acid (SSA) under mild conditions are described. Simple methodology, easy workup procedure, clean reaction and reusability of the catalyst are some advantages of this work. Georg Thieme Verlag Stuttgart New York.
- Zolfigol, Mohammad Ali,Vahedi, Hooshang,Azimi, Saeid,Moosavi-Zare, Ahmad Reza
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p. 1113 - 1116
(2013/06/27)
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- Synthesis of diarylmethanes via a Friedel-Crafts benzylation using arenes and benzyl alcohols in the presence of triphenylphosphine ditriflate
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Triphenylphosphine ditriflate (TPPD) was found to be an efficient promoter for the Friedel-Crafts benzylation of arenes with benzyl alcohols in CH 2Cl2 at room temperature. The good yields, the 1:1 molar ratio of arene and benzyl alcohol, the benzylation of chlorobenzene as a nonactivated aromatic compound at room temperature, and no by-product formation are the main advantages of this procedure.
- Khodaei, Mohammad Mehdi,Nazari, Ehsan
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experimental part
p. 5131 - 5135
(2012/09/22)
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- Design and performance of supported Lewis acid catalysts derived from metal contaminated biomass for Friedel-Crafts alkylation and acylation
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The main goal of this work was to prove the interest of metal hyperaccumulator plants in supported Lewis acid catalysis. Friedel-Crafts alkylation and acylation reveal the great catalytic activity of different plant extracts. This approach is a green solution with chemical benefits including high yield, excellent regioselectivity, small amounts of catalyst, mild conditions and concrete perspectives towards the depletion of mineral resources. The results also constitute an incentive for the development of phytoextraction programs on metal-bearing soils.
- Losfeld, Guillaume,Escande, Vincent,Vidal De La Blache, Paul,L'Huillier, Laurent,Grison, Claude
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experimental part
p. 111 - 116
(2012/09/08)
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- 4-N,N-dimethylaminopyridine promoted selective oxidation of methyl aromatics with molecular oxygen
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4-N,N-Dimethylaminopyridine (DMAP) as catalyst in combination with benzyl bromide was developed for the selective oxidation of methyl aromatics. DMAP exhibited higher catalytic activity than other pyridine analogues, such as 4-carboxypyridine, 4-cyanopyridine and pyridine. The sp3 hybrid carbon-hydrogen (C-H) bonds of different methyl aromatics were successfully oxygenated with molecular oxygen. The real catalyst is due to the formation of a pyridine onium salt from the bromide and DMAP. The onium salt was well characterized by NMR and the reaction mechanism was discussed.
- Zhang, Zhan,Gao, Jin,Wang, Feng,Xu, Jie
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body text
p. 3957 - 3968
(2012/07/27)
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- Iron-catalyzed benzylation reaction of arenes with benzyl thiocyanates
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A novel, regioselective protocol for the synthesis of diphenylmethane derivatives has been developed by using iron-catalyzed Friedel-Crafts reaction of arenes with benzyl thiocyanates. In the presence of FeBr3, a variety of benzyl thiocyanates underwent the reaction with arenes to selectively afford the corresponding diarylmethane derivatives in moderate to high yields. Georg Thieme Verlag Stuttgart · New York.
- Guo, Xiao-Kang,Zhao, Dong-Yun,Li, Jin-Heng,Zhang, Xing-Guo,Deng, Chen-Liang,Tang, Ri-Yuan
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experimental part
p. 627 - 631
(2012/03/27)
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- Tin exchanged heteropoly tungstate: An efficient catalyst for benzylation of arenes with benzyl alcohol
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The partial exchange of tin with the protons of 12-tungstophosphoric acid (TPA) results in a highly active heterogeneous catalyst for benzylation of arenes with benzyl alcohol as benzylating agent. The catalysts were characterized by X-ray diffraction, Laser-Raman and FT-IR of pyridine adsorption. The catalytic activity depends significantly on the extent of tin exchanged with the protons of heteropoly tungstate. The characterization results suggest the presence of Lewis acidic sites by the exchange of tin. The catalyst with partial exchange of Sn showed high benzylation activity, which in turn related to variation in acidity of the catalysts. The catalyst is highly active for benzylation reaction irrespective of the nature of substituted arenes and benzyl alcohols. These catalysts are highly active compared to other acid catalysts used for benzylation of different arenes. The catalyst is easy to separate from reaction mixture and exhibit consistent activity upon reuse. The plausible reaction mechanism based on the role of both Lewis and Bronsted acid sites of the catalyst was discussed.
- Ramesh Kumar, Ch.,Rao, K.T. Venkateswara,Sai Prasad,Lingaiah
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experimental part
p. 17 - 24
(2011/04/21)
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- Catalytic properties of the Cr-HMS materials in the benzylation of benzene with benzyl chloride
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A series of chromium-containing mesoporous silicas with different Cr contents were prepared and characterized with chemical analysis, N2 adsorption measurements (BET equation and BJH theory), X-ray diffraction, diffuse reflectance UV-visible and H2-temperature programmed reduction techniques. Excellent results in benzylation of benzene and substituted benzenes employing benzyl chloride as the alkylating agent were obtained. The mesoporous chromium-containing materials showed both high activity and high selectivity for benzylation of benzene. The activity of these catalysts for the benzylation of different aromatic compounds is in the following order: benzene > toluene > p-xylene > anisole. Kinetics of the benzene benzylation over these catalysts has also been investigated.
- Bachari,Touileb,Tahir,Saadi,Halliche,Cherifi
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experimental part
p. 48 - 54
(2011/05/17)
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- New mesoporous perovskite ZnTiO3 and its excellent catalytic activity in liquid phase organic transformations
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A new mesoporous perovskite ZnTiO3 material has been synthesized by the evaporation-induced self-assembly (EISA) method using non-ionic surfactant Pluronic P123 as template. After calcination of the dried gel of equimolar concentrations of Zn(II) and Ti(IV) at 673 K, a new perovskite mesophase of ZnTiO3 (MZT-11) formed, having highly crystalline cubic ZnTiO3 pore wall. Interestingly, in the absence of P123 but otherwise identical synthesis conditions showed no cubic structure and a mixed phase consisting of ZnO and TiO2 phases (ZT-11). The BET surface area of the mesoporous perovskite materials (MZT-11) was 136 m2 g -1 and the average dimension of the pores was ca. 5.1 nm. The material was thoroughly characterized by different analytical methods including small and wide angle powder XRD, FE SEM, TEM, FT IR, UV-visible, photoluminescence (PL) and X-ray fluorescence (XRF) analysis. This new mesoporous perovskite material showed excellent catalytic activity in the Friedel-Crafts (FC) benzylation of aromatics and in the Fischer esterification of different long chain carboxylic acids in the presence of methanol under solvent-free conditions.
- Pal, Nabanita,Paul, Manidipa,Bhaumik, Asim
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scheme or table
p. 153 - 160
(2011/11/07)
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- Synergistic catalysis of isolated Fe3+ and Fe2O 3 on FeOx/HZSM-5 catalysts for Friedel-Crafts benzylation of benzene
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FeOx/HZSM-5 catalyst with 8 wt.% Fe-loading (8-FeZ) exhibited significantly higher reactivity in the benzylation of benzene with benzyl chloride than FeOx/HZSM-5 catalyst with 2.5 wt.% Fe-loading (2.5-FeZ) because the synergistic catalysis between isolated Fe3+ and superfine Fe2O3 occurred on 8-FeZ in the reaction.
- Lin, Tao,Zhang, Xin,Li, Rong,Bai, Ting,Yang, Si Ying
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scheme or table
p. 639 - 642
(2012/02/01)
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- InBr3-catalyzed deoxygenation of carboxylic acids with a hydrosilane: Reductive conversion of aliphatic or aromatic carboxylic acids to primary alcohols or diphenylmethanes
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A simple and practical procedure for the direct reduction of aliphatic carboxylic acids with a variety of functional groups to a primary alcohol using the mild reducing reagent tetramethyldisiloxane (TMDS), in the presence of a catalytic amount of InBr3 has been developed. This simple reducing system, when used together with a hydrosilane, allows the preparation of the diphenylmethane derivative directly from an aromatic carboxylic acid and an aromatic compound. Copyright
- Sakai, Norio,Kawana, Keita,Ikeda, Reiko,Nakaike, Yumi,Konakahara, Takeo
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experimental part
p. 3178 - 3183
(2011/06/28)
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- Br?nsted acid-catalyzed synthesis of diarylmethanes under non-genotoxic conditions
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Triflic acid and triflimide were found to efficiently catalyze the formation of a wide diversity of diarylmethanes from the non-genotoxic benzylic acetates and electron-rich arenes or heteroarenes. The reaction worked best with acetates capable of generating a stabilized benzylic cationic species. In most cases, the reactions were conveniently run in the absence of solvent under mild conditions.
- Mendoza, Oscar,Rossey, Guy,Ghosez, Léon
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experimental part
p. 2235 - 2239
(2011/05/05)
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- Iron oxide nanoparticles grown on carboxy-functionalized graphite: An efficient reusable catalyst for alkylation of arenes
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Here we report a simple procedure for the synthesis of a novel hybrid catalyst by growing iron oxide nanoparticles on carboxy-functionalized graphite. This hybrid catalyst demonstrated superior catalytic activity towards the alkylation of arenes with alkyl halides in contrast to commercial graphite or unsupported iron oxide nanoparticles in terms of yields and general applicability. The catalyst can be reused up to five times with a minimal loss of catalytic activity. Georg Thieme Verlag Stuttgart.
- Rajpara, Vikul,Banerjee, Subhash,Sereda, Grigoriy
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experimental part
p. 2835 - 2840
(2010/10/04)
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- New mesoporous silicotitaniumphosphate and its application in acid catalysis and adsorption of As(III/V), Cd(II) and Hg(II)
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A new mesoporous silicotitaniumphosphate material has been synthesized by using a non-conventional phosphorous source trimethyl phosphite with the aid of Pluronic F127 as structure directing agent (SDA). The mesopores are generated due to the slow hydrolysis of the reactant materials in the presence of supramolecular-assembly of non-ionic surfactant under the evaporation induced self-assembly (EISA) process. The material has been characterized by powder XRD, N2 sorption, TEM, SEM-EDS, TG-DTA, FT-IR, XPS, 29Si, 31P MAS NMR and UV-vis spectroscopic techniques. This new mesoporous material has considerably high BET surface area (379 m2 g -1) and narrow pore size distribution with a peak pore width of 5.4 nm. The material showed good catalytic activity in the liquid phase Friedel-Crafts benzylation reaction suggesting strong acidity on its surface. It can also be used as good adsorbent for the removal of toxic metal ions As(III/V), Cd(II) and Hg(II) from the contaminated water.
- Paul, Manidipa,Pal, Nabanita,Ali,Bhaumik, Asim
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scheme or table
p. 49 - 55
(2010/12/24)
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- Mesoporous zirconium phosphate catalyzed reactions: Synthesis of industrially important chemicals in solvent-free conditions
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Mesoporous zirconium phosphate (m-ZrP) having high specific surface area and narrow pore size distributions is synthesized in basic medium using zirconium carbonate as source of zirconium. The concentration of phosphate in precursor solutions, as well as the calcination temperature, is found to influence the textural properties and acidity of synthesized m-ZrP significantly. Microscopic analysis indicates the presence of worm like pores with spherical morphology. The porous structure has remarkable thermal stability (up to 800 °C). DRIFT and NH3-TPD analysis suggest the presence of reasonable amount of Lewis and Bro?nsted acid sites. High catalytic activity of synthesized m-ZrP is observed towards Friedel-Craft (F.C.) benzylation reaction. The effect of acid strength of catalyst, reaction time, temperature and amount of catalyst towards Friedel-Craft benzylation reaction are also studied. The m-ZrP is highly active towards other acid catalyzed reactions in solvent-free conditions. The catalytic activity of m-ZrP is much higher than that of conventional layered ZrP. The catalysts were separated easily from reaction mixture, regenerated after a simple activation step and reused at least six times without significant loss in catalytic activity.
- Sinhamahapatra, Apurba,Sutradhar, Narottam,Roy, Biplab,Tarafdar, Abhijit,Bajaj, Hari C.,Panda, Asit Baran
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scheme or table
p. 22 - 30
(2011/02/23)
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- High catalytic efficiency of nanostructured molybdenum trioxide in the benzylation of arenes and an investigation of the reaction mechanism
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The synthesis and characterization of nanostructured MoO3 with a thickness of about 30 nm and a width of about 450 nm are reported. The composition formula of the MP (precipitation method) precursor was estimated to be [(NH4)2O]0.169·MoO 3· (H2O)0.239. The calcination of the precursor in air afforded nanostructured pellets of the α-MoO3 phase. The nano-structured MoO3 catalyst exhibited high efficiency in catalyzing the benzylation of various arenes with substituted benzyl alcohols, which were strikingly different to common bulk MoO3. Most reactions offered >99% conversion and >99% selectivity to monoalkylated compounds. MoO3 is a typical acid catalyst. However, the benzylation reaction over nanostructured MoO3 does not belong to the acid-catalyzed type or defect site-catalyzed type, since the catalyst has no acidity and defect site on surface. Characterization with thermal, spectroscopic, and electronic techniques reveal that the catalyst contains fully oxygen-coordinated MoO 6 octahedrons on the surface but partially reduced species (Mo 5+) within the bulk phase. The terminal oxygen atoms of Mo=O bonds on the (010) basal plane resemble oxygen anion radicals and act as active sites for the adsorption and activation of benzyl alcohols by electrophilic attack. Such sites are indispensable for catalytic reactions since the blocking of these sites by electron acceptors, such as tetracyanoethylene (TCNE), can greatly decrease catalytic activity. This work represents a successful example of combining a heterogeneous catalysis study with nanomaterial synthesis.
- Wang, Feng,Ueda, Wataru
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experimental part
p. 742 - 753
(2009/10/01)
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- A simple catalyst for the efficient benzylation of arenes by using alcohols, ethers, styrenes, aldehydes, or ketones
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The compound [IrCp* (OTf)2(InBu)] (I nBu = 1,3-di-n-butyl-imidazolylidene) is an effective catalyst in the benzylation of arenes with different benzylating agents, such as alcohols, ethers and styrenes, representing an unprecedented highly versatile catalyst for this type of process. The same compound also catalyses a remarkable tandem process that allows the use of aldehydes and ketones as benzylating agents, through the base-free hydrogenation of C=O bonds with iPrOH and further use of the resulting primary or secondary alcohols as benzylating agents.
- Prades, Amparo,Corberan, Rosa,Poyatos, Macarena,Peris, Eduardo
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experimental part
p. 4610 - 4613
(2009/12/26)
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- Synthesis of functionalized diaryl alkancs from azines
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Substituted diaryl alkanes arc synthesized from bcnzalazines and acctophenone/propiophenone azines via Friedel Craft's reaction with substituted mono- and poly-nuclear aromatic hydrocarbons. Diaryl methanes/ethanes and propanes are obtained by reaction with benzalazine, N,N'-bis (I-phenyl) azine and N, N'-bis (I-propyl) azine, respectively.
- Manih, Rudolf M.,Myrboh, Bekington
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experimental part
p. 146 - 151
(2009/12/01)
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- Nanostructured molybdenum oxides and their catalytic performance in the alkylation of arenes
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We report for the first time that nanostructured MoO3 is an excellent catalyst for the alkylation of a wide range of arenes with substituted benzyl alcohols as alkylating agents. The Royal Society of Chemistry.
- Wang, Feng,Ueda, Wataru
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supporting information; scheme or table
p. 3196 - 3198
(2009/02/04)
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- Versatile friedel-crafts-type alkylation of benzene derivatives using a molybdenum complex/ortho-chloranil catalytic system
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A variety of molybdenum complexes catalyze Friedel-Crafts-type alkylation reactions of benzene derivatives with alkenes and alcohols in the presence of an organic oxidant, o-chloranil. The utilization of [Mo(CO)6] and two equivalents of o-chloranil catalytically furnished the hydroarylation product of norbornene with p-xylene at 80°C, whereas [Cr(CO)6] and [W(CO)6] failed to catalyze the same reaction, thus indicating the importance of the molybdenum source. The best results were obtained when a molybdenum(II) complex [CpMoCl(CO)3] (Cp = cyclopentadienyl) was used as a precatalyst. The hydroarylation reactions also took place with styrenes, cyclohexenes, and 1 -hexene as olefin substrates. The electrophilic-substitution mechanism was proposed on the basis of the ortho/para selectivities and the Markovnikov selectivities observed for the hydroarylation products. Our hypothesis was further corroborated by the fact that in the presence of the [CpMoCl(CO)3]/o-chloranil catalytic system, secondary, benzylic, or allylic alcohols participated in the alkylation of benzenes with similar selectivities.
- Yamamoto, Yoshihiko,Itonaga, Kouhei
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experimental part
p. 10705 - 10715
(2009/12/01)
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- Molecular iodine-catalyzed benzylation of arenes with benzyl alcohols
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A novel molecular iodine-catalyzed benzylation of arenes with benzyl alcohols has been developed. The reaction can be carried out under mild conditions to afford a series of diarymethane derivatives in high yields and good regioselectivities.
- Sun, Gaojun,Wang, Zhiyong
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p. 4929 - 4932
(2008/09/21)
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- Esters as acylating reagent in a Friedel-Crafts reaction: Indium tribromide catalyzed acylation of arenes using dimethylchlorosilane
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(Chemical Equation Presented) The Friedel-Crafts acylation of arenes with esters by dimethylchlorosilane and 10 mol % of indium tribromide has been achieved. The key intermediate RCOOSi(Cl)Me2 is generated from alkoxy esters with the evolution of the corresponding alkanes. The scope of the alkoxy ester moiety was wide: tert-butyl, benzyl, allyl, and isopropyl esters were successful. In addition, we demonstrated the direct synthesis of the indanone intermediate 11 of salviasperanol from ester 10.
- Nishimoto, Yoshihiro,Babu, Srinivasarao Arulananda,Yasuda, Makoto,Baba, Akio
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supporting information; experimental part
p. 9465 - 9468
(2009/04/06)
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- Benzylation of arenes through FeCl3-catalyzed Friedel-Crafts reaction via C-O activation of benzyl ether
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Various benzyl ethers were converted to benzyl arenes via a FeCl3-catalyzed Friedel-Crafts alkylation reaction under mild condition in good yields. This method also offered a simple and practical approach to synthesize di- or tri-aryl methanes and aryl heteroaryl methanes through the activation of C-O bonds.
- Wang, Bi-Qin,Xiang, Shi-Kai,Sun, Zuo-Peng,Guan, Bing-Tao,Hu, Ping,Zhao, Ke-Qing,Shi, Zhang-Jie
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p. 4310 - 4312
(2008/09/21)
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- An efficient synthesis of unsymmetrical diarylmethanes from the dehydration of arenes with benzyl alcohols using InCl3·4H2O/acetylacetone catalyst system
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An efficient and practical synthesis of unsymmetrical diarylmethanes has been achieved from the dehydration of arenes with benzyl alcohols in the presence of catalytic amount of InCl3·4H2O/acetylacetone.
- Sun, Hong-Bin,Li, Biao,Chen, Songjie,Li, Jie,Hua, Ruimao
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p. 10185 - 10188
(2008/02/13)
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- The synthetic potential of graphite-catalyzed alkylation
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Unmodified graphite is introduced as a mild catalyst for alkylation of aromatic compounds and primary alcohols, applicable when utilization of strong Lewis acids is not feasible. The electrophilic intermediate has a significant carbocationic character and can be formed on a partially rate-limiting step.
- Sereda, Grigoriy A.,Rajpara, Vikul B.,Slaba, Ryan L.
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p. 8351 - 8357
(2008/02/07)
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- Intermolecular Friedel-Crafts reaction catalyzed by InCl3
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Our recent discovery that In(III) salts were able to activate halides catalytically under mild conditions for the intermolecular Friedel-Crafts cyclization prompted us to explore this highly efficient activation in intermolecular Friedel-Crafts reactions. The alkylation of p-xylene with allylic and benzylic halides was demonstrated under catalytic and mild condition to afford in some cases quantitative yields of the monoalkylated products without the need to employ large excesses of reactants.
- Kaneko, Miho,Hayashi, Ryuji,Cook, Gregory R.
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p. 7085 - 7087
(2008/03/11)
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- Versatile mesoporous carbonaceous materials for acid catalysis
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Starbon mesoporous materials were synthesized after pyrolysis of expanded starch and subsequently functionalised with sulfonated groups, providing highly active and reusable materials in various acid catalysed reactions. The Royal Society of Chemistry.
- Budarin, Vitaly L.,Clark, James H.,Luque, Rafael,Macquarrie, Duncan J.
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p. 634 - 636
(2007/10/03)
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