- Biomimetic Radical Ring Expansion and Aromatisation; a Model for the Biogenesis of Natural Ring-D Aromatic Steroids
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Photolysis of the thiohydroxamate 7 generated the carbon radical 9, which rearranged and aromatised to the methyltetralin 8, providing a model for the biogenesis of the insect antifeedant steroid nic-11 from the conventional C/D precursor nic-3 2: photolysis of the isomeric thiohydroxamate 13 gave both methyltetralins 8 and 14, through an unusual rearrangement sequence, possibly involving the benzvalene related radical 17.
- Green, Stuart P.,Whiting, Donald A.
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- Synthesis of Substituted Benzenes via Bi(OTf)3-Mediated Intramolecular Carbonyl Allylation of α-Prenyl or α-Geranyl β-Arylketosulfones
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Intramolecular carbonyl allylation of α-prenyl or α-geranyl β-arylketosulfones 5 in the presence of molecule sieves (MS) affords substituted benzenes 6-7 in moderate to good yields. The facile transformation proceeds by a synthetic sequence starting with the α-prenylation or α-geranylation of 1 and the Bi(OTf)3-mediated annulation of 5 followed by a sequential desulfonative aromatization or then an intramolecular Friedel-Crafts alkylation. A plausible mechanism has been studied and proposed.
- Chang, Meng-Yang,Cheng, Yu-Chieh,Lu, Yi-Ju
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- Effect of Composition of Cobalt-Molybdenum-Containing Sulfonium Thiosalts on the Hydrogenation Activity of Nanosized Catalysts In Situ Synthesized on Their Basis
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Abstract: Cobalt-molybdenum-containing thiosalts with different composition of the sulfonium cation are prepared. The activities of sulfide catalysts in situ synthesized on their basis in the hydrogenation of substituted naphthalenes are compared. It is shown that the sulfonium cation composition affects the morphology of the sulfide particles and the phase composition of the catalyst. It is demonstrated that the conversion of model alkyl-substituted bicyclic aromatic hydrocarbons is higher in the presence of the catalyst prepared from the phenylsulfonium thiosalt.
- Knyazeva,Panyukova,Kuchinskaya,Kulikov,Maximov
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- Hydroconversion of 2-methylnaphtalene and dibenzothiophene over sulfide catalysts in the presence of water under CO pressure
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Unsupported highly dispersed nanosized catalysts based on transition metal sulfides were prepared insitu, in water-oil emulsions, by high-temperature decomposition of oil soluble metal precursors using elemental sulfur as sulfiding agent. Their catalytic activity was tested in hydroconversion of 2-methylnaphtalene and dibenzothiophene at 380 °C under H2 pressure of 5 MPa. In addition, the catalysts were tested in the same reactions in the CO?H2O medium (p(CO) = 5 MPa, the CO: H2O molar ratio was 2: 1, ω(H2O) = 20 wt.%) in which hydrogen is formed through a water gas shift reaction (WGSR). Unsupported Ni?Mo-sulfide catalysts were found to be the most active compared to catalysts supported on alumina. Transmission electron microscopy served to investigate the structure and determine general geometric characteristics of Ni?Mo?S particles formed in toluene—water medium by decomposition of transition metal naphthenates and hexacarbonyls in the presence of elemental sulfur under CO pressure. The method described in this study enables one to synthesize nanosized catalysts with a high content of active sulfide phase.
- Glotov, A. P.,Karakhanov, E. A.,Maximov, A. L.,Vutolkina, A. V.
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- A new precursor for synthesis of nickel-tungsten sulfide aromatic hydrogenation catalyst
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The unsupported NiWS-catalyst was obtained from the precursor [Ph3S]2Ni(WS4)2 in a hydrocarbon medium (in situ) for hydrogenation bicyclic aromatic compounds. The precursor [Ph3S]2Ni(WS4)2 and the catalyst prepared on its basis were studied by the X-ray diffraction and X-ray absorption methods, XPS and TEM. It was found that the new catalyst formed in situ contains tungsten sulfide and nickel sulfide nanophases. Tungsten sulfide, which has a layered structure, partially forms an insertion compound with nickel that enters between the WS2 layers and bonds covalently to sulfur. The proposed catalyst has proved to be active in the hydrodearomatization processes of model aromatic compounds (naphthalene, methylnaphthalenes) and exhibited the maximum selectivity with the formation of decalins compared to other earlier studied catalysts formed from other precursors in the reaction medium.
- Serdyukov,Kniazeva,Sizova,Zubavichus,Dorovatovskii,Maximov
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- Pd-Ni BMNPs Encapsulated in UiO-66 as an Efficient Catalyst for the Activation of “Inert” C?O Bonds
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A catalytic system based on Pd?Ni bimetallic nanoparticles (BMNPs) encapsulated in the nanocavities of UiO-66 was established for the activation of C?O bonds in ethers. Pd0.25Ni4@UiO-66 catalyst show excellent catalytic performance in the directly methylation and arylation of ethers under a mild reaction condition. High catalytic activity of the catalyst could be ascribed to the “synergistic effect” between the two metal components and strong interaction between BMNPs and the carrier (UiO-66). BMNPs encapsulated in UiO-66 also guarantee a good reusability of the catalyst, the catalyst delivered high catalytic activity for at least four cycles. Our work highlights the great potential value of ethers as powerful alternatives for aryl halides as well as the bright future of BMNPs and MOFs in the catalysis field.
- Zhang, Jia-Wei,Li, Dan-Dan,Lu, Guo-Ping,Deng, Tao,Cai, Chun
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- Synthesis of renewable alkylated naphthalenes with benzaldehyde and angelica lactone
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Herein, we report a new route for the synthesis of renewable alkylated naphthalenes (ANs) with benzaldehyde and angelica lactone, two platform compounds that can be derived from lignocellulose.
- Cong, Yu,Li, Guangyi,Li, Ning,Wang, Aiqin,Wang, Ran,Wang, Xiaodong,Xu, Jilei,Zhang, Tao
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supporting information
p. 5474 - 5480
(2021/08/16)
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- Nickel–Tungsten and Nickel–Molybdenum Sulfide Diesel Hydrocarbon Hydrogenation Catalysts Synthesized in Pores of Aromatic Polymer Materials
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Abstract: Porous aromatic polymer materials based on tetraphenylmethane molecules linked by methylene groups have been synthesized. By impregnating these materials with nickel–tungsten and nickel–molybdenum thiosalts, catalysts for the hydrogenation of bicyclic aromatic hydrocarbons of the diesel fraction have been prepared. Nanoparticles of the active sulfide phase are formed in support pores during the reaction; it is assumed that after the formation of the nanoparticles, the support material will undergo partial degradation to rearrange the mesoporous structure into a macroporous structure providing the best diffusion of substrates to the surface of the sulfide nanoparticles. The synthesized catalysts have been tested in the hydrogenation of naphthalene and naphthalene derivatives at a hydrogen pressure of 5 MPa and a temperature of 380°C.
- Batryshin,Makeeva,Kulikov,Kardasheva, Yu. S.,Maksimov,Karakhanov
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p. 575 - 580
(2019/06/24)
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- Promoted catalysts for hydrogenation of bicyclic aromatic hydrocarbons obtained in situ from molybdenum and tungsten carbonyls
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Promoted Мo and W catalysts have been prepared in situ via thermal decomposition of precursors, oil-soluble salts Mo(CO)6, W(CO)6, С°C16H30O4, and NiC16H30O4. TiO2, Al2O3, and ZrO(NO3)2 · 6H2O have been used as the acidic additives. Also, Mo and W unsupported sulfide catalysts have been prepared in the presence of elemental sulfur as the sulfiding agent. The catalysts have been characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. The activity of the catalysts prepared in situ has been evaluated in the hydrogenation reaction of bicyclic aromatic hydrocarbons by the example of model mixtures of 10% solutions of naphthalenes (unsubstituted naphthalene, 1- and 2-methylnaphthalenes, and 1,5- and 2,3-dimethylnaphthalenes) in n-hexadecane. The effect of the precursor/acidic oxide ratio on the activity of the formed catalyst has been found. Hydrogenation of bicyclic aromatic hydrocarbons has been conducted at a hydrogen pressure of 2 and 5 MPa and a temperature of 380 and 400°C for 2 h. Hydrogenation of the unsubstituted aromatic ring has been preferable due to the absence of steric hindrances. The degree of conversion of n-hexadecane under the reaction conditions has been 1.5–7.5% depending on the reaction temperature. It has been found that the activity of the sulfided catalyst in the conversion of 1- and 2-methylnaphthalenes is inferior to the activity of the unsulfided analogue, while partial replacement of TiO2 by Al2O3 results in a decrease in the conversion of the substrates as opposed to the unsulfided catalysts, in which the use of nanocrystalline Al2O3 promotes an increase in the conversion.
- Zakharyan,Onishchenko,Maksimov
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- Hydrogenation of Aromatic Substrates over Dispersed Ni–Mo Sulfide Catalysts in System H2O/CO
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The activity of unsupported Ni–Mo sulfide catalysts formed during the in situ decomposition of oil-soluble precursors (molybdenum hexacarbonyl, nickel naphthenate) in the hydrogenation of aromatic and naphthene-aromatic compounds is studied. The catalysts are characterized by HRTEM and XPS. Catalytic experiments are conducted at temperatures of 340–380°C and an increased pressure of ?? in the presence of water providing the in situ generation of hydrogen via the water-gas shift reaction. The catalysts exhibit a high activity in the hydrogenation of model substrates (methyl- and dimethyl-substituted naphthalenes and anthracene).
- Vutolkina,Makhmutov,Zanina,Maximov,Glotov,Sinikova,Karakhanov
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p. 528 - 534
(2018/07/29)
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- Hybrid Catalysis Enabling Room-Temperature Hydrogen Gas Release from N-Heterocycles and Tetrahydronaphthalenes
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Hybrid catalyst systems to achieve acceptorless dehydrogenation of N-heterocycles and tetrahydronaphthalenes-model substrates for liquid organic hydrogen carriers-were developed. A binary hybrid catalysis comprising an acridinium photoredox catalyst and a Pd metal catalyst was effective for the dehydrogenation of N-heterocycles, whereas a ternary hybrid catalysis comprising an acridinium photoredox catalyst, a Pd metal catalyst, and a thiophosphoric imide organocatalyst achieved dehydrogenation of tetrahydronaphthalenes. These hybrid catalyst systems allowed for 2 molar equiv of H2 gas release from six-membered N-heterocycles and tetrahydronaphthalenes under mild conditions, i.e., visible light irradiation at rt. The combined use of two or three different catalyst types was essential for the catalytic activity.
- Kato, Shota,Saga, Yutaka,Kojima, Masahiro,Fuse, Hiromu,Matsunaga, Shigeki,Fukatsu, Arisa,Kondo, Mio,Masaoka, Shigeyuki,Kanai, Motomu
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supporting information
p. 2204 - 2207
(2017/02/23)
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- Hydrodearomatization catalysts based on molybdenum hexacarbonyl Mo(CO)6 supported on mesoporous aromatic frameworks
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A method for synthesizing fine hydrodearomatization catalysts based on the immobilization of molybdenum carbonyl into the pores of mesoporous aromatic frameworks is proposed. It is shown that the amount of the deposited metal and the average size of the resulting particles depend on the support and the deposition method characteristics. The catalytic activity of the synthesized materials in the hydrogenation of bicyclic hydrocarbons at a hydrogen pressure of 5.0 MPa in a temperature range of 330–500°C is studied using the example of naphthalene, methylnaphthalenes, and biphenyl as model substrates.
- Maksimov,Karakhanov,Kulikov,Terenina
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p. 589 - 594
(2017/07/22)
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- Synthesis of tetraline derivatives through depolymerization of polyethers with aromatic compounds using a heterogeneous titanium-exchanged montmorillonite catalyst
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A novel depolymerization of poly(tetramethylene glycol) (PTMG) with benzene to tetralin using titanium-exchanged montmorillonite (Ti4+-mont) as a solid acid catalyst is described. This catalyst is applicable to depolymerization of PTMG with some aromatic compounds. This is the first demonstration of the potential use of PTMG as a C4 synthon for organic synthesis.
- Maeno, Zen,Torii, Hiroyuki,Yamada, Shota,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro
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p. 89231 - 89233
(2016/10/03)
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- Selective hydroconversion of naphthalenes into light alkyl-aromatic hydrocarbons
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2-Ring aromatics such as naphthalene and alkyl-naphthalenes constitute a high fraction in the diesel boiling point range by-products from oil refining and petrochemical plants. A two-step catalytic process, consisting of a selective hydrogenation of naphthalenes to tetralins and a subsequent hydrocracking of tetralins into light alkyl-aromatic hydrocarbons rich in BTX (benzene, toluene, xylenes), was postulated and studied in a fixed bed down-flow reactor under a moderate pressure of 3-4 MPa. For the selective hydrogenation of naphthalenes to tetralins, it was found that the catalytic performances of Mo2C-supported catalysts were superior in terms of tetralins yield as well as selectivity to the conventional metal-supported catalysts such as Pt, Co, Ni and NiW supported catalysts. The hydrocracking of tetralin was demonstrated to produce light alkyl-aromatic hydrocarbons rich in BTX over a monofunctional H-Beta and a bifunctional Ni/H-Beta catalyst. For the high per pass yield of BTX in the hydrocracking of tetralin in which chemical equilibrium limits its conversion and product selectivity, the bifunctional Ni/H-Beta catalyst was found to be highly promising compared with the monofunctional H-Beta catalyst. The bifunctional Ni/H-Beta showed the BTX selectivity in liquid product and the total BTX yield as high as 69.5% and 40.7 wt%, respectively, at the tetralin conversion of 99.5% at 450 °C under 4 MPa. The catalytic behavior of Ni/H-Beta suggests that BTX yield can be much improved by properly controlling the hydrogenation power of metallic sites (i.e., suppressing the hydrogenation activity), the acidity of H-Beta and their balance on the bifunctional hydrocracking catalysts.
- Choi, Yeseul,Lee, Jihye,Shin, Jaeuk,Lee, Seulah,Kim, Donguk,Lee, Jung Kyoo
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p. 140 - 150
(2015/05/05)
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- Selective hydroconversion of naphthalenes into light alkyl-aromatic hydrocarbons
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2-Ring aromatics such as naphthalene and alkyl-naphthalenes constitute a high fraction in the diesel boiling point range by-products from oil refining and petrochemical plants. A two-step catalytic process, consisting of a selective hydrogenation of naphthalenes to tetralins and a subsequent hydrocracking of tetralins into light alkyl-aromatic hydrocarbons rich in BTX (benzene, toluene, xylenes), was postulated and studied in a fixed bed down-flow reactor under a moderate pressure of 3-4 MPa. For the selective hydrogenation of naphthalenes to tetralins, it was found that the catalytic performances of Mo2C-supported catalysts were superior in terms of tetralins yield as well as selectivity to the conventional metal-supported catalysts such as Pt, Co, Ni and NiW supported catalysts. The hydrocracking of tetralin was demonstrated to produce light alkyl-aromatic hydrocarbons rich in BTX over a monofunctional H-Beta and a bifunctional Ni/H-Beta catalyst. For the high per pass yield of BTX in the hydrocracking of tetralin in which chemical equilibrium limits its conversion and product selectivity, the bifunctional Ni/H-Beta catalyst was found to be highly promising compared with the monofunctional H-Beta catalyst. The bifunctional Ni/H-Beta showed the BTX selectivity in liquid product and the total BTX yield as high as 69.5% and 40.7 wt%, respectively, at the tetralin conversion of 99.5% at 450°C under 4 MPa. The catalytic behavior of Ni/H-Beta suggests that BTX yield can be much improved by properly controlling the hydrogenation power of metallic sites (i.e., suppressing the hydrogenation activity), the acidity of H-Beta and their balance on the bifunctional hydrocracking catalysts.
- Choi, Yeseul,Lee, Jihye,Shin, Jaeuk,Lee, Seulah,Kim, Donguk,Lee, Jung Kyoo
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p. 140 - 150
(2015/05/05)
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- Nickel-tungsten sulfide aromatic hydrocarbon hydrogenation catalysts synthesized in situ in a hydrocarbon medium
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Nickel-tungsten sulfide nanocatalysts for the hydrogenation of aromatic hydrocarbons (HCs) have been prepared by the in situ decomposition of a nickel thiotungstate precursor in a HC feedstock using 1-butyl-1-methylpiperidinium nickel thiotungstate complex [BMPip]2Ni[WS4]2 as the precursor. The in situ synthesized particles have been characterized by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. It has been shown that the resulting Ni-W-S particles are nanoplates associated in multilayer agglomerates; the average length of the Ni-W-S particles is 6 nm; the average number of layers in the multilayer packaging is three. The catalytic activity of the synthesized catalysts has been studied in the hydrogenation of model mixtures of mono- and bicyclic aromatic HCs and in the conversion of dibenzothiophene in a batch reactor at a temperature of 350°C and a hydrogen pressure of 5.0 MPa. It has been shown that the studied catalysts can be used for the hydrofining of light cycle oil.
- Sizova,Serdyukov,Maksimov
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p. 470 - 480
(2015/11/23)
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- Enamine/butadienylborane cycloaddition in the frustrated Lewis pair regime
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The dienylborane 2a was prepared by regioselective alkyne hydroboration of the conjugated enyne 1a with Piers' borane [HB(C6F5)2]. Its reaction with a series of acetophenone derived enamines 3 resulted in the formation of
- Chen, Guo-Qiang,Türkyilmaz, Fatma,Daniliuc, Constantin G.,Bannwarth, Christoph,Grimme, Stefan,Kehr, Gerald,Erker, Gerhard
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p. 10477 - 10486
(2015/11/10)
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- One-pot synthesis of tetralin derivatives from 3-benzoylpropionic acids: Indium-catalyzed hydrosilylation of ketones and carboxylic acids and intramolecular cyclization
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This reducing system was composed of a small amount (1 mol%) of In(OAc)3, Me2PhSiH, and I2 that effectively catalyzed the hydrosilylation of two different carbonyl groups, a ketone and a carboxylic acid found in 3-benzoylpropionic acids, followed by a subsequent intramolecular cyclization that led to the one-pot preparation of tetralin derivatives.
- Sakai, Norio,Kobayashi, Taichi,Ogiwara, Yohei
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supporting information
p. 1503 - 1505
(2015/11/24)
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- Quenched skeletal Ni as the effective catalyst for selective partial hydrogenation of polycyclic aromatic hydrocarbons
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Quenched skeletal Ni is an active and selective catalyst for selective partial hydrogenation of polycyclic aromatic hydrocarbons (PAHs). The molecular structure of PAHs significantly dominate the hydrogenation process and furthermore, the distribution of hydrogenated products.
- Liu, Chengyun,Rong, Zeming,Sun, Zhuohua,Wang, Yong,Du, Wenqiang,Wang, Yue,Lu, Lianhai
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p. 23984 - 23988
(2013/11/19)
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- Formal radical closure onto aromatic rings-a general route to carbocycles
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A general method is described for indirectly effecting radical carbocyclization of an alkyl chain onto an aromatic ring. Birch reductive-alkylation of aromatic tert-butyl esters with α,ω- dibromides, chromium(vi)-mediated oxidation of the resulting 1,4-dienes and Finkelstein displacement of Br- with NaI gives cross-conjugated ketones that undergo radical cyclization. The products are easily aromatized to phenols by silylation, Saegusa oxidation and treatment with BiCl 3.H2O. A special feature of the route is that it allows attachment of a substituent to the original aromatic ring in place of the phenolic oxygen of the normal product.
- Clive, Derrick L. J.,Sunasee, Rajesh,Chen, Zhenhua
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experimental part
p. 2434 - 2441
(2009/02/02)
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- Palladium-catalyzed benzannulation from alkynes and allylic compounds
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Various alkynes reacted with allyl tosylates in the presence of palladium catalysts, giving polysubstituted benzenes with good to high regioselectivity. Pentasubstituted and trisubstituted benzenes were readily prepared by reaction of internal alkynes and
- Tsukada, Naofumi,Sugawara, Shuichi,Nakaoka, Keiichiro,Inoue, Yoshio
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p. 5961 - 5966
(2007/10/03)
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- Ring-D aromatic phytosteroids; a model for biogenesis by way of carbon radical rearrangement
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A mechanism is postulated for the biogenesis of the unique ring-D aromatic phytosteroids from Nicandra physaloides, which involves rearrangement, ring expansion, and aromatisation of a carbon radical generated by cytochrome P450 (Scheme 1). In support, model hydrindene acids 15b and 18b have been synthesized and subjected to homolytic decarboxylation; the latter acid yielded 6-methyltetralin 24, in biomimetic fashion. The isomeric acid afforded not only 6-methyltetralin 24 but also 5-methyltetralin 26; mechanisms for this unusual rearrangement are discussed.
- Green, Stuart P.,Whiting, Donald A.
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p. 1027 - 1034
(2007/10/03)
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- Characterization of New Methyl-Substituted Tetralins and Indans by 13C NMR Spectroscopy
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In order to perform the analysis of the components contained in fossil fuels, carbon assignments of new methylated derivatives of tetralin and indan were obtained.Their chemical shifts were calculated by applying additivity rules. - Keywords: NMR; 13C NMR; tetralins; indans
- Laurens, T.,Schmit-Quiles, F.,Nicole, D.
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p. 523 - 528
(2007/10/02)
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- An N.M.R. Investigation of the Mills-Nixon Effect
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The 4J coupling constant, previously established as a probe of bond order, was used to examine the bond orders in a series of ortho-bridged compounds: benzocyclopropene, 1,2-dihydrobenzocyclobutene, indan and tetralin.No evidence for sterically induced bond fixation (i.e. the Mills-Nixon effect) was found, but some evidence for electronic distortion in the corresponding benzylic ketones was observed.The experimental results are in accord with SCF/MO calculations.
- Collins, Michael J.,Gready, Jill E.,Sternhell, Sever,Tansey, Charles W.
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p. 1547 - 1557
(2007/10/02)
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- 98. A Regioselective Cyclohexannulation Procedure via Dienamine Cycloaddition. Synthesis of Functionalised Decalins
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A regioselective cyclohexannulation procedure, whose key step involves the cycloaddition of dienamines 12-24 with methyl acrylate, allows the conversion of cycloalkanones 1-11 to bicyclic dienoates 25-37.The chemistry of 26 is briefly examined and, in the context of organoleptic studies concerning functionalised 5,5,9-trimethyldecalins, the transformation of 37 to ketones 44 and 46 as well as to acetates 53-56 is described.
- Snowden, Roger L.,Linder, Simon M.,Wuest, Manfred
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p. 892 - 905
(2007/10/02)
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- Reduction of Polycyclic Arenes by BH-Boranes, II Borane Catalyzed Hydrogenation of Naphthalenes to Tetralins
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Tetrapropyldiborane(6) (TPDB) and triethylborane (TEB) catalyze the regioselective and partial hydrogenation of naphthalene (N) and a number of substituted naphthalenes at 170 deg C to 200 deg C and hydrogen pressures of 25-100 bar.Tetralin (T) is formed quantitatively.Naphthalene derivatives are mainly hydrogenated in the least substituted ring.In the case of alkyl substituents, Lewis acid catalyzed migration and, to a lesser extent C-C bond rupture, lower the yield of the main tetralin derivative.Chlorinated naphthalenes and at the O-atom derivatized naphthols undergo also partial loss of the chloro or oxygen functional groups.The i nitially added borane acts only as a precatalyst and its slowly converted to catalytically active polyboranes of as yet unknown structures.Keywords: Hydroboranes/ Hydrogenation/ Naphthalenes/ Tetralins
- Yalpani, Mohamed,Lunow, Thomas,Koester, Roland
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p. 687 - 694
(2007/10/02)
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- Intermediate Formation ofMetacyclophane on Flash Vacuum Thermolysis
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Pyrolysis of 2,6-tetramethylene Dewar benzene (2a) under flash vacuum thermolysis (FVT) conditions at 400 deg C gave 6- and 5-methylindan (8a (2.5percent) and 10a (2.5percent), respectively) as well tetralin (5a) (45percent).These products indicate that metacyclophane (1a) was formed in the gas phase, but it decomposed under the reaction conditions either via homolytic cleavage of one of the benzylic bonds to yield a diradical (6a) leading to 8a and 10a or it gave 5a via benzvalene intermediate (4a).Deuterium labeling supports the proposed mechanism.A very similar course of events was observed on FVT of metacyclophane at 600 deg C; it yielded methyl-substituted tetralins (8c, 10c) as the sole products.The analogies and differences in the behavior of the two metacyclophanes are discussed.
- Kostermans, Gerardus, B. M.,Dansik, Paul van,Wolf, Willem H. de,Bickelhaupt, Friedrich
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p. 4531 - 4534
(2007/10/02)
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- SYNTHESIS OF ARYL METHYLTHIO ETHERS EMPLOYING α-OXOKETENE DITHIOACETALS
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Reaction of α-oxoketene dithioacetals with methallyl magnesium chloride followed by acid treatment affords simple and annulated aryl methylthio ethers.The methylthio substituent can be easily removed with Raney Ni, undergo a Ni catalyzed substitution reac
- Dieter, R. Karl,Lin, Yawares Jenkitkasemwong
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- Synthesis of Biological Markers in Fossil Fuels. 2. Synthesis and 13C NMR Studies of Substituted Indans and Tetralins
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Unambiguous syntheses of all possible methyl, ethyl, n-propyl, and n-butyl derivatives of indan and tetralin were developed using the Kumada coupling procedure involving the reaction of aryl or vinyl halides with Grignard reagents in the presence of nickel(II) chloride.An analysis of the 13C NMR spectra of these compounds was also completed.
- Adamczyk, Maciej,Watt, David S.,Netzel, Daniel A.
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p. 4226 - 4237
(2007/10/02)
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- Neighboring Group Participation in Solvolysis. X. Dissection of Ar1-5 and Ar2-6 Pathways in Trifluoroacetolysis of 4-Arylbutyl 6-Methyl-2-naphthalenesulfonates
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Trifluoroacetolysis rates and products were determined for eleven 4-(m- and p-substituted phenyl)butyl 6-methyl-2-naphthalenesulfonates.Most substrates solvolyze predominantly or even exclusively with aryl assisted (kΔ) pathway.Dissection of kΔ into Ar1-5 and Ar2-6 components was performed by means of quantitative 13C NMR study of suitably labeled p-methyl and p-fluoro derivatives; the results were 32.4percent Ar1-5 and 67.6percent Ar2-6 for the former and 43.3percent Ar1-5 and 56.7percent Ar2-6 for the latter.For other substrates the dissection was carried out by postulating two independent linear free energy relationships (LFER) for the two pathways determined by the above four partial rates.Ar2-6 is much prefered over Ar1-5 through the series; for the unsubstituted derivative 90.6percent Ar2-6 vs. 9.4percent Ar1-5 was determined.A completely different approach by means of non-linear regression analysis of kΔ as a sum of two independent LFER gave fairly different and rather unsettled results, limitations of such an approach being suggested.The characteristics of remote aryl participation are discussed based on the above data.
- Ando, Takashi,Yamawaki, Junko,Saito, Yoshimasa,Takai, Yoshio,Yamataka, Hiroshi
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p. 2348 - 2356
(2007/10/02)
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- Process for homogeneous hydrogenation of polycyclic aromatic hydrocarbons
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An improved process is described for the homogeneous hydrogenation of polycyclic aromatic hydrocarbons utilizing anionic Group VIII metal hydride compositions as catalysts which contain phosphorus, arsenic or antimony organoligands. Use of these anionic catalysts allows the process to be conducted under mild conditions of temperature and pressure with high selectivity for the production of partially hydrogenated derivatives of polycyclic aromatic hydrocarbons such as 1,2,3,4-tetrahydronaphthalene, and eliminates the need for the presence of base or carbon monoxide atmosphere in the process.
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