- Surfactant-assisted hydrothermally synthesized MoS2 samples with controllable morphologies and structures for anthracene hydrogenation
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MoS2 samples with controllable morphologies and structures were synthesized using surfactant-assisted hydrothermal processes. The effects of surfactants (PEG, PVP, P123, SDS, AOT, and CTAB) on the morphologies and structures of MoS2 samples were investigated. The results revealed that spherical, bulk-like, and flower-like MoS2 particles assembled by NH4+-intercalated MoS2 nano-sheets were synthesized. The morphologies of the MoS2 samples and their structures (including the slab length and the number of stacked layers) of MoS2 nano-sheets in these samples could be controlled by adjusting the surfactants. Mono-dispersed spherical MoS2 particles could be synthesized with PEG via the creation of MoS2 nano-sheets with slab lengths shorter than 15 nm and fewer than six stacked layers. Possible formation mechanisms of these MoS2 samples created via surfactant-assisted hydrothermal processes are proposed. Further, the catalytic activities of MoS2 samples for anthracene hydrogenation were evaluated in a slurry-bed reactor. The catalyst synthesized with the surfactant PEG exhibited the highest catalytic hydrogenation activity. Compared with the other catalysts, it had a smaller particle size, mono-dispersed spherical morphology, shorter slab length, and fewer stacked layers; these were all beneficial to exposing its active edges. This work provides an efficient approach to synthesize transition metal sulfides with controllable morphologies and structures.
- Li, Min,Wang, Donge,Li, Jiahe,Pan, Zhendong,Ma, Huaijun,Jiang, Yuxia,Tian, Zhijian,Lu, Anhui
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- N-Heterocyclic Carbene Boranes are Hydrogen Donors in Masamune-Bergman Reactions of Benzo[3,4]cyclodec-3-ene-1,5-diynes
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Thermal reactions of benzo[3,4]cyclodec-3-ene-1,5-diyne with N-heterocyclic carbene boranes (NHC-boranes) provided mixtures of 9-borylated 1,2,3,4-tetrahydroanthracenes along with 1,2,3,4-tetrahydroanthracene. These products indicate that NHC-boranes serve as hydrogen donors to a p-benzyne intermediate formed by the Masamune-Bergman reaction. Experimental results support a radical mechanism in nonpolar solvents, but suggest that ionic mechanisms compete in the production of 1,2,3,4-tetrahydroanthracene when the reaction is performed in a polar solvent.
- Watanabe, Takashi,Geib, Steven J.,Curran, Dennis P.,Taniguchi, Tsuyoshi
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- In Situ Formed Acetal-Facilitated Synthesis of Substituted Indene Derivatives from o-Alkenylbenzaldehydes
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A new protocol has been developed for the synthesis of indene derivatives in a diastereoselective manner from o-alkenylbenzaldehydes and enolizable ketones in the presence of trimethyl orthoformate and catalytic triflic acid. This method involves tandem in situ formed acetal-assisted Claisen-Schmidt condensation followed by 5-exo-trig cyclization/Michael addition in one-pot. It has also been shown that the chalcones derived from o-alkenylbenzaldehydes and ketones can effectively be transformed into indene derivatives in the presence of TfOH catalyst alone.
- Manojveer, Seetharaman,Balamurugan, Rengarajan
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- Photochemical cycloaromatization reactions of ortho-dialkynylarenes: A new class of DNA photocleaving agents
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We are intrigued by the possibility of consolidating the functional elements of the enediyne anticancer antibiotics, thereby simplifying the task of synthesizing potential chemotherapeutic agents which operate by DNA cleavage pathways. Thus, it was envisaged that certain polycyclic ortho-dialkynylarenes would intercalate into DNA and, moreover, the planar π systems might be further exploited by facilitating photochemical, as opposed to thermal, cycloaromatization/cleavage reactions. We report herein on the viability of this photochemical transformation and the resultant new class of DNA photocleaving agents, whose binding and photoactive domains are consolidated, and which generate two reactive sites for subsequent ribose hydrogen atom abstraction(s).
- Funk,Young,Williams,Flanagan,Cecil
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- Preliminary investigations on the catalytic hydrogenation of polycyclic aromatic hydrocarbons via WGSR
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The water-gas shift reaction (WGSR) is a crucial reaction in the direct liquefaction of lignite in a syngas (CO + H2) system. In this study, anthracene was utilized as a polycyclic model compound of lignite, to which hydrogen is donated by the H2/D2 produced from CO and H2O/D2O via the WGSR. The results show that the model compound of the polycyclic aromatic hydrocarbon in coal (anthracene) undergoes partial cracking and polycondensation under non-hydrogen-donor conditions at 400 °C. In addition, WGSR catalyzed by NiO can generate hydrogen for the hydrogenation of anthracene. Comparing the mass spectra of deuterated products with those of conventional hydrogenation products by isotope labeling, the alkyl side chain positions of toluene, 1,4-xylene, methylnaphthalene, 1,1-diphenylethylene, methylanthracene and other compounds are prone to deuteration, enabling speculation of the main hydrogenation route of anthracene, which provides theoretical support for the catalytic hydrogenation in direct liquefaction of lignite in a syngas (CO + H2) system.
- Chen, Dabo,Gu, Jiale,Huang, Sheng,Li, Huan,Wu, Shiyong,Wu, Youqing
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- Catalyzed transfer hydrogenation by 2-propanol for highly selective PAHs reduction
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Catalytic hydrogenation of mono-, di- and trinuclear aromatic compounds has been studied under hydrogen transfer conditions at 150 °C and 82 °C in 2-PrOH as a hydrogen donor and with Raney nickel as a catalyst. In contrast to conjugated or condensed aromatic rings, isolated ones demonstrated low reactivity in transfer hydrogenation (TH) that can be used to increase the hydrogenation selectivity of the reaction. So, naphthalene and biphenyl are partially hydrogenated into tetralin and cyclohexylbenzene, respectively, with excellent conversion (≥ 96 %) and selectivity (≥ 98 %) for 5–6 h at 82 °C. Increasing the reaction temperature to 150 °C results expectedly in the hydrogenation of second aromatic ring, which occurs slowly enough. Only 8 % of decaline and 42 % of dicyclohexyl, correspondingly, were obtained after 5 h at 150 °C. At the same time, TH of trinuclear anthracene and phenanthrene at 150 °C resulted in the formation of deeper hydrogenated octahydro-anthracenes and -phenanthrenes, respectively.
- Philippov,Chibiryaev,Martyanov
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- Ligand-enabled and magnesium-activated hydrogenation with earth-abundant cobalt catalysts
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Replacing expensive noble metals like Pt, Pd, Ir, Ru, and Rh with inexpensive earth-abundant metals like cobalt (Co) is attracting wider research interest in catalysis. Cobalt catalysts are now undergoing a renaissance in hydrogenation reactions. Herein, we describe a hydrogenation method for polycyclic aromatic hydrocarbons (PAHs) and olefins with a magnesium-activated earth-abundant Co catalyst. When diketimine was used as a ligand, simple and inexpensive metal salts of CoBr2in combination with magnesium showed high catalytic activity in the site-selective hydrogenation of challenging PAHs under mild conditions. Co-catalyzed hydrogenation enabled the reduction of two side aromatics of PAHs. A wide range of PAHs can be hydrogenated in a site-selective manner, which provides a cost-effective, clean, and selective strategy to prepare partially reduced polycyclic hydrocarbon motifs that are otherwise difficult to prepare by common methods. The use of well-defined diketimine-ligated Co complexes as precatalysts for selective hydrogenation of PAHs and olefins is also demonstrated.
- Han, Bo,Jiao, Hongmei,Ma, Haojie,Wang, Jijiang,Zhang, Miaomiao,Zhang, Yuqi
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p. 39934 - 39939
(2021/12/31)
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- A regionally selective hydrogenation method for chromium-catalyzed thick cyclic aromatic hydrocarbons and olefins based on magnesium-activated ligands
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The present invention relates to the field of hydrogenation, specifically to a chromium-activated complex cyclic aromatic hydrocarbons and olefins promoted by magnesium-activated ligands regionally selective hydrogenation method, which is based on the in situ reduction strategy of magnesium, with biimides as ligands, CrCl2 as catalyst precursors, to construct an efficient low-costchromium hydrogenation system, under mild conditions, to achieve unilateral cyclic hydrogenation of thick ring aromatic hydrocarbons and high-selective hydrogenation of olefins. The system of the present invention is suitable for a variety of substrates of fused cyclic aromatic hydrocarbons, such as tetraphenyl, benzoanthracene, pentabenzo and alfalfa and the like. This provides a simple and efficient strategy and pathway for the synthesis of partially saturated thick cyclic aromatic hydrocarbon compounds.
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Paragraph 0020
(2022/01/10)
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- Noble metal nanoparticles stabilized by hyper-cross-linked polystyrene as effective catalysts in hydrogenation of arenes
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This work is addressing the arenes’ hydrogenation—the processes of high importance for petrochemical, chemical and pharmaceutical industries. Noble metal (Pd, Pt, Ru) nanoparticles (NPs) stabilized in hyper-cross-linked polystyrene (HPS) were shown to be active and selective catalysts in hydrogenation of a wide range of arenes (monocyclic, condensed, substituted, etc.) in a batch mode. HPS effectively stabilized metal NPs during hydrogenation in different medium (water, organic solvents) and allowed multiple catalyst reuses.
- Bakhvalova, Elena S.,Bykov, Alexey V.,Demidenko, Galina N.,Kiwi-Minsker, Lioubov,Mikheev, Alexey V.,Nikoshvili, Linda Z.,Pinyukova, Arina O.,Sulman, Mikhail G.
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- Hydrogenation reaction method
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The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
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Paragraph 0034; 0229-0232
(2020/05/14)
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- Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
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A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
- Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
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supporting information
p. 4119 - 4129
(2020/08/10)
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- Chromium- and Cobalt-Catalyzed, Regiocontrolled Hydrogenation of Polycyclic Aromatic Hydrocarbons: A Combined Experimental and Theoretical Study
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Polycyclic aromatic hydrocarbons are difficult substrates for hydrogenation because of the thermodynamic stability caused by aromaticity. We report here the first chromium- and cobalt-catalyzed, regiocontrolled hydrogenation of polycyclic aromatic hydrocarbons at ambient temperature. These reactions were promoted by low-cost chromium or cobalt salts combined with diimino/carbene ligand and methylmagnesium bromide and are characterized by high regioselectivity and expanded substrate scope that includes tetracene, tetraphene, pentacene, and perylene, which have rarely been reduced. The approach provides a cost-effective catalytic protocol for hydrogenation, is scalable, and can be utilized in the synthesis of tetrabromo- and carboxyl-substituted motifs through functionalization of the hydrogenation product. The systematic theoretical mechanistic modelings suggest that low-valent Cr and Co monohydride species, most likely from zerovalent transition metals, are capable of mediating these hydrogenations of fused PAHs.
- Han, Bo,Ma, Pengchen,Cong, Xuefeng,Chen, Hui,Zeng, Xiaoming
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supporting information
p. 9018 - 9026
(2019/06/13)
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- Hydrogenation of naphthalene and anthracene on Pt/C catalysts
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Hydrogenation of naphthalene and anthracene deposited on Sibunit and active carbon was studied. The reactions were carried out at a temperature of 280 °C and a pressure of 90 atm. The directions for the complete hydrogenation of the investigated substrates were studied. Correlations between the structures of naphthalene and anthracene and their activity in hydrogen absorption are presented. The hydrogenation rates decrease as the substrate is saturated with hydrogen.
- Kalenchuk,Koklin,Bogdan,Kustov
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p. 1406 - 1411
(2018/10/31)
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- Ru-Catalyzed Transfer Hydrogenation of Nitriles, Aromatics, Olefins, Alkynes and Esters
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This paper reports the preparation of new ruthenium(II) complexes supported by a pyrazole-phosphine ligand and their application to transfer hydrogenation of various substrates. These Ru complexes were found to be efficient catalysts for the reduction of nitriles and olefins. Heterocyclic compounds undergo transfer hydrogenation with good to moderate yields, affording examples of unusual hydrogenation of all-carbon-rings. Internal alkynes with bulky substituents show selective reduction to olefins with the unusual E–selectivity. Esters with strong electron-withdrawing groups can be reduced to the corresponding alcohols, if ethanol is used as the solvent. Possible mechanisms of hydrogenation and olefin isomerization are suggested on the basis of kinetic studies and labelling experiments.
- Alshakova, Iryna D.,Gabidullin, Bulat,Nikonov, Georgii I.
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p. 4860 - 4869
(2018/10/02)
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- Hydrogenation of Anthracene and Dehydrogenation of Perhydroanthracene on Pt/C Catalysts
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The hydrogenation of anthracene on a heterogeneous catalyst containing 3 wt % Pt/C (Aldrich) at 215, 245, and 280°C and the pressures of 40 and 90 atm is studied. The hydrogenation of anthracene to a completely hydrogenated product is considered in detail
- Kalenchuk,Koklin,Bogdan,Lunin
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p. 663 - 668
(2018/04/12)
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- Method for selectively catalyzing and hydrogenating polycyclic aromatic hydrocarbon by virtue of chromium salt/methyl magnesium bromide
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The invention discloses a method for selectively catalyzing and hydrogenating polycyclic aromatic hydrocarbon by virtue of chromium salt/methyl magnesium bromide. The method comprises the step of carrying out normal temperature stirring reaction on polycyclic aromatic hydrocarbon in an H2 atmosphere by taking chromium salt and methyl magnesium bromide as catalysts, a diimine compound as a ligand and tetrahydrofuran as a solvent, so as to obtain a hydrogenation product. Based on the regulation and control of the diimine ligand and the synergetic catalysis of chromium salt and methyl magnesium bromide, the high-selectivity hydrocarbon of polycyclic aromatic hydrocarbon is realized at the room temperature; and the method has the advantages of low cost, mild reaction conditions, high selectivity and the like, high-temperature harsh conditions are avoided, and precious metal catalysts with relatively high costs are not used. The method is applicable to the hydrogenation of different 2-site, 9-site and 10-site substituted anthracene derivatives and other polycyclic aromatic hydrocarbon substrates.
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Paragraph 0028; 0029; 0030; 0031; 0032
(2017/10/13)
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- Acid-Catalyzed Skeletal Rearrangements in Arenes: Aryl versus Alkyl Ring Pirouettes in Anthracene and Phenanthrene
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In 1 M triflic acid/dichloroethane, anthracene is protonated at C9, and the resulting 9-anthracenium ion is easily observed by NMR at ambient temperature. When heated as a dilute solution in triflic acid/dichloroethane, anthracene undergoes conversion to phenanthrene as the major volatile product. Minor dihydro and tetrahydro products are also observed. MALDI analysis supports the simultaneous formation of oligomers, which represent 10-60% of the product. Phenanthrene is nearly inert to the same superacid conditions. DFT and CCSD(T)//DFT computational models were constructed for isomerization and automerization mechanisms. These reactions are believed to occur by cationic ring pirouettes which pass through spirocyclic intermediates. The direct aryl pirouette mechanism for anthracene has a predicted DFT barrier of 33.6 kcal/mol; this is too high to be consistent with experiment. The ensemble of experimental and computational models supports a multistep isomerization process, which proceeds by reduction to 1,2,3,4-tetrahydroanthracene, acid-catalyzed isomerization to 1,2,3,4-tetrahydrophenanthrene with a predicted DFT barrier of 19.7 kcal/mol, and then reoxidation to phenanthrene. By contrast, DFT computations support a direct pirouette mechanism for automerization of outer ring carbons in phenanthrene, a reaction demonstrated previously by Balaban through isotopic labeling.
- Skraba-Joiner, Sarah L.,Brulet, Jeffrey W.,Song, Min K.,Johnson, Richard P.
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p. 13076 - 13083
(2017/12/26)
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- Designing MoS2 nanocatalysts with increased exposure of active edge sites for anthracene hydrogenation reaction
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Designing MoS2 nanocatalysts rich with active edge sites by engineering of the nanostructures is an effective strategy to enhance their catalytic activity. A series of MoS2 nanoflowers with self-assembled nanosheets was successfully synthesized by engineering of nanostructures. The compositions and structures of MoS2 nanoflowers were characterized by elemental analysis, XPS, TG, XRD, Raman, SEM, and HRTEM. The growth mechanism for MoS2 samples was proposed. MoS2 nanoflowers with a short slab of 5-10 nm, 3-5 stacking layers and expanded basal spacing of 0.98 nm were synthesized via a one-pot solvothermal synthesis method using high boiling point and viscosity ethylene glycol as solvent, maximizing the exposure of active edge sites. In the catalytic anthracene hydrogenation reaction in a slurry-phase reactor, the hydrogenation percentage and selectivity to deep hydrogenation products of the optimized MoS2 nanoflowers are respectively 3.2 times and 31.2 times as high as those of commercial MoS2. The structure-activity relationship of MoS2 catalysts suggests that the engineering of nanostructures to increase the exposure of active edge sites can dramatically improve the catalytic hydrogenation performance of MoS2 catalysts. This study provides the theoretical instructions for designing MoS2 catalysts with improved activity. The increased understanding and research on MoS2 catalysts will drive the industrialization of heavy oil/residue conversion into clean fuels.
- Jiang, Yuxia,Wang, Donge,Li, Jiahe,Li, Min,Pan, Zhendong,Ma, Huaijun,Lv, Guang,Qu, Wei,Wang, Lin,Tian, Zhijian
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p. 2998 - 3007
(2017/08/01)
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- Synthesis of NHC-Oxazoline Pincer Complexes of Rh and Ru and Their Catalytic Activity for Hydrogenation and Conjugate Reduction
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We describe the preparation and catalytic reactions of new CCN pincer Rh and Ru complexes containing NCH-oxazoline hybrid ligands. Oxazolinyl-phenyl-imidazolium derivatives (3) were suitable ligand precursors for the CCN pincer scaffold. C-H bond activation of 3 with RhCl3·3H2O in the presence of NEt3 yielded the desired CCN pincer Rh complexes 5 in 13-27% yields. The related CCN pincer Ru complexes 8-10 were synthesized in good yields by C-H bond activation of p-cymene Ru complexes 7 in the presence of NaOAc in DMF. The chiral complexes 8 and 9 had two diastereomers according to the coordination of CO and OAc ligands. The CCN Rh complexes showed catalytic activity for conjugate reduction of ethyl β-methylcinnamate with hydrosilane, with moderate enantioselectivity. The CCN Ru complexes were found to be active in the hydrogenation of aromatic ketones. In particular, hydrogenation of 9-acetylanthracene took place at not only the C=O bond but also the anthracene ring. The Ru complexes were also used as catalysts in the transfer hydrogenation of 9-acetylanthracene with 2-propanol; again, both the C=O bond and the anthracene ring were hydrogenated.
- Ito, Jun-Ichi,Sugino, Kanae,Matsushima, Satoru,Sakaguchi, Hiroki,Iwata, Hiroshi,Ishihara, Takahiro,Nishiyama, Hisao
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p. 1885 - 1894
(2016/07/06)
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- Selective catalytic hydrogenation of polycyclic aromatic hydrocarbons promoted by ruthenium nanoparticles
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Ru nanoparticles stabilised by PPh3 are efficient catalysts for hydrogenation of polycyclic aromatic hydrocarbons (PAHs) containing 2-4 rings under mild reaction conditions. These compounds were partially hydrogenated with good to excellent selectivities just by optimizing the reaction conditions. The influence of the nature of substituents present in different positions of naphthalene on the selectivity of hydrogenation was also studied. Hydrogenation of products containing substituents at position 1 is slower than that of products containing substituents at position 2. In all cases, hydrogenation takes place mainly on the less substituted ring.
- Bresó-Femenia, Emma,Chaudret, Bruno,Castillón, Sergio
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p. 2741 - 2751
(2015/05/27)
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- Heteroatom-free arene-cobalt and arene-iron catalysts for hydrogenations
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75 years after the discovery of hydroformylation, cobalt catalysts are now undergoing a renaissance in hydrogenation reactions. We have evaluated arene metalates in which the low-valent metal species is - conceptually different from heteroatom-based ligands - stabilized by π coordination to hydrocarbons. Potassium bis(anthracene)cobaltate 1 and -ferrate 2 can be viewed as synthetic precursors of quasi-"naked" anionic metal species; their aggregation is effectively impeded by (labile) coordination to the various π acceptors present in the hydrogenation reactions of unsaturated molecules (alkenes, arenes, carbonyl compounds). Kinetic studies, NMR spectroscopy, and poisoning studies of alkene hydrogenations support the formation of a homogeneous catalyst derived from 1 which is stabilized by the coordination of alkenes. This catalyst concept complements the use of complexes with heteroatom donor ligands for reductive processes. Especially high selectivities were observed in the hydrogenation of various alkenes, ketones, and imines with bis(anthracene) cobaltate(-I) [K(dme)2{Co(C14H10)2}] under mild conditions (1-5 mol% cat., 1-10 bar H2, 20-60°C). Mechanistic studies indicate the operation in alkene hydrogenations of a homogeneous catalyst formed by initial ligand exchange and stabilized by the coordination of π-acidic alkenes or arenes.
- Gaertner, Dominik,Welther, Alice,Rad, Babak Rezaei,Wolf, Robert,Von Wangelin, Axel Jacobi
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supporting information
p. 3722 - 3726
(2014/04/17)
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- Ruthenium nanoparticles supported on magnesium oxide: A versatile and recyclable dual-site catalyst for hydrogenation of mono- and poly-cyclic arenes, N-heteroaromatics, and S-heteroaromatics
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The development of catalysts capable of promoting hydrogenation of aromatics while being resistant to poisoning by nitrogen- and sulfur-containing species is of much interest in connection with hydrotreating of fossil fuels. We report a catalyst composed of ruthenium nanoparticles supported on magnesia, designed to promote heterolytic hydrogen splitting and surface ionic hydrogenation pathways. The catalyst, prepared through a one-pot procedure, promotes the hydrogenation of mono- and poly-cyclic arenes, as well as N- and S-heteroaromatics representative of fossil fuels components. Of particular significance are the superior activity and wider substrate scope of the catalyst, in relation to other known supported noble metals, and the excellent recyclability and long catalyst lifetime. Based on our experimental data, a dual-site catalyst structure and an associated dual-pathway mechanism are proposed, which may have interesting implications for the development of new poison-tolerant noble metal catalytic systems.
- Fang, Minfeng,Sanchez-Delgado, Roberto A.
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p. 357 - 368
(2014/02/14)
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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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- Catalyzed hydrogenation of condensed three-ring arenes and their N-heteroaromatic analogues by a bis(dihydrogen) ruthenium complex
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A series of anthracene and acridine derivatives were hydrogenated under mild reaction conditions (80 °C, 3 bar of H2) using the bis(dihydrogen) complex [RuH2(η2-H2) 2{P(C6H11)3}2] (1) as a catalyst precursor. The influence of a methyl substituent on the substrate was studied. In all our systems, hydrogenation was only observed at the external rings leading to the corresponding 4H- or 8H-derivatives of anthracene and acridine. Three complexes resulting from the η4(C,C)-coordination of the substrate to the unsaturated fragment [RuH2{P(C 6H11)3}2] were characterized. In the case of 9-methyl acridine, the corresponding complex [RuH2(η 4-C14H11N){P(C6H11) 3}2] (4) turned out to be an active catalyst precursor leading to 1,2,3,4,5,6,7,8-octahydro-9-methylacridine as the sole product after 24 h. Regeneration of 1 from 4 supports the role of complex 4 in the catalytic cycle. Three hydrogenated products, 1,2,3,4-tetrahydroanthracene (4H-Anth), 1,2,3,4-tetrahydro-9-methylanthracene (4H-9-Me-Anth) and 1,2,3,4- tetrahydroacridine (4H-Acr), were characterized by X-ray diffraction. The Royal Society of Chemistry 2012.
- Borowski, Andrzej F.,Vendier, Laure,Sabo-Etienne, Sylviane,Rozycka-Sokolowska, Ewa,Gaudyn, Alicja V.
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p. 14117 - 14125
(2013/01/15)
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- Formation of the cobalt hydrogenation catalysts at the action of lithium aluminum hydride and lithium tri(tert-butoxy)aluminohydride and their properties
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The interaction of Co(acac)2(3) with LiAlH4 or LiAlH(t-BuO)3 was studied using NMR, UV, IR, ESR spectroscopy, electron microscopy, and volumometry. The basic stages of formation of cobalt catalysts for hydrogenation were suggested. The formation of the nanoparticles that are active in the hydrogenation process is shown to occur at a ratio of reagents 5 ≤ Red/Co ≤ 12. The nanoparticles are stabilized by an excess of LiAlH4 or LiAlH(t-BuO)3, as well as by the products of their catalytic decomposition under the action of cobalt in the reduced state. At the ratio LiAlH4 / Co> 12 to obtain the particles active in catalysis their activation by a proton-donor compound is required.
- Schmidt, F. K.,Titova, Yu.,Umanets, V. A.,Khutsishvili, S. S.,Belykh, L. B.
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p. 1334 - 1341,8
(2020/09/16)
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- Cyclization of (2-alkenylphenyl)carbonyl compounds to polycyclic arenes catalyzed by copper(II) trifluoromethanesulfonate or trifluoromethanesulfuric acid
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Various polycyclic arenes, such as naphthalenes, tetrahydroantharacenes, tetrahydrotetracenes, dihydropentacenes, and dihydropentaphenes are prepared from 2-alkenylphenyl ketones and aldehydes by the catalytic use of copper(II) trifluoromethanesulfonate (Cu(OTf)2) or trifluoromethanesulfuric acid (TfOH). Copyright
- Liu, Wei-Min,Tnay, Ya Lin,Gan, Kian Ping,Liu, Zhen-Hong,Tyan, Wan Huei,Narasaka, Koichi
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p. 1953 - 1969,17
(2012/12/12)
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- Cyclization of (2-alkenylphenyl)carbonyl compounds to polycyclic arenes catalyzed by copper(II) trifluoromethanesulfonate or trifluoromethanesulfuric acid
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Various polycyclic arenes, such as naphthalenes, tetrahydroantharacenes, tetrahydrotetracenes, dihydropentacenes, and dihydropentaphenes are prepared from 2-alkenylphenyl ketones and aldehydes by the catalytic use of copper(II) trifluoromethanesulfonate (Cu(OTf)2) or trifluoromethanesulfuric acid (TfOH). Copyright
- Liu, Wei-Min,Tnay, Ya Lin,Gan, Kian Ping,Liu, Zhen-Hong,Tyan, Wan Huei,Narasaka, Koichi
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p. 1953 - 1969
(2013/01/15)
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- Facile sonochemical synthesis of carbon nanotube-supported bimetallic Pt-Rh nanoparticles for room temperature hydrogenation of arenes
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Bimetallic Pt-Rh nanoparticles can be deposited uniformly on surfaces of carboxylate functionalized multi-walled carbon nanotubes (MWNTs) using a simple one-step sonochemical method. The bimetallic nanoparticle catalyst exhibits a strong synergistic effect relative to the individual Pt or Rh metal nanoparticles for catalytic hydrogenation of polycyclic aromatic hydrocarbons (PAHs), neat benzene and alkylbenzenes. Complete ring saturation of PAHs can be achieved using the bimetallic Pt-Rh/MWNTs catalyst at room temperature. This one-step synthesis technique provides a simple and rapid way of making highly active and recyclable CNT-supported monometallic and bimetallic nanocatalysts for low temperature hydrogenation reactions.
- Pan, Horng-Bin,Wai, Chien M.
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scheme or table
p. 1649 - 1660
(2011/10/08)
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- Bidentate Lewis acids for the activation of 1,2-diazines - A new mode of catalysis
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Bidentate Lewis acids were applied as catalysts for the inverse-electron-demand Diels-Alder (IEDDA) reaction of 1,2-diazines. The concept of catalysis is based on the coordination of the bidentate Lewis acid to both nitrogen atoms of the 1,2-diazine moiety, thereby reducing the electron density and lowering the energy of the LUMO. This should, according to frontier molecular orbital (FMO) theory, facilitate the cycloaddition step. This new concept was successfully applied to a variety of dienophiles and substituted phthalazine substrates. Careful investigations of the mechanism led to the isolation and characterization of key intermediates; all of which support the presented catalytic cycle. Copyright
- Kessler, Simon N.,Neuburger, Markus,Wegner, Hermann A.
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supporting information; experimental part
p. 3238 - 3245
(2011/07/08)
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- Rh(0) colloids supported on TiO2: A highly active and pertinent tandem in neat water for the hydrogenation of aromatics
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TiO2-supported Rh(0) nanoparticles were easily prepared in one step without calcination by a room temperature impregnation of the inorganic support with a prestabilized colloidal Rh(0) suspension. They are highly active and reusable catalysts for the hydrogenation of aromatics and chloroanisole derivatives in neat water with TOFs up to 33000 h-1. The comparison with the analogous silica system Rh@SiO2 was discussed showing higher catalytic selectivities and activities with Rh(0) colloids supported on TiO2.
- Hubert, Claudie,Bile, Elodie Guyonnet,Denicourt-Nowicki, Audrey,Roucoux, Alain
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experimental part
p. 1766 - 1771
(2011/09/19)
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- Hydrogenation of arenes and N-heteroaromatic compounds over ruthenium nanoparticles on poly(4-vinylpyridine): A versatile catalyst operating by a substrate-dependent dual site mechanism
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A nanostructured catalyst composed of Ru nanoparticles immobilized on poly(4-vinylpyridine) (PVPy) has been synthesized by NaBH4 reduction of RuCl3·3H2O in the presence of the polymer in methanol at room temperature. TEM measurements show well-dispersed Ru nanoparticles with an average diameter of 3.1 nm. Both powder XRD patterns and XPS data indicate that the Ru particles are predominantly in the zerovalent state. The new catalyst is efficient for the hydrogenation of a wide variety of aromatic hydrocarbons and N-heteroaromatic compounds representative of components of petroleum-derived fuels. The experimental data indicate the existence of two distinct active sites in the nanostructure that lead to two parallel hydrogenation pathways, one for simple aromatics involving conventional homolytic hydrogen splitting on Ru and a second one for N-heteroaromatics taking place via a novel heterolytic hydrogen activation on the catalyst surface, assisted by the basic pyridine groups of the support.
- Fang, Minfeng,MacHalaba, Nataliya,Sanchez-Delgado, Roberto A.
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experimental part
p. 10621 - 10632
(2011/11/29)
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- Lewis acid catalyzed inverse electron-demand diels-alder reaction of 1,2-diazines
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A systematic approach toward Lewis acid catalyzed inverse electron-demand Diels-Alder (IEDDA) reactions of 1,2-diazines is described. The general concept is first investigated by DFT calculations, supported by spectroscopic data, and finally proven in the experiment.
- Kessler, Simon N.,Wegner, Hermann A.
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supporting information; experimental part
p. 4062 - 4065
(2010/11/17)
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- O-Dihaloarenes as aryne precursors for nickel-catalyzed [2 + 2 + 2] cycloaddition with alkynes and nitriles
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o-Dihaloarenes acting as aryne precursors react with acetylenes and nitriles catalyzed by the NiBr2(dppe)/dppe/Zn system to give substituted naphthalene, phenanthridine or triphenylene derivatives depending on the reaction conditions in moderat
- Hsieh, Jen-Chieh,Cheng, Chien-Hong
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supporting information; experimental part
p. 2992 - 2994
(2009/02/04)
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- Hydrogenation of arenes by dual activation: Reduction of substrates ranging from benzene to C60 fullerene under ambient conditions
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(Chemical Equation Presented) Tackling aromaticity: The title reaction was accomplished by simultaneous activation of molecular hydrogen and the aromatic substrate by Pd/C and a Lewis acidic ionic liquid, respectively. Even benzene and C60 fullerene were hydrogenated under ambient conditions (1 bar of H2 at room temperature). An ionic hydrogenation mechanism (see scheme) is supported by characterization of a stabilized arenium intermediate.
- Deshmukh, Ravindra R.,Lee, Ji Woong,Shin, Ueon Sang,Lee, Jin Yong,Song, Choong Eui
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supporting information; body text
p. 8615 - 8617
(2009/05/15)
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- Activation of 1,1-difluoro-1-alkenes with a transition-metal complex: Palladium(II)-catalyzed friedel - crafts-type cyclization of 4,4-(difluorohomoallyl)arenes
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(Chemical Equation Presented) Cationic palladium(II) ([Pd(MeCN) 4](BF4)2) provides the first transition-metal-catalyzed method for electrophilic activation of electron-deficient 1,1-difluoro-1-alkenes, which allows their Friedel-Crafts-type cyclization with an intramolecular aryl group via a Wacker-type process. By using BF3·OEt2, the cyclization was effected by a catalytic amount of the palladium without its reoxidation.
- Yokota, Misaki,Fujita, Daishi,Ichikawa, Junji
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p. 4639 - 4642
(2008/03/15)
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- Reductive hydrogenation of polycyclic aromatic hydrocarbons catalyzed by metalloporphyrins
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The hydrogenation of polycyclic aromatic hydrocarbons (PAHs) (naphthalene, anthracene, and phenanthrene) catalyzed by metalloporphyrins based on cobalt, nickel or iron was studied in aqueous solutions at room temperature and ambient pressure. Nickel porphyrin (P1) activated by nanosized zero-valent iron (nano-ZVI) and cobalt porphyrins (P2) and (P4) activated by titanium(III) citrate as the electron donor were demonstrated to be promising catalysts for the reductive hydrogenation of PAHs. In particular, partially saturated di-, tetra-, and octahydrogenated products were obtained for anthracene or phenanthrene using a nickel porphyrin activated by nano-ZVI, while naphthalene was transformed to tetralin. Systems containing cobalt porphyrins activated by titanium(III) citrate exhibited a high selectivity and activity toward hydrogenation of anthracene, producing 9,10-dihydroanthracene. However, no formation of hydrogenated hydrocarbons was observed from naphthalene or phenanthrene using cobalt porphyrins.
- Nelkenbaum, Elza,Dror, Ishai,Berkowitz, Brian
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p. 210 - 217
(2008/02/04)
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- Near-monodisperse tetrahedral rhodium nanoparticles on charcoal: The shape-dependent catalytic hydrogenation of arenes
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The shape of things to come? Monodisperse (4.9±0.4)-nm tetrahedral rhodium nanoparticles on charcoal (/C) are compared to (4.8±0.4)-nm spherical rhodium nanoparticles on charcoal(?/C) and commercial Rh/C as a catalyst for the hydrogenation of anthracene (see picture). The former is 5.8- and 109-times more active than the latter two, respectively. It also shows a higher selectivity and excellent activity in the hydrogenation of several other arenes. (Graph Presented).
- Park, Kang Hyun,Jang, Kwonho,Kim, Hae Jin,Son, Seung Uk
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p. 1152 - 1155
(2008/03/15)
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- Oxidative addition of dihydrogen to (η6-arene)Mo(PMe 3)3 complexes: Origin of the naphthalene and anthracene effects
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In contrast to the benzene and naphthalene compounds (η6- PhH)Mo(PMe3)3 and (η6-NpH)Mo-(PMe 3)3, the anthracene complex (η6-AnH) Mo(PMe3)3 reacts with H2 to undergo a haptotropic shift and give the η4-anthracene compound (η4-AnH)Mo(PMe3)3H2. Density functional theory calculations indicate that the increased facility of naphthalene and anthracene to adopt η4-coordination modes compared to that of benzene is a consequence of the fact that the Mo-(η4-ArH) bonding interaction increases in the sequence benzene 6-ArH) bonding interaction follows the sequence benzene > naphthalene ≈ anthracene.
- Zhu, Guang,Janak, Kevin E.,Figueroa, Joshua S.,Parkin, Gerard
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p. 5452 - 5461
(2007/10/03)
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- Lewis acid-catalyzed [4 + 2] benzannulation between enynal units and enols or enol ethers: Novel synthetic tools for polysubstituted aromatic compounds including indole and benzofuran derivatives
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The reaction of enynals 1, including o-(alkynyl)benzaldehydes, and carbonyl compounds 2, such as aldehydes and ketones, in the presence of a catalytic amount of AuBr3 in 1,4-dioxane at 100 °C gave the functionalized aromatic compounds 3 in high yields. Similarly, the AuBr3-catalyzed reactions of 1 with acetal compounds 5 afforded the corresponding aromatic compounds 3 in good yields. On the other hand, when the reaction was carried out in the presence of a catalytic amount of Cu(NTf2)2 and 1 equiv of H2O in (CH2Cl)2 at 100 °C, the decarbonylated naphthalene products 4 were obtained selectively over 3. Benzofused heteroaromatic compounds, such as indole derivatives 13 and benzofuran derivatives 15, were also synthesized by using the present benzannulation methodology.
- Asao, Naoki,Aikawa, Haruo
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p. 5249 - 5253
(2007/10/03)
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- Nickel-catalyzed cocyclotrimerization of arynes with diynes; a novel method for synthesis of naphthalene derivatives
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The NiBr2(dppe)-Zn system effectively catalyzes the [2 + 2 + 2] cocyclotrimerization of arynes with diynes, leading to substituted naphthalene derivatives in moderate to good yields. This cocyclotrimerization reaction shows excellent tolerance of functional groups and leads to products of 5- to 7-membered fused-ring sizes. The Royal Society of Chemistry 2005.
- Hsieh, Jen-Chieh,Cheng, Chien-Hong
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p. 2459 - 2461
(2007/10/03)
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- Polymerizations initiated by diradicals from cycloaromatization reactions
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Four cycloaromatization substrates each produce diradicals that lead to the initiation of polymerization of vinyl monomers. All the initiators produce significant amounts of polymer, especially with methacrylate monomers. Intramolecular termination of short diradical chains produces oligomeric byproducts and limits the amount of high polymer that is formed. The polymer yield can be increased through the addition of a chain transfer agent by presumably converting unproductive diradicals into pairs of monoradicals. The enediynes that contain terminal acetylenes are less effective initiators because they retard radical polymerization. Bergman cyclization substrates are better initiators than Myers cyclization substrates.
- Rule, Joseph D.,Moore, Jeffrey S.
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p. 7266 - 7273
(2007/10/03)
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- Microemulsion-templated synthesis of carbon nanotube-supported Pd and Rh nanoparticles for catalytic applications
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Palladium, rhodium, and bimetallic Pd/Rh nanoparticles synthesized in a water-in-hexane microemulsion can be deposited directly on surfaces of functionalized multiwalled carbon nanotubes with high yields. The CNT-supported Pd nanoparticles are active catalysts for hydrogenation of olefins, for carbon-carbon bond formation, and for carbon-oxygen bond cleavage reactions. The CNT-supported Rh nanoparticles are active catalysts for hydrogenation of arenes, and the CNT-supported bimetallic Pd/Rh nanoparticles show an unusually high catalytic activity for hydrogenation of anthracene. This simple and novel synthetic technique for making CNT-supported monometallic and bimetallic nanoparticles may have a wide range of catalytic applications for chemical syntheses. Copyright
- Yoon, Byunghoon,Wai, Chien M.
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p. 17174 - 17175
(2007/10/03)
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- Pd/C-catalyzed transfer reduction of aryl chlorides with sodium formate in water
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Sodium formate catalytic transfer reduction, in the presence of palladium on carbon, accomplishes not only the rapid dehalogenation of aromatic chlorocarbons in water at room temperature, but also the reduction of the aromatic moieties to alicyclic rings at 100 °C. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Arcadi, Antonio,Cerichelli, Giorgio,Chiarini, Marco,Vico, Raquel,Zorzan, Daniel
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p. 3404 - 3407
(2007/10/03)
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- AuBr3-catalyzed [4 + 2] benzannulation between an enynal unit and enol
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The reaction of enynals 1, including o-alkynylbenzaldehydes, and carbonyl compounds 2 in the presence of a catalytic amount of AuBr3 in 1,4-dioxane at 100 °C gave the functionalized aromatic compounds 3 in high yields. The AuBr3-catalyzed formal [4 + 2] benzannulation proceeds most probably through the coordination of the triple bond of 1 to AuBr3, the formation of a pyrylium auric ate complex via the nucleophilic addition of the carbonyl oxygen atom, the reverse electron demand-type Diels-Alder addition of the enols, derived from 2, to the auric ate complex, and subsequent dehydration and bond rearrangement. Similarly, the AuBr3-catalyzed reactions of 1 with acetal compounds afforded the corresponding aromatic compounds in good yields. Copyright
- Asao, Naoki,Aikawa, Haruo,Yamamoto, Yoshinori
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p. 7458 - 7459
(2007/10/03)
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- Annulations Using Phosphonium Salts and Enolate Anions - A Direct Route to Naphthalenes
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Ketone enolates react with an aldehyde phosphonium salt to produce naphthalenes in a one-pot reaction.
- Kraus, George A.,Choudhury, Prabir K.
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- The NiCl2-Li-Arene (cat.) Combination as Reducing System, Part 9: Catalytic Hydrogenation of Organic Compounds using the NiCl 2-Li-(Naphthalene or Polymer-Supported Naphthalene) (cat.) Combination
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The reaction of lithium powder, a catalytic amount of naphthalene or polymer-supported naphthalene, and anhydrous nickel(II) chloride, in THF at room temperature, generates a finely divided and very reactive nickel(0) which has been efficiently applied to the catalytic hydrogenation of different organic compounds such as alkenes, alkynes, carbonyl compounds, imines, organic halides, aromatic compounds, hydrazines, azoxy compounds, and N-oxides.
- Alonso, Francisco,Candela, Pablo,Gómez, Cecilia,Yus, Miguel
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p. 275 - 279
(2007/10/03)
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- Novel direct reduction of diaryl ketones to diarylmethanes using supercritical 2-propanol
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We found that diaryl ketones reduce directly to diaryl alkanes under supercritical 2-propanol. This method was applied to one-pot synthesis of anthracene from anthraquinone derivatives by the addition of sulfur in excellent yields.
- Hatano, Bunpei,Tagaya, Hideyuki
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p. 6331 - 6333
(2007/10/03)
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- A comparison between silica-immobilized ruthenium(II) single sites and silica-supported ruthenium nanoparticles in the catalytic hydrogenation of model hetero- and polyaromatics contained in raw oil materials
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HDS and HDN are very important hydrotreating reactions that remove sulfur and nitrogen from fossil fuels where they are contained in various organic compounds, which include polyaromatic heterocycles, aliphatic and aromatic thiols and amines, thioethers, disulfides, and nitriles. A comparative study of the hydrogenation of various heterocycles, model compounds in raw oil materials, by either Ru(II) complex immobilized on mesoporous silica or Ru(0) nanoparticles deposited on the same support was conducted. The single-site catalyst contained the molecular precursor [Ru(NCMe)3(sulphos)](OSO2 CF3) tethered to partially dehydroxylated high-surface-area silica through hydrogen bonds between silanol groups of the support and SO3- groups from the sulphos ligand [-O3S(C6H4) CH2C(CH2PPh2)3] and the triflate counter anion. The heterocycles (benzo[b]thiophene, quinoline, indole, acridine) were hydrogenated to cyclic thioethers or amines. Ru(II)-based catalysts were much more efficient for the hydrogenation of S-heterocycles than for N-heterocycles.
- Bianchini, Claudio,Dal Santo, Vladimiro,Meli, Andrea,Moneti, Simonetta,Moreno, Marta,Oberhauser, Werner,Psaro, Rinaldo,Sordelli, Laura,Vizza, Francesco
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- Thermal reduction of 7H-benz[d,e]anthracen-7-one and related ketones under hydrogen-transfer conditions
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In the presence of hydrogen donor solvents and at elevated temperatures, aromatic ketones can be selectively deoxygenated to the corresponding hydroaromatic compounds. The kinetics for reduction of 7H-benz[d,e]anthracen-7-one (benzanthrone, 6) into 7H-benz[d,e]anthracene (benzanthrene, 1) in 9,10-dihydroanthracene (3) solvent has been investigated in detail. The relatively slow hydrogenation of 6 is due to reversibility of the initial hydrogen-transfer step according to a reverse radical disproportionation (RRD). The dynamics could well be rationalized using the energetics of species computed by density functional theory (DFT). The application of hydrogen donors such as 1 as a hydrogen-transfer agent, although favorable in terms of a low benzylic carbon-hydrogen bond dissociation enthalpy, is limited due to the slow self-hydrogenation, which in case of 1 gives 5,6-dihydro-4H-benz[d,e]anthracene (7).
- Mulder,Hemmink,De Heer,Lupo,Santoro,Korth
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p. 6611 - 6619
(2007/10/03)
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- Catalytic hydrogenation of anthracene on modified iron sulfide catalysts
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The kinetics of anthracene hydrogenation in the presence of an iron sulfide solid solution and activated bentonite was studied. The catalytic additive was found to enhance the dehydrogenation and hydrogenolysis reactions of the hydrogenation products.
- Nurmaganbetova,Baikenov,Meiramov,Mukhtar,Ordabaeva,Khrupov
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