- Studies towards the Total Synthesis of Drimentine C. Preparation of the AB and CDEF Ring Fragments
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The drimentine family is a class of hybrid isoprenoids derived from actinomycete bacteria. Members of this family display weak antitumor and antibacterial activity. Herein we report our efforts toward the total synthesis of drimentine C using three distinct approaches incorporating palladium-catalyzed cyanoamidation, reductive cross-coupling, and photoredox-catalyzed α-alkylation of an aldehyde as key steps. Our synthetic efforts use a convergent synthesis to assemble the terpenoid and alkaloid portions of drimentine C from readily available l-tryptophan, l-proline, and (+)-sclareolide.
- Pound, Sarah M.,Underwood, Steven J.,Douglas, Christopher J.
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- Fabricating nickel phyllosilicate-like nanosheets to prepare a defect-rich catalyst for the one-pot conversion of lignin into hydrocarbons under mild conditions
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The one-pot conversion of lignin biomass into high-grade hydrocarbon biofuels via catalytic hydrodeoxygenation (HDO) holds significant promise for renewable energy. A great challenge for this route involves developing efficient non-noble metal catalysts to obtain a high yield of hydrocarbons under relatively mild conditions. Herein, a high-performance catalyst has been prepared via the in situ reduction of Ni phyllosilicate-like nanosheets (Ni-PS) synthesized by a reduction-oxidation strategy at room temperature. The Ni-PS precursors are partly converted into Ni0 nanoparticles by in situ reduction and the rest remain as supports. The Si-containing supports are found to have strong interactions with the nickel species, hindering the aggregation of Ni0 particles and minimizing the Ni0 particle size. The catalyst contains abundant surface defects, weak Lewis acid sites and highly dispersed Ni0 particles. The catalyst exhibits excellent catalytic activity towards the depolymerization and HDO of the lignin model compound, 2-phenylethyl phenyl ether (PPE), and the enzymatic hydrolysis of lignin under mild conditions, with 98.3% cycloalkane yield for the HDO of PPE under 3 MPa H2 pressure at 160 °C and 40.4% hydrocarbon yield for that of lignin under 3 MPa H2 pressure at 240 °C, and its catalytic activity can compete with reported noble metal catalysts.
- Cao, Meifang,Chen, Bo,He, Chengzhi,Ouyang, Xinping,Qian, Yong,Qiu, Xueqing
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supporting information
p. 846 - 857
(2022/02/09)
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- The solvent determines the product in the hydrogenation of aromatic ketones using unligated RhCl3as catalyst precursor
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Alkyl cyclohexanes were synthesized in high selectivity via a combined hydrogenation/hydrodeoxygenation of aromatic ketones using ligand-free RhCl3 as pre-catalyst in trifluoroethanol as solvent. The true catalyst consists of rhodium nanoparticles (Rh NPs), generated in situ during the reaction. A range of conjugated as well as non-conjugated aromatic ketones were directly hydrodeoxygenated to the corresponding saturated cyclohexane derivatives at relatively mild conditions. The solvent was found to be the determining factor to switch the selectivity of the ketone hydrogenation. Cyclohexyl alkyl-alcohols were the products using water as a solvent.
- Bartling, Stephan,Chakrabortty, Soumyadeep,De Vries, Johannes G.,Kamer, Paul C. J.,Lund, Henrik,Müller, Bernd H.,Rockstroh, Nils
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p. 7608 - 7616
(2021/12/13)
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- Aromatic compound hydrogenation and hydrodeoxygenation method and application thereof
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The invention belongs to the technical field of medicines, and discloses an aromatic compound hydrogenation and hydrodeoxygenation method under mild conditions and application of the method in hydrogenation and hydrodeoxygenation reactions of the aromatic compounds and related mixtures. Specifically, the method comprises the following steps: contacting the aromatic compound or a mixture containing the aromatic compound with a catalyst and hydrogen with proper pressure in a solvent under a proper temperature condition, and reacting the hydrogen, the solvent and the aromatic compound under the action of the catalyst to obtain a corresponding hydrogenation product or/and a hydrodeoxygenation product without an oxygen-containing substituent group. The invention also discloses specific implementation conditions of the method and an aromatic compound structure type applicable to the method. The hydrogenation and hydrodeoxygenation reaction method used in the invention has the advantages of mild reaction conditions, high hydrodeoxygenation efficiency, wide substrate applicability, convenient post-treatment, and good laboratory and industrial application prospects.
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Paragraph 0094-0095; 0123-0125; 0127-0130
(2021/05/29)
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- One-Pot Conversion of Lignin into Naphthenes Catalyzed by a Heterogeneous Rhenium Oxide-Modified Iridium Compound
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The direct transformation of lignin into fuels and chemicals remains a huge challenge because of the recalcitrant and complicated structure of lignin. In this study, rhenium oxide-modified iridium supported on SiO2 (Ir-ReOx/SiO2) is employed for the one-pot conversion of various lignin model compounds and lignin feedstocks into naphthenes. Up to 100 percent yield of cyclohexane from model compounds and 44.3 percent yield of naphthenes from lignin feedstocks are achieved. 2 D HSQC NMR spectroscopy before and after the reaction confirms the activity of Ir-ReOx/SiO2 in the cleavage of the C?O bonds and hydrodeoxygenation of the depolymerized products. H2 temperature-programmed reduction, temperature-programmed desorption of NH3, IR spectroscopy of pyridine adsorption, X-ray photoelectron spectroscopy, X-ray absorption fine structure analysis, and control experiments reveal that a synergistic effect between Ir and ReOx in Ir-ReOx/SiO2 plays a crucial role in the high performance; ReOx is mainly responsible for the cleavage of C?O bonds, whereas Ir is responsible for hydrodeoxygenation and saturation of the benzene rings. This methodology opens up an energy-efficient route for the direct conversion of lignin into valuable naphthenes.
- Li, Xinxin,Zhang, Bo,Pan, Xiaoli,Ji, Jianwei,Ren, Yujing,Wang, Hua,Ji, Na,Liu, Qiying,Li, Changzhi
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p. 4409 - 4419
(2020/03/04)
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- Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts
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Super Lewis acids containing the triflate anion [e.g., Hf(OTf)4, Ln(OTf)3, In(OTf)3, Al(OTf)3] and noble metal catalysts (e.g., Ru/C, Ru/Al2O3) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage through selective bonding to etheric oxygens while the noble metal catalyzed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt % of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates by protonating hydroxyl groups and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote deoxygenation reactions catalyzed by super Lewis acids.
- Wang, Hongliang,Wang, Huamin,Kuhn, Eric,Tucker, Melvin P.,Yang, Bin
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p. 285 - 291
(2017/11/20)
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- Stainless Steel-Mediated Hydrogen Generation from Alkanes and Diethyl Ether and Its Application for Arene Reduction
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Hydrogen gas can be generated from simple alkanes (e.g., n-pentane, n-hexane, etc.) and diethyl ether (Et2O) by mechanochemical energy using a planetary ball mill (SUS304, Fritsch Pulverisette 7), and the use of stainless steel balls and vessel is an important factor to generate the hydrogen. The reduction of organic compounds was also accomplished using the in-situ-generated hydrogen. While the use of pentane as the hydrogen source facilitated the reduction of the olefin moieties, the arene reduction could proceed using Et2O. Within the components (Fe, Cr, Ni, etc.) of the stainless steel, Cr was the metal factor for the hydrogen generation from the alkanes and Et2O, and Ni metal played the role of the hydrogenation catalyst.
- Sawama, Yoshinari,Yasukawa, Naoki,Ban, Kazuho,Goto, Ryota,Niikawa, Miki,Monguchi, Yasunari,Itoh, Miki,Sajiki, Hironao
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supporting information
p. 2892 - 2896
(2018/05/29)
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- Reduction of diphenylacetylene using Al powder in the presence of noble metal catalysts in water
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Diphenylacetylenes can be reduced to the corresponding diphenylethanes (2) in water in excellent yield using Al powder and Pd/C at 60?°C for 3?h in a sealed tube. In addition, the complete reduction of both aromatic rings required 80?°C for 15?h with Al powder in the presence of Pt/C. However, the nature of hydrogenated product formed was found to be strongly influenced by the reaction temperature, time, volume of water and the amount of catalyst being employed.
- Rayhan, Ummey,Kowser, Zannatul,Redshaw, Carl,Yamato, Takehiko
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supporting information
p. 6943 - 6947
(2016/10/14)
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- Hydrogen Self-Sufficient Arene Reduction to Cyclohexane Derivatives Using a Combination of Platinum on Carbon and 2-Propanol
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Various arenes have been hydrogenated using platinum on carbon in a 2-propanol-aqueous mixed solvent at 100 C without the addition of flammable hydrogen gas to give the corresponding cyclohexane derivatives. 2-Propanol plays a role as an efficient hydrogen source based on the platinum on carbon-catalyzed dehydrogenation.
- Sawama, Yoshinari,Mori, Misato,Yamada, Tsuyoshi,Monguchi, Yasunari,Sajiki, Hironao
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supporting information
p. 3667 - 3670
(2016/01/25)
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- Mesoporous ZSM-5 zeolite-supported ru nanoparticles as highly efficient catalysts for upgrading phenolic biomolecules
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Zeolite-based catalysts have been widely used in the conversion of biomass recently, but the catalytic yields of the desired products are strongly limited by the relatively small micropores of zeolite. Here, we reported a hierarchically porous ZSM-5 zeolite with micropore and b-axis-aligned mesopore-supported Ru nanoparticles (Ru/HZSM-5-OM) that are highly efficient for the hydrodeoxygenation of both small and bulky phenolic biomolecules to the corresponding alkanes. Compared with the conventional ZSM-5 zeolite-supported Ru catalyst, the high catalytic activities and alkane selectivities over Ru/HZSM-5-OM are attributed to the abundant exposed acidic sites in HZSM-5-OM with open mesopores. This feature is potentially important for future phenolic bio-oil upgrading.
- Wang, Liang,Zhang, Jian,Yi, Xianfeng,Zheng, Anmin,Deng, Feng,Chen, Chunyu,Ji, Yanyan,Liu, Fujian,Meng, Xiangju,Xiao, Feng-Shou
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p. 2727 - 2734
(2015/05/13)
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- Biomass-derived lignin to jet fuel range hydrocarbons via aqueous phase hydrodeoxygenation
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A catalytic process, involving the hydrodeoxygenation (HDO) of dilute alkali extracted corn stover lignin catalysed by noble metal catalyst (Ru/Al2O3) and acidic zeolite (H+-Y), to produce lignin-substructure-based hydrocarbons (C7-C18), primarily C12-C18 cyclic structure hydrocarbons in the jet fuel range, was demonstrated.
- Wang, Hongliang,Ruan, Hao,Pei, Haisheng,Wang, Huamin,Chen, Xiaowen,Tucker, Melvin P.,Cort, John R.,Yang, Bin
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supporting information
p. 5131 - 5135
(2015/12/08)
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- Copper-catalyzed oxidative homo- and cross-coupling of grignard reagents using diaziridinone
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Transition-metal-catalyzed cross-coupling reactions are among the most powerful synthetic transformations. This paper describes an efficient copper-catalyzed homo- and cross-coupling of Grignard reagents with di-tert-butyldiaziridinone as oxidant under mild conditions, giving the coupling products in good to excellent yields. The reaction process has a broad substrate scope and is also effective for the C(sp)-C(sp3) coupling.
- Zhu, Yingguang,Xiong, Tao,Han, Wenyong,Shi, Yian
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supporting information
p. 6144 - 6147
(2015/01/09)
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- An improved method for the complete hydrogenation of aromatic compounds under 1 bar H2 with platinum nanowires
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A little pressure for a lot of gain: An efficient method has been developed for the controlled hydrogenation of phenol using a platinum nanowire catalyst under mild conditions (>98.4%, 1atm H2, 60°C). The catalyst also exhibited high levels of activity and selectivity towards other selected aromatic compounds bearing a variety of different substituents, demonstrating its generality towards the hydrogenation of aromatic compounds.
- Yu, Tingting,Wang, Jiaqing,Li, Xinming,Cao, Xueqin,Gu, Hongwei
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p. 2852 - 2855
(2013/10/21)
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- Catalytic double C-Cl bond activation in CHlby iron(III) salts with grignard reagents
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Cross-coupling of Grignard reagents with dichloromethane is achieved using iron(III) catalysts. Aryl- and benzylmagnesium bromides show a range of activity toward double C-Cl bond activation resulting in the insertion of methylene fragments between two equivalents of the nucleophilic partner. Georg Thieme Verlag Stuttgart.
- Qian, Xin,Kozak, Christopher M.
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experimental part
p. 852 - 856
(2011/06/21)
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- Nickel-catalyzed cross-coupling of alkyl zinc halides for the formation of C(sp2)-C(sp3) bonds: Scope and mechanism
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Optimal conditions for a general Ni-catalysed Negishi cross-coupling of alkyl zinc halides with aryl, heteroaryl and alkenyl halides have been determined. These conditions allow the reaction to take place smoothly, with low catalyst loading, and in the pr
- Phapale, Vilas B.,Guisan-Ceinos, Manuel,Bunuel, Elena,Cardenas, Diego J.
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supporting information; experimental part
p. 12681 - 12688
(2010/06/12)
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- Raney Ni-Al alloy-mediated reduction of benzils in wate
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Raney Ni-Al alloy in a dilute aqueous alkaline solution has been shown to be a powerful reducing agent and is highly effective for the reduction of alkylbenzils and alkoxybenzils to afford the corresponding 1,2-diarylethers at 90°C, in the absence of organic solvents. 4,4'-Dinitrobenzil was transformed selectively to 1,2-bis(4-aminophenyl) ethane.
- Liu, Guo-Bin,Zhao, Hong-Yun,Dai, Lu,Thiemann, Thies,Tashiro, Hideki,Tashiro, Masashi
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experimental part
p. 579 - 581
(2010/02/28)
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- A three-phase emulsion/solid-heterogenization method for transport and catalysis
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No organic solvents are required using this novel concept for the heterogenization of (catalytic) reactions. The method relies on a multiphase transport process, namely on the transport of emulsified hydrophobic substrates to a hydrophobically derivatized sol-gel entrapped catalyst (see figure; S = substrate), and the transport of the resulting emulsified product from the catalyst-entrapping environment back into the aqueous bulk.
- Abu-Reziq, Raed,Avnir, David,Blum, Jochanan
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p. 4132 - 4134
(2007/10/03)
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- New homo-coupling reaction of alkyl, aryl, vinyl, and allyl grignard reagents using trifluoromethanesulfonic anhydride
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Homo-coupling reaction of various alkyl, aryl, vinyl, and allyl Grignard reagents with trifluoromethanesulfonic anhydride provides a simple and straightforward method for the syntheses of symmetrical carbon-carbon coupling products under mild conditions and in moderate to good yields.
- Nishiyama, Tomihiro,Seshita, Takeshi,Shodai, Hiroshi,Aoki, Kazushige,Kameyama, Hideaki,Komura, Kenichi
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p. 549 - 550
(2007/10/03)
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- Hydrogenation of Biphenyls over the Hydrogen Storage Alloy MmNi3.5Co0.7Al0.8H4
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Hydrogenation of biphenyl with the activated hydrogen storage alloy, MmNi3.5Co0.7Al0.8H4 (Mm: La, 30; Ce, 52; Pr, 5; Nd, 13 wtpercent), as a stoichiometric reductant proceeded effectively at 160 deg C for 3 h under nitrogen to give either phenylcyclohexane or bicyclohexyl selectively, according to the ratio of the alloy to biphenyl.
- Nakagawa, Shin-ichi,Murata, Satoru,Sakai, Tetsuo,Nomura, Masakatsu
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p. 431 - 432
(2007/10/02)
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- FACILE HYDROGENATION OF AROMATIC NUCLEI WITH SODIUM BOROHYDRIDE-RHODIUM CHLORIDE IN HYDROXYLIC SOLVENTS
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Sodium borohydride-rhodium chloride in hydroxylic solvent was proved to be very useful for the reduction of aromatic nuclei to the corresponding saturated cycles under mild conditions.
- Nishiki, Mayumi,Miyataka, Hideki,Niino, Yasunori,Mitsuo, Naoki,Satoh, Toshio
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p. 193 - 196
(2007/10/02)
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