- NHC-Iridium-Catalyzed Deoxygenative Coupling of Primary Alcohols Producing Alkanes Directly: Synergistic Hydrogenation with Sodium Formate Generated in Situ
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The direct conversion of alcohols into long-chain alkanes is an attractive but extremely challenging approach for biomass upgrading. Here, we describe the highly selective deoxygenative coupling of aryl ethanols with primary alcohols to produce alkanes, using a bis-N-heterocyclic carbene iridium (bis-NHC-Ir) complex as the catalyst. Up to quantitative yields and selectivity with a broad substrate scope are attained in both homo- and cross-coupling reactions. Mechanistic studies reveal that the further synergistic hydrogenation of the alkene intermediates by the formate generated in situ in the presence of bis-NHC-Ir is crucial for alkane production.
- Lu, Zeye,Zheng, Qingshu,Yang, Siqi,Qian, Chun,Shen, Yajing,Tu, Tao
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p. 10796 - 10801
(2021/09/08)
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- Method for preparing alkane through coupling of primary alcohol catalyzed by N-heterocyclic carbene metal compound
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The invention belongs to the technical field of transition metal catalysis and coupling reaction of biomass alcohol, and particularly relates to a method for preparing alkane in one step through self-coupling and cross-coupling of primary alcohol catalyzed by an N-heterocyclic carbene metal compound. The invention firstly provides a catalyst, namely a homogeneous N-heterocyclic carbene metal compound, for preparing alkane through primary alcohol coupling. The method comprises the following steps: by taking primary alcohol as a reaction raw material, tert-butyl alcohol salt of alkali metal, hydroxide and other strong alkalis as alkalis, the N-heterocyclic carbene metal compound as a catalyst and tertiary alcohol, benzene analogue or long-chain alkane as a solvent, reacting at 80-200 DEG C for 4-24 hours to obtain a corresponding alkane product. Compared with the prior art, the method disclosed by the invention has the advantages that the cheap and easily available biomass alcohol can be used as the starting raw material, the use of toxic phosphine-containing ligands with poor stability is avoided, the reaction selectivity and the yield can be quantified, the operation is simple and convenient, different high-purity alkane products can be obtained only through simple post-treatment, and the method is suitable for industrial amplification and application.
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Paragraph 0101-0106
(2021/08/19)
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- Direct α-Benzylation of Methyl Enol Ethers with Activated Benzyl Alcohols: Its Rearrangement and Access to (±)-Tetrahydronyasol, Propterol A, and 1,3-Diarylpropane
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Herein, we report a one-pot Lewis acid mediated synthesis of bi- and triarylpropanal derivatives and their corresponding isomeric ketones from aromatic enol ethers. This transformation takes place via nucleophilic attack of enol ethers to electron-rich be
- Jena, Tapan Kumar,Khan, Faiz Ahmed
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p. 14270 - 14280
(2019/10/17)
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- [...] compound and mesogenic medium
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wherein R11, R12, MG11, MG12 and CG1 have the meaning given in claim 1, to the use of bimesogenic compounds of formula I in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the pre
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- Ligand-Controlled Chemoselective C(acyl)-O Bond vs C(aryl)-C Bond Activation of Aromatic Esters in Nickel Catalyzed C(sp2)-C(sp3) Cross-Couplings
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A ligand-controlled and site-selective nickel catalyzed Suzuki-Miyaura cross-coupling reaction with aromatic esters and alkyl organoboron reagents as coupling partners was developed. This methodology provides a facile route for C(sp2)-C(sp3) bond formation in a straightforward fashion by successful suppression of the undesired β-hydride elimination process. By simply switching the phosphorus ligand, the ester substrates are converted into the alkylated arenes and ketone products, respectively. The utility of this newly developed protocol was demonstrated by its wide substrate scope, broad functional group tolerance and application in the synthesis of key intermediates for the synthesis of bioactive compounds. DFT studies on the oxidative addition step helped rationalizing this intriguing reaction chemoselectivity: whereas nickel complexes with bidentate ligands favor the C(aryl)-C bond cleavage in the oxidative addition step leading to the alkylated product via a decarbonylative process, nickel complexes with monodentate phosphorus ligands favor activation of the C(acyl)-O bond, which later generates the ketone product.
- Chatupheeraphat, Adisak,Liao, Hsuan-Hung,Srimontree, Watchara,Guo, Lin,Minenkov, Yury,Poater, Albert,Cavallo, Luigi,Rueping, Magnus
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p. 3724 - 3735
(2018/03/21)
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- Cycloalumination of allylbenzenes with triethylaluminum in the presence of Cp2ZrCl2. One-pot synthesis of 2-benzylbutane-1,4-diols as precursors of dibenzylbutane lignans
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One-pot synthesis of 2-[(hydroxy- and methoxyphenyl)methyl]butane-1,4-diols in an overall yield of 60–65% by cycloalumination of allylbenzenes (4-allyl-1-methoxybenzene, 4-allyl-1,2-dimethoxybenzene, 5-allyl-2-methoxyphenol, and 5-allyl-1,2,3-trimethoxybenzene) with triethylaluminum in the presence of Cp2ZrCl2is reported for the first time. The developed procedure opens a new synthetic route to practically important β-substituted butane-1,4-diols that are precursors to dibenzylbutane lignans.
- Parfenova,Kovyazin,Tyumkina,Khalilov,Dzhemilev
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p. 1750 - 1755
(2017/02/19)
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- Understanding the reactivity of enol ether radical cations: Investigation of anodic four-membered carbon ring formation
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The reactivity of enol ether radical cations was investigated in anodic four-membered carbon ring formations, advancing the mechanistic understanding of these reactions. The mono-ring-containing aromatic cations were reduced through inter- or intramolecular electron transfer to give mono- or bis-ring-containing compounds, respectively. Small structural changes in the hydrocarbon linkers tethering two aromatic rings exerted a powerful effect on the efficiency of such electron transfer events.
- Yamaguchi, Yusuke,Okada, Yohei,Chiba, Kazuhiro
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p. 2626 - 2638
(2013/04/23)
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- Arylalkyl ketones, benzophenones, desoxybenzoins and chalcones inhibit TNF-α induced expression of ICAM-1: Structure-activity analysis
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The interaction between leukocytes and the vascular endothelial cells (EC) via cellular adhesion molecules plays an important role in the pathogenesis of various inflammatory and autoimmune diseases. Small molecules that block these interactions have been targeted as potential therapeutic agents against acute and chronic inflammatory diseases. In an effort to identify potent intercellular cell adhesion molecule-1 (ICAM-1) inhibitors, a large number of arylalkyl ketones, benzophenones, desoxybenzoins and chalcones and their analogs (54 in total) have been synthesized and screened for their ICAM-1 inhibitory activity. The structure-activity relationship studies of these compounds identified three potent chalcone derivatives and also demonstrated the possible mechanism for their ICAM-1 inhibitory activities. The most active compound was found to be 79. A large number of arylalkyl ketones, benzophenones, desoxybenzoins and chalcones as well as their analogs (54 in total) were synthesized and screened for their ICAM-1 inhibitory activity. The structure-activity relationship studies of these compounds identified three potent chalcone derivatives and also demonstrated a possible mechanism of their ICAM-1 inhibitory activities. The most active compound was found to be 79. Copyright
- Kumar, Sarvesh,Reddy L, Chandra Shekhar,Kumar, Yogesh,Kumar, Amit,Singh, Brajendra K.,Kumar, Vineet,Malhotra, Shashwat,Pandey, Mukesh K.,Jain, Rajni,Thimmulappa, Rajesh,Sharma, Sunil K.,Prasad, Ashok K.,Biswal, Shyam,Van Der Eycken, Erik,Depass, Anthony L.,Malhotra, Sanjay V.,Ghosh, Balaram,Parmar, Virinder S.
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p. 368 - 377
(2012/07/31)
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- Iridium-catalyzed reactions of ω-Arylalkanols to α,ω- Diarylalkanes
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The long and the short of it: An atom-economical route to α,ω-diarylalkanes from ω-arylalkanols was achieved by a direct one-step method, or a sequential two-step method depending on the alkyl chain length. The reaction proceeded through the formation of β-methylhydroxy- α,ω-diarylalkanes by dehydrogenation/β-alkylation, followed by dehydrogenation/decarbonylation. Copyright
- Obora, Yasushi,Anno, Yuka,Okamoto, Ryuhei,Matsu-Ura, Toyomi,Ishii, Yasutaka
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supporting information; experimental part
p. 8618 - 8622
(2011/11/11)
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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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- Photoreduction of 1,2-diarylcyclopropanes by hydroxide ion
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The photoreduction of 1,2-diarylcyclopropanes 1 by NaOH yielded the corresponding 1,3-diarylpropanes 2 in i-PrOH. The efficiency of the photoreduction was dependent on the electron deficiency of 1 and the excitation wavelength, solvent, and additive. This is a rare example of a cyclopropane serving as an electron acceptor to afford a reduction product. Copyright
- Yoshimi, Yasuharu,Wada, Naohisa,Sasamoto, Koichi,Itou, Tatsuya,Hatanaka, Minoru
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p. 782 - 783
(2008/12/21)
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- THE PREPARATION OF α,ω-BIS-PARA-ANISYLALKANES
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An improved method for the preparation of a homologous series of α,ω-bis-para-anisylalkanes is described.
- Kadkhodayan, Miryam,Singleton, Terry,Heldrich, F. J.
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p. 707 - 712
(2007/10/02)
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