- Method for preparing biaryl hydrocarbon compound from alcohol compound
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The invention provides a method for preparing a biaryl hydrocarbon compound from an alcohol compound. The method comprises the following steps: sequentially adding the alcohol compound, sodium borohydride and iodine (the molar ratio is 1: (2-3): (0.5-1)) into a reaction tube containing acetonitrile solvent, sealing the reaction tube, heating to 100 DEG C, reacting for 10-20 hours, quenching with water after the reaction is completed, drying an organic phase with anhydrous magnesium sulfate, and carrying out rotary evaporation to remove the solvent and obtain a target product. The method has the advantages of convenience in operation, easiness in product separation, high yield, small environmental pollution and the like, is an ideal method for producing the high-energy-density hydrocarbon by utilizing oxygen-enriched biomass raw materials, and has important practical value.
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Paragraph 0021-0023
(2020/02/14)
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- Photoredox-Catalysis-Modulated, Nickel-Catalyzed Divergent Difunctionalization of Ethylene
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Divergent synthesis that enables a catalytic reaction to selectively produce different products from common substrates will allow the charting of wider chemical space and the unveiling of distinct mechanistic paradigms. A common strategy for it employs different ligands to modulate organometallic catalysts. Dramatic developments in photocatalysis have enabled previously inaccessible transformations. In particular, photoredox catalysis modulates the oxidation state of transition-metal complexes, offering enormous opportunities for methodology development. Herein, we developed a photo-mediated divergent ethylene difunctionalization via modulating oxidation states of the nickel catalyst by using different photoredox catalysts. This work will inspire new perspectives for value-added chemical synthesis using ethylene as a feedstock and shed light on photoredox-catalyst-based divergent synthesis, which fundamentally differs from ligand-controlled transition-metal catalysis.Divergent synthesis represents a powerful strategy for directly accessing different molecular scaffolds originating from the same starting materials. Access to different end products via transition-metal catalysis is conventionally achieved by ligand control. We herein demonstrate the use of ethylene feedstock and commercially available aryl halides to accomplish the divergent synthesis of 1,2-diarylethanes, 1,4-diarylbutanes, or 2,3-diarylbutanes in a highly selective fashion through the synergistic combination of nickel and photoredox catalysis. Mechanistic studies suggest that the observed selectivity was due to different active states of Ni(I) and Ni(0) modulated by Ru- and Ir-based photoredox catalysts, respectively. The ability to access different organometallic oxidation states via photoredox catalysis promises to inspire new perspectives for synergistic transition-metal-catalyzed divergent synthesis.Functionalization of ethylene without polymerization is challenging under photo-irradiation conditions. We have demonstrated that the photo-transformation of ethylene can be controllable by merging photoredox and transition-metal catalysis. In our study, the use of different photoredox catalysts was able to modulate the oxidation state of the nickel catalyst. Through different oxidation states, the nickel-catalyzed couplings proceeded via distinct pathways to generate divergent ethylene difunctionalization products selectively from the same feedstock.
- Li, Jiesheng,Luo, Yixin,Cheo, Han Wen,Lan, Yu,Wu, Jie
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supporting information
p. 192 - 203
(2019/01/21)
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- Ni(II)/Al(0) mediated benzylic Csp 3 - Csp 3 coupling in aqueous media
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Abstract : The reaction of benzyl bromides and chlorides with aluminium metal powder or foil (1.2 eqv.) in the presence of catalytic nickel nitrate (10 mol%) in water at room temperature resulted in homocoupling to the corresponding bibenzyl products which were isolated in moderate to good yields. In sharp contrast, the same reaction in organic solvents like dichloromethane, dimethylformamide, acetonitrile, methanol and toluene yielded only a trace amount of the desired product. The scope of the reaction was tested with substituents on the aromatic ring such as Me-, Cl-, CN-, F-, NO 2-, Ph- as well as 2 ° benzyl halides. Graphical abstract: The reagent combination of aluminium metal and catalytic Ni(NO3)2 promotes the homocoupling of benzyl bromides and chlorides giving rise to the corresponding bibenzyl products in good to excellent yields. The reaction is greatly facilitated in water and showed good functional group tolerance. Besides the mild reaction condition and bench-friendliness, the present reaction constitutes the first example of aluminium-mediated homocoupling of a halide in water. [Figure not available: see fulltext.].
- Nayak, Mukesh Kumar,Mukhi, Priyabrata,Mohanty, Anuradha,Rana, Sohel Samim,Arora, Rajat,Narjinari, Himani,Roy, Sujit
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- Reductive Homocoupling of Organohalides Using Nickel(II) Chloride and Samarium Metal
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A homocoupling method for organohalides and organosulfonates promoted by samarium metal and HMPA, and catalyzed by NiCl2 has been developed. Various organohalides (benzyl, aryl, heterocyclic, alkenyl and alkyl halides), α-haloacetophenones, and phenyl organosulfonates were tolerated, and the reaction afforded coupling products with high efficiency. Excellent chemoselectivity was exhibited between halides and other groups, such as ?COOH, ?NO2, halogen, heterocyclic ring, ester, and ketone groups. The stereoselectivity suggested that the reaction mechanism might involve an organosamarium species.
- Liu, Yongjun,Xiao, Shuhuan,Qi, Yan,Du, Feng
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p. 673 - 678
(2017/03/22)
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- A well-defined low-valent cobalt catalyst Co(PMe3)4 with dimethylzinc: a simple catalytic approach for the reductive dimerization of benzyl halides
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Herein, we report the first catalytic version of a cobalt-catalysed reductive homocoupling of benzyl halides which proceeds with low catalyst loadings (0.5 to 5 mol%). By synthetizing each cobalt intermediate we demonstrate that reaction proceeds through two single electron transfers (SET) and that dimethylzinc is only involved in the regeneration of the catalytic species.
- Fallon, Brendan J.,Corcé, Vincent,Amatore, Muriel,Aubert, Corinne,Chemla, Fabrice,Ferreira, Franck,Perez-Luna, Alejandro,Petit, Marc
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p. 9912 - 9916
(2016/12/07)
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- New preparation of benzylic aluminum and zinc organometallics by direct insertion of aluminum powder
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The reaction of commercial Al-powder (3 equiv) and InCl3 (1-5 mol %) with benzylic chlorides provides various functionalized benzylic aluminum sesquichlorides under mild conditions (THF, 20 °C, 3-24 h) without homocoupling (5%). These new benz
- Bluemke, Tobias D.,Groll, Klaus,Karaghiosoff, Konstantin,Knochel, Paul
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scheme or table
p. 6440 - 6443
(2012/01/15)
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- Synthesis of unsymmetrical arylheteroarylmethanes by direct "on water" cross-coupling between benzylic and heteroaromatic halides
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Walking on water: Pharmacologically important unsymmetrical arylheteroarylmethanes are prepared by simple palladium-catalyzed zinc-mediated Negishi-like cross-couplings in good yields. This reaction tolerates various benzylic chlorides and heteroaromatic bromides "on water" and at room temperature.
- Krasovskaya, Valeria,Krasovskiy, Arkady,Lipshutz, Bruce H.
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supporting information; experimental part
p. 1974 - 1976
(2011/10/31)
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- Kinetics and mechanism of the reaction of benzyl bromide with copper in hexamethylphosphoramide
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The reaction of copper with benzyl bromides in hexamethylphosphoramide has been studied. The kinetic and thermodynamic parameters of the reaction have been obtained. Hammett plots of log (script k sign/script k sign°) vs the substituent constant σ gave good correlations (ρ = 0.15, S ρ = 0.02, r = 0.954). The structure of the organic group has little effect on the rate of reaction of benzyl bromide with copper. In the absence of atmospheric oxygen, the oxidative dissolution of copper occurred by the mechanism of single-electron transfer with the formation of 1,2-diphenylethane and copper(I) complexes. The stereochemistry and intermediates compound was also investigated. The reaction mechanism is discussed.
- Egorov, Anatoly M.,Matyukhova, Svetlana A.,Anisimov, Alexander V.
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p. 296 - 305
(2007/10/03)
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- Mechanism of the Solution-Phase Reaction of Alkyl Sulfides Atomic Hydrogen. Reduction via a 9-S-3 Radical Intermediate
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The low selectivity of benzyl alkyl sulfide fragmentation subsequent to its reaction with atomic hydrogen is indicative of a reaction that proceeds via an early transition state. The competitive reduction of a series of substituted-benzyl alkyl sulfides was insensitive to the substituent on the aromatic ring (ρ = -0.13, r = 0.99). The relative rates of fragmentation of a series of the substituted-benzyl alkyl sulfides gave a V-shaped Hammett plot. Both electron-donating and electron-withdrawing groups destabilized the transition state (ρ = +0.99, r = 0.999; ρ = -0.82, r = 0.992). Since the relative rates of disappearance of the alkyl benzyl sulfides are not substituent dependent, but the relative rates of fragmentation are, a 9-S-3 intermediate is preferred as the structure leading to products.
- Tanner, Dennis D.,Koppula, Sudha,Kandanarachchi, Pramod
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p. 4210 - 4215
(2007/10/03)
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- Titanium-Mediated Carbonyl Olefinations. 2. Benzylidenations of Carbonyl Compounds with Dibenzyltitanocene
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Mild thermolysis of carbonyl compounds with dibenzyltitanocene affords phenyl-substituted olefins, enol ethers, and enamines.
- Petasis, Nicos A.,Bzowej, Eugene I.
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p. 1327 - 1330
(2007/10/02)
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- Structure-Activity Studies on Benzhydrol-Containing Nipecotic Acid and Guvacine Derivatives as Potent, Orally-Active Inhibitors of GABA Uptake
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The introduction of lipophilic groups onto the ring nitrogen of nipecotic acid and guvacine, two known GABA uptake inhibitors, afforded potent, orally-active anticonvulsant drugs.A series of compounds is reported which explores the structure-activity relationships (SAR) in this series.Among the areas explored: side-chain SAR (aromatic-, heterocyclic-, and tricyclic-containing side chains) and modifications to the tetrahydropyridine ring.The benzhydrol ether-containing side chains afforded the most potent compounds with several exhibiting in vitro IC50 values for GABA uptake of 1 μM (including 5, Table I; 37, 43, Table IV; and 44, Table V).Compound 44 was selected for extensive evaluation and subsequently progressed to Phase 1 clinical trials with severe adverse effects seen after single dose administration to humans.
- Pavia, Michael R.,Lobbestael, Sandra J.,Nugiel, David,Mayhugh, Daniel R.,Gregor, Vlad E.,et al.
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p. 4238 - 4248
(2007/10/02)
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- A FACILE REDUCTIVE CLEAVAGE OF ALLYLIC AND BENZYLIC ESTERS WITH LOW VALENT TITANIUM REAGENTS
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The reaductive cleavage of allylic and benzylic esters 1a-g with titanium(II) reagent derived from Mg/Hg-TiCl4 yielded the corresponding acids 3a-g and dimeric hydrocarbons 2a-g under mild reaction conditions.
- Satyanarayana, K.,Chidambaram, N.,Chandrasekaran, S.
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p. 2159 - 2166
(2007/10/02)
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- Chemistry of the tert-Butyl Radical: Polar Character, ρ Value for Reaction with Toluenes, and the Effect of Radical Polarity on the Ration of Benzylic Hydrogen Abstraction to Addition to Aromatic Rings
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We have reexamined the reactions of tert-butyl radicals with toluenes and have obtained a ρ value of 0.49 +/- 0.04 at 80 deg C.The new, independent system involves the quantification of all of the principal products from the reaction of tert-butyl radicals with mixtures of toluene and substituted toluene.Five major products contain benzyl fragments and are formed in significant yields: two symmetrical bibenzyls, the cross bibenzyl, and the two neopentylbenzenes that result from combination of tert-butyl and the two benzyl radicals.Attack on the side chain is a major reaction of free tert-butyl radicals and is the only significant reaction that they undergo other than cage and termination reactions. tert-Butyl radicals do not add to the ring of toluenes.Data on the relative rates of addition to benzenes and hydrogen abstraction from toluenes are collected for a series of radicals including hydrogen atoms; methyl, isopropyl, and tert-butyl radicals; and p-nitrophenyl, p-bromophenyl, and phenyl radicals.The data demonstrate that more electrophilic radicals have a larger tendency to add to rings whereas more nucleophilic radicals have a larger tendency to abstract benzylic hydrogens.
- Pryor, William A.,Tang, Felicia Y.,Tang, Robert H.,Church, Daniel F.
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p. 2885 - 2891
(2007/10/02)
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