- Ni/Co-catalyzed homo-coupling of alkyl tosylates
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A direct reductive homo-coupling of alkyl tosylates has been developed by employing a combination of nickel and nucleophilic cobalt catalysts. A single-electron-transfer-type oxidative addition is a pivotal process in the well-established nickel-catalyzed coupling of alkyl halides. However, the method cannot be applied to the homo-coupling of ubiquitous alkyl tosylates due to the high-lying σ*(C–O) orbital of the tosylates. This paper describes a Ni/Co-catalyzed protocol for the activation of alkyl tosylates on the construction of alkyl dimers under mild conditions.
- Komeyama, Kimihiro,Tsunemitsu, Ryusuke,Michiyuki, Takuya,Yoshida, Hiroto,Osaka, Itaru
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- Electron transfer-induced reduction of organic halides with amines
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Reduction of a variety of organo halides was examined by using amines as a sacrificial hydrogen source. UV light-induced reduction of vinyl and aryl halides with triethylamine proceeded smoothly to give the corresponding reduced products. High temperature heating also caused the reduction and DABCO (1,4-diazabicyclo[2.2.2]octane) also served as a good reducing reagent.
- Fukuyama, Takahide,Fujita, Yuki,Miyoshi, Hayato,Ryu, Ilhyong,Kao, Shih-Chieh,Wu, Yen-Ku
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supporting information
p. 5582 - 5585
(2018/06/04)
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- NMR-based molecular ruler for determining the depth of intercalants within the lipid bilayer. Part III: Studies on keto esters and acids
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The development of "molecular rulers" would allow one to quantitatively locate the penetration depth of intercalants within lipid bilayers. To this end, an attempt was made to correlate the 13C NMR chemical shift of polarizable "reporter" carbons (e.g., carbonyls) of intercalants within DMPC liposomal bilayers - with the polarity it experiences, and with its Angstrom distance from the interface. This requires families of molecules with two "reporter carbons" separated by a known distance, residing at various depths/polarities within the bilayer. For this purpose, two homologous series of dicarbonyl compounds, methyl n-oxooctadecanoates and the corresponding n-oxooctadecanoic acids (n = 4-16), were synthesized. To assist in assignment and detection several homologs in each system were prepared 13C-enriched in both carbonyls. Within each family, the number of carbons and functional groups remains the same, with the only difference being the location of the second ketone carbonyl along the fatty acid chain. Surprisingly, the head groups within each family are not anchored near the lipid-water interface, nor are they even all located at the same depth. Nevertheless, using an iterative best fit analysis of the data points enables one to obtain an exponential curve. The latter gives substantial insight into the correlation between polarity (measured in terms of the Reichardt polarity parameter, ET(30)) and penetration depth into the liposomal bilayer. Still missing from this curve are data points in the moderate polarity range.
- Afri, Michal,Alexenberg, Carmit,Aped, Pinchas,Bodner, Efrat,Cohen, Sarit,Ejgenburg, Michal,Eliyahu, Shlomi,Gilinsky-Sharon, Pessia,Harel, Yifat,Naqqash, Miriam E.,Porat, Hani,Ranz, Ayala,Frimer, Aryeh A.
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p. 105 - 118
(2015/02/19)
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- Novel reducing properties of a series of lanthanoid metals in the presence of SmI2
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The reduction of dodecyl iodide, as model compound, with a series of lanthanoid (Ln) metals in the presence of catalytic amounts of samarium diiodide (SmI2) has been investigated in detail. The reducing activity of SmI2/Ln and the kinds of reduced products were found to be dependent on the individual Ln, but not on SmI2.
- Tomisaka, Yuri,Yoshimura, Aya,Nomoto, Akihiro,Sonoda, Motohiro,Ogawa, Akiya
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- Dilithium tetrachlorocuprate(II) catalyzed oxidative homocoupling of functionalized grignard reagents
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An efficient procedure is described for the oxidative homocoupling of functionalized Grignard reagents using a catalytic amount of dilithium tetrachlorocuprate(II) (CuLi2Cl4) in the presence of pure oxygen gas. This method is applied successfully to a variety of aryl, heteroaryl, alkyl, alkenyl and alkynyl halides, which are converted into the corresponding homocoupled products in good to excellent yields. Georg Thieme Verlag Stuttgart · New York.
- Hua, Si-Kai,Hu, Qiu-Peng,Ren, Jiangmeng,Zeng, Bu-Bing
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p. 518 - 526
(2013/03/29)
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- Efficient heterogeneous dual catalyst systems for alkane metathesis
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A fully heterogeneous and highly efficient dual catalyst system for alkane metathesis (AM) has been developed. The system is comprised of an alumina-supported iridium pincer catalyst for alkane dehydrogenation/olefin hydrogenation and a second heterogeneous olefin metathesis catalyst. The iridium catalysts bear basic functional groups on the aromatic backbone of the pincer ligand and are strongly adsorbed on Lewis acid sites on alumina. The heterogeneous systems exhibit higher lifetimes and productivities relative to the corresponding homogeneous systems as catalyst/catalyst interactions and bimolecular decomposition reactions are inhibited. Additionally, using a two-pot device, the supported Ir catalysts and metathesis catalysts can be physically separated and run at different temperatures. This system with isolated catalysts shows very high turnover numbers and is selective for the formation of high molecular weight alkanes.
- Huang, Zheng,Rolfe, Eleanor,Carson, Emily C.,Brookhart, Maurice,Goldman, Alan S,El-Khalafy, Sahar H.,Roy MacArthur, Amy H.
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experimental part
p. 125 - 135
(2010/06/20)
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- Glassy carbon modified by a silver-palladium alloy: cheap and convenient cathodes for the selective reductive homocoupling of alkyl iodides
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Micrometer-thick layers of silver-palladium alloy were elaborated in order to modify the surface of glassy carbon electrodes. Such a surface modification can be readily achieved via a preliminary silver galvanostatic deposit onto carbon followed by a 'palladization' step, thanks to a simple immersion in acidic PdII-based solutions producing a displacement reaction. The as-prepared metallic interfaces exhibit outstanding catalytic capabilities especially in the cleavage of carbon-halogen bonds while being chemically/electrochemically quite stable and relatively inexpensive. More specifically, the use of such glassy carbon/Ag-Pd electrodes in dimethylformamide (DMF) containing tetraalkylammonium salts (TAA+X-) makes the one-electron reductions of primary alkyl iodides possible; this reduction leads to the formation of homodimers in high yields. Formation of a free radical as transient resulted from the homocoupling reaction.
- Poizot, Philippe,Jouikov, Viatcheslav,Simonet, Jacques
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body text
p. 822 - 824
(2009/05/07)
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- On the potentially excellent reducing ability of a series of low-valent rare earths induced by photoirradiation
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Mixed systems of a series of rare earth metals such as La, Ce, Pr, Nd, Sm, Eu, and Yb and their low-valent rare earth diiodides exhibit excellent reducing ability toward the reductive deiodation from 1-iodododecane as a model compound compared with their single systems. More importantly, under photoirradiation conditions, the C-I bond reduction using 'Ln/LnI2' takes place efficiently in refluxing THF, even in the cases of heavy rare earths such as Gd, Tb, Dy, Ho, Er, and Tm.
- Tomisaka, Yuri,Nomoto, Akihiro,Ogawa, Akiya
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scheme or table
p. 584 - 586
(2009/05/11)
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- Nanosized iron- or copper-catalyzed homocoupling of aryl, heteroaryl, benzyl, and alkenyl grignard reagents
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Under very mild reaction conditions, iron or copper nanoparticles efficiently promoted the homocoupling of different Grignard reagents in tetrahydrofuran at room temperature. The nanosized iron or copper particles were generated in situ in a simple and economical way from commercially available FeCl2 or CuCl2, respectively, an excess of lithium powder, and a catalytic amount (5 mol%) of 4,4′-di-tert-butylbiphenyl (DTBB) as electron carrier. The reaction of a series of aryl, heteroaryl, benzyl, and alkenyl Grignard reagents in the presence of a substoichiometric amount of the iron or copper nanoparticles led to the formation of the corresponding homocoupling products in good yield. Copyright Taylor & Francis Group, LLC.
- Moglie, Yanina,Mascaro, Evangelina,Nador, Fabiana,Vitale, Cristian,Radivoy, Gabriel
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experimental part
p. 3861 - 3874
(2009/04/11)
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- DEGRADATION OF POLYCYCLIC AROMATIC HYDROCARBONS TO RENDER THEM AVAILABLE FOR BIODEGRADATION
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A method for the degradation of polycyclic aromatic compounds is disclosed that involves dissolving ozone in a bipolar solvent comprising a non-polar solvent in which is of sufficiently non-polar character to solubilized the polycyclic aromatic compounds, and a polar-water-compatible solvent which is fully miscible with the non-polar solvent to form a single phase with the non-polar solvent. The bipolar solvent with dissolved ozone is contacted with the polycyclic aromatic compounds to solubilize the polycyclic aromatic compounds and react the dissolved polycyclic aromatic compounds with the ozone to degrade the dissolved polycyclic aromatic compounds to oxygenated intermediates. The bipolar solvent is then mixed with sufficient water to form separate non-polar and polar phases, the non-polar phase comprising the non-polar solvent and the polar phase comprising the non-polar solvent and the oxygenated intermediates. The polar phase is then diluted and incubated with bacteria to biodegrade the oxygenated intermediates.
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Page/Page column 5-8; 15-16
(2008/12/07)
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- Process for hydrogenation of carboxylic acids and derivatives to hydrocarbons
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A process for hydrogenating a carboxylic acid and/or derivative thereof having a carboxylate group represented by the general formula R1COO-, which process comprises feeding hydrogen and the carboxylic acid and/or derivative thereof to a reactor and maintaining conditions within the reactor such that hydrogen reacts with the carboxylic acid and/or derivative thereof to produce a product stream comprising carbon dioxide, carbon monoxide, methane and hydrocarbons represented by general formulae R1H and R1CH3, characterised in that the molar ratio of R1H : R1CH3 is above a pre-determined value and/or the mole ratio of the sum of carbon dioxide, carbon monoxide and methane to carboxylate groups is above a pre-determined value.
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Page/Page column 7-8
(2008/06/13)
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- METHOD FOR THE PRODUCTION OF PRIMARY LONG-CHAIN ALCOHOLS
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The invention relates to a method for the production of linear long-chain alcohols with 20 to 40 carbon atoms by means of a growth reaction with ethylene on aluminium compounds.
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Page/Page column 10
(2010/02/15)
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- Product selectivity in the electroreduction of thioesters
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The electroreduction of differently substituted aromatic and aliphatic thioesters (RCOSR′) led to regioselective reactions depending on the nature of the substituents. Thus, the cleavage between the carbonyl group and the SR′ group afforded α-diketones an
- We?wer,Olivero,Du?ach
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p. 1709 - 1714
(2007/10/03)
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- Synthesis of the four stereoisomers of 7-acetoxy-15-methylnonacosane, a component of the female sex pheromone of the screwworm fly, Cochliomyia hominivorax
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The four stereoisomers of 7-acetoxy-15-methylnonacosane (1), a component of the female sex pheromone of the New World screwworm fly (Cochliomyia hominivorax) were synthesized. The stereogenic center at C-15 of 1 originated from that of the enantiomers of citronellal, and that at C-7 was generated by lipase-catalyzed asymmetric acetylation of (3RS,11R)- and (3RS,11S)-17-methyl-1- trimethylsilylpentacos-1-yn-3-ol (13). Three of the stereoisomers of 1 showed equivalent good pheromone activity, while the activity of (7R,15R)-1 was weak.
- Mori, Kenji,Ohtaki, Takashi,Ohrui, Hiroshi,Berkebile, Dennis R.,Carlson, David A.
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p. 1768 - 1778
(2007/10/03)
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- Reduction of organic halides with lanthanum metal: A novel generation method of alkyl radicals
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Results of the reaction of alkyl halides with lanthanum metal have been shown. The reduction of alkyl iodide with 1/3 equiv of lanthanum metal efficiently proceeded to give the corresponding reductive dimerized products along with the formation of reduction and dehydroiodination products. In the case of alkyl bromides and chlorides, the reaction did not proceed under the same reaction conditions as that of alkyl iodides; however, the reaction was dramatically promoted by the addition of a catalytic amount of iodine. A reaction pathway including alkyl radicals was suggested.
- Nishino, Toshiki,Watanabe, Toshihisa,Okada, Mitsuo,Nishiyama, Yutaka,Sonoda, Noboru
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p. 966 - 969
(2007/10/03)
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- Carbon-carbon bond formation by electrochemical catalysis in conductive microemulsions
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Bicontinuous microemulsions made from oil, water, and surfactants were examined as substitutes for organic solvents in carbon-carbon bond-forming reactions. Conjugated additions of primary alkyl iodides 3a-c to 2-cyclohexen-1-one (4) to give 3-alkyl cyclohexanones 5a-c and cyclization of 2-(4-bromobutyl)-2-cyclohexen-1-one (9) to 1-decalone (10) were mediated by the Co(I)L complex vitamin B12s generated at carbon cloth electrodes under mild conditions. Reaction of the Co(I)L nucleophile with the alkyl halides gives a Co-alkyl complex. Cleavage of the Co-alkyl complexes by using an electrode potential of -0.85 V (all vs SCE) and irradiation with visible light, or a potential of -1.45 V in the dark, were compared. Addition of the resulting alkyl radicals to the activated double bonds gave comparable yields of 3-alkylcyclohexanone 5a-c (70-80% using -0.85 V + light) and 1-decalone (90%, both cleavage modes) 10 in microemulsions and in DMF. Microemulsions containing hexadecyltrimethylammonium bromide (CTAB) gave remarkable stereoselectivity for the trans isomer of 10, while homogeneous DMF and a sodium dodecylsulfate (SDS) microemulsion gave little stereoselectivity.
- Gao, Jianxin,Rusling, James F.,Zhou, De-Ling
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p. 5972 - 5977
(2007/10/03)
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- Organotellurium Chemistry. The Telluroxide Elimination Reaction
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In an effort to clarify the nature of the organotelluroxide elimination reaction, dodecyl-(4-methoxyphenyl)tellurium oxide and dioxide were thermolysed; mechanisms involving tellurenic acid for the oxide and a 1,2-oxygen shift for the dioxide are proposed.
- Lee, Hosull,Cava, Michael P.
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p. 277 - 278
(2007/10/02)
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- The Reductive Coupling of Organic Halide Using Hydrazine and a Palladium Catalyst.II. Homocoupling of 1-Iodoalkanes
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The hydrogenolysis and dimerization of iodoalkanes were catalyzed by Pd in the presence of an appropriate reducing agent.Hydrazine was found to be effective for the coupling of 1-iodoeicosane to give tetracontane, C40H82, in a 74 percent yield.The yield of the coupling product decreased with the decrease of the number of the carbon atoms in the 1-iodoalkanes.Both alkylhydrazines and alkenes were shown not to take part in the reaction as a reaction intermediate.
- Nakajima, Riichiro,Morita, Kazuhiro,Hara, Tadashi
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p. 3599 - 3600
(2007/10/02)
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