- Theoretical and experimental investigation of palladium(II)-catalyzed decarboxylative addition of arenecarboxylic acid to nitrile
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The reaction mechanism of palladium(II)-catalyzed decarboxylative addition of 2,6-dimethoxybenzoic acid to acetonitrile was investigated by means of density functional theory (DFT) calculations. Calculations of the free energy profile for decarboxylation and carbopalladation indicated carbopalladation as the rate-determining step of the reaction. Investigation of the free energy profile for a series of experimentally evaluated nitrogen-based bidentate palladium ligands revealed that higher energy is required for decarboxylation and carbopalladation employing the experimentally least efficient ligand. The DFT investigation also showed that the relative free energies of the transition states were lowered in polar solvent, and preparative experiments confirmed that a nonoptimal ligand could be greatly improved by addition of water to the reaction system.
- Svensson, Fredrik,Mane, Rajendra S.,Saevmarker, Jonas,Larhed, Mats,Skoeld, Christian
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Read Online
- Metal-ligand cooperativity in a ruthenium(II) complex of bis-azoaromatic ligand for catalytic dehydrogenation of alcohols
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Herein a new Ru-phosphine complex (1) with molecular formula [RuL(PPh3)Cl2] is reported where L is a redox active pincer ligand 2,6-bis(phenylazo)pyridine. The isolated complex has been characterized by usual spectroscopic techniques including single crystal X-ray crystallographic analysis. Complex 1 efficiently catalyzes aerobic oxidation of a wide range of primary and secondary benzylic, allylic, heterocyclic, alicyclic alcohols under mild conditions and is found to be superior over several other Ru (0, +2 and +3), Ru-H and Ru-PPh3 catalysts. Mechanistic studies indicate that a transient Ru-H intermediate is formed in the catalytic cycle which gets switched into a Ru-hydrazo intermediate via hydrogen-walking mechanism. The catalyst is regenerated by aerial oxidation producing H2O2 as a by-product.
- Saha, Tanushri,Pramanick, Rajib,Sengupta, Debabrata,Goswami, Sreebrata
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p. 160 - 166
(2018/09/29)
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- Ni-Catalyzed β-Alkylation of Cyclopropanol-Derived Homoenolates
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Metal homoenolates are valuable synthetic intermediates which provide access to β-functionalized ketones. In this report, we disclose a Ni-catalyzed β-alkylation reaction of cyclopropanol-derived homoenolates using redox-active N-hydroxyphthalimide (NHPI) esters as the alkylating reagents. The reaction is compatible with 1°, 2°, and 3° NHPI esters. Mechanistic studies imply radical activation of the NHPI ester and 2e β-carbon elimination occurring on the cyclopropanol.
- Mills, L. Reginald,Zhou, Cuihan,Fung, Emily,Rousseaux, Sophie A. L.
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supporting information
p. 8805 - 8809
(2019/11/03)
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- Hydrogen bond donor solvents enabled metal and halogen-free Friedel–Crafts acylations with virtually no waste stream
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We have developed a metal and halogen-free Friedel–Crafts acylation protocol with virtually no waste stream generation. We propose a hydrogen bonding donor solvent will form a hydrogen bonding network and may provide significant rate enhancement for Friedel–Crafts reactions. Trifluoroacetic acid is one of the strongest H-bond donor solvents, which is also volatile and can be easily recovered by distillation without need for reaction workup. Our protocol is a ‘green’ Friedel–Crafts acylation process: 1) the catalyst can be recovered and reused; 2) using halogen free starting material (carboxylic acids anhydride or carboxylic acids); 3) no need for aqueous reaction work-up; 4) minimum or no waste steam generation.
- Liu, Guangchang,Xu, Bo
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supporting information
p. 869 - 872
(2018/02/09)
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- Hexafluoro-2-propanol-Promoted Intermolecular Friedel-Crafts Acylation Reaction
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The intermolecular Friedel-Crafts acylation was carried out in hexafluoro-2-propanol to yield aryl and heteroaryl ketones at room temperature without any additional reagents.
- Vekariya, Rakesh H.,Aubé, Jeffrey
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supporting information
p. 3534 - 3537
(2016/08/16)
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- BORON-CONTAINING SMALL MOLECULES
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This invention provides novel compounds of the following formula and pharmaceutical compositions containing such compounds.
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Paragraph 0244
(2015/02/19)
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- Palladium(II)-catalyzed decarboxylative heck arylations of acyclic electron-rich olefins with internal selectivity
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Despite the recent emergence of decarboxylative C-C bond forming reactions, methodologies providing internally arylated electron-rich olefins are still lacking. We herein report on palladium(II)-catalyzed decarboxylative Heck arylations of linear electron-rich olefins with excellent selectivity for the internal position. The method allows a variety of electron-rich linear olefins to undergo arylation with ortho-functionalized aromatic carboxylic acids, including heterocycles. The reaction mechanism has been explored with ESI-MS studies to confirm previous findings, and to reveal the formation of a highly stable palladium complex as a result of the Heck product reacting with the catalyst.
- Fardost, Ashkan,Lindh, Jonas,Sjoeberg, Per J. R.,Larhed, Mats
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p. 870 - 878
(2014/04/03)
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- Reactivity switch enabled by counterion: Highly chemoselective dimerization and hydration of terminal alkynes
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A counterion-controlled reactivity tuning in Pd-catalyzed highly chemoselective and regioselective dimerization and hydration of terminal alkynes is reported. The use of acetate as counterion favors the formation of an alkenyl alkynyl palladium intermediate which forms hitherto less reported 1,3-diaryl-substituted conjugated enynes after reductive elimination. Using chloride, which is a better leaving group, leads to anion exchange on the alkenylpalladium intermediate with hydroxide which after reductive elimination and tautomerization delivered the hydration products.
- Xu, Caixia,Du, Weiyuan,Zeng, Yi,Dai, Bin,Guo, Hao
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p. 948 - 951
(2014/03/21)
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- An improved palladium(II)-catalyzed method for the synthesis of aryl ketones from aryl carboxylic acids and organonitriles
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A palladium(II)-catalyzed decarboxylative protocol for the synthesis of aryl ketones has been developed. The addition of TFA was shown to improve the reaction yield and employing THF as solvent enabled the use of solid nitriles and in only a small excess. Using this method, five different benzoic acids reacted with a wide range of nitriles to produce 29 diverse (hetero)aryl ketone derivatives in up to 94% yield.
- Axelsson, Linda,Veron, Jean-Baptiste,S?vmarker, Jonas,Lindh, Jonas,Odell, Luke R.,Larhed, Mats
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supporting information
p. 2376 - 2380
(2014/05/06)
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- 1 -HYDROXY-BENZOOXABOROLES AS ANTIPARASITIC AGENTS
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Provided are compounds useful for controlling endoparasites both in animals and agriculture. Further provided are methods for controlling endoparasite infestations of an animal by administering an effective amount of a compound as described above, or a pharmaceutically acceptable salt thereof, to an animal, as well as formulations for controlling endoparasite infestations using the compounds described above or an acceptable salt thereof, and an acceptable carrier. The claimed compounds are described by the following Markush formula:A typical example for a compound according to above formula is: A typical example for a compound according to above formula is:
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Page/Page column 51
(2014/10/03)
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- Sustainable flow oppenauer oxidation of secondary benzylic alcohols with a heterogeneous zirconia catalyst
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A flow chemistry process for the Oppenauer oxidation of benzylic secondary alcohols using partially hydrated zirconium oxide and a simple carbonyl containing oxidant such as acetone, cyclohexanone, and neopentanal is reported. The heterogeneous oxidative system could be applied to a wide range of functionalized alcohol substrates, allowing clean and fast delivery of ketone products within a few minutes between 40 and 100 C.
- Chorghade, Rajeev,Battilocchio, Claudio,Hawkins, Joel M.,Ley, Steven V.
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supporting information
p. 5698 - 5701
(2013/12/04)
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- A prototype device for evaporation in batch and flow chemical processes
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We report a convenient and efficient prototype device for evaporating, concentrating and switching solvents in continuous flow and batch processing and batch mode fashion. One of the main features of this system is the level of recyclability, whereby all solvents removed can be easily collected and reused, with reduced environmental impact.
- Deadman, Benjamin J.,Battilocchio, Claudio,Sliwinski, Eric,Ley, Steven V.
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supporting information
p. 2050 - 2055
(2013/09/24)
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- A Machine-assisted flow synthesis of SR48692: A probe for the investigation of neurotensin receptor-1
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Here we report the direct comparison of a conventional batch mode synthesis of Meclinertant (SR48692, 1), a neurotensin receptor-1 antagonist, with its machine-assisted flow chemistry alternative. By using these enabling tools, combined with solid-supported reagents and scavengers, many process advantages were observed. Care, however, must be taken not to convert these techniques into expensive solutions to problems that do not exist. Copyright
- Battilocchio, Claudio,Deadman, Benjamin J.,Nikbin, Nikzad,Kitching, Matthew O.,Baxendale, Ian R.,Ley, Steven V.
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p. 7917 - 7930
(2013/07/19)
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- Synthesis of aryl ketones by palladium(II)-catalyzed decarboxylative addition of benzoic acids to nitriles
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An efficient, sustainable method for the preparation of aryl ketones from ortho-substituted benzoic acids proceeds through their decarboxylation to generate an aryl-palladium species, followed by addition to a nitrile and hydrolysis of the intermediate ketimine.
- Lindh, Jonas,Sjoeberg, Per J. R.,Larhed, Mats
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supporting information; experimental part
p. 7733 - 7737
(2011/01/05)
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- Niobium pentachloride-silver perchlorate as an efficient catalyst in the Friedel-Crafts acylation and Sakurai-Hosomi reaction of acetals
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Friedel-Crafts acylation catalyzed by niobium pentachloride with silver salt is described. Aromatic compounds with Ac2O or Bz2O were smoothly converted into the corresponding ketones in good to excellent yields. This system was also applied to the Sakurai-Hosomi reaction using acetals. The reaction proceeded quite rapidly to give the desired products in excellent yields.
- Arai, Shigeru,Sudo, Yukinori,Nishida, Atsushi
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p. 4639 - 4642
(2007/10/03)
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- ANTIVIRAL AGENT
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The present invention provides an integrase inhibitor. The inventors have have found the following compound of formula (I) possessing an integrase inhibitory activity. (wherein, R C and R D taken together with the neighboring carbon atoms form a ring which may be a condensed ring, Y is hydroxy, mercapto or amino; Z is O, S or NH ; R A is a group shown by (wherein, C ring is N-containing aromatic heterocycle) or the like)
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- Aluminum dodecatungstophosphate (AlPW12O40) as a non-hygroscopic Lewis acid catalyst for the efficient Friedel-Crafts acylation of aromatic compounds under solvent-less conditions
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Stable and non-hygroscopic aluminum dodecatungstophosphate (AlPW 12O40), which is prepared easily from cheap and commercially available compounds was found to be an effective catalyst for Friedel-Crafts acylation reactions using carboxylic acids, acetic anhydride and benzoyl chloride in the absence of solvent under mild reaction conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Nowrouzi, Farhad
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p. 10843 - 10850
(2007/10/03)
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- A flash photolytic investigation of the photosolvolysis of α-(2,6-dimethoxyphenyl)vinyl chloride. Characterization of the 2,6-dimethoxyacetophenone keto-enol system
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Photosolvolysis of α-(2,6-dimethoxyphenyl)vinyl chloride in trifluoroethanol solution at 25°C was found to produce the α-(2,6-dimethoxyphenyl)vinyl cation as a transient species with the lifetime τ = 1 μs. Addition of water reduced this lifetime markedly, until, at compositions greater than 80% water, it was too short to measure (τ 20 ns); extrapolation of the data suggests τ = 9 ns in pure water. Hydration of this cation gave the much longer lived enol of 2,6-dimethoxyacetophenone whose rates of ketonization were measured in dilute perchloric acid and sodium hydroxide solutions. These data, when combined with rates of enolization of the ketone determined by iodine scavenging, give pK(E) = 6.98 for the keto-enol equilibrium constant in the 2,6-dimethoxyacetophenone system, pK(a)(E) = 10.72 for the acidity constant of the enol ionizing as an oxygen acid and pK(a)(K) = 17.70 for the acidity constant of the ketone ionizing as a carbon acid; these constants refer to wholly aqueous solution at 25°C and ionic strength = 0.10 M.
- Chiang,Eliason,Jones,Kresge,Evans,Gandour
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p. 1964 - 1969
(2007/10/02)
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Functionalisation in 2 position of benzenes 1,3-disubstituted by para-directing groups has been investigated, involving 2-trimethylsilylated intermediates when the classical methods (particularly these involving the anion in 2 position) are ineffective. Thus 2-trimethylsilyl derivatives of 1,3-dihalo- or 1,3-dimethoxybenzene have been prepared in good yields. Their conversion into the corresponding 1,2,3-trisubstituted benzenes has been conveniently performed upon acetylation, iodination or sulfonation, except in the case of the sulfonation of the 1,3-dimethoxylated compound in which the ipso effect of the silyl group is surpassed by the directing effect of the methoxy substituents. In contrast, whith the same substrate, cyanation in position 2 was successfully carried out using chlorosulfonyl isocyanate: to our knowledge this reaction is the first example of substitution of a trimethylsilyl by a cyano group in the aromatic series.
- Bennetau, Bernard,Rajarison, Florent,Dunogues, Jacques,Babin, Pierre
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p. 10843 - 10854
(2007/10/02)
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- Vinyl ether hydrolysis XXVIII. The mechanism of reaction of methyl α-(2,6-dimethoxyphenyl)vinyl ether
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The acid-catalyzed hydrolysis of methyl α-(2,6-dimethoxyphenyl)vinyl ether in aqueous solution at 25 deg C occurs with the hydronium ion catalytic coefficient kH+ = 2.86 M-1 s-1 and gives the solvent isotope effect kH+/kD+ = 3.68; this indicates that reaction occurs by rate-determining proton transfer from the catalyst to the substrate to generate an alkoxycarbocation intermediate.An oxygen-18 tracer study shows further that, despite the steric hindrance provided by its two ortho substituents, this cation then reacts by addition of water to the cationic carbon atom to generate a hemiacetal, and not by nucleophilic attack of water on the methyl group remote from the carbocationic center:
- Jones, J.,Kresge, A. J.
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- FACILE PREPARATIONS OF 4-FLUORORESORCINOL
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Two facile methods for preparing 4-fluororesorcinol have been developed.In the first method, the direct fluorination of 1,3-dimethoxybenzene with trifluoromethyl hypofluorite carried out in Freon 11 at -78 deg C afforded 2,4-dimethoxyfluorobenzene.Demethylation by heating under reflux in 48percent HBr in acetic acid gave 4-fluororesorcinol in an overall yield of 60percent.The second method involved the fluorination of 2,6-dimethoxycetophenone by trifluoromethyl hypofluorite in Freon 11 at -78 deg C, leading to 2,6-dimethoxy-3-fluorocetophenone.On heating under reflux in 48percent HBr in acetic acid, 4-fluororesorcinol was obtained in an overall yield of 74percent.The latter is the method of choice for preparing 4-fluororesorcinol.
- Belanger, Patrice C.,Lau, C. K.,Williams, Haydn W. R.,Dufresne, C.,Scheigetz, John
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p. 1479 - 1482
(2007/10/02)
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