- Solvent free permanganate oxidations
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The oxidations of organic compounds by permanganate under solvent free conditions have been studied. Thiols and primary aromatic amines undergo oxidative coupling reactions to give disulfides and diazenes, respectively, sulfides are oxidized to sulfones, primary and secondary alcohols are converted to aldehydes and ketones, 1,4-diols and cyclic ethers give lactones and arenes are oxidized to the corresponding α-ketones. The experimental procedure is simple and the products are easily isolated in good yields.
- Shaabani, Ahmad,Lee, Donald G.
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- Regioselectivity in the Semiconductor-Mediated Photooxidation of 1,4-Pentanediol
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Optimum conditions have been established for the selective semiconductor-photocatalyzed oxidation by long-wavelength ultraviolet light of the primary alcohol functionality in 1,4-pentanediol.On platinized (2percent) TiO2 powder suspended in oxygenated aqueous (4 vol percent) acetonitrile, the initial rate ratio for oxidation of the primary/secondary alcohol site was > 7.Analysis of further oxidation products allowed for mechanistic delineation of the course of the semiconductor-mediated reaction.The selectivity is attributed to the essential role of adsorption, with the criticalphotoinduced electron transfer occurring at the surface of the irradiated particle.ZrO2 and SnO2 samples were much less active than TiO2 as photocatalysts.The effects of oxygen pressure, metal cocatalyst loading, and water content of acetonitrile are discussed.
- Fox, Marye Anne,Ogawa, Haruo,Pichat, Pierre
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- Analytical methodology for determination of organic aerosol functional group distributions
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Secondary organic aerosol (SOA) particles result from the condensation of oxidized volatile organic compounds (VOC) and consist of a complex mixture that is not conducive to complete compositional analysis. We present a simple methodology for determining the quantities of aldehydes and ketones, alcohols, and carboxylic acids in such samples via derivatization and high-performance liquid chromatography (HPLC) with ultraviolet-visible absorption detection and tandem mass spectrometry (MS/MS). Useful concentration ranges are presented with an examination of the specificity of these compounds in multiply substituted systems. Such data are valuable in modeling the formation of laboratory-generated aerosols and in identifying point sources of field-collected aerosol samples. Calibration curves on standard samples, MS/MS transitions, including collisionally induced dissociation (CID) products, and a quantitative examination of the specificity of the derivatization reagents toward multiple functional groups are presented for a series of aliphatic standard samples. These methods are then applied to filter extracts from SOA derived from 1-iodooctane photolysis at 254 nm to demonstrate the methodology on a complex system. Ultimately, this methodology enables the measurement of variations in the chemical nature of the oxygen within an SOA particle, providing a distribution of functional group concentrations. This article not subject to U.S. Copyright. Published 2013 by the American Chemical Society.
- Kalafut-Pettibone, Alicia J,McGivern, W. Sean
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- Fe(III)-porphyrin heterogenized on MCM-41: Matrix effects on the oxidation of 1,4-pentanediol
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The metal complex iron meso-tetrakis (2,6-dichlorophenyl)porphyrin (Fe IIIP) has been covalently linked on the surface of the mesoporous material MCM-41 and of amorphous SiO2 to give the photocatalysts FeIIIP/MCM-41 and FeIIIP/SiO2 respectively. The effect of porphyrin addition on specific surface area and porosity of these materials has been evaluated by means of BET and BJH model applied to N 2 adsorption/desorption isotherms. It is seen that the MCM-41 sample presents the largest modification due to the presence of porphyrin: the pore size changes in average value and distribution, the pores formed in the presence of porphyrin being smaller and presenting a larger distribution. The photochemical characterization of FeIIIP/MCM-41 reveals that this is a robust photocatalyst able to induce the O2-assisted oxidation of 1,4-pentanediol. In particular, photoexcitation of FeIIIP/MCM-41 causes the conversion of 1,4-pentanediol to the aldehyde derivative compound with 70% regioselectivity. It is noteworthy that this product can be accumulated with no formation of further oxidized compounds. Due to its high specific surface area, which guarantees a good dispersion of the active centres, Fe IIIP/MCM-41 is about four times more efficient than Fe IIIP/SiO2. Moreover, the nature of the support controls the regioselectivity of the photocatalytic process: this is due to both uptake phenomena and steric effects, which can control the approach of the diol to the photoactive iron porphyrin.
- Molinari, Alessandra,Maldotti, Andrea,Bratovcic, Amra,Magnacca, Giuliana
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- Catalytic cascade conversion of furfural to 1,4-pentanediol in a single reactor
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The synthesis of bio-based linear diols is the subject of many research studies. However, one of the main obstacles in industrial development is the difficulty in controlling product selectivity. Here, we report the catalytic conversion of furfural to 1,4-pentanediol (PD) in the presence of Ru supported on an ordered mesoporous carbon (CMK-3) under pressure of H2 and CO2 in water. In contrast to previous catalytic pathways, this work is distinct in that it yields 1,4-PD as an exclusive product, instead of a mixture of 1,2- and 1,5-PD as usual. Under optimized conditions, 1,4-PD was obtained in 90% yield, and in a one-pot reaction, directly from furfural. We disclose that the conversion of furfural to 1,4-PD followed an unusual catalytic route. It implies a bifunctional catalytic pathway based on sequential catalytic hydrogenation reactions and an acid-catalyzed Piancatelli's rearrangement.
- Liu, Fei,Liu, Qiaoyun,Xu, Jinming,Li, Lei,Cui, Yi-Tao,Lang, Rui,Li, Lin,Su, Yang,Miao, Shu,Sun, Hui,Qiao, Botao,Wang, Aiqin,Jér?me, Francois,Zhang, Tao
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- Tweaking the acid-sensitivity of transiently thermoresponsive Polyacrylamides with cyclic acetal repeating units
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Merging the characteristics of thermoresponsive and stimuli-degradable polymers yields so-called transiently thermoresponsive polymers, which can find application for the design of injectable gels, nanoparticles, etc. within a biomedical context. Among these polymers, only a limited number is reported which shows selective degradation under mild acidic conditions. However, extension of the library of transiently thermoresponsive polymers is desired to broadening the biomaterials toolbox to suit specific needs. Three monomers were developed by modification of 2-hydroxyethylacrylamide (HEAm) via tetrahydropyranylation or -furanylation with 3,4-dihydro-2H-pyran (DHP), 2,3-dihydrofuran (DHF) or 2,3-dihydro-5-methylfuran (MeDHF). The presence of an acetal or ketal bond provided the monomers a pH-dependent hydrolysis behavior ranging from minutes to days. RAFT polymerisation allowed for the construction of homopolymers with temperature responsive behavior and pH-dependent hydrolysis which was strongly influenced by nature of the monomeric repeating units.
- De Geest, Bruno G.,Van Herck, Simon
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- Catalytic production of 1,4-pentanediol from furfural in a fixed-bed system under mild conditions
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Furfural is one of the most important biomass-derived chemicals. Its large-scale availability calls for the exploration of new transformation methods for further valorization. Here we report on the direct, one-step conversion of furfural into 1,4-pentanediols (1,4-PeDs) using a combination of Amberlyst-15 and Ru-FeOx/AC catalysts. It is interesting to find that the introduction of a suitable amount of FeOxresults in a great improvement in the dispersion of Ru and a decrease in the Lewis acidity. Both XPS and H2-TPR show that there is electron transfer from Ru to Fe, and the electronic interaction facilitates the reduction of both Ru and Fe species. When used in combination with Amberlyst-15, the Ru-6.3FeOx/AC catalyst afforded the best performance with a 1,4-PeD yield of 86%; by contrast, Ru/AC free of FeOxonly gave levulinic acid as the major product, demonstrating the key role of the acid/metal balance in the one-pot conversion of furfural to 1,4-PeD. Moreover, such a dual catalyst exhibited excellent durability within 175 h time-on-stream.
- Liu, Fei,Liu, Qiaoyun,Qiao, Botao,Su, Yang,Wang, Aiqin,Zhang, Leilei,Zhang, Tao
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- Palladium(II)-catalyzed oxidation of terminal alkenes to methyl ketones using molecular oxygen
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Palladium(II) acetate catalyzes the aerobic oxidation of terminal alkenes in toluene into the corresponding methyl ketones in the presence of a catalytic amount of pyridine using propan-2-ol as a reductant and molecular oxygen as an oxidant. Two catalytic cycles sharing a Pd(II)-OOH species are proposed. One is the formation of a Pd(II)-H species in the oxidation of propan-2-ol to acetone, followed by reaction with molecular oxygen to give a Pd(II)-OOH species, and the other is peroxypalladation of an alkene with the Pd(II)-OOH species produced to afford a methyl ketone in the presence of H2O2 produced by the former catalytic cycle. The Royal Society of Chemistry 2000.
- Nishimura, Takahiro,Kakiuchi, Nobuyuki,Onoue, Tomoaki,Ohe, Kouichi,Ucmura, Sakae
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- Ru Nanoparticles on a Sulfonated Carbon Layer Coated SBA-15 for Catalytic Hydrogenation of Furfural into 1, 4-pentanediol
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Furfural (FFR) is one of the most important biomass-derived chemicals. Its large-scale availability calls for the exploration of new transformation methods for further valorization. Herein, we demonstrate that Ru nanoparticles (Ru NPs)-supported on a sulfonated carbon layer coated SBA-15 can be employed as an efficient bi-functional catalyst for one step conversion of FFR into 1,4-pentanediol (1,4-PeDO). The optimum bi-functional catalyst can afford the full the conversion of FFR and 86% selectivity to 1,4-PeDO. The catalysts have been characterized thoroughly by using a complementary combination of powder X-ray diffraction, N2 adsorption–desorption, scanning/transmission electron microscopy, Fourier transform infrared spectroscopy, elemental analysis, and X-ray photoelectron spectroscopy. The characterization revealed that acidic groups (–SO3H) have been introduced on the surface of the carbon layer coated SBA-15 support after sulfonation with 98% H2SO4 and the surface acidity can be tuned facilely by the sulfonating time. Meantime, Ru(0) sites was highly dispersed via an impregnation and sequential reduction and directly adjacent to the surface –SO3H group. There existed an electronic interaction between Ru(0) sites and sulfonic groups, in which the electronic transfer from sulfonic sites to Ru(0) sites occurred. Br?nsted acid sites (–SO3H) have a significant influence on the FFR conversion and the selectivity to 1,4-PeDO. The ordered mesoporous structure, the appropriate density of acid sites and the electron-rich Ru(0) sites accounted for the the excellent performance of the catalyst for an efficient production of 1,4-PeDO from FFR. Graphic Abstract: [Figure not available: see fulltext.].
- Cui, Kai,Qian, Wei,Shao, Zhengjiang,Zhao, Xiuge,Gong, Honghui,Wei, Xinjia,Wang, Jiajia,Chen, Manyu,Cao, Xiaoming,Hou, Zhenshan
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- Supported gold nanoparticles as a reusable catalyst for synthesis of lactones from diols using molecular oxygen as an oxidant under mild conditions
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The oxidative lactonization of various diols using molecular oxygen as a primary oxidant can be efficiently catalyzed by hydrotalcite-supported Au nanoparticles (Au/HT). For instance, lactonization of 1,4-butanediol gave γ-butyrolactone with an excellent turnover number of 1400. After lactonization, the Au/HT can be recovered by simple filtration and reused without any loss of its activity and selectivity.
- Mitsudome, Takato,Noujima, Akifumi,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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- Selective Oxidation of Diols by H2O2/TS-1 System and by DMDO.
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Selective oxidations of secondary hydroxyl groups vs. primary ones in 1,n-diols by TS-1/H2O2 catalitic system and by dimethyldioxirane, new reagents with low environmental pollution, are reported.
- Bovicelli, Paolo,Lupattelli, Paolo,Sanetti, Anna,Mincione, Enrico
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- Conversion of pentynol to pentanone catalysed by Pd(II) metal centres
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The cyclization of 3- or 4-pentyn-1-ol is catalysed by PdCl2 or trans-[PdCl2L2] (L = R-camphorimine; R = Ph; Pri; NMe2) complexes at room temperature affording heterocyclic compounds, respectively, 2-methyl-2-pent-3-ynyloxy-tetrahydrofuran or 2-methyl-2-pent-4-ynyloxy-tetrahydrofuran which subsequently add water to give selectively 5-(2-methyl-tetrahydrofuran-2-yloxy)-pentan-2-one from both starting materials. By hydrolysis 5-(2-methyl-tetrahydrofuran-2-yloxy)-pentan-2-one undergoes ring cleavage to form 5-hydroxy-2-pentanone. The catalytic activity and selectivity of complexes trans-[PdCl2L2] (L = R-camphorimine) depend on the characteristics of the R group (NMe2 > Pri > Ph). The catalytic activity of PdCl2 is comparable to that of trans-[PdCl2L2] (L = Ph-camphorimine) which is the less efficient catalyst.
- Carvalho, M. Fernanda N.N.,Ferreira, Ana S.D.,Herrmann, Rudolf
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- Na4H3[SiW9Al3(H2O)3O37]·12H2O/H2O: a new system for selective oxidation of alcohols with H2O2 as oxidant
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This work describes a catalytic system consisting of both Na4H3[SiW9Al3(H2O)3O37]·12H2O(SiW9Al3) and water as solvents (a?small quantity of organic solvents were used as co-solvent for a few substrates) that can be good for selective oxidation of alcohols to ketones (aldehydes) using 30% H2O2 without any phase-transfer catalyst under mild reaction conditions. The catalyst system allows easy product/catalyst separation. Under the given conditions, the secondary hydroxyl group was highly chemoselectively oxidized to the corresponding ketones in good yields in the presence of primary hydroxyl group within the same molecule, and hydroxides are selectively oxidized even in the presence of alkene. Benzylic alcohols were selectively oxidized to the corresponding benzaldehydes in good yields without over oxidation products in solvent-free conditions. Nitrogen, oxygen, sulfur-based moieties, at least for the cases where these atoms are not susceptible to oxidation, do not interfere with the catalytic alcohol oxidation.
- Wang, Jianmin,Yan, Liang,Qian, Guang,Li, Shunqing,Yang, Keli,Liu, Haitao,Wang, Xiaolai
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- Selective photooxidation of diols with silica bound W10 O324 -
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The decatungstate anion W10 O324 - has been heterogenized on silica previously functionalized with different ammonium cations covalently bound to the surface of the solid support. These materials are investigated as photocatalysts for the oxygen-assisted oxidation of 1,3-butanediol and 1,4-pentanediol. Product distribution and adsorption experiments indicate that the polarity of the environment surrounding the photoactive anion plays a crucial role in controlling the adsorption of diols on the surface and, consequently, their reaction with the photoexcited decatungstate. Proper reaction conditions are found for obtaining more than 90% of 4-hydroxy-2-butanone from 1,3-butanediol and for stopping the oxidation of 1,4-pentanediol to 4-hydroxypentanal with good yield. The employed photocatalysts present a very good stability in repeated experiments.
- Maldotti,Molinari,Bigi
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- Oxidant-free lactonization of diols using a hydrotalcite-supported copper catalyst
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We newly synthesized well-crystallized hydrotalcite-supported copper nanoparticles, denoted as Cu/HT(c), which acted as a highly efficient heterogeneous catalyst for oxidant-free lactonization of various diols under liquid-phase conditions. The Cu/HT(c) catalyst could be recovered by simple filtration and reused without the significant loss of its activity and selectivity.
- Mikami, Yusuke,Ebata, Kaori,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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- Solvent effect on the rate and direction of furfural transformations during hydrogenation over the Pd/C catalyst
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The rate and directions of transformations during the liquid-phase hydrogenation of furfural with molecular hydrogen in the presence of the 5%Pd/C catalyst (at 423 K, 3 MPa) depend substantially on the chemical nature of the solvent. The main products of
- Belskaya, O. B.,Likholobov, V. A.,Mironenko, R. M.
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- Radical Annulation of 2-Cyanoaryl Acrylamides via C=C Double Bond Cleavage: Access to Amino-Substituted 2-Quinolones
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A novel annulation of 2-cyanoaryl acrylamides via C=C double bond cleavage has been developed for facile and efficient access to a broad spectrum of functionalized 4-amino-2-quinolones, which are important N-heterocycles. In this transformation, the solvent THF is demonstrated to play a crucial role, and the addition of alkyl radicals to nitrile, 1,5-hydride shift, and cleavage of the C-C bond are involved in the mechanism.
- Xia, Wen-Jin,Fan, Tai-Gang,Zhao, Zhi-Wei,Chen, Xin,Wang, Xiang-Xiang,Li, Ya-Min
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supporting information
p. 6158 - 6163
(2021/08/18)
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- Mild reduction with silanes and reductive amination of levulinic acid using a simple manganese catalyst
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A manganese-based catalytic system using the commercially available complex [Mn(CO)5Br] was studied for the selective reduction of levulinic acid (LA) to 2-methyl-tetrahydrofuran (MTHF). We further studied the production of pyrrolidines via its reductive amination using silanes (phenylsilane and tetramethyldisiloxane). The results showed high efficiency and selectivity for this reaction leading to high yields using mild reaction conditions.
- Garcia, Juventino J.,Roa, Diego A.
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- Method for synthesizing cyclopropyl methyl ketone
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The synthesis method, uses :1) methylfuran as the raw material 2 - to obtain,chloro - 2 2-pentanone, and the method comprises the following steps ;2): carrying out hydrogen hydrolysis 1) through one-pot hydrogenation hydrolysis, in the presence of the hydrogenation catalyst 5 - hydrogen and water.3). The method 2) for synthesizing the cyclopropylmethyl ketone according to step 5 - comprises the following steps: preparing the cyclopropylmethyl ketone, through a one-pot hydrogenation hydrolysis reaction and a ring-closing reaction step. to prepare the cyclopropylmethyl ketone, by a one-pot, hydrogenation hydrolysis reaction. 2 - The method comprises the following steps: synthesizing,methyl furan as, a raw material, through a one- pot 2 - hydrogenation hydrolysis reaction and, a ring- closing reaction to, prepare the. cyclopropylmethyl ketone by a one- pot hydrogenation hydrolysis reaction and a ring-closing reaction to obtain the cyclopropylmethyl ketone.
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Paragraph 0029; 0031; 0032; 0035-0036; 0039-0040
(2020/03/17)
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- Application of supported bifunctional catalyst in preparation of 3-acetylpropanol from furfural
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The invention relates to an application of a supported bifunctional catalyst in preparation of 3-acetylpropanol from furfural. The catalyst disclosed by the invention is an ammonium type molecular sieve supported ruthenium bifunctional catalyst, has acidity and catalytic hydrogenation performance, can efficiently catalyze selective hydrogenation of furfural to prepare furfuryl alcohol, can catalyze furfuryl alcohol to prepare 3-acetylpropanol with high selectivity through in-situ acid catalysis, and has the advantages of cheap and easily available raw materials, simple preparation method, easyand convenient recycling, easy product separation, high reaction activity and high selectivity in preparing of 3-acetylpropanol from furfural, and the like.
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Paragraph 0020-0060
(2020/06/16)
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- Method for preparing 3-acetyl-1-propanol from furfural (or furfuryl alcohol) in CO2/H2O system
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The invention relates to a method for preparing 3-acetyl-1-propanol from furfural (or furfuryl alcohol) in a CO2/H2O system. The furfural (or furfuryl alcohol) is converted into 3-acetyl-1-propanol inone step under the catalysis of a bifunctional catalysis system with an in situ acid system formed by CO2/H2O as a medium. The catalyst is a supported ruthenium-based catalyst, and the Ru content is0.1-10% of the total mass of the catalyst. The CO2/H2 volume ratio is adjusted to make the yield of the 3-acetyl-1-propanol under optimal reaction conditions reach 84% or above. The method has the remarkable advantages of cheap and easily available raw materials, simplicity in operation, recyclability, and easiness in recovery.
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Paragraph 0020-0024
(2019/06/30)
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- Method for preparing 3-acetylpropanol and 1,4-pentanediol by catalytic hydrogenation of furan derivative acids
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The invention relates to a method for preparing 3-acetylpropanol and 1,4-pentanediol by selective hydrogenation of furan derivatives. The 3-acetylpropanol and the 1,4-pentanediol are prepared by selective hydrogenation/ring opening of the furan derivatives in the presence of a bifunctional catalytic system and a water solvent in an intermittent agitating reactor or a continuous fixed bed at a reaction temperature of 40 to 200 DEG C under the hydrogen pressure of 0.1 to 5 MPa. The catalytic system comprises a catalyst A and a catalyst B, wherein the catalyst A is a supported ruthenium-based catalyst, and the catalyst B is an acid catalyst. The Ru content is 0.5-5 wt% of the total mass of the catalyst A. The method has the advantages that the raw materials are cheap and easy to obtain, the preparation method of the catalyst is simple, the recovery is simple, the product is easy to separate, and high reactivity and selectivity are achieved for preparing 3-acetylpropanol and 1,4-pentanediol by selective hydrogenation of the furan derivatives.
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Paragraph 0022; 0023; 0024; 0025; 0026; 0027; 0028-0053
(2019/03/23)
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- Combination of Metal-Catalyzed Cycloisomerizations and Biocatalysis in Aqueous Media: Asymmetric Construction of Chiral Alcohols, Lactones, and γ-Hydroxy-Carbonyl Compounds
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The combination of the metal-catalyzed cycloisomerization of alkynes containing a tethered nucleophile as substituent in aqueous media (followed by the spontaneous hydrolysis, hydroalkoxylation, or aminolysis of the transiently formed five-membered heterocycles) with the subsequent enantioselective ketone bioreduction (mediated by KREDs) has been achieved. The overall transformations, which formally involve a three-step one-pot reaction, provide a variety of enantiopure valuable molecules (e.g., 1,4-diols, lactones, and γ-hydroxy-carbonyl compounds (carboxylic acids, esters, and amides)) with high conversions and enantioselectivities and under mild reaction conditions, disclosing the concept of integrated metal-catalyzed cycloisomerizations of alkynes and enzymatic catalysis in water.
- Rodríguez-álvarez, María J.,Ríos-Lombardía, Nicolás,Schumacher, S?ren,Pérez-Iglesias, David,Morís, Francisco,Cadierno, Victorio,García-álvarez, Joaquín,González-Sabín, Javier
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p. 7753 - 7759
(2017/11/10)
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- Oxidation of Secondary Methyl Ethers to Ketones
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We present a mild way of converting secondary methyl ethers into ketones using calcium hypochlorite in aqueous acetonitrile with acetic acid as activator. The reaction is compatible with various oxygen- and nitrogen-containing functional groups and afforded the corresponding ketones in up to 98% yield. The use of this methodology could expand the application of the methyl group as a useful protecting group.
- Gilissen, Pieter J.,Blanco-Ania, Daniel,Rutjes, Floris P. J. T.
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p. 6671 - 6679
(2017/07/15)
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- Preparation method of gamma-acetyl n-propanol
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The invention discloses a preparation method of gamma-acetyl n-propanol. The method includes the steps of (1) adding the hydrolysate of plant fiber or xylose and other raw materials into a reaction still, adding a two-phase reactive solvent and a catalyst, inletting hydrogen, and heating the reaction still to react for several hours; (2) carrying out standing, liquid separation and then solid-liquid separation on reaction materials in the reaction still, obtaining water phase, oil phase and the catalyst, and recycling the catalyst for reutilization; (3) concentrating water phase products, extracting 1, 4-pentanediol in the oil phase, mixing with the concentrated solution, and carrying out further separation to obtain a crude product of 1, 4-pentanediol; (4) pumping the crude product of 1, 4-pentanediol obtained from the water phase and the oil phase in step (3) to a fixed bed reactor, carrying out dehydrogenation to produce gamma-acetyl n-propanol under the action of a catalytic dehydrogenation catalyst or an oxydehydrogenation catalyst. According to the preparation method, raw materials have extensive sources, the production cost is low, no inorganic acid system is used, and the reaction process is environment-friendly.
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Paragraph 0026; 0027; 0028; 0029; 0030; 0031-0033
(2017/12/09)
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- The mechanism of gold(I)-catalyzed hydroalkoxylation of alkynes: An extensive experimental study
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An extensive experimental study of the mechanism of gold(I)-catalyzed hydroalkoxylation of internal alkynes has been conducted by using NMR spectroscopy. This study was focused on the organogold intermediates, observations of actual catalytic intermediates in situ, and the reaction kinetics that are involved in this reaction. Based on the experimental results, a complete mechanistic picture was established, including on- and off-cycle processes that explain the role of diaurated species. We have shown that gold-catalyzed hydroalkoxylation of internal alkynes is a reaction that requires only one gold atom for the catalytic cycle, disproving a recent hypothesis regarding the involvement of cooperative gold catalysis.
- Zhdanko, Alexander,Maier, Martin E.
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supporting information
p. 1918 - 1930
(2014/03/21)
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- Sulfonated water-soluble N-heterocyclic carbene silver(I) complexes: Behavior in aqueous medium and as NHC-transfer agents to platinum(II)
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This report describes the synthesis of water-soluble silver(I) and platinum(II) complexes bearing sulfonated mono- or dianionic N-heterocyclic carbene ligands. Thus, treatment of the corresponding zwitterionic imidazolium derivative with silver(I) oxide in water afforded the light-sensitive bis(carbene) complexes Ag[Ag(NHC)2] (2Ag+), which were transformed into the stable salts Na[Ag(NHC)2] (2) by addition of sodium chloride. In contrast, the same reaction in dmso afforded mono(carbenes) of general formula Na[AgCl(NHC)] (3). The solvent-dependence of the reaction product can be rationalized on the basis of the equilibrium [AgCl 2]- - AgCl + Cl-. The precipitation of silver chloride is more favored in protic solvents than in aprotic solvents such as dmso, thus explaining the formation of bis(carbenes) in water. The formation of silver chloride may also promote the hydrolysis of silver NHC complexes under some conditions. The water-soluble platinum(II) complexes Na[PtCl 2(dmso)(NHC)] were synthesized by using either mono(carbene) silver complexes 3 as carbene-transfer agents or by direct metalation of the imidazolium salt with cis-[PtCl2(dmso)2] in the presence of NaHCO3 as base. The (NHC)Pt(II) complexes were tested as catalysts for the hydration of alkynes in the aqueous phase and found to be active in neat water without the need for acidic cocatalysts.
- Baquero, Edwin A.,Silbestri, Gustavo F.,Gomez-Sal, Pilar,Flores, Juan C.,De Jesus, Ernesto
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p. 2814 - 2826
(2013/06/26)
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- Platinum(II) diphosphinamine complexes for the efficient hydration of alkynes in micellar media
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Highly active monomeric bis-cationic platinum(II) catalysts bearing small bite angle diphosphinamine [N,N-bis(diarylphosphino)amine] 'PNP' ligands efficiently catalyze Markovnikov hydration of terminal and internal alkynes to the corresponding ketones in water. Catalyst solubilization in water is achieved via ion pairing with anionic micelles formed by surfactant addition. The micelles ensure dissolution of apolar alkynes and promote the intimate contact between reagents and catalyst, while in organic-water media in the absence of surfactants the reaction is sluggish. Hydration products can be isolated by means of extraction with an apolar solvent and the catalyst, that remains confined in the aqueous phase, can be recycled up to four times without loss of catalytic activity. Copyright
- Trentin, Francesco,Chapman, Andrew M.,Scarso, Alessandro,Sgarbossa, Paolo,Michelin, Rino A.,Strukul, Giorgio,Wass, Duncan F.
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scheme or table
p. 1095 - 1104
(2012/05/20)
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- A biocatalytic hydrogenation of carboxylic acids
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The hyperthermophile Pyrococcus furiosus catalyses the hydrogenation of a broad range of carboxylic acids selectively to the corresponding primary alcohols. Other functional groups such as isolated CC-double bonds are not touched. The chemoselectivity of the carboxylate reduction may be directed towards aldehydes by simple medium engineering.
- Ni, Yan,Hagedoorn, Peter-Leon,Xu, Jian-He,Arends, Isabel W. C. E.,Hollmann, Frank
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supporting information
p. 12056 - 12058
(2013/01/16)
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- Reaction of 1,2,3-oxadiazole 3-oxides
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1,2,3-Oxadiazole 3-oxides with an alkoxymethyl group at the 5-position were reduced by reacting them with sodium borohydride to produce 4,5-dihydro-1,2,3-oxadiazole 3-oxides in good yields, which were further transformed into substituted diazene N-oxides by reacting with Grignard reagents.
- Sugihara, Takumichi,Murakawa, Akira,Sawanaka, Chiemi,Seki, Megumi,Iio, Natsuki,Iizuka, Ayano,Oohora, Takuya,Honzawa, Shinobu
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p. 1039 - 1044
(2013/08/15)
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- Novel reactivity of N-bridged diiron phthalocyanine in the activation of C-H bonds: Hydroacylation of olefins as an example of the efficient formation of C-C bonds
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Bridge over troubled iron: An N-bridged diiron tetra-tert- butylphthalocyanine complex, usually employed for oxidation reactions, also catalyzes the addition of acetaldehyde to olefins (see scheme) to provide methylketones with a high selectivity (up to 92%) and high turnover numbers (3600-5700). Copyright
- Alvarez, Leonardo X.,Kudrik, Evgeny V.,Sorokin, Alexander B.
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supporting information; experimental part
p. 9298 - 9301
(2011/10/09)
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- New reactions of anticancer-platinum complexes and their intriguing behaviour under various experimental conditions
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The anticancer platinum complexes here described react with organic substrates (such as acids, alkenes, alkynes) and catalyze transformations that can occur in biomolecules which contain unsaturated functions. We have analyzed the role of the platinum complexes in the observed reactions and studied the progress of the detected transformations upon variation of the reaction conditions. The Royal Society of Chemistry 2010.
- Aleman, Jose,Del Solar, Virginia,Cubo, Leticia,Quiroga, Adoracion G.,Navarro Ranninger, Carmen
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experimental part
p. 10601 - 10607
(2011/01/05)
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- Synthesis of water-soluble dendritic phosphine ligands and their application to hydration of alkynes in aqueous media
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A series of water-soluble dendritic ligands with a phosphine core was synthesized through the coupling of tris(4-hydroxyphenyl)phosphine oxide with poly(benzyl ether) dendron having tri(ethylene glycol) units, followed by reduction. By employing the corresponding water-soluble phosphine-gold(I) dendrimers as a catalyst, the hydration of alkynes proceeded smoothly. Furthermore, by membrane separation based on the nano-order size of the dendritic catalyst, the gold(I) catalyst was recycled without deactivation. ? 2009 The Chemical Society of Japan.
- Fujita, Ken-Ichi,Kujime, Masato,Muraki, Takahito
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experimental part
p. 261 - 266
(2009/05/30)
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- Aerobic oxidation of alkenes mediated by porphyrin rhodium(iii) complexes in water
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Selective oxidation of alkenes in water to ketones using molecular oxygen as the oxidant is mediated by rhodium porphyrin complexes through observed β-hydroxy alkyl complexes.
- Zhang, Jiadi,Li, Shan,Fu, Xuefeng,Wayland, Bradford B.
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scheme or table
p. 3661 - 3663
(2009/08/15)
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- Sunlight oxidation of alkyl aryl tellurides to the corresponding carbonyl compounds: A new carbonyl precursor
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Alkyl aryl tellurides were efficiently transformed to the corresponding carbonyl compounds by photo-oxidation with sunlight without affecting various functional groups in the alkyl moiety. The tellurides can be used as a new carbonyl precursor, and the photolysis can be conducted without special equipment for light sources.
- Ouchi, Akihiko,Hyugano, Takeshi,Liu, Chuanxiang
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supporting information; experimental part
p. 4870 - 4873
(2010/01/06)
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- Facile photochemical transformation of alkyl aryl selenides to the corresponding carbonyl compounds by molecular oxygen: Use of selenides as masked carbonyl groups
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(Chemical Equation Presented) Alkyl aryl selenides with and without functional groups on the alkyl group were transformed efficiently into the corresponding carbonyl compounds, particulary primary alkyl aryl selenides in good yields, by a simple photolysis in the presence of air or oxygen. This transformation can be conducted without protection of functional groups. The yield of carbonyl compounds was much affected by the solvent viscosity, reaction temperature, concentration of dissolved oxygen in the solvents, wavelength of light, and structure of the aryl substituents. The present study indicates that aryl selenides can be considered as a masked carbonyl group that can be easily converted to a carbonyl group by very mild reaction conditions even in the presence of various unprotected functional groups. Therefore, this functional group transformation can be used as an important tool in organic synthesis due to its simplicity and mild reaction condition.
- Hyugano, Takeshi,Liu, Suyou,Ouchi, Akihiko
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supporting information; scheme or table
p. 8861 - 8866
(2009/04/05)
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- Processes for Producing Optically Active 1-Substituted 2-Methylpyrrolidine and Intermediate Therefor
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The present invention relates to a process for producing an optically active 1,4-pentanediol by asymmetrically reducing 5-hydroxy-2-pentanone, which is easily available at low cost. The present invention also relates to a process for producing an optically active 1-substituted 2-methylpyrrolidine including sulfonylating the optically active 1,4-pentanediol to convert it to an optically active sulfonate compound, and reacting the compound with an amine. According to the processes of the present invention, an optically active 1,4-pentanediol and an optically active 1-substituted 2-methylpyrrolidine, which are useful as an intermediate for medicines and an intermediate for agricultural chemicals, can be simply produced from an inexpensive starting material.
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- Regio- and stereoselective reduction of diketones and oxidation of diols by biocatalytic hydrogen transfer
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The asymmetric reduction of symmetrical and nonsymmetrical diketones as well as the stereoselective oxidation of various diols by biocatalytic hydrogen transfer was investigated by employing lyophilized cells of Rhodococcus ruber DSM 44541 containing alcohol dehydrogense ADH-'A'. Symmetrical and nonsymmetrical diketones at the (ω-1)- and (ω-2)-positions are reduced to the Prelog product with high stereopreference, while sterically more demanding ketone moieties, for example those at the (ω-3)-position, remain unchanged. For the oxidation mode, differentiation between primary and secondary alcohols is achieved, and the (S)-configured secondary alcohols at the (ω-1)- and (ω-2)-positions are oxidized preferentially. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Edegger, Klaus,Stampfer, Wolfgang,Seisser, Birgit,Faber, Kurt,Mayer, Sandra F.,Oehrlein, Reinhold,Hafner, Andreas,Kroutil, Wolfgang
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p. 1904 - 1909
(2007/10/03)
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- Catalytic ring opening of acetylcyclopropane by water and alcohols under the action of copper or palladium salts
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The possibility of the cleavage of the C-C bond in acetylcyclopropane (ACP) under the action of water or alcohols in the presence of copper or palladium salts was demonstrated for the first time. At 175-180 °C, the reactions proceeded regioselectively wit
- Dzhemilev,Khusnutdinov,Atnabaeva,Muslimov,Parfenova,Tomilov
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p. 1242 - 1247
(2007/10/03)
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- Bromide ions and methyltrioxorhenium as cocatalysts for hydrogen peroxide oxidations and brominations
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Oxidation of alcohols by hydrogen peroxide is negligible; even when catalyzed by methyltrioxorhenium (MTO), the process requires a long reaction time. The addition of a catalytic quantity of bromide ions, as HBr or NaBr, greatly enhances the rate. Some of the reactions were carried out on a larger scale in glacial acetic acid, and others at kinetic concentrations. The data establish that Br2 is the active oxidizing agent in the system, because the catalytic rates under suitable circumstances match those for the independently measured Br2 reaction with alcohol (benzyl alcohol, in particular). At much lower levels of MTO, however, Br2 formation plays a role in the kinetics. Certain other reluctant transformations are conveniently carried out with the MTO/H2O2/Br- combination: aldehydes to methyl esters; 1,3-dioxolanes to glycol monoesters; and ethers (with cleavage) to ketones (mostly), but in fair yield only. When Br- was used in stoichiometric quantity, certain bromination reactions occur. Thus, phenyl acetylenes (PhC2R, R = H, Me, Ph) are converted to dibromoalkenes that are entirely or largely formed as the trans isomer, and phenols are brominated. The latter reaction shows the preference para > ortho > meta. Kinetic studies of benzyl alcohol oxidation with MTO/H2O2Br- were carried out in aqueous solution. With sufficient (normal) levels of MTO, the rate constant for the formation of benzaldehyde agreed with the independently determined value for Br2 + PhCH2OH, k = 4.3 x 10-3 L mol-1 s-1 at 25.0 °C; for sec- phenethyl alcohol, k = (9.8 ± 0.4) x 10-3 L mol-1 s-1. Bromine is formed from the known oxidation of Br- with H2O2, catalyzed by MTO. This reaction results in BrO-/HBOr, which is then rapidly converted to Br2. However, with substantially lower concentrations of MTO, the buildup of benzaldehyde is ca. 4-fold slower, reflecting the diminished rate of Br- oxidation.
- Espenson,Zhu,Zauche
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p. 1191 - 1196
(2007/10/03)
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- HOF·CH3CN, made directly from F2 and water, as an ecologically friendly oxidizing reagent
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The complex HOF·CH3CN, made directly from fluorine and aqueous acetonitrile, was used for oxidation of secondary alcohols and for Baeyer Villiger oxidation of ketones. By using 18O labeled reagent it was found that the ketone oxidation proceeds through the original dioxirane mechanism which Baeyer and Villiger suggested a century ago for reactions with peracids but was later discounted.
- Rozen, Shlomo,Bareket, Yifat,Kol, Moshe
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p. 8169 - 8178
(2007/10/02)
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- RADIATION-INITIATED ADDITION OF ACETALDEHYDE TO ALLYL ALCOHOL AND CONVERSION OF THE 1:2-TELOMER INTO 1-METHYL-2,8-DIOXABICYCLONONANE
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Radiation-initiated addition of acetaldehyde to allyl alcohol gave a mixture of 5-hydroxy-2-pentanone (1:1-aduct I), 2-methyl-2-(4-oxopentyloxy)tetrahydrofuran (II), 7-hydroxy-4-hydroxymethyl-2-heptanone (1:2-telomer III) and 1,1-bis(4-oxopentyloxy)ethane (IV).The telomer III was dehydrated to afford 3-acetonyltetrahydropyran (V), 1-methyl-2,8-dioxabicyclononane (VI) and 3,10-dimethyl-4,11,16,17-tetraoxatricyclo3,8>octadecane (VII).
- Liska, Frantisek,Fikar, Jiri,Trska, Petr,Valenta, Miroslav
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p. 3278 - 3283
(2007/10/02)
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- Cyclopentapyrazole and tetrahydroindazole compounds and their use as anti-inflammatory and anti-allergic agents
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The present invention provides novel compositions of matter and their therapeutic applications. More particularly, the present invention consists of novel cyclopentapyrazole and tetrahydroindazole compounds of formula XXX and their use as antiallergy agents, antiinflammatory agents or intermediates. STR1
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- ACYL TRANSFER REACTIONS WITH PHOSPHINE OXIDES: SYNTHESIS OF E-HOMOALLYLIC ALCOHOLS, CYCLOPROPYL KETONES, AND γ-HYDROXY KETONES
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Esters of 3-hydroxypropylphosphine oxides rearrange in base by O to C acyl (RCO) transfer to give the hydroxy ketones (8). threo-Selective reduction of (8) leads to pure E-homoallylic alcohols whilst C to O acyl )Ph2PO) transfer leads to γ-hydroxy ketones with nucleophilic aqueous base or cyclopropyl ketones with BuOKt - HOBut.
- Wallace, Paul,Warren, Stuart
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p. 2971 - 2978
(2007/10/02)
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- UV-LIGHT- AND RADIATION-INITIATED ADDITION OF ACETALDEHYDE TO ALLYL ALKANOATES
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UV-light- and γ-60Co-initiated addition of acetaldehyde to allyl formate (I) and allyl acetate (II) yielded the 1:1 adducts - 4-oxopentyl formate (III) and 4-oxopentyl acetate (IV), respectively, together with the 1:2 telomers - 7-formyloxy-4-formyloxymethyl-2-heptanone (V) and 7-acetoxy-4-acetoxymethyl-2-heptanone (VI).The initial radiation yields are: G(III) = 200.8, G(IV) = 211.3, G(V) = 39.5, G(VI) = 37.9.Base-catalyzed transesterification of oxopentyl alkanoates III and IV afforded 5-hydroxy-2-pentanone (XIV), the same reaction of dialkylalkanoates VI and VII gave 5-hydroxy-4-hydroxymethyl-2-heptanone (XV).
- Liska, Frantisek,Valenta, Miroslav,Fikar, Jiri,Jandova, Martina,Pesek, Miroslav,Trska, Petr
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p. 1287 - 1296
(2007/10/02)
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- OZONOLYSIS OF ALKENES AND REACTIONS OF POLYFUNCTIONAL COMPOUNDS. XXIX. SYNTHESIS OF ACYCLIC (Z)-1,5-POLYENE ISOPRENOID KETO ACETALS
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A convenient method was developed for the synthesis of acyclic (Z)-1,5-polyene isoprenoid keto acetals on the basis of the partial ozonolysis of regular (Z)-1,4-polyisoprene with subsequent reduction of the peroxides to ω-acetylaldehydes and selective protection of the formyl group.The individual dimethyl acetals of (Z)-1,5-polyene isoprenoid ω-acetylaldehydes with 1-5 (Z)-isoprene units were isolated by vacuum distillation of the mixture of isoprenologs.
- Odinokov, V. N.,Ignatyuk, V. K.,Krivonogov, V. P.,Tolstikov, G. A.
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p. 848 - 851
(2007/10/02)
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