- Oxidation of Alcohols with Peracetic Acid in Ethyl Acetate in the Presence of Sodium Bromide
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Aliphatic primary alcohols and 1,ω-diols were oxidized to the dimeric esters and lactones, respectively, by peracetic acid in ethyl acetate in the presence of sodium bromide under mild conditions.Aliphatic secondary and benzylic alcohols were converted smoothly to the corresponding carbonyl compounds by the same system.
- Morimoto, Takashi,Hirano, Masao,Hamaguchi, Takayoshi,Shimoyama, Masahide,Zhuang, Xiumin
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- Synthesis of Unsymmetrical N-Heterocyclic Carbene-Nitrogen-Phosphine Chelated Ruthenium(II) Complexes and Their Reactivity in Acceptorless Dehydrogenative Coupling of Alcohols to Esters
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Two novel ruthenium complexes RuH(CO)Cl(PPh3)(κ2-CP) (1) and [fac-RuH(CO)(PPh3)(κ3-CNP)]Cl (2) bearing unsymmetrical N-heterocyclic carbene-nitrogen-phosphine (CNP) were synthesized and characterized with 1H NMR, 31P NMR, and HRMS. The structure of complex 2 was further confirmed by single-crystal X-ray diffraction. An anion exchange experiment proved that complex 2 could transform into complex 1 in solution. The two complexes exhibited a highly catalytic performance in acceptorless dehydrogenative coupling of alcohols to esters, and the excellent isolated yields of esters were given in a catalyst loading of 1% for para- and meta-substituted benzyl alcohols and long-chain primary alcohols. Although some ortho-substituted benzyl alcohols displayed a relatively low reactivity due to the steric hindrance and the coordination of electron donor with the ruthenium center, the good product yields were still obtained by prolonging the reaction time. Especially, this system successfully realized the dehydrogenative cross-coupling to esters between two different primary alcohols.
- He, Xiaochun,Li, Yaqiu,Fu, Haiyan,Zheng, Xueli,Chen, Hua,Li, Ruixiang,Yu, Xiaojun
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- RUTHENIUM CATALYZED TRANSFORMATION OF ALCOHOLS TO ESTERS AND LACTONES
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Homogeneous catalytic oxidative condensation of alcohols and diols to their corresponding esters and lactones has been accomplished using RuH2(PPh3)4.
- Murahashi, Shun-Ichi,Ito, Kei-ichiro,Naota, Takeshi,Maeda, Yoshihiro
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- Spin glass behavior and oxidative catalytic property of Zn2MnO4 from a metathesis driven metastable precursor
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The reaction of chloride salts of zinc and manganese with NaOH yielded a cubic spinel structured metastable precursor at room temperature, driven mainly by the salt elimination process's energetics. While classical drying processes failed to produce the monophasic oxide, recrystallization under the hydrothermal conditions yielded Zn2MnO4 in nano dimensions. The sample consisted of crystallites with an average 6 nm size and had a lattice dimension of 8.396 (13) ?. The selected area electron diffraction pattern reiterated the occurrence of cubic inverse spinel. The presence of fingerprint (A1g and F2g) modes of an inverse spinel at 663 and 561 cm?1 in the Raman spectrum further supported our finding. The TEM-EDS analysis confirmed the ratio of Zn: Mn as 1.95:1. The sample showed an optical bandgap of 2.54 eV. X-ray photoelectron spectral analysis established the existence of manganese in the IV oxidation state. The presence of Mn (IV) with small amounts of Mn (III) (up to 20%) was confirmed from the electron paramagnetic spectra recorded at room temperature and 77 K. An average oxidation state of 3.85 was deduced from the chemical redox titration experiments. The pseudocapacitive behavior of the sample was evident in cyclic voltammetric experiments. The sample exhibited paramagnetic behavior at 298 K within the applied magnetic field of ±50 kOe. In the temperature-dependent measurements, the zero-field and field cooled data points of Zn2MnO4 diverged at 13 K, suggesting a spin-glass behavior. An effective magnetic moment of 4.31 BM was deduced for the sample. The inverse spinel effectively catalyzed the oxidation of phenol. It facilitated nearly 100% degradation of bisphenol-A to salicylaldehyde and phenylethyl alcohol (as major products) in the presence of H2O2 and at a pH of 9.
- Kushwaha, Shreya,Nagarajan, Rajamani
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- A TEMPO-like nitroxide combined with an alkyl-substituted pyridine: An efficient catalytic system for the selective oxidation of alcohols with iodine
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An efficient method for the oxidation of alcohols to aldehydes or ketones in a two-phase CH2Cl2/NaHCO3 (aq.) system, using iodine and catalytic amounts of 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxyl and 2,4,6-trimethylpyridine, was developed. The performance of the method was demonstrated by the selective oxidation of 37 variously substituted alcohols in ≥90% yield, including the gram-scale synthesis of the important chemical 2,5-diformylfuran from biomass-derived 5-hydroxylmethylfurfural.
- Kashparova, Vera P.,Klushin, Victor A.,Zhukova, Irina Yu.,Kashparov, Igor S.,Chernysheva, Daria V.,Il'chibaeva, Irina B.,Smirnova, Nina V.,Kagan, Efim Sh.,Chernyshev, Victor M.
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- One-pot electrochemical synthesis of acid anhydrides from alcohols
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One-pot indirect electrochemical oxidation of alcohols in the methylene chloride–aqueous solution of sodium hydrocarbonate two-phase system in the presence of potassium iodide, 4-acetylamino-2,2,6,6-tetramethylpiperidin-1-oxyl, and 2,6-lutidine results in
- Kashparova,Papina,Kashparov,Zhukova, I. Yu.,Ilchibaeva,Kagan, E. Sh.
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- Pyridinium chlorochromate catalyzed oxidation of alcohols to aldehydes and ketones with periodic acid
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A facile pyridinium chlorochromate (PCC) catalyzed (2 mol %) oxidation of alcohols to ketones and aldehydes using 1.05 equiv of H5IO 6 in acetonitrile is described here.
- Hunsen, Mo
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- Oxidative dimerization of primary alcohols to esters catalyzed by iridium complexes
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Primary alcohols undergo efficiently oxidative dimerization by iridium complexes under air without any solvent to form esters in fair to good yields. For instance, the reaction of 1-dodecanol in the presence of [IrCl(coe)2]2 (3 mol %) at 95 °C for 15 h produced dodecyl dodecanoate in 91% isolated yield. This is the first successful Ir-catalyzed oxidative dimerization of primary alcohols to esters using air as an oxidant. Various primary alcohols are converted to the corresponding esters in fair to good yields.
- Izumi, Aki,Obora, Yasushi,Sakaguchi, Satoshi,Ishii, Yasutaka
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- Oxidative esterification of primary alcohols with TEMPO/CaCl2/Oxone under hydrous conditions
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Symmetric esters are important compounds in the chemical industry, which creates demand for simple and efficient synthetic routes. Oxidative esterification is a promising method to achieve these aims. Here, we show that TEMPO/CaCl2/Oxone forms a convenient catalytic system for the synthesis of the aforementioned symmetric esters from primary alcohols in a biphasic dichloromethane-water solvent mixture. The substrate scope of the reaction method is complementary to those previously published and the terminal oxidant appears to play an important role. In addition, the method is shown to oxidize thiols preferentially over alcohol functional groups to give disulfide-bridged compounds.
- Hackbusch, Sven,Franz, Andreas H.
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- Staudinger’s phosphazene as an efficient esterifying reagent
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A new application of Staudinger’s phosphazene as an efficient esterifying reagent is reported. Staudinger’s phosphazene formed in situ by the reaction of organic mono-azide with triphenylphosphine, which is trapped by carboxylic acid, to afford amide exclusively. In contrast, interestingly the same phosphazene behaves in a different way as an efficient esterifying reagent, affording ester under a solvent-free microwave-assisted protocol wherein alcohol is added as the another component in addition to the other reactants. This discovery adds yet another new application of Staudinger’s phosphazene to synthetic chemistry.
- Dinesh, Murugan,Ranganathan, Raja,Archana, Sivasubramaniyan,Sathishkumar, Murugan,Roshan Banu, Mohamed Sulthan,Ponnuswamy, Alagusundaram
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- Kinetic Analysis as an Optimization Tool for Catalytic Esterification with a Moisture-Tolerant Zirconium Complex
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This work describes the use of kinetics as a tool for rational optimization of an esterification process with down to equimolar ratios of reagents using a recyclable commercially available zirconocene complex in catalytic amounts. In contrast to previously reported group IV metal-catalyzed esterification protocols, the work presented herein circumvents the use of water scavengers and perfluorooctane sulfonate (PFOS) ligands. Insights into the operating mechanism are presented.
- Dalla-Santa, Oscar,Lundberg, Helena,Szabó, Zoltán,Villo, Piret
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p. 6959 - 6969
(2020/06/27)
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- Aldehyde effect and ligand discovery in Ru-catalyzed dehydrogenative cross-coupling of alcohols to esters
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The presence of different aldehydes is found to have a significant influence on the catalytic performance when using PN(H)P type ligands for dehydrogenation of alcohols. Accordingly, hybrid multi-dentate ligands were discovered based on an oxygen-transfer alkylation of PNP ligands by aldehydes. The relevant Ru-PNN(PO) system provided the desired unsymmetrical esters in good yields via acceptorless dehydrogenation of alcohols. Hydrogen bonding interactions between the phosphine oxide moieties and alcohol substrates likely assisted the observed high chemoselectivity.
- Jiang, Xiaolin,Zhang, Jiahui,Zhao, Dongmei,Li, Yuehui
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p. 2797 - 2800
(2019/03/27)
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- Cobalt-catalysed reductive C-H alkylation of indoles using carboxylic acids and molecular hydrogen
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The direct CH-alkylation of indoles using carboxylic acids is presented for the first time. The catalytic system based on the combination of Co(acac)3 and 1,1,1-tris(diphenylphosphinomethyl)-ethane (Triphos, L1), in the presence of Al(OTf)3 as co-catalyst, is able to perform the reductive alkylation of 2-methyl-1H-indole with a wide range of carboxylic acids. The utility of the protocol was further demonstrated through the C3 alkylation of several substituted indole derivatives using acetic, phenylacetic or diphenylacetic acids. In addition, a careful selection of the reaction conditions allowed to perform the selective C3 alkenylation of some indole derivatives. Moreover, the alkenylation of C2 position of 3-methyl-1H-indole was also possible. Control experiments indicate that the aldehyde, in situ formed from the carboxylic acid hydrogenation, plays a central role in the overall process. This new protocol enables the direct functionalization of indoles with readily available and stable carboxylic acids using a non-precious metal based catalyst and hydrogen as reductant.
- Cabrero-Antonino, Jose R.,Adam, Rosa,Junge, Kathrin,Beller, Matthias
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p. 6439 - 6450
(2017/08/29)
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- Oxidative dimerization of alcohols in the presence of nitroxyl radical–iodine catalytic system
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Pyridine catalyzes oxidation of alcohols with 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl–iodine catalytic system at room temperature. Symmetric esters are formed in good yields.
- Kashparova,Kashparov,Zhukova, I. Yu.,Astakhov,Ilchibaeva,Kagan, E. Sh.
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p. 2423 - 2426
(2016/12/24)
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- Direct Ruthenium-Catalyzed Hydrogenation of Carboxylic Acids to Alcohols
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The "green" reduction of carboxylic acids to alcohols is a challenging task in organic chemistry. Herein, we describe a general protocol for generation of alcohols by catalytic hydrogenation of carboxylic acids. Key to success is the use of a combination of Ru(acac)3, triphos and Lewis acids. The novel method showed broad substrate tolerance and a variety of aliphatic carboxylic acids including biomass-derived compounds can be smoothly reduced.
- Cui, Xinjiang,Li, Yuehui,Topf, Christoph,Junge, Kathrin,Beller, Matthias
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supporting information
p. 10596 - 10599
(2015/09/02)
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- A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions
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A novel tropylium-based coupling reagent has been developed to facilitate the synthesis of a series of esters, amides, lactones and peptides under mild reaction conditions. Remarkably, this reagent can be used in catalytic amounts in conjunction with a sacrificial reagent, offering a new and efficient method for nucleophilic coupling reactions of carboxylic acids.
- Nguyen, Thanh V.,Lyons, Demelza J.M.
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supporting information
p. 3131 - 3134
(2015/06/17)
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- Bis azide-triphenylphosphine as a reagent for esterification at room temperature
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Modified Staudinger reaction is a well-established reaction for the amide synthesis from organic azides and carboxylic acids in the presence of phosphorous reagents. In contrary to this, it is notable that bis azide in the presence of triethylphosphite or trimethylphosphite does not afford the expected bis amides but affords the ethyl or methyl esters of the carboxylic acids respectively. This serendipitous observation when further investigated results in the discovery of bis azide-triphenylphosphine as an efficient reagent for esterification at room temperature.
- Dinesh, Murugan,Archana, Sivasubramaniyan,Ranganathan, Raja,Sathishkumar, Murugan,Ponnuswamy, Alagusundaram
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supporting information
p. 6975 - 6979
(2015/11/27)
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- Efficient and simple approaches towards direct oxidative esterification of alcohols
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The present article describes novel oxidative protocols for direct esterification of alcohols. The protocols involve successful demonstrations of both "cross" and "self" esterification of a wide variety of alcohols. The cross-esterification proceeds under a simple transition-metal-free condition, containing catalytic amounts of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy)/TBAB (tetra-n-butylammonium bromide) in combination with oxone (potassium peroxo monosulfate) as the oxidant, whereas the self-esterification is achieved through simple induction of Fe(OAc)2/dipic (dipic=2,6-pyridinedicarboxylic acid) as the active catalyst under an identical oxidizing environment. One-pot oxidative esterification: A wide variety of alcohols undergo transition-metal-free (in the presence of oxone/2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)/tetra-n-butylammonium bromide (TBAB)) selective "cross" esterification in moderate to excellent yields (see Figure). The "self" esterification process has however been achieved in the presence of Fe(OAc)2/2,6-pyridinedicarboxylic acid (dipic) as the active catalytic species under a similar oxidizing environment.
- Ray, Ritwika,Jana, Rahul Dev,Bhadra, Mayukh,Maiti, Debabrata,Lahiri, Goutam Kumar
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supporting information
p. 15618 - 15624
(2016/02/18)
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- Four acid-catalysed dehydration reactions proceed without interference
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Four acid-catalysed dehydration reactions can proceed in one pot, simultaneously and without interference, to yield one imine, one acetal (or boronic ester), one ester and one alkene, even though many other cross-products could be conceived. This advanced
- Lirag, Rio Carlo,Miljani?, Ognjen ?.
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supporting information
p. 9401 - 9404
(2014/08/05)
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- An efficient N-heterocyclic carbene based ruthenium-catalyst: Application towards the synthesis of esters and amides
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A highly stable benzimidazolylidene based N-heterocyclic carbene (NHC) ruthenium catalyst was prepared starting with readily accessible starting materials. Under inert gas atmosphere and in air the catalyst showed high activity for the direct synthesis of esters from primary alcohols and of amides from primary alcohols and amines. Di-, tri-, and oligo-amides were obtained by using specific starting materials.
- Malineni, Jagadeesh,Merkens, Carina,Keul, Helmut,M?ller, Martin
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- Ruthenium-catalyzed self-coupling of primary and secondary alcohols with the liberation of dihydrogen
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The dehydrogenative self-condensation of primary and secondary alcohols has been studied in the presence of RuCl2(IiPr)(p-cymene). The conversion of primary alcohols into esters has been further optimized by using magnesium nitride as an additive, which allows the reaction to take place at a temperature and catalyst loading lower than those described previously. Secondary alcohols were dimerized into racemic ketones by a dehydrogenative Guerbet reaction with potassium hydroxide as the additive. The transformation gave good yields of the ketone dimers with a range of alkan-2-ols, whereas more substituted secondary alcohols were unreactive. The reaction proceeds by dehydrogenation to the ketone, followed by an aldol reaction and hydrogenation of the resulting enone.
- Makarov, Ilya S.,Madsen, Robert
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p. 6593 - 6598
(2013/07/26)
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- Acceptorless and base-free dehydrogenation of alcohols and amines using ruthenium-hydride complexes
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An efficient, operatively simple, acceptorless, and base-free dehydrogenation of secondary alcohols and nitrogen-containing heterocyclic compounds was achieved by using readily available ruthenium hydride complexes as precatalysts. The complex RuH2(CO)(PPh3)3 (1) and Shvo's complex (2) showed excellent activities for the dehydrogenation of secondary alcohols and nitrogen containing heterocycles. In addition to complexes 1 and 2, the complex RuH2(PPh3)4 (3) also showed moderate to excellent activity for the acceptorless dehydrogenation of nitrogen-containing heterocyclic compounds. Kinetic studies on the oxidation reaction of 1-phenylethanol using complex 1 were carried out in the presence and the absence of external triphenylphosphine (PPh3). External addition of PPh3 had a negative influence on the rate of the reaction, which suggested that dissociation of PPh3 occurred during the course of the reaction. Hydrogen was evolved from the oxidation reaction of 1-phenylethanol by using 1 mol% of 1 (88%) and 2 (92%), which demonstrated the possible usage of the catalytic systems in hydrogen generation. Copyright
- Muthaiah, Senthilkumar,Hong, Soon Hyeok
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p. 3045 - 3053
(2013/01/15)
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- Dehydrogenative coupling of primary alcohols to form esters catalyzed by a ruthenium N-heterocyclic carbene complex
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The ruthenium complex [RuCl2(IiPr)(p-cymene)] catalyzes the direct condensation of primary alcohols into esters and lactones with the release of hydrogen gas. The reaction is most effective with linear aliphatic alcohols and 1,4-diols and is believed to proceed with a ruthenium dihydride as the catalytically active species.
- Solvhoj, Amanda,Madsen, Robert
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experimental part
p. 6044 - 6048
(2012/01/13)
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- Solvent-free selective oxidation of primary alcohols-to-aldehydes and aldehydes-to-carboxylic acids by molecular oxygen over MgO-supported nano-gold catalyst
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Magnesium oxide supported nano-gold catalyst (prepared by the homogeneous deposition precipitation technique) showed high activity/selectivity and excellent reusability in the oxidation of different primary alcohols and aldehydes to corresponding aldehydes and carboxylic acids, respectively, by molecular oxygen (under atmospheric pressure) in the absence of any solvent. Influence of the catalyst calcination temperature (400-900 °C), reaction temperature (50-120 °C) and use of different solvents (viz. toluene, p-xylene, DMF or DMSO) on the oxidation reaction has also been studied.
- Choudhary, Vasant R.,Dumbre, Deepa K.
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experimental part
p. 82 - 86
(2012/06/01)
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- N-heterocyclic carbene based ruthenium-catalyzed direct amide synthesis from alcohols and secondary amines: Involvement of esters
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A well-defined N-heterocyclic carbene based ruthenium complex was developed as a highly active precatalyst for the direct amide synthesis from alcohols and secondary amines. Notably, reaction of 1-hexanol and dibenzylamine afforded 60% of the corresponding amide using our catalytic system, while no amide formation was observed for this reaction with the previously reported catalytic systems. Unlike the previously reported amidation with less sterically hindered alcohols and amines, involvement of ester intermediates was observed (Figure presented).
- Chen, Cheng,Zhang, Yao,Hong, Soon Hyeok
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experimental part
p. 10005 - 10010
(2012/02/05)
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- Rhodium(III)-catalyzed dimerization of aldehydes to esters
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No sooner said than done: A rhodi- um(III) hydride complex is an outstandingly effective and selective catalyst for the dimerization of aldehydes to the corresponding esters (see scheme). Evidence for an unusual mechanism in catalysis by rhodium is given.
- Tejel, Cristina,Ciriano, Miguel A.,Passarelli, Vincenzo
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experimental part
p. 91 - 95
(2011/03/21)
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- Protic acid immobilized on solid support as an extremely efficient recyclable catalyst system for a direct and atom economical esterification of carboxylic acids with alcohols
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(Chemical Equation Presented) A convenient and clean procedure of esterification is reported by direct condensation of equimolar amounts of carboxylic acids with alcohols catalyzed by an easy to prepare catalyst system of perchloric acid immobilized on silica gel (HClO4-SiO2). The direct condensation of aryl, heteroaryl, styryl, aryl alkyl, alkyl, cycloalkyl, and long-chain aliphatic carboxylic acids with primary/secondary alkyl/cycloalkyl, allyl, propargyl, and long-chain aliphatic alcohols has been achieved to afford the corresponding esters in excellent yields. Chiral alcohol and N-t-Boc protected chiral amino acid also resulted in ester formation with the representative carboxylic acid or alcohol without competitive N-t-Boc deprotection and detrimental effect on the optical purity of the product demonstrating the mildness and chemoselectivity of the procedure. The esters of long-chain (>C10) acids and alcohols are obtained in high yields. The catalyst is recovered and recycled without significant loss of activity. The industrial application of the esterification process is demonstrated by the synthesis of prodrugs of ibuprofen and a few commercial flavoring agents. Other protic acids such as H2SO4, HBr, TfOH, HBF4, and TFA that were adsorbed on silica gel were less effective compared to HClO4-SiO2 following the order HClO4-SiO 2 ? H2SO4-SiO2 > HBr-SiO 2 > TfOH-SiO2 ? HBF4-SiO2 ≈ TFA-SiO2. When HClO4 was immobilized on other solid supports the catalytic efficiency followed the order HClO4-SiO 2 > HClO4-K10 > HClO4-Al 2O3 (neutral) > HClO4-Al2O 3 (acidic) > HClO4-Al2O3 (basic).
- Chakraborti, Asit K.,Singh, Bavneet,Chankeshwara, Sunay V.,Patel, Alpesh R.
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supporting information; experimental part
p. 5967 - 5974
(2009/12/24)
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- Phase-transfer catalyzed asymmetric arylacetate alkylation
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Phenethyl arylacetates are alkylated under phase-transfer conditions with cinchona catalysts with alkyl halides in high yield with excellent enantioselectivity (84-99% ee) following recrystallization. Cinchonidine (CD) derived catalyst gave the (R)-product and cinchonine (CN) catalyst produced the (S)-product. The phenethyl (PE) ester group is removed, using ammonium formate and catalytic Pd/C, to give alkylated carboxylic acid products in high selectivity. The utility of the approach is demonstrated by a direct synthesis of (S)-naproxen.
- Andrus, Merritt B.,Harper, Kaid C.,Christiansen, Michael A.,Binkley, Meisha A.
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supporting information; experimental part
p. 4541 - 4544
(2009/12/03)
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- Ruthenium catalysed N-alkylation of amines with alcohols
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The conversion of primary amines into secondary amines has been achieved using alcohols as the alkylating agent, catalysed by [Ru(p-cymene)Cl 2]2 and a bidentate phosphine ligand. The Royal Society of Chemistry.
- Hamid, Malai Haniti S. A.,Williams, Jonathan M. J.
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p. 725 - 727
(2007/10/03)
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- Solubilizing agents for active or functional organic compounds
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An active or functional organic compound is solubilized in a diaryl organic compound having a polar or polarizable functional group therein, as a solvent, cosolvent or additive, to form a composition thereof. Representative active or functional organic compounds include those present in personal care products, e.g., sunscreens containing UVA/UVB absorbing compounds, such as avobenzone, benzophenone-3, and 4-methylbenzylidene camphor. Such compositions also show increased SPF, UVA/UVB absorbance ratio, and critical wavelength performance properties.
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- Oxoammonium salts. 6. 4-Acetylamino-2,2,6,6-tetramethylpiperidine-1- oxoammonium perchlorate: A stable and convenient reagent for the oxidation of alcohols. Silica gel catalysis
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4-Acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium perchlorate, 1, is a stable, nonhygroscopic oxoammonium salt that is easily prepared and can be used for the oxidation of alcohols to ketones or aldehydes in near quantitative yields. The reaction is colorimetric, does not require anhydrous conditions, does not involve heavy metals, and can be carried out conveniently. Furthermore, the oxidant can be easily regenerated. The oxidation is somewhat specific in that the relative reactivities of an allyl alcohol (geraniol), benzaldehyde, and 1-decanol are about 100:1:0.1. The reaction is catalyzed by silica gel.
- Bobbitt, James M.
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p. 9367 - 9374
(2007/10/03)
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- Oxidation of Alkynes by Hydrogen Peroxide Catalyzed by Methylrhenium Trioxide
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The oxidation of alkynes with hydrogen peroxide is catalyzed by methylrhenium tioxide.The reactions can be rationalized by postulating that an oxirene intermediate is formed between a rhenium peroxide and the alkyne.Internal alkynes yield α-diketones and carboxylic acids, the latter from the complete cleavage of the triple bonds.Rearrangement products were observed only for aliphatic alkynes.Terminal alkynes gave carboxylic acids and their derivatives and α-keto acids as the major products, but their yields varied with the solvent used.
- Zhu, Zuolin,Espenson, James H.
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p. 7728 - 7732
(2007/10/03)
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- Oxidation Using Quaternary Ammonium Polyhalides. III. An Effective Oxidation of Alcohols and Ethers by the Use of Benzyltrimethylammonium Tribromide
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The reaction of primary alcohols or simple ethers and α,ω-diols or cyclic ethers with a stoichiometric amount of benzyltrimethylammonium tribromide (BTMA) Br3) in carbon tetrachloride in the presence of Na2HPO4 aq or in acetic acid in the presence of CH3CO2Na aq at 60-70 deg C gave dimeric esters and lactones respectively in good yields.The reaction of secondary alcohols with 1 equiv of BTMA Br3 in the presence of a buffer at 60 deg C gave ketones.
- Kajigaeshi, Shoji,Kawamukai, Hiroshi,Fujisaki, Shizuo
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p. 2585 - 2588
(2007/10/02)
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- Ruthenium-Catalyzed Oxidative Transformation of Alcohols and Aldehydes to Esters and Lactones
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Primary alcohols undergo oxidative condensation upon treatment with RuH2(PPh3)4 catalyst to give esters and molecular hydrogen.Similarly, 1,4- and 1,5-diols can be converted into the corresponding γ- and δ-lactones, respectively.The lactonization is greatly enhanced by accepting hydrogen with an appropriate hydrogen acceptor such as acetone.Primary alcohols are oxidized chemoselectively in the presence of secondary alcohols to give the corresponding lactones.These reactions are operationally simple and highly efficient for synthesis of esters and lactones from alcohols.The principle of the oxidative condensation of alcohols can be extended to ester formation from aldehydes and alcohols.The ruthenium-catalyzed reaction of aldehydes with water gives esters, while the same reaction in the presence of a hydrogen acceptor gives carboxylic acids.The key step of these reactions is the oxidative addition of ruthenium into the OH bonds of alcohols and subsequent β-elimination of (RuH) species to give the corresponding carbonyl compounds.
- Murahashi, Shun-Ichi,Naota, Takeshi,Ito, Keiichiro,Maeda, Yoshihiro,Taki, Hiroshi
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p. 4319 - 4327
(2007/10/02)
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- INTERMOLECULAR DEHYDRATION BETWEEN CARBOXYLIC ACIDS AND ALCOHOLS BY THE USE OF DIETHYL AZODICARBOXYLATE AND 3-METHYLBENZOTHIAZOLE-2-SELONE
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The reaction of carboxylic acids with alcohols in the presence of diethyl azodicarboxylate and 3-methylbenzothiazole-2-selone gave the corresponding esters with retention of configuration at the alcoholic carbon atom.
- Mitsunobu, Oyo,Takemasa, Akira,Endo, Ryosuke
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p. 855 - 858
(2007/10/02)
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- A FACILE OXIDATIVE LACTONIZATION OF 1,ω-DIOLS WITH SODIUM BROMITE
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A practically useful method for the oxidation of 1,ω-diols to lactones is described.The scope and limitations are also presented.
- Kageyama, Toshifumi,Kawahara, Shuji,Kitamura, Kohji,Ueno, Yoshio,Okawara, Makoto
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p. 1097 - 1100
(2007/10/02)
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- Oxidation of Primary and Secondary Alcohols by the Catalysis of Palladium
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Saturated and unsaturated alcohols are oxidized to the corresponding ketones in good or excellent yields by using an aryl halide (phenyl bromide or mesityl bromide) as an oxidant and palladium(0) or -(II) as a catalyst (0.6-3 mol percent relative to the alcohol) in the presence of a base (NaH or K2CO3).The similar oxidation of primary alcohols provides the corresponding aldehydes and/or esters.The aldehyde/ester selectivity is correlated to the steric and electronic features of substrates.The procedure is applied to the oxidation of 1-primary,ω-primary diols to lactones.
- Tamaru, Yoshinao,Yamada, Yoshimi,Inoue, Kenji,Yamamoto, Youichi,Yoshida, Zen-ichi
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p. 1286 - 1292
(2007/10/02)
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