- Visible-light-initiated manganese-catalyzed Giese addition of unactivated alkyl iodides to electron-poor olefins
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Herein, we report a mild protocol for direct visible-light-initiated Giese addition of unactivated alkyl iodides to electron-poor olefins (Michael acceptors) with catalysis by decacarbonyl dimanganese, Mn2(CO)10, an inexpensive earth-abundant-metal catalyst. This protocol is compatible with a wide array of sensitive functional groups and has a broad substrate scope with regard to both the alkyl iodide and the Michael acceptor.
- Dong, Jianyang,Wang, Xiaochen,Wang, Zhen,Song, Hongjian,Liu, Yuxiu,Wang, Qingmin
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- Palladium nanoparticles obtained from palladium salts and tributylamine in molten tetrabutylammonium bromide: Their use for hydrogenolysis-free hydrogenation of olefins
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Carbon-carbon double bonds have been selectively hydrogenated at room temperature in the presence of benzyloxy groups using an atmospheric pressure of hydrogen, toluene or [bmim]PF6 as the solvent and palladium nanoparticles stabilized with tetrabutylammonium bromide. The system [bmim]PF6/palladium nanoparticles can be recycled without noticeable decrease of activity.
- Le Bras, Jean,Mukherjee, Deb Kumar,Gonzalez, Sara,Tristany, Mar,Ganchegui, Benjamin,Moreno-Manas, Marcial,Pleixats, Roser,Henin, Francoise,Muzart, Jacques
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- Synthesis of butyrate using a heterogeneous catalyst based on polyvinylpolypyrrolidone
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A heterogeneous polyvinylpolypyrrolidone supported Br?nsted acidic catalyst ([PVPP-BS]HSO4) was used to synthesize butyrate in this paper. The prepared catalysts were characterized by FT-IR, TG, and FESEM and their catalytic activity in butyric acid esterification with benzyl alcohol was investigated. The influencing factors such as the amount of catalyst, reaction temperature, and reaction time were carefully studied. Under the optimized condition with the butyric acid to benzyl alcohol mole ratio of 1 : 1.2 and the reaction temperature of 130°C, the yield of benzyl butyrate reached 96.8 % within 4 h in the presence of 8 mass % of catalyst. Moreover, the catalyst could be reused six times without noticeable drop in activity. This catalyst was also used to synthesize other kinds of butyrates achieving the butyrate yield above 90 %.
- Wang, Song,Chang, Qian-Qian,Shawgi, Nazar,Li, San-Xi,Zhang, Lin-Nan
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- Glycoluril as an efficient molecular template for intramolecular Claisen-type condensations
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The readily prepared 3,4,7,8-tetramethylglycoluril 1 acts as a template to promote efficient intramolecular Claisen-like condensations between two acyl groups which are attached to the N-1 and N-6 positions. Thus, two sequential acylations of 1 give symmetric or unsymmetric diacylglycolurils 9-18 in good yield. Treatment of 9-18 with lithium tert-alkoxides furnishes N-(β-ketoacyl)glycolurils 19-27 under mild conditions and in high yields; rate-limiting deprotonation, predominantly on the least substituted of the two acyl groups, precedes a fast intramolecular Claisen-type condensation. Reduction of the keto group in 19 and 26, followed by elimination of water gives alk-2-enoylglycolurils 6 and 7; conjugate hydride addition (L-Selectride) then gives alkanoylglycoluril 5. Compounds 5-7 undergo further rounds of N-acylation then intramolecular condensation. Linear chains can thus be constructed on 1 by repetitive sequences of acylation-condensation-functional group transformation. N1-Alk-2-enoyl-N6-alkanoylglycolurils 14-17 also afford condensation products with high selectivity upon treatment with L-Selectride, effecting a method for net reversal of the regioselectivity observed in the base-promoted rearrangement. The synthesized chains can be readily removed from the template, regenerating 1. The efficiency of the condensation reaction, the sequence of transformations and the ability to grow linear carbon chains in a repetitive manner mimic these aspects of the catalytic cycle of fatty acid synthases and polyketide synthases.
- Sun, Sengen,Edwards, Louise,Harrison, Paul
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- N, O-ligand accelerated zinc-catalyzed transesterification of alcohols with vinyl esters
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N-Phenyldiethanolamine (1f) is an efficient ligand for zinc-catalyzed transesterification of alcohols with vinyl acetate (R3 = Me) at room temperature. In the case of using other vinyl esters (R3 = Et, n-Pr, Ph), the corresponding products were easily obtained in the presence of pyridine-type ligand 2 instead of aminoalcohol 1f.
- Mino, Takashi,Hasegawa, Tae,Shirae, Yoshiaki,Sakamoto, Masami,Fujita, Tsutomu
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- Metal-Free Direct Oxidation of Aldehydes to Esters Using TCCA
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Aromatic and aliphatic aldehydes are simply converted into esters by an efficient oxidative esterification carried out under mild conditions. The aldehydes are converted in situ into their corresponding acyl chlorides, which are then reacted with primary and secondary aliphatic, benzylic, allylic, and propargylic alcohols and phenols. A variety of esters are obtained in high yields.
- Gaspa, Silvia,Porcheddu, Andrea,De Luca, Lidia
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- Ionic liquids as reaction media for esterification of carboxylate sodium salts with alkyl halides
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Ionic liquids based on 1,3-dialkylimidazolinium methanesulfonate have been used as effective reusable reaction media in the esterification of several carboxylate sodium salts with different alkyl halides. Products are easily isolated by extraction with ether, and the protocol is mild and green, compared to the existing methods based on toxic solvents. Proper 'design' of the ionic liquid allows us to obtain esters always in quantitative yields.
- Brinchi,Germani,Savelli
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- The combine use of ultrasound and lipase immobilized on co-polymer matrix for efficient biocatalytic application studies
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In this work, we have investigated the combine use of ultrasound and lipase (Pseudomonas cepacia: PCL) immobilized on co-polymer of polyvinyl alcohol (PVA) and chitosan (CHI) for biocatalytic applications. Initially, we have screened different free and immobilized biocatalysts to find-out the robust biocatalyst. The immobilized biocatalyst PVA:CHI:PCL (5:5:2.5) worked as a robust biocatalyst to provide superior conversion (99%) for the synthesis of model ultrasound assisted reaction. Subsequently, various reaction parameters were optimized in details to obtain the higher yield. Besides this, developed biocatalytic protocol was used to synthesize various industrially important butyrate compounds which provided excellent conversion of 99% under ultrasonic conditions. The developed biocatalyst showed excellent recyclability upto studied five cycles under ultrasonic condition. The immobilized PVA:CHI:PCL biocatalyst displayed 2.4 folds higher activity as compared to free lipases in ultrasonic condition. Moreover, PVA:CHI:PCL biocatalyst in ultrasound media showed 4.5 folds higher activity as compared to free lipases in conventional media. The energy assessment was performed which demonstrated feasibility of combine use of immobilization and ultrasonication to carry out efficient biocatalytic process.
- Badgujar, Kirtikumar Chandulal,Bhanage, Bhalchandra Mahadeo
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- Tandem Continuous Flow Curtius Rearrangement and Subsequent Enzyme-Mediated Impurity Tagging
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The use of continuous flow as an enabling technology within the fine chemical and pharmaceutical industries continues to gain momentum. The associated safety benefits with flow for handling of hazardous or highly reactive intermediates are often exploited to offer industrially relevant and scalable Curtius rearrangements. However, in many cases the Curtius rearrangement requires excess nucleophile for the reaction to proceed to high conversions. This can complicate work procedures to deliver high-purity products. However, tandem processing and coupling of the Curtius rearrangement with an immobilized enzyme can elegantly facilitate chemoselective tagging of the residual reagent, resulting in a facile purification process under continuous flow.
- Baumann, Marcus,Leslie, Alexander,Moody, Thomas S.,Smyth, Megan,Wharry, Scott
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- Efficient Enzymatic Preparation of Flavor Esters in Water
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A straightforward biocatalytic method for the enzymatic preparation of different flavor esters starting from primary alcohols (e.g., isoamyl, n-hexyl, geranyl, cinnamyl, 2-phenethyl, and benzyl alcohols) and naturally available ethyl esters (e.g., formate, acetate, propionate, and butyrate) was developed. The biotransformations are catalyzed by an acyltransferase from Mycobacterium smegmatis (MsAcT) and proceeded with excellent yields (80-97%) and short reaction times (30-120 min), even when high substrate concentrations (up to 0.5 M) were used. This enzymatic strategy represents an efficient alternative to the application of lipases in organic solvents and a significant improvement compared with already known methods in terms of reduced use of organic solvents, paving the way to sustainable and efficient preparation of natural flavoring agents.
- Perdomo, Igor Chiarelli,Gianolio, Stefania,Pinto, Andrea,Romano, Diego,Contente, Martina Letizia,Paradisi, Francesca,Molinari, Francesco
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- Iron perchlorate on silica gel as multi-purpose reagent for catalysis of closure and rupture of carbon-oxygen bond in epoxides, alcohols, and esters
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Aliphatic alcohols and water in the presence of catalytic amounts of Fe3+ ion introduced as iron(III) perchlorate on silica gel carrier perform efficient regiospecific opening of an epoxy ring. Carbon acids esterification with various type alcohols was carried out using the system Fe(ClO4)3-silica gel in dichloromethane under conditions excluding solvolysis. Acetylation and formylation of alcohols was performed by efficient transesterification with ethyl acetate and ethyl formate.
- Salechi,Khodaei,Ghareghani,Motlagh
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- ENZYMATIC REACTIONS IN ORGANIC SYNTHESIS: 2- ESTER INTERCHANGE OF VINYL ESTERS
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Ester interchange of vinyl esters appears to be a rapid and efficient way to obtain esters of primary and secondary alcohols, provided there is a hydrogen atom on the carbon adjacent to the carbonyl of the acyl moiety.
- Degueil-Castaing, M.,Jeso, B. De,Drouillard, S.,Maillard, B.
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- Graphite oxide as an efficient solid reagent for esterification reactions
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Esterification of organic acids with alcohols under mild conditions in high yields using graphite oxide, a readily available and inexpensive material, as an effective reagent is described.
- Mirza-Aghayan, Maryam,Rahimifard, Mahshid,Boukherroub, Rabah
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- Zr-MOF-808 as Catalyst for Amide Esterification
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In this work, zirconium-based metal–organic framework Zr-MOF-808-P has been found to be an efficient and versatile catalyst for amide esterification. Comparing with previously reported homogeneous and heterogeneous catalysts, Zr-MOF-808-P can promote the reaction for a wide range of primary, secondary and tertiary amides with n-butanol as nucleophilic agent. Different alcohols have been employed in amide esterification with quantitative yields. Moreover, the catalyst acts as a heterogeneous catalyst and could be reused for at least five consecutive cycles. The amide esterification mechanism has been studied on the Zr-MOF-808 at molecular level by in situ FTIR spectroscopic technique and kinetic study.
- Villoria-del-álamo, Beatriz,Rojas-Buzo, Sergio,García-García, Pilar,Corma, Avelino
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- Solvent stability study with thermodynamic analysis and superior biocatalytic activity of Burkholderia cepacia lipase immobilized on biocompatible hybrid matrix of poly(vinyl alcohol) and hypromellose
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In the present study, we have synthesized a biocompatible hybrid carrier of hypromellose (HY) and poly(vinyl alcohol) (PVA) for immobilization of Burkholderia cepacia lipase (BCL). The immobilized biocatalyst HY:-PVA:BCL was subjected to determination of half-life time (τ) and deactivation rate constant (KD) in various organic solvents. Biocatalyst showed higher τ-value in a nonpolar solvent like cyclohexane (822 h) as compared to that of a polar solvent such as acetone (347 h), which signifies better compatibility of biocatalyst in the nonpolar solvents. Furthermore, the KD-value was found to be less in cyclohexane (0.843 × 10-3) as compared to acetone (1.997 × 10-3), indicating better stability in the nonpolar solvents. Immobilized-BCL (35 mg) was sufficient to achieve 99% conversion of phenethyl butyrate (natural constituent of essential oils and has wide industrial applications) using phenethyl alcohol (2 mmol) and vinyl butyrate (6 mmol) at 44 °C in 3 h. The activation energy (Ea) was found to be lower for immobilized-BCL than crude-BCL, indicating better catalytic e fficiency of immobilized lipase BCL. The immobilized-BCL reported 6-fold superior biocatalytic activity and 8 times recyclability as compared to crude-BCL. Improved catalytic activity of immobilized enzyme in nonpolar media was also supported by thermodynamic activation parameters such as enthalpy (ΔH?), entropy (ΔS?) and Gibb 's free energy (ΔG?) study, which showed that phenethyl butyrate synthesis catalyzed by immobilized-BCL was feasible as compared to crude-BCL. The present work explains a thermodynamic investigation and superior biocatalytic activity for phenethyl butyrate synthesis using biocompatible immobilized HY:PVA:BCL in nonaqueous media for the first time. (Graph Presented).
- Badgujar, Kirtikumar C.,Bhanage, Bhalchandra M.
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- Lipase dissolution and stabilization in ether-functionalized ionic liquids
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Ionic liquids (ILs) with various structures and properties have been extensively investigated in many biocatalytic reactions and processes. However, although hydrophobic ILs tend to stabilize the insoluble (suspended) enzymes, they usually have low hydrogen-bonding basicity with solutes, which limits the solubility of many substrates (such as D-glucose, ascorbic acid, and cellulose). In contrast, hydrophilic ILs (such as those based on chloride, acetate and dicyanamide) are able to dissolve many of these substances that are not quite soluble in common organic solvents. Unfortunately, enzymes are not always active in these hydrophilic media due to strong interactions (such as H-bonding) between proteins and ILs. To resolve this dilemma, we recently synthesized new acetate-based ILs carrying a long alkyloxyalkyl chain in their cations, and found that these ether-functionalized solvents are lipase-compatible and can dissolve considerable amounts of D-glucose and cellulose (Green Chem., 2008, 10, 696). In this study, we further observed that these ILs could dissolve high concentrations of lipase B from Candida antarctica (CALB) (> 5 mg/mL at 50 °C), as well as other substrates including amino acids and betulinic acid. Therefore, these novel media offer new opportunities for carrying out homogeneous enzymatic reactions, which is practically important for large substrate molecules. In this article, we further confirmed the lipase compatibility of these ILs through the transesterification between ethyl butyrate and 1-butanol. The second derivative infrared spectra of CALB suggest the conservation of secondary structures of proteins in these ILs. We further investigated these ether-functionalized ILs in two important biocatalytic reactions: enzymatic synthesis of methyl-phthalate of betulinic acid, and CALB-catalyzed synthesis of D-glucose fatty acid esters. These substrates are not very soluble in conventional organic solvents, but very soluble in ILs, which improved the catalytic efficiency of these reactions. Moderate to high conversions were achieved in both reactions.
- Zhao, Hua,Jones, Cecil L.,Cowins, Janet V.
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- N-Heterocyclic Carbene/Carboxylic Acid Co-Catalysis Enables Oxidative Esterification of Demanding Aldehydes/Enals, at Low Catalyst Loading
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We report the discovery that simple carboxylic acids, such as benzoic acid, boost the activity of N-heterocyclic carbene (NHC) catalysts in the oxidative esterification of aldehydes. A simple and efficient protocol for the transformation of a wide range of sterically hindered α- and β-substituted aliphatic aldehydes/enals, catalyzed by a novel and readily accessible N-Mes-/N-2,4,6-trichlorophenyl 1,2,4-triazolium salt, and benzoic acid as co-catalyst, was developed. A whole series of α/β-substituted aliphatic aldehydes/enals hitherto not amenable to NHC-catalyzed esterification could be reacted at typical catalyst loadings of 0.02–1.0 mol %. For benzaldehyde, even 0.005 mol % of NHC catalyst proved sufficient: the lowest value ever achieved in NHC catalysis. Preliminary studies point to carboxylic acid-induced acceleration of acyl transfer from azolium enolate intermediates as the mechanistic basis of the observed effect.
- Berkessel, Albrecht,Biswas, Animesh,Harnying, Wacharee,Sudkaow, Panyapon
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supporting information
p. 19631 - 19636
(2021/08/09)
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- Membrane transport inspired hydrolysis of non-activated esters at near physiological pH
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A positively charged micelle loaded with substrates was transported selectively to the reaction site (cathode) to promote the proximity and localization of the reactants (ester and hydroxide). The guided vehicular delivery coupled with electrolysis allows the hydrolysis of non-activated esters at near physiological pH with significant yields along with recyclability.
- Mandal, Raki,Mahanty, Kingshuk,Mandal, Subhendu,De Sarkar, Suman,Tarafdar, Pradip K.
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supporting information
p. 11088 - 11091
(2021/10/30)
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- ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
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An amide/iminium zwitterion catalyst has a catalyst pocket size that promotes transesterification and dehydrative esterification. The amide/iminium zwitterions are easily prepared by reacting aziridines with aminopyridines. The reaction can be applied a wide variety of esterification processes including the large-scale synthesis of biodiesel. The amide/iminium zwitterions allow the avoidance of strongly basic or acidic condition and avoidance of metal contamination in the products. Reactions are carried out at ambient or only modestly elevated temperatures. The amide/iminium zwitterion catalyst is easily recycled and reactions proceed in high to quantitative yields.
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Paragraph 0019; 0031
(2021/01/29)
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- Benzyne-Mediated Esterification Reaction
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A benzyne-mediated esterification of carboxylic acids and alcohols under mild conditions has been realized, which is made possible via a selective nucleophilic addition of carboxylic acid to benzyne in the presence of alcohol. After a subsequent transesterification with alcohol, the corresponding esters can be produced efficiently. This benzyne-mediated protocol can be used on the modification of Ibuprofen, cholesterol, estradiol, and synthesis of nandrolone phenylpropionate. In addition, benzyne can also be used to promote lactonization and amidation reaction.
- Li, Yang,Shi, Jiarong,Zhao, Jinlong
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supporting information
p. 7274 - 7278
(2021/10/01)
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- Hydrofluoromethylation of alkenes with fluoroiodomethane and beyond
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A process for the direct hydrofluoromethylation of alkenes is reported for the first time. This straighforward silyl radical-mediated reaction utilises CH2FI as a non-ozone depleting reagent, traditionally used in electrophilic, nucleophilic and carbene-type chemistry, but not as a CH2F radical source. By circumventing the challenges associated with the high reduction potential of CH2FI being closer to CH3I than CF3I, and harnessing instead the favourable bond dissociation energy of the C-I bond, we demonstrate that feedstock electron-deficient alkenes are converted into products resulting from net hydrofluoromethylation with the intervention of (Me3Si)3SiH under blue LED activation. This deceptively simple yet powerful methodology was extended to a range of (halo)methyl radical precursors including ICH2I, ICH2Br, ICH2Cl, and CHBr2F, as well as CH3I itself; this latter reagent therefore enables direct hydromethylation. This versatile chemistry was applied to18F-,13C-, and D-labelled reagents as well as complex biologically relevant alkenes, providing facile access to more than fifty products for applications in medicinal chemistry and positron emission tomography.
- Chen, Xuanxiao,Gouverneur, Véronique,Hell, Sandrine M.,Meyer, Claudio F.,Ortalli, Sebastiano,Sap, Jeroen B. I.
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p. 12149 - 12155
(2021/09/28)
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- An effective cis-β-octahedral Mn(iii) SALPN catalyst for the Mukaiyama-Isayama hydration of α,β-unsaturated esters
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Two cis-β-MnIIISALPN catalysts were synthesised and tested in the Mukaiyama-Isayama hydration of α,β-unsaturated esters. The MnIIIEtOSALPN(acac) complex 7 is the most active and catalyses hydration with little or no detectable undesired alkene reduction. This catalyst is superior for alkene hydration compared to the originally reported Mn(dpm)3 catalyst.
- Donnelly, Paul S.,North, Andrea J.,Radjah, Natalia Caren,Ricca, Michael,Robertson, Angus,White, Jonathan M.,Rizzacasa, Mark A.
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supporting information
p. 7699 - 7702
(2019/07/09)
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- Amide/Iminium Zwitterionic Catalysts for (Trans)esterification: Application in Biodiesel Synthesis
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A class of zwitterionic organocatalysts based on an amide anion/iminium cation charge pair has been developed. The zwitterions are easily prepared by reacting aziridines with aminopyridines. They are catalytically applicable to transesterifications and dehydrative esterifications. Mechanistic studies reveal that the amide anion and iminium cation work synergistically in activating the reaction partners, with the iminium cationic moiety interacting with the carbonyl substrates through nonclassical hydrogen bonding. The reaction can be applied to large-scale synthesis of biodiesel under mild conditions.
- Lam, Ying-Pong,Ng, Wing-Hin,Tan, Fei,Tse, Ying-Lung Steve,Wang, Xinyan,Yeung, Ying-Yeung
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p. 8083 - 8092
(2019/08/26)
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- Preparation, structure, and reactivity of bicyclic benziodazole: A new hypervalent iodine heterocycle
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A new bicyclic organohypervalent iodine heterocycle derivative of benziodazole was prepared by oxidation of 2-iodo-N,N'-diiso-propylisophthalamide with m-chloroperoxybenzoic acid under mild conditions. Single crystal X-ray crystallography of this compound revealed a five-membered bis-heterocyclic structure with two covalent bonds between the iodine atom and the nitrogen atoms. This novel benziodazole is a very stable compound with good solubility in common organic solvents. This compound can be used as an efficient reagent for oxidatively assisted coupling of carboxylic acids with alcohols or amines to afford the corresponding esters or amides in moderate yields.
- Jarvi, Melissa E.,Makitalo, Cody L.,Rohde, Gregory T.,Saito, Akio,Shea, Michael T.,Yoshimura, Akira,Yusubov, Mekhman S.,Zhdankin, Viktor V.
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supporting information
p. 1016 - 1020
(2020/05/06)
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- Aerobic oxidative esterification and thioesterification of aldehydes using dibromoisocyanuric acid under mild conditions: No metal catalysts required
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A practical direct method for the direct preparation of esters and thioesters from aldehydes is described. Esters and thioesters were synthesized by oxidative esterification and thioesterification via in situ generated acyl bromide intermediates, which were used to react with various alcohols and thiols. The esterification and thioesterification were readily performed in the presence of dibromoisocyanuric acid in dichloromethane, without any metal catalysts and under mild conditions. By using this reaction protocol, various esters and thioesters were prepared in high yields. This effective method offers a promising approach for the facile esterification and thioesterification of aldehydes.
- Kwon, Young-Do,La, Minh Thanh,Kim, Hee-Kwon
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p. 10833 - 10841
(2018/07/05)
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- Synthetic method of an ester compound
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The invention discloses a synthetic method of an ester compound and belongs to the technical field of organic synthesis. The synthetic method includes the steps of: dissolving an aldehyde compound (1) and a halogenated hydrocarbon compound (2) in a solvent, adding an oxidant and a catalyst, and performing a reaction at 60-100 DEG C to obtain the target product ester compound (3). A reaction equation of the synthetic method is represented as follows. The method, compared with the prior art, has the following advantages: 1) the raw materials are easy to obtain and are low in cost; 2) the reaction conditions are mild, operations are simple, and reaction time is short; and 3) a substrate has wide available range and can be used for synthesis of various ester compounds.
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Paragraph 0105; 0106; 0107
(2017/02/02)
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- The scope and mechanism of palladium-catalysed Markovnikov alkoxycarbonylation of alkenes
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Hydroesterification reactions represent a fundamental type of carbonylation reaction and constitute one of the most important industrial applications of homogeneous catalysis. Over the past 70 years, numerous catalyst systems have been developed that allow for highly linear-selective (anti-Markovnikov) reactions and are used in industry to produce linear carboxylates starting from olefins. In contrast, a general catalyst system for Markovnikov-selective alkoxycarbonylation of aliphatic olefins remains unknown. In this paper, we show that a specific palladium catalyst system consisting of PdX2/N-phenylpyrrole phosphine (X, halide) catalyses the alkoxycarbonylation of various alkenes to give the branched esters in high selectivity (branched selectivity up to 91%). The observed (and unexpected) selectivity has been rationalized by density functional theory computation that includes a dispersion correction.
- Li, Haoquan,Dong, Kaiwu,Jiao, Haijun,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
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p. 1159 - 1166
(2016/11/28)
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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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- Versatile and sustainable alcoholysis of amides by a reusable CeO 2 catalyst
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CeO2 catalyzed the esterification between an equivalent molar ratio of primary amides and alcohols under neutral conditions, which provides the first versatile reusable catalytic system for direct alcoholysis of amides to esters with wider scope and 67 times higher turnover number (TON) than previous catalytic systems.
- Siddiki, S. M. A. Hakim,Touchy, Abeda Sultana,Tamura, Masazumi,Shimizu, Ken-Ichi
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p. 35803 - 35807
(2014/11/07)
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- Aromatic cation activation: Nucleophilic substitution of alcohols and carboxylic acids
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A new method for the nucleophilic substitution of alcohols and carboxylic acids using aromatic tropylium cation activation has been developed. This article reports the use of chloro tropylium chloride for the rapid generation of alkyl halides and acyl chlorides under very mild reaction conditions. It demonstrates, for the first time, the synthetic potential of tropylium cations in promoting chemical transformations.
- Nguyen, Thanh V.,Bekensir, Alp
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supporting information
p. 1720 - 1723
(2014/04/17)
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- A basic germanodecatungstate with a - 7 charge: Efficient chemoselective acylation of primary alcohols
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The synthesis of highly negatively charged polyoxometalates with electrically and structurally controlled uniform basic sites can lead to the unique base catalysis. In this work, a γ-Keggin germanodecatungstate, [γ-HGeW10O36]7- (A), having a -7 charge was, for the first time, successfully synthesized by the reaction of [γ-H2GeW10O36]6- with one equivalent of [(n-C4H9)4N]OH under non-aqueous conditions. The activities of germanodecatungstates for base-catalyzed reactions dramatically increased with increase in the number negative charges from -6 to -7. In the presence of A, various combinations of acylating agents and primary alcohols including those with acid-sensitive functional groups chemoselectively gave the desired acylated products in high yields even under the stoichiometric conditions.
- Sugahara, Kosei,Satake, Naoto,Kamata, Keigo,Nakajima, Takahito,Mizuno, Noritaka
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supporting information
p. 13248 - 13252
(2015/01/09)
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- Palladium on charcoal as a catalyst for stoichiometric chemo- and stereoselective hydrosilylations and hydrogenations with triethylsilane
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Stoichiometric quantities of triethylsilane in the presence of activated Pd/C as the catalyst can be used to effect chemo-, regio-, and stereoselective hydrosilylation and transfer hydrogenation reactions. α,β-Unsaturated aldehydes and ketones are selectively hydrosilylated to give the corresponding enol silanes or transfer hydrogenated to give the saturated carbonyl compounds in the presence of other reducible functional groups.
- Tuokko, Sakari,Pihko, Petri M.
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p. 1740 - 1751
(2015/02/19)
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- Ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (o -NosylOXY): A recyclable coupling reagent for racemization-free synthesis of peptide, amide, hydroxamate, and ester
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Ubiquitousness of amide and ester functionality makes coupling reactions extremely important. Although numerous coupling reagents are available, methods of preparation of the common and efficient reagents are cumbersome. Those reagents generate a substantial amount of chemical waste and lack recyclability. Ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (o-NosylOXY), the first member of a new generation of coupling reagents, produces byproducts that can be easily recovered and reused for the synthesis of the same reagent, making the method more environmentally friendly and cost-effective. The synthesis of amides, hydroxamates, peptides, and esters using this reagent is described. The synthesis of the difficult sequences, for example, the islet amyloid polypeptide (22-27) fragment (with a C-terminal Gly, H-Asn-Phe-Gly-Ala-Ile-Leu-Gly-NH 2) and acyl carrier protein (65-74) fragment (H-Val-Gln-Ala-Ala-Ile- Asp-Tyr-Ile-Asn-Gly-OH), following the solid-phase peptide synthesis (SPPS) protocol and Amyloid β (39-42) peptide (Boc-Val-Val-IIe-Ala-OMe), following solution-phase strategy is demonstrated. Remarkable improvement is noticed with respect to reaction time, yield, and retention of stereochemistry. A mechanistic investigation and recyclability are also described.
- Dev, Dharm,Palakurthy, Nani Babu,Thalluri, Kishore,Chandra, Jyoti,Mandal, Bhubaneswar
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p. 5420 - 5431
(2014/07/08)
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- Aniline mediated oxidative C-C bond cleavage of α-alkoxy aldehydes in air and a model reaction for the synthesis of α-(d)-amino acid derivatives
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A metal-free and 4-methyl aniline mediated method for the oxidative C-C bond cleavage has been developed. The reaction proceeds in air using molecular oxygen as the oxidant, affording one-carbon shortened esters in moderate to good yields within a short time. Moreover, it provides a model reaction for the highly enantioselective synthesis of (d)-serine esters by combining with a l-proline catalyzed Mannich reaction.
- Hu, Bin,Li, Yunfeng,Li, Zhongjun,Meng, Xiangbao
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supporting information
p. 4138 - 4141
(2013/07/05)
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- Replacing conventional carbon nucleophiles with electrophiles: Nickel-catalyzed reductive alkylation of aryl bromides and chlorides
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A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (-OH, -NHTs, -OAc, -OTs, -OTf, -COMe, -NHBoc, -NHCbz, -CN, -SO2Me), and the reactions are assembled on the benchtop with no special precautions to exclude air or moisture. The reaction displays different chemoselectivity than conventional cross-coupling reactions, such as the Suzuki-Miyaura, Stille, and Hiyama-Denmark reactions. Substrates bearing both an electrophilic and nucleophilic carbon result in selective coupling at the electrophilic carbon (R-X) and no reaction at the nucleophilic carbon (R-[M]) for organoboron (-Bpin), organotin (-SnMe3), and organosilicon (-SiMe2OH) containing organic halides (X-R-[M]). A Hammett study showed a linear correlation of σ and σ(-) parameters with the relative rate of reaction of substituted aryl bromides with bromoalkanes. The small ρ values for these correlations (1.2-1.7) indicate that oxidative addition of the bromoarene is not the turnover-frequency determining step. The rate of reaction has a positive dependence on the concentration of alkyl bromide and catalyst, no dependence upon the amount of zinc (reducing agent), and an inverse dependence upon aryl halide concentration. These results and studies with an organic reductant (TDAE) argue against the intermediacy of organozinc reagents.
- Everson, Daniel A.,Jones, Brittany A.,Weix, Daniel J.
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supporting information; experimental part
p. 6146 - 6159
(2012/05/07)
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- Molecular recognition driven catalysis using polymeric nanoreactors
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The concept of using polymeric micelles to catalyze organic reactions in water is presented and compared to surfactant based micelles in the context of molecular recognition. We report for the first time enzyme-like specific catalysis by tethering the catalyst in the well-defined hydrophobic core of a polymeric micelle.
- Cotanda, Pepa,O'Reilly, Rachel K.
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supporting information
p. 10280 - 10282,3
(2020/09/09)
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- Conjugate reduction of α,β-unsaturated carbonyl and carboxyl compounds with poly(methylhydrosiloxane) catalyzed by a silica-supported compact phosphane-copper complex
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A silica-supported, cage-type, compact phosphane (Silica-SMAP) was used for the copper-catalyzed conjugate reduction of α,β-unsaturated carbonyl and carboxyl compounds with poly(methylhydrosiloxane) (PMHS). The heterogeneous catalyst system showed high activity and chemoselectivity, and was easily separable from the reaction mixture after the reaction. Furthermore, the catalyst was reusable without loss of its high catalytic activity or selectivity.
- Kawamorita, Soichiro,Yamazaki, Kenji,Ohmiya, Hirohisa,Iwai, Tomohiro,Sawamura, Masaya
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supporting information
p. 3440 - 3444
(2013/02/22)
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- Catalytic performance of acidic ionic liquid in esterification of benzyl alcohol with butyric acid
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Response surface methodology is successfully applied to optimize esterification of benzyl alcohol with butyric acid by an ionic liquid viz., [HSO3-pmim]HSO4. The effects of various reaction conditions, including reaction time, alcohol/acid molar ratio, the amount of water carrying agent and ionic liquid are investigated. A Box-Behnken experimental design has been employed to search for the optimal yield of benzyl butyrate. The analysis confirms that the relationship between the amount of water carrying agent and the amount of ionic liquid is the most significant parameters affecting the yield of benzyl butyrate. The coefficient of determination of this model is 0.9907. The optimum reaction conditions are established and verified experimental trial performed for validating the obtained results. Under the optimum conditions, the yield of benzyl butyrate reaches 99.4 %. The ionic liquid could be reused five times without noticeable drop in activity.
- Wu, Xiaodan,Han, Xiaoxiang,Zhou, Lingxiao,Li, Ang
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experimental part
p. 791 - 799
(2012/09/08)
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- The non-metathetic role of Grubbs' carbene complexes: From hydrogen-free reduction of α,β-unsaturated alkenes to solid-supported sequential cross-metathesis/reduction
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An efficient and high-yielding "hydrogen-free" reduction of α,β-unsaturated alkenes was carried out employing Grubbs' catalyst in a non-metathetic role and Et3SiH. Conditions were optimized under microwave irradiation. Application to the solid-phase organic synthesis allows a facile construction of sp3-sp3 carbon bonds through a sequential cross metathesis/olefin reduction.
- Poeylaut-Palena, Andres A.,Testero, Sebastian A.,Mata, Ernesto G.
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supporting information; experimental part
p. 1565 - 1567
(2011/03/20)
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- Practical preparation of esters and thioacetates from alkyl halides and carboxylates or thioacetate catalyzed by PEG400 without solvent
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Carboxylic esters and thioacetates were conveniently prepared in good to excellent yields under mild conditions by the reaction of alkyl halides with sodium carboxylates or sodium thioacetate catalyzed by PEG400 in the absence of solvents. Copyright Taylor & Francis Group, LLC.
- Cao, Yu-Qing,Wu, Guo-Qiang,Li, Ya-Bin,Dai, Zhi,Chen, Bao-Hua
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p. 3353 - 3358
(2007/10/03)
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- Transformation of primary benzyl amines to benzyl esters
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Primary benzyl amines, upon treatment with aq. NaNO2 and appropriate organic acids at 0-5°C, give their respective benzyl esters. Copyright Taylor & Francis, Inc.
- Naik, Ramesh,Pasha
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p. 2823 - 2826
(2007/10/03)
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- Efficient esterification of carboxylic acids with alkyl halides catalyzed by fluoride ions in ionic liquids
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Ionic liquids based on 1,3-dialkylimidazolinium methanesulfonate have been used as efficient reusable reaction media in the esterification of several carboxylic acids with alkyl halides catalyzed by fluoride ions. The method has wide applicability, and it is mild and green; it is useful for the protection of acids, via ester formation, for alkali labile molecules.
- Brinchi,Germani,Savelli
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p. 6583 - 6585
(2007/10/03)
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- Process for the preparation of carboxylic benzyl esters
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Carboxylic benzyl esters can be prepared by reacting benzyl chloride with carboxylic acids in the presence of one or more quaternary ammonium carboxylates as catalyst.
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- Ceric ammonium nitrate (CAN) - A useful catalyst for the rapid and high-yield esterification of carboxylic acids and alcohols with special reference to steroid and other multi-functional natural products
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Ceric ammonium nitrate (CAN) acts as a versatile catalyst for the esterification of carboxylic acids and alcohols, including steroids and other multi-functional natural products, in excellent yields under mild and convenient reaction conditions.
- Goswami,Chowdhury
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p. 955 - 957
(2007/10/03)
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- Oxidative Transformations of Aldazines and Ketazines with Organic Peroxyacids
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Oxidation of aromatic aldazines and ketazines with various peroxycarboxylic acids was investigated.It was found that one part of azine molecule 2 was converted into carbonyl compound 1 or related acid 3 while the second part was transformed into carboxylic ester 4 related to peroxyacid used as an oxidant.It was revealed that aromatic azines could be used as a source of diazaarylmethanes and mechanisms of reactions studied were postulated. aldazines, carboxylic esters, ketazines, oxidation, peroxycarboxylic acids
- Mlochowski, J.,Giurg, M.
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p. 2333 - 2342
(2007/10/02)
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- Microwave irradiation promoted reactions of carboxylic acids with halides in the presence of quarternary ammonium salt
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The reactions of carboxylic acids with halides which could not take place by conventional heating are promoted by microwave irradiation in the presence of quaternary ammonium salt as a catalyst, without a base.
- Yuan,Jiang,Gao
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p. 3109 - 3114
(2007/10/02)
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- Novel Template Effects of Distannoxane Catalysts in Highly Efficient Transesterification and Esterification
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The transesterification of carboxylic esters and the esterification of carboxylic acids are effected under mild conditions under catalysis by 1,3-disubstituted tetraalkyldistannoxanes 1.Various functional groups remain unaffected and otherwise difficult to obtain esters are accessible.An ester bearing a tertiary butyl group in the carboxylic acid moiety remained unchanged in competition experiments with a less bulky ester, which undergoes transesterification quantitatively.The unique features of the reactions are attributable to the template effects of the dimeric structure of 1.The facility with which compounds 1 can be converted into alkoxystannoxanes 2 and the synergistic effect of the proximate tin atoms of 2 play key roles in permitting smooth reactions and high selectivity.Another notable feature of compounds 1 is their unusually high solubility in organic solvents, even though the compounds have a metaloxane core as a major skeletal part.The double-layered structure of 1, in which the inorganic moiety is surrounded by eight alkyl groups, permits esterification to be driven to completion simply by heating a mixture of the carboxylic acid and the alcohol.The distannoxane-catalyzed esterification is irreversible, and thus, no hydrolysis of the product esters occurs when compounds 1 are used as catalysts.
- Otera, Junzo,Dan-oh, Nobushisa,Nozaki, Hitosi
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p. 5307 - 5311
(2007/10/02)
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- NEW OXIDATIVE ESTERIFICATION OF ALCOHOLS WITH ALDEHYDES BY THE Br2-HMPT-NaHCO3.
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A new aldehyde-mediated oxidative esterification using a bromine/HMPT complex in the presence of sodium hydrogen carbonate is described.
- Al Neirabeyeh, Mamdouh,Pujol, M. Dolors
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p. 2273 - 2276
(2007/10/02)
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