- Synthesis of amides and esters containing furan rings under microwave-assisted conditions
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In this work, we present a novel method for the synthesis of ester and amide derivatives containing furan rings (furfural derivatives) under mild synthetic conditions supported by microwave radiation. N-(Furan-2-ylmethyl)furan-2-carboxamide and furan-2-ylmethyl furan-2-carboxylate were produced using 2-furoic acid, furfurylamine, and furfuryl alcohol. The reactions were carried out in a microwave reactor in the presence of effective coupling reagents: DMT/NMM/TsO? or EDC. The reaction time, the solvent, and the amounts of the substrates were optimized. After crystallization or flash chromatography, the final compounds were isolated with good or very good yields. Our method allows for the synthesis of N-blocked amides using N-blocked amino acids (Boc, Cbz, Fmoc) and amine. As well as compounds with a monoamide and ester moiety, products with diamides and diester bonds (N,N-bis(furan-2-ylmethyl) furan-2,5-dicarboxamide, bis(furan-2-ylmethyl) furan-2,5dicarboxylate, and furan-3,4-diylbis(methylene) bis(furan-2-carboxylate)) were synthesized with moderate yields in the presence of DMT/NMM/TsO– or EDC, using 2,5-furan-dicarboxylic acid and 3,4-bis(hydroxymethyl)furan as substrates.
- Janczewski, ?ukasz,Zieliński, Dariusz,Kolesińska, Beata
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p. 265 - 280
(2021/03/17)
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- Sodium organoaluminate containing bidentate pyrrolyl ligand: Synthesis, structure, and catalytic activity for the Tishchenko reaction
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An novel sodium organoaluminate containing bidentate pyrrolyl ligand [C4H3NH(2-CH2NHtBu)] was efficiently synthesized and characterized by X-ray crystallography. The molecular structure shows it is a monodimensional infinite chain structures with linear arrangements. Its basic repeat unit comprises the Al atom bonded to two deprotonated pyrrole rings and Na atom coordinated to of nitrogen atoms of –NtBu fragment, which undergoes further to coordinates a pyrrolyl ring of an adjacent molecule in a ?2-fasion. Furthermore, this sodium organoaluminate exhibited high catalytic activities for Tishchenko reaction.
- Liu, Yu,Guo, Zhiqiang,Wang, Yakong
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- Base-Free and Acceptorless Dehydrogenation of Alcohols Catalyzed by an Iridium Complex Stabilized by a N, N, N-Osmaligand
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The preparation of a N,N,N-osmaligand, its coordination to iridium to afford an efficient catalyst precursor, and the catalytic activity of the latter in dehydrogenation reactions of hydrogen carriers based on alcohols are reported. Complex OsH2Cl2(PiPr3)2 (1) reacts with 3-(2-pyridyl)pyrazol to give the osmium(II) complex 2H, which contains an acidic hydrogen atom. Deprotonation of the latter by the bridging methoxy groups of the dimer [Ir(μ-OMe)(n4-COD)]2 (COD = 1,5-cyclooctadiene) leads to Ir(2)( n 4-COD) (3), where osmaligand 2 has a free-nitrogen atom. Iridium complex 3 catalyzes the dehydrogenation of secondary and primary alcohols to ketones and aldehydes or esters, respectively, and the dehydrogenation of diols to lactones. Cyclooctatriene is detected during the catalysis by GC-MS, suggesting that the true catalyst of the reactions is a dihydride IrH2(2)-species with osmaligand 2 acting as N,N,N-pincer. The presence of a phenyl group in the substrates favors the catalytic processes. The dehydrogenative homocoupling of primary alcohols to esters appears to take place via the transitory formation of hemiacetals.
- Alabau, Roberto G.,Esteruelas, Miguel A.,Martínez, Antonio,Oliván, Montserrat,O?ate, Enrique
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p. 2732 - 2740
(2018/09/10)
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- Synthesis, characterization and catalytic performances of benzimidazolin-2-iminato actinide (IV) complexes in the Tishchenko reactions for symmetrical and unsymmetrical esters
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A new family of benzimdazolin-2-iminato actinide?(IV) complexes [(Bim7-MeDipp/MeN)An(N(SiMe3)2)3] (An = U (3), Th (4)) and [(Bim4-MeDipp/MeN)An(N(SiMe3)2)3] (An = U (5), Th (6)) were synthesized and their solid state structures were established by single-crystal X-ray diffraction analysis. The catalytic performances of complexes 3–6 towards the homo- and cross-coupling of aldehydes (Tishchenko reaction) were studied and the thorium complexes 4 and 6 displayed moderate to high activities for the production of the corresponding symmetric and unsymmetrical esters. Coupling of aldehyde and alcohols, known as the tandem proton-transfer esterification, and the intermolecular coupling reaction between aldehyde and trifluoromethylketones were also investigated by these thorium complexes, indicating a complementary method to obtain unsymmetrical esters selectively. Plausible mechanisms for these reactions are proposed based on stoichiometric studies.
- Liu, Heng,Khononov, Maxim,Fridman, Natalia,Tamm, Matthias,Eisen, Moris S.
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p. 123 - 137
(2017/10/25)
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- Furoate cigarette spice, preparation method of furoate cigarette spice and application of furoate cigarette spice to cigarettes
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The invention belongs to the technical field of cigarette spice, and particularly relates to furoate cigarette spice, a preparation method of the furoate cigarette spice and application of the furoatecigarette spice to cigarettes. The cigarette spice uses furoic acid as raw materials, and another alcohol containing spice ingredients as ligands; through N,N'-carbonyl di-imidazole activation to synthesize the novel furoate sweet aroma compound; the compound has a simple structure; the synthesis method is simple; the burning smoking process thermal cracking study is performed on the compound; furan ingredients and other substances with unique fragrance features can be obtained through cracking. When the compound is applied to tobacco flavoring, the smoke gas richness can be enhanced; the smoke gas mouthfeel can be coordinated; the miscellaneous qi is reduced; the irritation is reduced; the aftertaste is improved; meanwhile, the mouthfeel such as sweet aroma and fruit aroma can also be obtained during the cigarette smoking evaluation through the spice addition; the smoking quality is improved.
- -
-
Paragraph 0026; 0030-0032; 0043-0046
(2021/03/25)
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- Rhodium-catalyzed synthesis of imines and esters from benzyl alcohols and nitroarenes: Change in catalyst reactivity depending on the presence or absence of the phosphine ligand
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The [Rh(COD)Cl]2/xantphos/Cs2CO3 system efficiently catalyzes the reductive N-alkylation of aryl nitro compounds with alcohols by a borrowing-hydrogen strategy to afford the corresponding imine products in good to excellent yields. In the absence of xantphos, the [Rh(COD)Cl]2/Cs2CO3 catalytic system behaves as an effective catalyst for the dehydrogenative coupling of alcohols to esters, with nitrobenzene as a hydrogen acceptor. The reactivity of the rhodium catalytic system can be easily manipulated to selectively afford the imine or ester.
- Song, Taemoon,Park, Ji Eun,Chung, Young Keun
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p. 4197 - 4203
(2018/04/14)
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- Thorium complexes possessing expanded ring N-heterocyclic iminato ligands: Synthesis and applications
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Six and seven membered N-heterocyclic iminato ligands (L) are introduced allowing access a new class of Th(iv) complexes of the type Cp?2Th(L)(CH3). These complexes were studied in the Tishchenko reaction. Stoichiometric reactions together with kinetic and thermodynamic studies permit us to propose a plausible mechanism.
- Ghatak, Tapas,Drucker, Shani,Fridman, Natalia,Eisen, Moris S.
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supporting information
p. 12005 - 12009
(2017/09/25)
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- Nitrous Oxide as a Hydrogen Acceptor for the Dehydrogenative Coupling of Alcohols
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The oxidation of alcohols with N2O as the hydrogen acceptor was achieved with low catalyst loadings of a rhodium complex that features a cooperative bis(olefin)amido ligand under mild conditions. Two different methods enable the formation of either the corresponding carboxylic acid or the ester. N2 and water are the only by-products. Mechanistic studies supported by DFT calculations suggest that the oxygen atom of N2O is transferred to the metal center by insertion into the Rh-H bond of a rhodium amino hydride species, generating a rhodium hydroxy complex as a key intermediate.
- Gianetti, Thomas L.,Annen, Samuel P.,Santiso-Quinones, Gustavo,Reiher, Markus,Driess, Matthias,Grützmacher, Hansj?rg
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supporting information
p. 1854 - 1858
(2016/02/03)
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- The promoted Tishchenko reaction and catalytic intermediate by 2-aminopyrrolyl dilithium compounds
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The dimerization of aldehydes to the analogous carboxylic esters (Tischenko reaction) has been achieved in impressive yields using the dilithium compounds containing bidentate di-anionic pyrrolyl ligands as initiators. The initiated intermediate {[2-(tBuNCH)C4H3NLi][PhCH2OLi(TMEDA)]}2 was isolated and characterized by satisfactory C, H and N microanalysis, 1H, 13C{1H} and 7Li NMR spectra in pyridine-d5 at ambient temperature, and single crystal X-ray structural data. The processes involve a redox reaction of 2-aminopyrrolyl dilithium compound with aldehyde.
- Guo, Zhiqiang,Wei, Xuehong,Tong, Hongbo,Chao, Jianbin,Liu, Diansheng
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supporting information
p. 73 - 76
(2015/03/14)
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- Mixed Imidazolin-2-iminato-Cp? Thorium(IV) Complexes: Synthesis and Reactivity Toward Oxygen-Containing Substrates
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The mixed pentamethylcyclopentadienyl thorium(IV) imidazolin-2-iminato complexes Cp?2Th(ImDippN)(Me) (2) and Cp?2Th(ImMesN)(Me) (3) were synthesized in quantitative yields via rapid protonolysis of Cp?2Th(Me)2 (1) with the respective neutral imidazolin-2-iminato ligand ImRNH. Cp?2Th(ImDippN)(Me) (2) and Cp?2Th(ImMesN)(Me) (3) display short Th-N bond lengths and large Th-N-C angles. The reactivity of complex 2 and 3 toward oxygen-containing substrates was studied, and the catalytic activity of 2 was compared to the dimethyl (bispentamethyl-cyclopentadienyl) thorium complex 1. Complex 2 was applied in the catalytic Tishchenko reaction with aromatic, heteroaromatic, and branched aliphatic aldehydes, displaying a higher catalytic activity than Cp?2Th(Me)2 and Cp?2Th(ImMesN)(Me). Furthermore, 2 was applied as a catalyst in the crossed Tishchenko reaction and in the oligomerization of bis(aldehydes), as well as in the ring-opening polymerization of ε-caprolactone. In all reactions, the activity of Cp?2Th(ImDippN)(Me) (2) and Cp?2Th(ImMesN)(Me) (3) was higher than that observed for Cp?2Th(Me)2 (1), which can be attributed to the increased electron density introduced by the coordination of the imidazolin-2-iminato ligand. (Chemical Equation Presented).
- Karmel, Isabell S. R.,Fridman, Natalia,Tamm, Matthias,Eisen, Moris S.
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supporting information
p. 2933 - 2942
(2015/06/30)
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- Alkali metal tert-butoxides, hydrides and bis(trimethylsilyl)amides as efficient homogeneous catalysts for Claisen-Tishchenko reaction
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Shelf-available alkali metal tert-butoxides, hydrides and bis(trimethylsilyl)amides were shown to be highly efficient homogeneous precatalysts for the disproportionation of aldehydes to the corresponding carboxylic esters. Potassium compounds in combination with 18-crown-6 ether could drastically increase the rate of reaction in a few cases. Alternatively, efficient aldol condensations were found for aldehydes possessing an enolizable methylene group at the α-position to the aldehyde functionality. The active species involved in this esterification using any of these alkali metal catalysts is expected to be the metal alkoxide. Potassium compounds were found to be much more efficient when compared to analogous sodium compounds and kinetic studies revealed the rate-determining step to be a second order concerted hydride transfer from a potassium hemiacetal species to another molecule of aldehyde. Copyright
- Rajesh, Kunjanpillai,Berke, Heinz
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supporting information
p. 901 - 906
(2013/05/08)
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- Synthesis, structures, and reactivities of guanidinatozinc complexes and their catalytic behavior in the Tishchenko reaction
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Treatment of a secondary amine (pipH, Bz2NH, Et2NH) with sequentially diethylzinc and N,N′-dicyclohexylcarbodiimide in hexane has afforded in good yield the new crystalline guanidinatozinc complexes. Each has been X-ray and solution NMR spectrally characterized. Three are dimeric (mono)guandinatozinc alkyls, two are dinuclear (tris)guanidinatozinc amides, and one is a homoleptic zinc bis(guanidinate). The reactions of dinuclear (tris)guanidinatozinc amides with diethylzinc and N,N′- dicyclohexylcarbodiimide in the molar ratios of 1:2:1 led to the dimeric (mono)guandinatozinc alkyls; homoleptic zinc bis(guanidinate) with an equimolar portion of diethylzinc also yielded dimeric (mono)guandinatozinc alkyls. Each of the complexes exhibited good to excellent catalytic activity for the solvent-free Tishchenko reaction under mild conditions.
- Li, Jie,Shi, Jingchao,Han, Hongfei,Guo, Zhiqiang,Tong, Hongbo,Wei, Xuehong,Liu, Diansheng,Lappert, Michael F.
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p. 3721 - 3727
(2013/07/26)
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- Solvent-controlled copper-catalyzed oxidation of benzylic alcohols to aldehydes and esters
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A procedure for the copper-catalyzed selective oxidation of primary alcohols to esters and aldehydes was developed. Under solvent-free conditions, self-oxidative esterification and cross-esterification of benzyl alcohols with various aliphatic alcohols proceed smoothly to give the corresponding esters in good yields. If DMF was used as a solvent, the benzyl alcohols were selectively converted into the corresponding aldehydes in excellent yields. Depend on solvent! Under solvent-free conditions, Cu-catalyzed oxidative self-esterification and cross-esterification of benzylic alcohols with various aliphatic alcohols proceed smoothly to give the corresponding esters in good yields. If DMF is used as a solvent, the benzylic alcohols are selectively converted into the corresponding aldehydes in excellent yields. DTBP = di-tert-butyl peroxide. Copyright
- Zhu, Yefeng,Wei, Yunyang
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supporting information
p. 4503 - 4508
(2013/07/26)
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- Selenide ions as catalysts for homo- and crossed-Tishchenko reactions of expanded scope
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Selenide ions have been shown to catalyze the Tishchenko reaction for the first time. These catalysts are superior to previously reported thiolate analogues and promote the disproportionation of aldehydes with increased reaction rates and broader scope at lower catalyst loadings and temperatures. Significantly improved catalyst performance was also observed in the aryl selenide mediated crossed intermolecular Tishchenko reaction.
- Curran, Simon P.,Connon, Stephen J.
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supporting information; experimental part
p. 1074 - 1077
(2012/03/27)
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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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- Organoactinides promote the dimerization of aldehydes: Scope, kinetics, thermodynamics, and calculation studies
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Surprising catalytic activities have been found for the actinide complexes Cp*2ThMe2 (1), Th(NEtMe)4 (2), and Me2SiCp″2Th(C4H9) 2(3) toward oxygenated substrates. During the catalytic dimerization of benzaldehydes to their corresponding esters, complexes 1 and 2 gave 65 and 85% yield in 48 h, respectively, while the geometry-constrained complex 3 gave 96% yield in 24 h. Exploring the effect of substituents on benzaldehyde, it has been found that, in general, electron-withdrawing groups facilitate the reaction. Kinetic study with complexes 1 and 3 reveals that the rate of the reaction is first order in catalyst and substrate, which suggests the rate equation "rate = k[catalyst]1[aldehyde]1". The activation energy of the reaction was found to be 7.16 ± 0.40 and 3.47 ± 0.40 kcal/mol for complexes 1 and 3 respectively, which clearly indicates the advantage of the geometry-constrained complex. Astonishing are the reactivity of the organoactinide complexes with oxygen-containing substrates, and especially the reactivity of complex 3, toward the dimerization of substrates like p-methoxybenzaldehyde, m/p-nitrobenzaldehyde, and furanaldehyde and the reactivity toward the polymerization of terephthalaldehyde. Density functional theory mechanistic study reveals that the catalytic cycle proceeds via an initially four-centered transition state (+6 kcal/mol), followed by the rate-determining six-centered transition state (+13.5 kcal/mol), to yield thermodynamically stable products.
- Sharma, Manab,Andrea, Tamer,Brookes, Nigel J.,Yates, Brian F.,Eisen, Moris S.
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experimental part
p. 1341 - 1356
(2011/04/16)
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- Rare-earth metal allyl and hydrido complexes supported by an (NNNN)-type macrocyclic ligand: Synthesis, structure, and reactivity toward biomass-derived furanics
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The preparation and characterization of a series of neutral rare-earth metal complexes [Ln(Me3TACD)(η3-C3H 5)2] (Ln=Y, La, Ce, Pr, Nd, Sm) supported by the 1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane anion (Me3TACD -) are reported. Upon treatment of the neutral allyl complexes [Ln(Me3TACD)(η3-C3H5) 2] with Bronsted acids, monocationic allyl complexes [Ln(Me3TACD)(η3-C3H5)(thf) 2][B(C6X5)4] (Ln=La, Ce, Nd, X=H, F) were isolated and characterized. Hydrogenolysis gave the hydride complexes [Ln(Me3TACD)H2]n (Ln=Y, n=3; La, n=4; Sm). X-ray crystallography showed the lanthanum hydride to be tetranuclear. Reactivity studies of [Ln(Me3TACD)R2]n (R=η3-C3H5, n=0; R=H, n=3,4) towards furan derivatives includes hydrosilylation and deoxygenation under ring-opening conditions.
- Abinet, Elise,Martin, Daniel,Standfuss, Sabine,Kulinna, Heiko,Spaniol, Thomas P.,Okuda, Jun
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experimental part
p. 15014 - 15026
(2012/02/06)
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- General and selective palladium-catalyzed oxidative esterification of alcohols
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Selectively esterified: Primary alcohols react with dioxygen as a benign oxidant in a palladium-catalyzed oxidative esterification (see scheme). The corresponding aldehydes and esters are formed highly selectively depending on the catalyst system. The reactions take place in the presence of commercially available ligands without the need for additional organic hydrogen acceptors. Copyright
- Gowrisankar, Saravanan,Neumann, Helfried,Beller, Matthias
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supporting information; experimental part
p. 5139 - 5143
(2011/06/25)
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- Sodium hydride catalyzed Tishchenko reaction
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A convenient and practical method for the dimerization of aldehydes is described. The conversion of aromatic and even heteroaromatic aldehydes in the presence of catalytic amounts of sodium hydride leads to the corresponding Tishchenko esters in high yields (up to 95 %). The reaction can be performed under standard laboratory conditions and on a multigram scale (up to 10 g). The use of catalytic amounts of sodiumhydride as an efficient promoter for the dimerization of aromatic and even heteroaromatic aldehydes under standard laboratory conditions is reported. A range of substituted aromatic and heteroaromatic aldehydes was converted, and the corresponding esters were obtained in good to excellent yields even on a multigram scale. Copyright
- Werner, Thomas,Koch, Juliane
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supporting information; experimental part
p. 6904 - 6907
(2011/02/23)
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- Nickel-catalyzed Tishchenko reaction via hetero-nickelacycles by oxidative cyclization of aldehydes with nickel(0) complex
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A Ni(0)-catalyzed Tishchenko reaction which can be applied to a variety of aliphatic aldehydes (1°, 2°, 3°) and aromatic aldehydes was developed. The reaction might proceed via a hetero-nickelacycle intermediate.
- Ogoshi, Sensuke,Hoshimoto, Yoichi,Ohashi, Masato
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supporting information; experimental part
p. 3354 - 3356
(2010/07/14)
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- An in situ generated ruthenium catalyst for the Tishchenko reaction
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A simple and efficient catalytic system for the selective dimerization of aldehydes, the Tishchenko reaction, is described. High yields of symmetrical esters were generally achieved using an in situ generated ruthenium catalyst in association with the electron-rich and hindered cyclohexyl-(diphenyl)phosphane (CyPPh2) ligand.
- Simon, Marc-Olivier,Darses, Sylvain
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supporting information; experimental part
p. 305 - 308
(2010/06/11)
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- An environmentally benign solvent-free Tishchenko reaction
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Herein, we describe the solvent-free ball milling Tishchenko reaction. Using high speed ball milling and a sodium hydride catalyst, the Tishchenko reaction was performed for aryl aldehydes in high yields in 0.5 hours. The reaction is not affected by the type of ball bearing used and can be successful when conducted in a liquid nitrogen environment.
- Waddell, Daniel C.,Mack, James
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experimental part
p. 79 - 82
(2010/04/22)
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- Lanthanide formamidinates as improved catalysts for the Tishchenko reaction
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The tris(formamidinato)lanthanum(III) complexes [La(o-TolForm) 3(thf)2] [1; o-TolForm = N,N′-bis(o-tolyl) formamidin-ate], [La(XylForm)3(thf)] [2; XylForm = N,N′-bis(2,6-dimethylphenyl)formamidinate], and [La(EtForm)3] [3, EtForm = N,N′-bis(2,6-diethylphenyl)formamidinate] are a new class of precatalysts for the Tishchenko reaction. Their catalytic activity is a result of their high Lewis acidity and the ease with which the ligand spheres can be interchanged. For the dimerization of benzaldehyde to give benzyl benzoate, which is a benchmark reaction, compound 1 is, to the best of our knowledge, the most active catalyst ever reported. On a preparative scale, the reaction can be performed in the absence of solvent. A range of aromatic, heteroaromatic, and aliphatic aldehydes was rapidly converted into the corresponding esters by using catalysts 1-3. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Zuyls, Agustino,Roesky, Peter W.,Deacon, Glen B.,Konstas, Kristina,Junk, Peter C.
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p. 693 - 697
(2008/09/17)
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- Modification of mesoporous silicate SBA-15 with tris[bis(trimethylsilyl) amido]samarium and its utility in Tishchenko reaction
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Treatment of mesoporous silicate SBA-15 with Sm[N(SiMe3) 2]3 led to the formation of a novel organolanthanide/ inorganic hybrid material [SBA-15]Sm[N(SiMe3)2] x via abstraction of N(SiMe3)2 by terminal silanol groups and subsequent surface silylation. The hybrid material was characterized by elemental analyses, IR spectroscopy, X-ray diffraction, and nitrogen sorption, indicating a successful tailoring inside the silicate SBA-15 and the maintenance of the well-ordered mesostructure. This hybrid material is a promising heterogeneous catalyst for the Tishchenko reaction, where it is superior to the homogeneous correspondent in deactivation behavior, reusability and relative tolerance to oxygen, particularly in the control of selectivity of mixed Tishchenko reaction due to the steric hindrance and the diffusion control derived from the surface confinement.
- Chen, Yinghua,Zhu, Zhenyu,Zhang, Jie,Shen, Jianzhong,Zhou, Xigeng
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p. 3783 - 3789
(2007/10/03)
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- Homoleptic lanthanide amides as homogeneous catalysts for alkyne hydroamination and the Tishchenko reaction
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The homoleptic bis(trimethylsilyl)amides of Group 3 metals and lanthanides of the general type [Ln{N(SiMe3)2}3] (1) (Ln = Y, lanthanide) represent a new class of Tishchenko precatalysts and, to a limited extent, precatalysts for the hydroamination/cyclization of aminoalkynes. It is shown that 1 is the most active catalyst for the Tishchenko reaction. This contribution presents investigations on the scope of the reaction, substrate selectivity, lanthanide-ion size-effect, and kinetic/ mechanistic aspects of the Tishchenko reaction catalyzed by 1. The turnover frequency is increased by the use of large-center metals and electron-with-drawing substrates. The reaction rate is second order with respect to the substrate. While donor atoms, such as nitrogen, oxygen, or sulfur, on the substrate decrease the turnover frequency, 1 shows a tolerance for a large number of functional groups. For the hydroamination/cyclization of aminoalkynes, 1 is less active than the well-known metallocene catalysts. On the other hand, 1 is much more readily accessible (one-step synthesis or commercially available), than the metallocenes and might therefore be an attractive alternative catalyst.
- Buergstein, Markus R.,Berberich, Helga,Roesky, Peter W.
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p. 3078 - 3085
(2007/10/03)
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- Calcium oxide and strontium oxide as environmentally benign and highly efficient heterogeneous catalysts for the tishchenko reaction of furfural
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CaO and SrO exhibit high activities for the challenging Tishchenko reaction of furfural.
- Seki,Akutsu,Hattori
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p. 1000 - 1001
(2007/10/03)
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- Homoleptic lanthanide amides as homogeneous catalyst for the Tishchenko reaction
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Known for about 25 years, the bis(trimethylsilyl)amides of Group 3 metals and lanthanides, M[N(SiMe3)2]3, are well suited as highly efficient catalysts for the dimerization of aldehydes [Tishchenko reaction, Eq. (1)].
- Berberich, Helga,Roesky, Peter W.
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p. 1569 - 1571
(2007/10/03)
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- Lanthanoid-catalysed Tishchenko reaction of mono- or di-aldehydes
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Lanthanoid complexes are found to be very active catalysts for the Tishchenko reaction of aldehydes. In the presence of Cp*2LnCH(SiMe3)2 (Ln = Nd, La), esters are obtained from corresponding monoaldehydes in high yields. This method is applicable to dialdehydes. The reaction of o-phthalaldehyde proceeds intramolecularly to give phthalide quantitatively. Terephthalaldehyde and di(4-formylphenyl) ether are cleanly converted into the poly[p-(carboxymethylene)phenylene] (II) and poly[p-(carboxymethylene)(p-phenylenoxy)phenylene] (III), respectively. On the other hand, isophthalaldehyde polymerizes first and then the polymer is transformed into a macrocyclic lactone 1,5,11-trioxo-2,4;8,10;14,16-tribenzo-6,12,18-trioxacyclooctadecane (1-a) in high yields. The 18-membered macrocyclic structure of 1-a was determined by the X-ray analysis. Stoichiometric reactions of the La complex with benzaldehyde indicated the intermediacy of alkoxo complexes in the catalysis.
- Onozawa, Shun-Ya,Sakakura, Toshiyasu,Tanaka, Masato,Shiro, Motoo
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p. 4291 - 4302
(2007/10/03)
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- Lanthanoid-Catalyzed Aldehyde Dimerization and Its Application to Polyester Synthesis
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A wide variety of aldehydes are efficiently dimerized to esters by a catalytic amount of (C5Me5)2LnCH(SiMe3)2 (Ln=Nd, La).The reaction is applicable to the synthesis of polyesters from dialdehydes.A stoichiometric reaction of the lanthanum complex with benzaldehyde indicates the intermediacy of alkoxo complexes in the catalysis.
- Onozawa, Shun-ya,Sakakura, Toshiyasu,Tanaka, Masato
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p. 531 - 534
(2007/10/02)
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- Homogeneous Metal-Catalyzed Sequential Rosenmund-Tishchenko Reactions
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Esters can be isolated in good yields by the reaction of acid chlorides with hydrogen in the presence of 2,4,6-collidine and catalytic quantities of either (Ph3P)3Ru(H)Cl or (Ph3P)RuCl2 in toluene.Acrylruthenium hydrides are possible reaction intermediates.
- Grushin, Vladimir V.,Alper, Howard
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p. 5159 - 5161
(2007/10/02)
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- Reaction of Aromatic Aldehydes with Alkali Metals: Formation of Arylmethyl Aroates
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An efficient preparative procedure for arylmethyl aroates from araldehyde using catalytic quantities of alkali metals in nonpolar solvents is reported.The Tischenko reaction, at least under these conditions, appears to proceed via an electron-transfer mechanism.
- Pasha, M. A.,Ravindranath, B.
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p. 1068 - 1069
(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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