- Kinetics and mechanism of styrene hydrocarboalkoxylation catalyzed by Pd° complex in the presence of toluenesulfonic acid
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The kinetics of the catalytic reaction of styrene with CO and n-butanol in the Pd(dba)2 - TsOH - Ph3P system in dioxane (383 K) was studied. The initial rates of accumulation of regioisomeric products (butyl 2-and 3-phenylpropionates) were measured as functions of the CO pressure, reactant concentrations, and the catalytic system components. A kinetic model of the process and a hydride mechanism with the HPd(Ph3P)3+ cationic complex acting as a key intermediate were proposed.
- Noskov,Petrov
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Read Online
- Convenient synthesis of poly(butylene succinate) catalyzed by distannoxane
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A convenient method for the synthesis of poly(butylene succinate) (1) of high molecular weight has been developed. This polyester was prepared readily by the distannoxane-catalyzed polycondensation of succinic acid (2) with 1,4-butanediol (3) in decalin a
- Takahashi, Hiroyuki,Hayakawa, Teruaki,Ueda, Mitsuru
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Read Online
- Selective Reduction of Carboxylic Acids to Alcohols in the Presence of Alcohols by a Dual Bulky Transition-Metal Complex/Lewis Acid Catalyst
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Here, we report a molecular method for the generally applicable reduction of mono-and dicarboxylic acids that selectively furnishes a diverse variety of alcohols, including mono-and diols. One of the inherent drawbacks of the direct hydrogenation of carboxylic acids to alcohols is the in situ formation of the corresponding esters via condensation of the carboxylic acids with the produced alcohols. Especially, the hydrogenation of polycarboxylic acids frequently suffers from the formation of a complex mixture of oligomeric esters. This issue was successfully overcome by the combined use of a dual catalyst that consists of a bulky (PNNP)iridium complex and a Lewis acid. Owing to the steric bulk and robustness of the iridium catalyst, the main role of the Lewis acid is to independently catalyze the esterification, albeit the cooperative activation of (a resting state of) the iridium catalyst by the Lewis acid also seems to be implied.
- Gr?mer, Bendik,Saito, Susumu,Yoshioka, Shota
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p. 1957 - 1964
(2022/02/10)
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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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supporting information
p. 4588 - 4598
(2020/12/25)
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- C-C Bond Cleavage of Unactivated 2-Acylimidazoles
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2-Acylimidazoles are widely used as post-Transformable carboxylic acid equivalents in chemoselective and enantioselective reactions. Their transformations, however, require pretreatment with highly reactive, toxic methylating reagents to facilitate C-C bond cleavage. Here, we demonstrate that such pretreatment can be avoided and the C-C bond cleaved under neutral conditions without the use of additional reagents or catalysts. The scope of the reaction, including the use of products reported in the literature as substrates, and some mechanistic insights are described.
- Xin, Hai-Long,Pang, Bo,Choi, Jeesoo,Akkad, Walaa,Morimoto, Hiroyuki,Ohshima, Takashi
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p. 11592 - 11606
(2020/10/23)
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- Pentamethylphenyl (Ph*) and Related Derivatives as Useful Acyl Protecting Groups for Organic Synthesis: A Preliminary Study
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A study of acyl protecting groups derived from the Ph? motif is reported. While initial studies indicated that a variety of functional groups were not compatible with the Br 2-mediated cleavage conditions required to release the Ph? group, strategies involving the use of different reagents or a modification of Ph? itself (Ph*OH) were investigated to solve this problem.
- Cheong, Choon Boon,Frost, James R.,Donohoe, Timothy J.
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p. 1828 - 1832
(2020/10/06)
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- Esterification of Tertiary Amides: Remarkable Additive Effects of Potassium Alkoxides for Generating Hetero Manganese–Potassium Dinuclear Active Species
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A catalyst system of mononuclear manganese precursor 3 combined with potassium alkoxide served as a superior catalyst compared with our previously reported manganese homodinuclear catalyst 2 a for esterification of not only tertiary aryl amides, but also tertiary aliphatic amides. On the basis of stoichiometric reactions of 3 and potassium alkoxide salt, kinetic studies, and density functional theory (DFT) calculations, we clarified a plausible reaction mechanism in which in situ generated manganese–potassium heterodinuclear species cooperatively activates the carbonyl moiety of the amide and the OH moiety of the alcohols. We also revealed details of the reaction mechanism of our previous manganese homodinuclear system 2 a, and we found that the activation free energy (ΔG≠) for the manganese–potassium heterodinuclear complex catalyzed esterification of amides is lower than that for the manganese homodinuclear system, which was consistent with the experimental results. We further applied our catalyst system to deprotect the acetyl moiety of primary and secondary amines.
- Akiyama, Shoko,Himo, Fahmi,Hirai, Takahiro,Katayama, Shoichiro,Kato, Daiki,Mai, Binh Khanh,Mashima, Kazushi,Nagae, Haruki
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- Imidazolium Based Fluorous N-Heterocyclic Carbenes as Effective and Recyclable Organocatalysts for Redox Esterification
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A series of new highly fluorophilic ionic liquids (f > 110) was synthetized from 3-iodopropyltris(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)silane and N-alkyl imidazoles, followed by anion exchange. N-heterocyclic carbenes generated in situ from obtained imidazolium salts were employed to catalyze redox esterification (umpolung) of cinnamaldehyde with alcohols. The most effective N-methyl derivative with iodide as a counter anion was studied in detail with respect to the optimization of reaction conditions, substrate scope and recyclability. Recovery of the precatalyst was achieved using either fluorous extraction or performing the reaction in suitable fluorous biphase system with direct recycling of the fluorinated precatalyst phase. For both tested options, the catalytic activity did not significantly decrease within 5 subsequent cycles. The redox esterification was shown to proceed also in supercritical carbon dioxide (scCO2) as an alternative solvent where the activity of the fluorinated catalyst was also superior to the nonfluorinated model, while retaining the benefit of easy recycling.
- ?ervenková ??astná, Lucie,Bílková, Veronika,Cézová, Tereza,Cu?ínová, Petra,Karban, Jind?ich,?ermák, Jan,Krupková, Alena,Stra?ák, Tomá?
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p. 3591 - 3598
(2020/06/17)
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- Ionic liquid catalytic synthesis of styrene-acrylic acid ester derivative of the method (by machine translation)
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The invention provides an ionic liquid catalytic synthesis of styrene-acrylic acid ester derivative of the method, the method adopts the imidazole ionic liquid as catalyst, in order to cinnamic aldehyde or its derivatives and nandrolone or testosterone alcohol or phenol derivatives as raw materials, without any additional acid and alkali, one-step reaction, to obtain the styrene-acrylic acid ester derivative. Compared with the prior art, the maximum of this invention is characterized in that the raw materials are all simple and easy to obtain, security and stability of the compound, the reaction time is short, after the reaction by simple extraction, concentration or crystallization can be obtained pure product, at the same time can also be realized in the use of the recycling of the catalyst, catalyst recycled is very convenient and almost no "wastes" problem. The invention it has less catalyst levels, the reaction selectivity is high, and the yield is high, the operation is simple, pollution is small, green high degree of several advantages; in the setting under the reaction conditions, the conversion of raw materials and the yield of the product are as high as 90% or more. (by machine translation)
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Paragraph 0030
(2019/05/08)
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- Dinuclear manganese alkoxide complexes as catalysts for C-N bond cleavage of simple tertiary: N, N -dialkylamides to give esters
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Amide bonds are stable due to the resonance between the nitrogen lone pair and the carbonyl moiety, and therefore the chemical transformation of amides, especially tertiary amides, involving C-N bond fission is considered one of the most difficult organic reactions, unavoidably requiring harsh reaction conditions and strong acids or bases. We report the catalytic C-N bond cleavage of simple tertiary N,N-dialkylamides to give corresponding esters using a catalyst system (2 mol% based on Mn atoms) of a tetranuclear manganese alkoxide, [Mn(acac)(OEt)(EtOH)]4 (1c), combined with four equivalents of 4,7-bis(dimethylamino)-1,10-phenanthroline (L1: Me2N-Phen). Regarding the reaction mechanism, we isolated a dinuclear manganese complex, [Mn(acac)(OEt)(Phen)]2 (6c), which was revealed as the catalytically active species for the esterification of tertiary amides.
- Nagae, Haruki,Hirai, Takahiro,Kato, Daiki,Soma, Shusei,Akebi, Shin-Ya,Mashima, Kazushi
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p. 2860 - 2868
(2019/03/13)
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- A Straightforward Conversion of Activated Amides and Haloalkanes into Esters under Transition-Metal-Free Cs 2 CO 3 /DMAP Conditions
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The esterification of activated amides, N -acylsaccharins, under transition-metal-free conditions with good functional group tolerance has been developed, resulting in C-N cleavage leading to efficient synthesis of a variety of esters in moderate to good yields. This work demonstrates that esterification may proceed by using simple N -acylsaccharins, haloalkanes, and Cs 2 CO 3 as oxygen source.
- Chen, Liuqing,Gu, Ying,Jian, Junsheng,Liu, Yueping,Miao, Liqiong,Wang, Zijia,Zeng, Zhuo
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p. 4078 - 4084
(2019/10/28)
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- Direct Catalytic Alcoholysis of Unactivated 8-Aminoquinoline Amides
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Direct catalytic alcoholysis of unactivated amides is one of the most difficult challenges in organic chemistry, and an applicable method for cleaving amides used as directing groups in regioselective functionalization reactions has not been reported. Herein, we report direct catalytic alcoholysis of 8-aminoquinoline amides, which are highly effective directing groups in regioselective functionalization reactions. The reactions proceeded with a simple combination of substrates, air-stable catalysts, and alcohols, affording the corresponding esters in good yields with broad functional group tolerance. Highly chemoselective cleavage of the 8-aminoquinoline amides in the presence of related carbonyl functionalities and preliminary mechanistic studies are also described.
- Deguchi, Toru,Xin, Hai-Long,Morimoto, Hiroyuki,Ohshima, Takashi
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p. 3157 - 3161
(2017/06/09)
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- A simple route to 1,4-addition reactions by Co-catalyzed reductive coupling of organic tosylates and triflates with activated alkenes
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An efficient Co-catalyzed 1,4-addition reaction of alkyl/aryl triflates and tosylates with activated alkenes is described. In this reaction, an air-stable cobalt(ii) complex, a mild reducing agent Zn and a simple proton source (H2O) are used. A radical mechanism for the addition of alkyl tosylates to activated alkenes is likely involved.
- Hsieh, Jen-Chieh,Chu, Yi-Hua,Muralirajan, Krishnamoorthy,Cheng, Chien-Hong
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p. 11584 - 11587
(2017/10/27)
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- Simple Zn(II) Salts as Efficient Catalysts for the Homogeneous Trans-Esterification of Methyl Esters
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Abstract: This study aimed to optimize the zinc-catalyzed trans-esterification, and pointed to assess the effect of the solvent, the catalyst, its loading and the nature of the substrate. The screening disclosed the remarkable ability of zinc(II) acetate to promote the reaction in refluxing toluene at low catalyst loading. A significant improvement ensued with respect to recently results on the same reactions, in terms of less restrictive conditions and more convenient catalyst precursors. Graphical Abstract: [Figure not available: see fulltext.]
- Cucciolito, Maria E.,Lega, Matteo,Papa, Veronica,Ruffo, Francesco
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p. 1113 - 1117
(2016/06/01)
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- Ligand-free nickel-catalysed 1,4-addition of arylboronic acids to α,β-unsaturated carbonyl compounds
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A simple and efficient ligand-free nickel-based catalytic system has been developed for the 1,4-addition of arylboronic acids to α,β-unsaturated carbonyl compounds. With catalyst loadings of 1-2 mol%, a series of 1,4-adducts from chalcones and cinnamates was obtained in moderate to excellent yields within 5-30 min under a nitrogen atmosphere and microwave irradiation. The 1,4-addition of arylboronic acids to acrylates is less efficient.
- Chen, Wen,Sun, Lu,Huang, Xi,Wang, Jiayi,Peng, Yanqing,Song, Gonghua
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p. 1474 - 1482
(2015/05/19)
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- Ambulation of Incipient Proton during Gas-Phase Dissociation of Protonated Alkyl Dihydrocinnamates
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Upon activation in the gas phase, protonated alkyl dihydrocinnamates undergo an alcohol loss. However, the mechanism followed is not a simple removal of an alkanol molecule after a protonation on the alkoxy group. The mass spectrum of the m/z 166 ion for deuteron-charged methyl dihydrocinnamate showed two peaks of 1:5 intensity ratio at m/z 133 and 134 to confirm that the incipient proton is mobile. The proton initially attached to the carbonyl group migrates to the ring and randomizes before a subsequent transfer of one of the ring protons to the alkoxy group for the concomitant alcohol elimination. Moreover, protonated methyl dihydrocinnamate undergoes more than one H/D exchange. The spectra recorded from m/z 167 and 168 ions obtained for di- and tri-deuterio isotopologues showed peak pairs at m/z 134, 135 and 135, 136, at 1:2 and 1:1 intensity ratios, respectively, confirming the benzenium ion intermediate achieves complete randomization before the proton transfer. Additionally, protonated higher esters of alkyl dihydrocinnamates undergo a cleavage of the O-CH2 bond to form an ion/neutral complex, which, upon activation, dissociates generating a carbenium ion and dihydrocinnamic acid, or rearranges to generate protonated dihydrocinnamic acid and an alkene by a nonspecific proton transfer.
- Xu, Sihang,Zhang, Yong,Errabelli, Ramu,Attygalle, Athula B.
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p. 9468 - 9479
(2015/10/12)
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- Manganese(II)-Catalyzed Esterification of N-β-Hydroxyethylamides
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A catalyst system of manganese with 2,2-bipyridine for amide alcoholysis of N-β-hydroxyethylamides is described. This protocol enabled selective cleavage of the amide bond through a mechanism involving sequential N,O-acyl rearrangement and transesterification.
- Nishii, Yuji,Akiyama, Shoko,Kita, Yusuke,Mashima, Kazushi
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supporting information
p. 1831 - 1834
(2015/08/06)
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- Catalyzation of 1,4-additions of arylboronic acids to α,β- unsaturated substrates using nickel(I) complexes
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Nickel(I) complexes were generated in situ from Ni (PPh3) 2Cl2 using activated iron and the complexes combined with N,N′-bis(4-fluorobenzylidene) ethane-1,2-diamine (BFBED) were then used as a catalyst for the 1,4-addition reaction of arylboronic acids to α,β-unsaturated substrates. The reaction proceeded to completion and did not require the addition of a base but the addition of potassium iodide is crucial to this cross-coupling reaction. Moreover, experimental observations suggested a possible Ni(I)-Ni(III) catalytic cycle mechanism.
- Meng, Jing-Jing,Gao, Min,Dong, Min,Wei, Yu-Ping,Zhang, Wen-Qin
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p. 2107 - 2109
(2014/04/03)
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- Ru-catalyzed 1,4-addition of arylboronic acids to acrylic acid derivatives in the presence of phenols
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[Ru(p-cymene)Cl2]2-catalyzed 1,4-addition reactions between arylboronic acids and butyl acrylate and acrylamide in the presence of phenols were investigated, good to excellent yields were obtained. The addition of phenols remarkably promoted the protonolysis and inhibited the β-H elimination of the 1,4-addition intermediates, and also efficiently suppressed the protonolysis of arylboronic acids. The Royal Society of Chemistry 2013.
- Zhang, Lei,Xie, Xiaomin,Peng, Zhiyong,Fu, Lei,Zhang, Zhaoguo
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supporting information
p. 8797 - 8799
(2013/09/24)
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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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- Cobalt(II)-catalyzed 1,4-addition of organoboronic acids to activated alkenes: An application to highly cis-stereoselective synthesis of aminoindane carboxylic acid derivatives
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It all adds up: The 1,4-addition of organoboronic acids to activated alkenes catalyzed by [Co(dppe)Cl2] is described. A [3+2]-annulation reaction of ortho-iminoarylboronic acids with acrylates to give various aminoindane carboxylic acid derivatives with cis-stereoselectivity is also demonstrated (see scheme; dppe=1,2-bis(diphenylphosphino)ethane).
- Chen, Min-Hsien,Mannathan, Subramaniyan,Lin, Pao-Shun,Cheng, Chien-Hong
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supporting information
p. 14918 - 14922
(2013/01/15)
-
- ZINC CLUSTER
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Disclosed is a novel zinc cluster compound represented by general formula (1): Zn4O (OCOR)6 (RCOOH)n, wherein R represents an alkyl group which has 1 to 4 carbon atoms and may be substituted with a halogen atom, and n repr
- -
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Page/Page column 3
(2012/07/14)
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- Zinc-catalyzed amide cleavage and esterification of β- hydroxyethylamides
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Snipping tool: Zn(OTf)2 is an efficient catalyst for selective cleavage of amides bearing a β-hydroxyethyl group on the nitrogen atom. The mechanism involves an N,O-acyl rearrangement and transesterification. This new catalytic system can be applied to sequence-specific peptide bond scission at the amine side of a serine residue. Tf=trifluoromethanesulfonyl. Copyright
- Kita, Yusuke,Nishii, Yuji,Higuchi, Takafumi,Mashima, Kazushi
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supporting information; experimental part
p. 5723 - 5726
(2012/08/07)
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- An investigation into the one-pot Heck olefination-hydrogenation reaction
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Herein is described an operationally simple process concerning the observation that, following either inter-, or intramolecular Heck olefination, stirring of the so formed substituted alkenyl product under an atmosphere of hydrogen efficiently effects alkene hydrogenation. Overall this two-operation, one-pot "reductive Heck" sequence is notable since direct reductive Heck processes, using additives such as formate salts, are restricted to a limited range of substrates. In total 25 examples are reported (yields ranging from 0 to 95%), which were selected in order to probe the scope and limitations of this method. Finally, the utility of this sequence was demonstrated in a short synthesis of the calcimimetic agent, cinacalcet.
- Geoghegan, Kimberly,Kelleher, Susan,Evans, Paul
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experimental part
p. 2187 - 2194
(2011/05/14)
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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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- Triphenylphosphine dibromide: a simple one-pot esterification reagent
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We report a one-pot, expedient protocol for the conversion of carboxylic acids to their esters using excess triphenylphosphine dibromide, base, and the alcohol. The reaction gave the esterified product in moderate-to-high yields (30-95%). For chiral acids, the reaction proceeded with little or no racemization. Use of a chiral alcohol in this transformation gave the ester with retention of configuration of the stereogenic center. Information is presented indicating that esterification proceeds through the intermediate generation of an acyloxyalkoxyphosphorane and where steric interactions play an important role in the energetics of the reaction.
- Salomé, Christophe,Kohn, Harold
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supporting information; experimental part
p. 456 - 460
(2009/04/06)
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- Rhodium-catalyzed conjugate addition of Sb-aryl-1,5-azastibocines to α,β-unsaturated carbonyl compounds
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Rhodium-catalyzed conjugate addition of Sb-aryl-1,5-azastibocines to α,β-unsaturated carbonyl compounds is described. The rhodium-catalyzed reaction was carried out in aqueous N-methy-2-pyrrolidinone (NMP) to give 1,4-conjugate adduct exclusively, while t
- Kakusawa, Naoki,Yasuike, Shuji,Kurita, Jyoji
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experimental part
p. 1269 - 1283
(2010/10/03)
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- Rhodium fluoroapatite catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carbonyl compounds
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Rhodium fluoroapatite (RhFAP) is an efficient catalyst for conjugate addition of organoboron reagents to α,β-unsaturated carbonyl compounds. A variety of arylboronic acids and α,β-unsaturated carbonyl compounds were converted to the corresponding conjugat
- Kantam, Mannepalli Lakshmi,Subrahmanyam, Vura Bala,Kumar, Kota Balaji Shiva,Venkanna, Gopaladasu T.,Sreedhar, Bojja
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scheme or table
p. 1947 - 1953
(2009/02/07)
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- Palladium/phosphite-catalyzed 1,4-addition of arylboronic acids to acrylic acid derivatives
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(Chemical Equation Presented) 1,4-Addition of arylboronic acids to acrylic acid derivatives proceeds efficiently in the presence of a palladium catalyst system of Pd(OAc)2/(PhO)3P to produce the corresponding 3-arylpropionic acid derivatives. The use of the phosphite ligand is the key to conducting the addition smoothly with suppressing the competing Mizoroki-Heck-type oxidative coupling.
- Horiguchi, Hakaru,Tsurugi, Hayato,Satoh, Tetsuya,Miura, Masahiro
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p. 1590 - 1592
(2008/09/17)
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- Polymer-supported ytterbium perfluorooctanesulfonate [Yb(OPf)3]: A recyclable catalyst for organic reactions
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Amberlyst A-21, a kind of well-known and cheap polymeric material, was treated with ytterbium perfluorooctanesulfonate [Yb(OPf)3] giving a reagent with a ytterbium loading of 1.34 (wt%). The polymer-supported fluorous ytterbium catalyses the highly efficient nitration, esterification, Fridel-Crafts acylation, and aldol condensation. The catalyst can be recovered by simple filtration and used again without a significant loss of catalytic activity. The protocol avoids the use of fluorous solvents during the reaction or workup, which are expensive and can leach in small amounts.
- Yi, Wen-Bin,Cai, Chun
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p. 524 - 528
(2008/12/22)
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- Rhodium catalyzed 1,4-conjugate addition of 1,5-azastibocines with electron deficient olefins
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The rhodium-catalyzed reaction of Sb-aryl-1,5-azastibocines with α,β-unsaturated ketones and esters is described. Exclusive formation of 1,4-conjugate adduct was achieved in aqueous NMP (N-methyl-2-pyrrolidinone) in the presence of 5 mol% of [RhCl(cod)]s
- Kakusawa, Naoki,Kurita, Jyoji
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scheme or table
p. 1502 - 1504
(2009/10/24)
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- Highly efficient and reusable polyaniline-supported palladium catalysts for open-air oxidative heck reactions under base-and ligand-free conditions
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Oxidative Heck reactions of arylboronic acids and alkenes are carried out in the presence of polyaniline-supported palladium catalysts using air as a co-oxidant to afford the Heck products with excellent yields and selectivities under base-and ligand-free conditions. The catalyst was recovered by simple filtration and used for several cycles with consistent activity.
- Likhar, Pravin R.,Roy, Moumita,Roy, Sarabindu,Subhas,Kantam, M. Lakshmi,Sreedhar
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experimental part
p. 1968 - 1974
(2009/07/25)
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- Copper-catalyzed synthesis of esters from ketones. Alkyl group as a leaving group
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The conversion of ketones to esters has been achieved through the use of Cu catalyst and tetrabutylammonium nitrite. This reaction involves the activation of the less activated C-C bond, and the alkyl group is removed as a leaving group. Various isopropyl ketones are found to be good substrates for this reaction.
- Nakatani, Yuji,Koizumi, Yuichiro,Yamasaki, Ryu,Saito, Shinichi
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supporting information; experimental part
p. 2067 - 2070
(2009/04/08)
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- Palladium-catalyzed oxidative carbonylation of alkyl and aryl indium reagents with CO under mild conditions
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CO now can react with organoindium reagents. A novel palladium-catalyzed oxidative carbonylation reaction of organoindium reagents by CO gas with desyl chloride as oxidant was developed in supplementation with the classical methods for preparation of carboxylic acid derivatives. Primary, secondary alkyl indium reagents with β-hydrogens and aryl indium reagents were suitable substrates, and the reaction could be carried out at 60°C under 50 psi CO. Carbonylation of alkyl indium reagents can occur smoothly without additional base. Although the indium reagents were prepared from corresponding Grignard reagents (at low temperature), they displayed full compatibility with various functional groups under the protic reaction conditions. Preliminary mechanistic studies including stoichiometric and catalytic reaction examination provided evidence to support the operation of the mechanism consisted of oxidative addition of deslyl chloride to Pd(0) and quick tautomerization to give a palladium enolate species II (ROPdCl), displacement of the enolate group in II by R2OH, followed by CO insertion to give alkoxycarbonyl palladium complex V, which undergoes transmetalation with R13ln and reductive elimination to afford the product and a Pd(0) species. In this mechanism, the alkoxycarbonyl group was transferred to the palladium center prior to the alkyl group, different from traditional ways initiated from oxidative addition of alkyl halides to a Pd(0) species.
- Zhao, Yingsheng,Jin, Liqun,Li, Peng,Lei, Aiwen
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supporting information; body text
p. 9429 - 9433
(2009/02/03)
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- Transesterification of various methyl esters under mild conditions catalyzed by tetranuclear zinc cluster
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(Chemical Equation Presented) A new catalytic transesterification promoted by a tetranuclear zinc cluster was developed. The mild reaction conditions enabled the reactions of various functionalized substrates to proceed in good to high yield. A large-scale reaction under solvent-free conditions proceeded with a low E-factor value (0.66), indicating the high environmental and economical advantage of the present catalysis.
- Iwasaki, Takanori,Maegawa, Yusuke,Hayashi, Yukiko,Ohshima, Takashi,Mashima, Kazushi
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p. 5147 - 5150
(2008/09/21)
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- Palladium-catalyzed heck coupling-hydrogenation: Highly efficient one-pot synthesis of dibenzyls and alkyl phenyl esters
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An efficient method for the synthesis of industrially important dibenzyls and alkyl phenyl esters via sequential Heck coupling and hydrogenation of the alkenyl double bond in one pot with a single recyclable catalyst under mild conditions has been realised. The catalyst was recovered by simple filteration and reused for several cycles with consistent activity.
- Kantam, M. Lakshmi,Chakravarti, Rajashree,Chintareddy, Venkat Reddy,Sreedhar,Bhargava, Suresh
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supporting information; experimental part
p. 2544 - 2550
(2009/08/14)
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- Heck-type coupling vs. conjugate addition in phosphine-rhodium catalyzed reactions of aryl boronic acids with α,β-unsaturated carbonyl compounds: A systematic investigation
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The competition between Heck-type coupling and conjugate addition in phosphine-rhodium catalyzed reactions of aryl boronic acids with α,β-unsaturated carbonyls has been systematically investigated in a toluene-H2O biphasic system. Aside from the intrinsic nature of rhodium and the enolization of carbonyls, the phosphine supporting ligand on rhodium, the ratio of aryl boronic acid to α,β-unsaturated carbonyl and the pH value of the aqueous phase were found to affect the competition significantly. Highly selective rhodium-based catalyst systems have therefore been developed for both Heck-type coupling and conjugate addition by synergistically tuning the supporting ligand, the boronic acid to olefin ratio and other reaction conditions. Conjugate addition with selectivity >99% and Heck-type coupling with selectivity of up to 100%, 98% and 84% for acrylates, acrylamides and methyl vinyl ketone, respectively, could be achieved in the rhodium-catalyzed reactions of aryl boronic acids with α,β- unsaturated carbonyls using the corresponding optimized rhodium-based catalyst systems. The Royal Society of Chemistry.
- Zou, Gang,Guo, Jianping,Wang, Zhiyong,Huang, Wen,Tang, Jie
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p. 3055 - 3064
(2008/02/09)
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- Reaction of dicarbonates with carboxylic acids catalyzed by weak Lewis acids: General method for the synthesis of anhydrides and esters
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The reaction between carboxylic acids (RCOOH) and dialkyl dicarbonates [(R1OCO)2O], in the presence of a weak Lewis acid such as magnesium chloride and the corresponding alcohol (R1OH) as the solvent, leads to the esters RCOOR1 in excellent yields. The mechanism involves a double addition of the acid to the dicarbonate, affording a carboxylic anhydride [(RCO)2O], R1OH and carbon dioxide. The esters arise from the attack of the alcohols on the anhydrides. Exploiting the lesser reactivity of tert-butyl alcohol in comparison with other alcohols, a clean synthesis of both carboxylic anhydrides and esters has been set up. In the former reaction, an acid/Boc2O molecular ratio of 2:1 leads to the anhydride in good to excellent yields, depending on the stability of the resulting anhydride to the usual workup conditions. In the latter reaction, stoichiometric mixtures of the acid and Boc2O are allowed to react with a twofold excess of a primary alcohol, secondary alcohol or phenol (R 2OH) to give the corresponding esters (RCOOR2). Purification of the products is particularly easy since all byproducts are volatile or water soluble. A very easy chromatography is required only in the case of nonvolatile alcohols. A broad variety of sensitive functional groups is tolerated on both the acid and the alcohol, in particular a high chemoselectivity is observed. In fact, no transesterification processes occur with the acid-sensitive acetoxy group and methyl esters. Georg Thieme Verlag Stuttgart.
- Bartoli, Giuseppe,Bosco, Marcella,Carlone, Armando,Dalpozzo, Renato,Marcantoni, Enrico,Melchiorre, Paolo,Sambri, Letizia
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p. 3489 - 3496
(2008/09/19)
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- [IrCl(cod)]2-catalyzed direct oxidative esterification of aldehydes with alcohols
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[IrCl(cod)]2 catalyzed the oxidative esterification of a variety of aldehydes with methanol as a solvent in combination with K2CO3 under mild conditions (rt, 12 h). The oxidative esterification reaction of aliphatic aldehydes also took place with olefinic alcohols as reagents in toluene under similar conditions.
- Kiyooka, Syun-ichi,Wada, Yosuke,Ueno, Mahuyu,Yokoyama, Takeshi,Yokoyama, Reiko
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p. 12695 - 12701
(2008/03/14)
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- A facile, catalytic and environmentally benign method for esterification of carboxylic acids and transesterification of carboxylic esters with nearly equimolar amounts of alcohols
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A practical and green chemical process for the esterification of carboxylic acids with alcohols and transesterification of carboxylic esters in good to excellent yields by using K5CoW12O14· 3H2O (0.1 mol%) as catalyst is reported. The catalyst exhibited remarkable reusable activity. Georg Thieme Verlag Stuttgart.
- Bose, D. Subhas,Satyender, Apuri,Das, A. P. Rudra,Mereyala, Hari Babu
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p. 2392 - 2396
(2008/02/08)
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- Solid-supported green synthesis of substituted hydrocinnamic esters by focused microwave irradiation
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An efficient chemoselective hydrogenation protocol for substituted cinnamic esters is developed for the synthesis in quantitative yield of corresponding bioactive dihydrocinnamic esters with solid-supported palladium chloride/ammonium formate (cat.) in HCOOH/H2O 1:2 as a hydrogenating agent under focused-microwave irradiation for 10 min.
- Kumar, Vinod,Sharma, Anuj,Sinha, Arun K.
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p. 483 - 495
(2007/10/03)
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- Iridium-catalyzed oxidative esterification reaction of aliphatic aldehydes and olefinic alcohols with precoordination of the double bond of alcohols to iridium
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A novel iridium-catalyzed oxidative esterification reaction of aliphatic aldehydes and olefinic alcohols in toluene was found under mild conditions of [IrCl(cod)]2 (5 mol %) in combination with K2CO 3 (10 mol %) at rt.
- Kiyooka, Syun-Ichi,Ueno, Mahuyu,Ishii, Eri
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p. 4639 - 4642
(2007/10/03)
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- A new method for the esterification of carboxylic acids with various alcohols by using di-2-thienyl carbonate, a new coupling reagent
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Esterification of carboxylic acids with alcohols by using di-2-thienyl carbonate in the presence of a catalytic amount of 4-(dimethylamino)pyridine (DMAP) proceeded smoothly under mild conditions to afford the corresponding esters and 2(5H)-thiophenone in good to high yields.
- Mukaiyama, Teruaki,Oohashi, Yoshiaki,Fukumoto, Kentarou
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p. 552 - 553
(2007/10/03)
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- Efficient method for the esterification of carboxylic acids with alcohols using di-2-thienyl carbonate promoted by DMAP and iodine
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Reaction of carboxylic acids with alcohols by using an equimolar amount of di-2-thienyl carbonate (2-DTC) in the presence of a catalytic amount of 4-(dimethylamino)pyridine (DMAP) followed by addition of an equimolar amount of iodine proceeded smoothly to afford the corresponding esters and 2(5H)-thiophenone in good to high yields.
- Oohashi, Yoshiaki,Fukumoto, Kentarou,Mukaiyama, Teruaki
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p. 968 - 969
(2007/10/03)
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- Iridium-catalyzed Mizoroki-Heck-Type reaction of organosilicon reagents
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Independent of substrate and solvent, the C-C bond-forming reaction of organosilicon reagents with α,β-unsaturated carbonyl compounds can be catalyzed by an iridium complex to give exclusively the Mizoroki-Heck-type addition/elimination product (see scheme). This result sharply contrasts the analogous reaction with a rhodium catalyst under similar conditions in which the 1,4-addition product is obtained preferentially. cod=cycloocta-1,5-diene.
- Koike, Tooru,Du, Xiaoli,Sanada, Tomoyuki,Danda, Yasuaki,Mori, Atsunori
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- Lewis Acids as Highly Efficient Catalysts for the Decarboxylative Esterification of Carboxylic Acids with Dialkyl Dicarbonates
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Mild Lewis acids such as Mg(ClO4)2 show a new level of catalytic activity for the decarboxylative esterification of carboxylic acids with commercially available dialkyl dicarbonates. In the presence of as little as one mol % Mg(ClO4)2 catalyst, carboxylic acids can thus easily and near quantitatively be protected at room temperature, e.g., as methyl, benzyl, or t-butyl esters. Only volatile by-products are released so that the purification of the products is particularly easy. Many sensitive functionalities are tolerated, including even phenol esters, or free hydroxy and BOC groups.
- Goossen,Doehring
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p. 943 - 947
(2007/10/03)
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- Room-temperature ionic liquids as new solvents for organic electrosynthesis. The first examples of direct or nickel-catalysed electroreductive coupling involving organic halides
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Direct or Ni-catalysed electroreductive homocouplings of organic halides and couplings of organic halides with activated olefins are efficiently conducted by constant current electrolyses in an undivided cell in room-temperature ionic liquids as the solvent-electrolyte media.
- Barhdadi, Rachid,Courtinard, Coralie,Nedelec, Jean Yves,Troupel, Michel
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p. 1434 - 1435
(2007/10/03)
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- Silicone as an organosilicon reagent 2. Rhodium-catalyzed conjugate addition of the silicone reagent to α,β-unsaturated carbonyl compounds
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The reaction of poly(phenylmethylsiloxane) with α,β-unsaturated carbonyl compounds in the presence of aqueous K2CO3 and 3 mol% of [Rh(OH)(cod)]2 gives 1,4-conjugate addition product in good yields. Arylchlorosilanes also u
- Koike, Tooru,Du, Xiaoli,Mori, Atsunori,Osakada, Kohtaro
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p. 301 - 303
(2007/10/03)
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- Esterification of carboxylic acids catalyzed by in situ generated tetraalkylammonium fluorides
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Esterification of carboxylic acids with alkyl halides can be efficiently catalyzed by tetrabutylammonium fluoride (TBAF) generated in situ from tetrabutylammonium hydrogensulfate (TBAHSO4) and KF·2H2O in THF. The general applicability and the characteristic feature of this approach has been amply demonstrated.
- Ooi, Takashi,Sugimoto, Hayato,Doda, Kanae,Maruoka, Keiji
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p. 9245 - 9248
(2007/10/03)
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