- Development of a triazinedione-based dehydrative condensing reagent containing 4-(dimethylamino)pyridine as an acyl transfer catalyst
-
A new triazinedione-based reagent, (N,N′-dialkyl)triazinedione-4-(dimethylamino)pyridine (ATD-DMAP) was developed for the operationally simple dehydrative condensation of carboxylic acids. This reagent comprises an ATD core and DMAP as the leaving group, which is liberated into the reaction system to accelerate acyl transfer reactions. Upon adding ATD-DMAP to a mixture of carboxylic acids and alcohols in the presence of an amine base, the corresponding esters were formed rapidly at room temperature. Moreover, dehydrative condensation between carboxylic acids and amines using ATD-DMAP proceeded in high yield.
- Liu, Jie,Fujita, Hikaru,Kitamura, Masanori,Shimada, Daichi,Kunishima, Munetaka
-
supporting information
p. 4712 - 4719
(2021/06/11)
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- Macrolactonization Reactions Driven by a Pentafluorobenzoyl Group**
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Macrolactones constitute a privileged class of natural and synthetic products with a broad range of applications in the fine chemicals and pharmaceutical industry. Despite all the progress made towards their synthesis, notably from seco-acids, a macrolactonization promoter system that is effective, selective, flexible, readily available, and, insofar as possible, compatible with manifold functional groups is still lacking. Herein, we describe a strategy that relies on the formation of a mixed anhydride incorporating a pentafluorophenyl group which, due to its high electronic activation enables a convenient access to macrolactones, macrodiolides and esters with a broad versatility. Kinetic studies and DFT computations were performed to rationalize the reactivity of the pentafluorophenyl group in macrolactonization reactions.
- Ciofini, Ilaria,Force, Guillaume,Leb?uf, David,Mayer, Robert J.,Perfetto, Anna
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supporting information
p. 19843 - 19851
(2021/08/13)
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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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- Rhodium-Catalyzed Carbonylative Coupling of Alkyl Halides with Phenols under Low CO Pressure
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A rhodium-catalyzed carbonylative transformation of alkyl halides under low pressure of CO has been developed. This robust catalyst system allows using phenols as the carbonylative coupling partner and, meanwhile, exhibits high functional group tolerance and good chemoselectivity. Substrates even with a large steric hindrance group or multiple reaction sites can be selectively converted into the desired products in good to excellent yields. A gram-scale experiment was performed and delivered an almost quantitative amount of the product. Control experiments were performed as well, and a possible reaction mechanism is proposed.
- Ai, Han-Jun,Li, Chong-Liang,Wang, Hai,Wu, Xiao-Feng
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p. 5147 - 5152
(2020/05/27)
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- Method for preparing organic carboxylic ester through combined catalysis of aryl bidentate phosphine ligand
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The invention discloses a method for preparing organic carboxylic ester by combined catalysis of an aryl bidentate phosphine ligand. The method comprises the following steps: under the action of a palladium compound/aryl bidentate phosphine ligand/acidic additive combined catalyst, carrying out a hydrogen esterification reaction on terminal olefin, carbon monoxide and alcohol so as to generate theorganic carboxylic ester with one more carbon than olefin. According to the invention, by adoption of the palladium compound/aryl bidentate phosphine ligand/acidic additive combined catalyst, good catalytic activity and selectivity for the hydrogen esterification reaction of the olefin are achieved, and olefin carbonylation to synthesize organic carboxylic ester can be efficiently catalyzed. Thearyl bidentate phosphine ligand has a rigid skeleton structure of a rigid ligand and the flexibility of a flexible ligand, so the aryl bidentate phosphine ligand has proper flexibility due to the characteristic that the aryl bidentate phosphine ligand is soft and rigid, and a most favorable coordination mode and a stable active structure in space are favorably formed. In addition, the aryl bidentate phosphine ligand has the advantages of high stability, simple and convenient synthesis method and the like; and a novel industrial technology is provided for production of organic carboxylate compounds.
- -
-
Paragraph 0048
(2020/05/29)
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- Palladium-Catalyzed Aerobic Oxidative Coupling of Amides with Arylboronic Acids by Cooperative Catalysis
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The first fluoride and palladium co-catalyzed conversion of amide to ester through an aerobic oxidative coupling pathway is reported. This new approach presents a practical process that employs easily available oxygen and commercially available arylboronic acids as coupling partners, uses a wide range of N- tosylamides, and proceeds under mild reaction conditions. This protocol demonstrates broad functional group tolerance, and provides an alternative option to synthesize esters from N-tosylamides which obtained by simply N-functionalization of secondary amides.
- Li, Yue,Wu, Hongxiang,Zeng, Zhuo
-
supporting information
p. 4357 - 4361
(2019/07/09)
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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)
- -
-
Paragraph 0041
(2019/05/08)
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- Development of triazine-based esterifying reagents containing pyridines as a nucleophilic catalyst
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We have developed new triazine-based esterifying reagents comprising pyridines that can act as a nucleophilic catalyst. 1-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-3,5-lutidinium chloride (DMT-3,5-LUT) was found to exhibit a superior reactivity for the dehydrating condensation reaction between carboxylic acids and alcohols. The reaction of DMT-3,5-LUT with carboxylic acids produces intermediacy of acyloxytriazines, which is known to exhibit moderate reactivity toward alcohols, with concomitant liberation of 3,5-lutidine. The subsequent chemical transformation of the acyloxytriazines and alcohols into esters can be accelerated by the action of 3,5-lutidine as a nucleophilic catalyst. The detailed reaction mechanism revealed by a time-course analysis of the reactions is also discussed.
- Yamada, Kohei,Liu, Jie,Kunishima, Munetaka
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supporting information
p. 6569 - 6575
(2018/09/25)
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- Direct C-C Bond Formation from Alkanes Using Ni-Photoredox Catalysis
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A method for direct cross coupling between unactivated C(sp3)-H bonds and chloroformates has been accomplished via nickel and photoredox catalysis. A diverse range of feedstock chemicals, such as (a)cyclic alkanes and toluenes, along with late-stage intermediates, undergo intermolecular C-C bond formation to afford esters under mild conditions using only 3 equiv of the C-H partner. Site selectivity is predictable according to bond strength and polarity trends that are consistent with the intermediacy of a chlorine radical as the hydrogen atom-abstracting species.
- Ackerman, Laura K. G.,Martinez Alvarado, Jesus I.,Doyle, Abigail G.
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p. 14059 - 14063
(2018/10/24)
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- Catalytic, Enantioselective β-Protonation through a Cooperative Activation Strategy
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The NHC-catalyzed transformation of unsaturated aldehydes into saturated esters through an organocatalytic homoenolate process has been thoroughly studied. Leveraging a unique “Umpolung”-mediated β-protonation, this process has evolved from a test bed for homoenolate reactivity to a broader platform for asymmetric catalysis. Inspired by our success in using the β-protonation process to generate enals from ynals with good E/Z selectivity, our early studies found that an asymmetric variation of this reaction was not only feasible, but also adaptable to a kinetic resolution of secondary alcohols through NHC-catalyzed acylation. In-depth analysis of this process determined that careful catalyst and solvent pairing is critical for optimal yield and selectivity; proper choice of nonpolar solvent provided improved yield through suppression of an oxidative side reaction, while employment of a cooperative catalytic approach through inclusion of a hydrogen bond donor cocatalyst significantly improved enantioselectivity.
- Wang, Michael H.,Barsoum, David,Schwamb, C. Benjamin,Cohen, Daniel T.,Goess, Brian C.,Riedrich, Matthias,Chan, Audrey,Maki, Brooks E.,Mishra, Rama K.,Scheidt, Karl A.
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p. 4689 - 4702
(2017/05/12)
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- μ-Oxo-Dinuclear-Iron(III)-Catalyzed O-Selective Acylation of Aliphatic and Aromatic Amino Alcohols and Transesterification of Tertiary Alcohols
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A highly chemoselective and reactive μ-oxo-dinuclear iron(III) salen catalyst for transesterification was developed. The developed iron complex catalyzed acylation of aliphatic amino alcohols with nearly perfect O-selectivity, even when using activated esters, for which chemoselectivity is more difficult to control. In addition, O-selective transesterification of aromatic amino alcohols was achieved for the first time. The high activity of the iron complex enabled the use of sterically congested tertiary alcohols, including unprecedented tert-butanol.
- Horikawa, Rikiya,Fujimoto, Chika,Yazaki, Ryo,Ohshima, Takashi
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supporting information
p. 12278 - 12281
(2016/08/24)
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- Indium-Catalyzed Reductive Sulfidation of Esters by Using Thiols: An Approach to the Diverse Synthesis of Sulfides
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A new reductive preparation of unsymmetrical sulfides from esters and thiols in the presence of InI3 and either 1,1,3,3-tetramethyldisiloxane (TMDS) or PhSiH3 as the reductant was developed. This protocol was applied to not only benzoic acid esters that have a methoxy, methyl, chloro, bromo, iodo, or trifluoromethyl group on the aromatic ring but also aliphatic acid esters with either aromatic or aliphatic thiols. A reaction mechanism is proposed by using Hammett plot results and several control experiments. The reductive preparation of unsymmetrical sulfides from esters and thiols by using InI3 and either 1,1,3,3-tetramethyldisiloxane (TMDS) or PhSiH3 was developed. Several mechanistic studies support that the present transformation proceeds through O,S-and S,S-acetals as the reaction intermediates. TMDS = 1,1,3,3-tetramethyldisiloxane, R = aliphatic group.
- Miyazaki, Takahiro,Kasai, Shinsei,Ogiwara, Yohei,Sakai, Norio
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supporting information
p. 1043 - 1049
(2016/03/01)
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- Palladium-Catalyzed Highly Regio- and Enantioselective Hydroesterification of Aryl Olefins with Phenyl Formate
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An effective Pd-catalyzed regio- and enantioselective hydroesterification of aryl olefins with phenyl formate is described. A variety of phenyl 2-arylpropanoates can be obtained in good yields with high b/l ratios and ee's without using toxic CO gas.
- Li, Jingfu,Chang, Wenju,Ren, Wenlong,Dai, Jie,Shi, Yian
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supporting information
p. 5456 - 5459
(2016/11/17)
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- The insertion of arynes into the O-H bond of aliphatic carboxylic acids
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The insertion of arynes into the O-H bond of aliphatic carboxylic acids promoted by sodium carboxylates is described. The reactions led to the formation of aryl carboxylates in good yields with good chemoselectivities under mild conditions.
- Wen, Chunxiao,Chen, Qian,He, Zhenwen,Yan, Xinxing,Zhang, Changyuan,Du, Zhiyun,Zhang, Kun
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supporting information
p. 5470 - 5473
(2015/09/15)
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- Pd-Catalyzed Regiodivergent Hydroesterification of Aryl Olefins with Phenyl Formate
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An effective Pd-catalyzed regiodivergent hydroesterification of aryl olefins with phenyl formate is described. Either linear or branched phenyl arylpropanoates can be obtained in good yields with high regioselectivities by the judicious choice of ligand without the use of toxic CO gas.
- Ren, Wenlong,Chang, Wenju,Wang, Yang,Li, Jingfu,Shi, Yian
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supporting information
p. 3544 - 3547
(2015/07/28)
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- Ligand-free palladium-catalyzed aerobic oxidative coupling of carboxylic anhydrides with arylboronic acids
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We report a new, effective and environmentally friendly protocol for selective aerobic oxidative coupling of arylboronic acids with carboxylic anhydrides in the presence of ligand-free palladium catalyst. The aryl benzoates are obtained in good to excellent yields.
- Yin, Weiyan,He, Haifeng,Zhang, Yani,Long, Tong
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p. 2402 - 2406
(2014/10/15)
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- Novel ruthenium-catalyst for hydroesterification of olefins with formates
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An alternative ruthenium-based catalyst for the hydroesterification of olefins with formates is reported. The good activity of our system is ensured by the use of a bidentate P,N-ligand and ruthenium dodecacarbonyl. A range of formates can be used for selective alkoxycarbonylation of aromatic olefins. In addition, the synthesis of selected aliphatic esters is realized. The proposed active ruthenium complex has been isolated and characterized. This journal is the Partner Organisations 2014.
- Profir, Irina,Beller, Matthias,Fleischer, Ivana
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supporting information
p. 6972 - 6976
(2014/10/15)
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- N-heterocyclic carbene-catalyzed oxidation of aldehydes for the synthesis of amides via phenolic esters
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N-heterocyclic carbene-catalyzed oxidation using TEMPO is reported for the conversion of aldehydes to amides. A wide range of amides were synthesized in good yields (up to 72%) via a one-pot, sequential protocol involving oxidative esterification of aldehydes and subsequent aminolysis. To promote efficient aminolysis, various alkoxide leaving groups were evaluated.
- Ji, Miran,Lim, Seungyeon,Jang, Hye-Young
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p. 28225 - 28228
(2014/07/22)
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- Phosphorus oxychloride as an efficient coupling reagent for the synthesis of esters, amides and peptides under mild conditions
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A mild method is described for the conversion of carboxylic acids into esters, amides, as well as peptides without racemization through carboxyl activation by the reagent combination of POCl3 and DMAP. Long chain alcohols could be converted to the corresponding ester in good yields. 31P NMR spectrum was used to detect phosphorus-containing intermediates in ongoing reactions directly, and a possible mechanism has been proposed based on these results. The Royal Society of Chemistry 2013.
- Chen, Hu,Xu, Xunfu,Liu, Liu,Tang, Guo,Zhao, Yufen
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p. 16247 - 16250
(2013/09/23)
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- Rhodium(I)-catalyzed arylation of β-chloro ketones and related derivatives through domino dehydrochlorination/conjugate addition
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Highly efficient arylations of β-chloro ketones and their ester and amide derivatives were achieved by means of domino dehydrochlorination/Rh(I)- catalyzed conjugate addition. In situ generated vinyl ketones and their analogues were identified as the reaction intermediates. The present synthetic protocol provides a concise route to (chiral) β-aryl ketones, esters, and amides. Copyright
- Jiang, Quanbin,Guo, Tenglong,Wang, Qingfu,Wu, Ping,Yu, Zhengkun
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supporting information
p. 1874 - 1880
(2013/07/19)
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- N-heterocyclic carbene catalysed oxidative coupling of aldehydes with alcohols/thiols and one-pot oxidation/esterification of allylic alcohols
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A versatile carbene-catalysed oxidation protocol involving N-heterocyclic carbene catalysts and 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) is described for the synthesis of esters, cinnamic acids, and thioesters. A wide range of esters, thioesters, and cinnamic acids were obtained by metal-free coupling of aldehydes with aliphatic, allylic and aromatic alcohols, benzyl mercaptan, and water. In addition to the oxidative coupling of aldehydes with nucleophiles, dehydrogenation of saturated aldehydes and oxidation of allylic alcohols were found under our oxidative coupling conditions. Unlike other TEMPO-mediated oxidative esterification reactions, this reaction does not proceed through a TEMPO ester intermediate to form esters and thioesters. N-Heterocyclic carbene complexes catalyse various oxidative coupling reactions in the presence of TEMPO. A variety of α,β-unsaturated and saturated esters, and aromatic esters and thioesters were synthesised. Copyright
- Ji, Miran,Wang, Xi,Lim, Yu Na,Kang, Ye-Won,Jang, Hye-Young
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supporting information
p. 7881 - 7885
(2014/01/06)
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- Engaging unactivated alkyl, alkenyl and aryl iodides in visible-light-mediated free radical reactions
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Radical reactions are a powerful class of chemical transformations. However, the formation of radical species to initiate these reactions has often required the use of stoichiometric amounts of toxic reagents, such as tributyltin hydride. Recently, the use of visible-light-mediated photoredox catalysis to generate radical species has become popular, but the scope of these radical precursors has been limited. Here, we describe the identification of reaction conditions under which photocatalysts such as fac-Ir(ppy) 3 can be utilized to form radicals from unactivated alkyl, alkenyl and aryl iodides. The generated radicals undergo reduction via hydrogen atom abstraction or reductive cyclization. The reaction protocol utilizes only inexpensive reagents, occurs under mild reaction conditions, and shows exceptional functional group tolerance. Reaction efficiency is maintained upon scale-up and decreased catalyst loading, and the reaction time can be significantly shortened when the reaction is performed in a flow reactor.
- Nguyen, John D.,D'Amato, Erica M.,Narayanam, Jagan M. R.,Stephenson, Corey R. J.
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p. 854 - 859
(2012/11/07)
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- Site-specific hydrogen exchange and hydrogen transfer processes preceding the fragmentation of long-lived radical cations of ethyl dihydrocinnamate and related arylalkanoates
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An electron ionisation study on the fragmentation of metastable molecular radical cations of ethyl 3-phenylpropanoate (ethyl dihydrocinnamate) and related arylalkanoic acid esters was performed by mass-analysed ion kinetic energy (MIKE) spectrometry. Six deuterium-labelled isotopomers of ethyl dihydrocinnamate were synthesised and studied by MIKE spectrometry. The fragmentation leading to ions C7H7O+ (m/z 107) involving migration of the alkoxycarbonyl group was also observed in the 70-eV mass spectra of related alkyl dihydrocinnamates, but it was found to be a high-energy process that does not compete at low energies in metastable molecular ions. Instead, the metastable ions of ethyl dihydrocinnamate undergo competing losses of carbon monoxide, ethanol and the combined loss of these neutral fragments, giving ionised styrene, C8H8 ?+ (m/z 104). A highly specific H/D interchange involving the four hydrogen atoms at the benzylic α- and ortho-positions was found to precede the losses of ethanol and [ethanol + CO]. This represents another striking case of complete 4H - scrambling that enables the molecular ion to fully equilibrate the interchanging hydrogen atoms prior to fragmentation. A mechanism rationalising these observations and extending previously suggested mechanisms is proposed involving a series of distonic ions and the intermediacy of an ion/neutral complex. The metastable ions of the related esters exhibit in part similar fragmentation behaviour, but the McLafferty reaction turns out to be more favourable with higher alkyl dihydrocinnamates. For example, n-propyl 3-phenylpropanoate and isopropyl 3-phenylpropanoate react through highly distinct fragmentation channels.
- Amick, Aaron W.,Hoegg, Edward,Harrison, Sean,Houston, Katelyn R.,Hark, Richard R.,Reingold, I. David,Barth, Dieter,Letzel, Matthias C.,Kuck, Dietmar
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experimental part
p. 206 - 215
(2012/07/01)
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- One-pot sequential synthesis of ethers from an aliphatic carboxylic acid and an alcohol by indium-catalyzed deoxygenation of an ester
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We have developed a widely applicable and direct method of etherification from a carboxylic acid and an alcohol by indium-catalyzed deoxygenation of the transient ester formed in a one-pot reaction. This simple catalytic reducing system appears to be remarkably tolerant of several functional groups including alkenes, halogens, nitro and heterocyclic groups. A reducing system composed of InBr3 and an economical hydrosiloxane, PMHS (polymethylhydrosiloxane) , enabled one-pot etherification by using a variety of aliphatic carboxylic acids and alcohols. Copyright
- Sakai, Norio,Usui, Yuta,Moriya, Toshimitsu,Ikeda, Reiko,Konakahara, Takeo
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p. 4603 - 4608
(2012/10/30)
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- METAL-CATALYSED CARBONYLATION OF UNSATURATED COMPOUNDS
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The invention provides a method for the hydroxycarbonylation, alkoxycarbonylation, aryloxycarbonylation or thiocarbonylation of an unsaturated molecule. The method includes a hydroxycarbonylation, alkoxycarbonylation, aryloxycarbonylationor thiocarbonylation reaction on the unsaturated molecule in which a complex including a ligand comprising a [n,n′]cyclophane comprising two non-fused monocyclic aromatic rings bridged by two linear and aliphatic linkages, in which each of the non-fused monocyclic aromatic rings is substituted with a phosphorus atom-containing substituent, is used to catalyse the reaction.
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Page/Page column 14
(2012/07/27)
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- METAL CATALYSED CARBONYLATION OF UNSATURATED COMPOUNDS
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The invention provides a method for the hydroxycarbonylation, alkoxycarbonylation, aryloxycarbonylation or thiocarbonylation of an unsaturated molecule comprising effecting a hydroxycarbonylation, alkoxycarbonylation, aryloxycarbonylation or thiocarbonylation reaction on the unsaturated molecule in which a complex comprising a ligand comprising a [n,n']cyclophane comprising two non-fused monocyclic aromatic rings bridged by two linear and aliphatic linkages, in which each of the non-fused monocyclic aromatic rings is substituted with a phosphorus atom-containing substituent, is used to catalyse the hydroxycarbonylation, alkoxycarbonylation, aryloxycarbonylation or thiocarbonylation reaction.
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Page/Page column 33
(2011/04/18)
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- Palladium-catalyzed hydroesterification of alkynes employing aryl formates without the use of external carbon monoxide
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A highly efficient hydroesterification of alkynes employing aryl formates has been developed without the use of external carbon monoxide and at ambient pressure. The reaction in the presence of a palladium-xantphos catalyst system selectively affords α,β-unsaturated esters in good to high yields. Use of an aryl formate is crucial and alkyl formates did not react at all. The hydroesterification of norbornene and terminal alkenes also readily proceeded under similar reaction conditions. A mechanistic study showed that conversion of aryl formates to carbon monoxide and phenol derivatives occurred in the hydroesterification. Xantphos is highly effective as a ligand both in the conversion of aryl formates and the hydroesterification reactions.
- Katafuchi, Yuko,Fujihara, Tetsuaki,Iwai, Tomohiro,Terao, Jun,Tsuji, Yasushi
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p. 475 - 482
(2011/04/22)
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- Studies on the Lossen-type rearrangement of N-(3-phenylpropionyloxy) phthalimide and N-tosyloxy derivatives with several nucleophiles
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The reaction of N-(3-phenylpropionyloxy)phthalimide (1a) and N-tosyloxy (5a,b) derivatives with nucleophiles was examined and found to give the products via Lossen-type rearrangement. In order to obtain the scope of this reaction mechanism, further studies the reaction of several N-sulfonyloxyimide derivatives with various nucleophiles under similar conditions were carried out and found to afford the corresponding same types of products in high yields.
- Chanmiya Sheikh,Takagi, Shunsuke,Ogasawara, Asako,Ohira, Masayuki,Miyatake, Ryuta,Abe, Hitoshi,Yoshimura, Toshiaki,Morita, Hiroyuki
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supporting information; experimental part
p. 2132 - 2140
(2010/04/26)
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- Mechanistic studies of DCC/HOBt-mediated reaction of 3-phenylpropionic acid with benzyl alcohol and studies on the reactivities of 'active ester' and the related derivatives with nucleophiles
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Despite of the extensive study for peptide synthesis, DCC-mediated esterification is left still unclear. Therefore, DCC- and DCC/HOBt-mediated reactions of 3-phenylpropionic acid (1) with benzyl alcohol were carried out under several mechanistic considerations. Further, in order to determine the reactivities of the so-called 'active esters' compounds changing the substituents bearing carbonyl and related derivatives group for the purpose of the development of new class of non-symmetry cross-linkers, we have studied the reaction of model compounds, N-(3-phenylpropionyloxy)benzotriazole (6), N-(3-phenylpropionyloxy)phthalimide (7), 3-phenylpropionyloxybenzothiazole (8), and N-(3-phenylpropionyl)benzotriazole (9) with various nucleophiles under similar conditions were carried out for the comparison. It was revealed to exhibit the order of 6>>8>9>7.
- Sheikh, Md. Chanmiya,Takagi, Shunsuke,Yoshimura, Toshiaki,Morita, Hiroyuki
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supporting information; experimental part
p. 7272 - 7278
(2010/10/02)
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- Palladium-catalyzed aromatic esterification of aldehydes with organoboronic acids and molecular oxygen
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A palladium-catalyzed aromatic esterification reaction of aldehydes with arylboronic acids under an air atmosphere was achieved. This reaction tolerates many functional groups and provides aryl benzoate derivatives with yields ranging from moderate to good. Dioxygen takes part in the reaction and is crucial for this transformation.
- Qin, Changming,Wu, Huayue,Chen, Jiuxi,Liu, Miaochang,Cheng, Jiang,Su, Weike,Ding, Jinchang
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supporting information; experimental part
p. 1537 - 1540
(2009/04/07)
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- Protonation of homoenolate equivalents generated by N-heterocyclic carbenes
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Homoenolate equivalents are generated by Lewis basic N-heterocyclic carbene catalysts and then protonated to generate efficiently saturated esters from unsaturated aldehydes. This reactivity is extended to the generation of β-acylvinyl anions from alkynyl aldehydes. The asymmetric protonation of a homoenolate equivalent generated from a β,β-disubstituted aldehyde can be accomplished with a chiral N-heterocyclic carbene. Georg Thieme Verlag Stuttgart.
- Maki, Brooks E.,Chan, Audrey,Scheidt, Karl A.
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p. 1306 - 1315
(2008/12/22)
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- Pyridine-3-carboxylic anhydride (3-PCA): A versatile, practical, and inexpensive reagent for condensation reaction between carboxylic acids and alcohols
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A synthesis of carboxylic esters from various carboxylic acids and alcohols is successfully carried out by using a condensation reagent, pyridine-3-carboxylic anhydride (3-PCA). This reaction materialized synthesis of various carboxylic esters to be carried out under mild conditions by simple experimental procedure. Copyright
- Mukaiyama, Teruaki,Funasaka, Setsuo
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p. 326 - 327
(2008/02/04)
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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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- Mild, powerful, and robust methods for esterification, amide formation, and thioesterification between acid chlorides and alcohols, amines, thiols, respectively
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We developed two efficient practical methods for esterification, amide formation, and thioesterification between acid chlorides and alcohols, amines, thiols, respectively. The present mild and robust reaction was performed by two separate methods both by combining cheap and readily available amines, N-methylimidazole, and N,N,N′,N′-tetramethylethylenediamine (TMEDA). Method A uses catalytic N-methylimidazole and TMEDA with an equimolar amount of K2CO3, whereas Method B uses equimolar amounts of N-methylimidazole and TMEDA. The salient features are as follows. (i) With regard to reactivity, Method B was superior to Method A for esterification and thioesterification, whereas cost-effective Method A was superior to Method B for amide formation. (ii) Amide formation proceeded smoothly between acid chlorides and less nucleophilic and stereocongested amines such as 2,6-dichloroaniline. (iii) This protocol was applied to the successful synthesis of two agrochemicals, bromobutide and carpropamid.
- Nakatsuji, Hidefumi,Morimoto, Mami,Misaki, Tomonori,Tanabe, Yoo
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p. 12071 - 12080
(2008/03/13)
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- Water solvent method for esterification and amide formation between acid chlorides and alcohols promoted by combined catalytic amines: Synergy between N-methylimidazole and N,N,N′,N′-tetramethylethylenediamine (TMEDA)
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An efficient method for esterification between acid chlorides and alcohols in water as solvent has been developed by combining the catalytic amines, N-methylimidazole and N,N,N′,N′-tetramethylethylenediamine (TMEDA). The present Schotten-Baumann-type reaction was performed by maintaining the pH at around 11.5 using a pH controller to prevent the decomposition of acid chlorides and/or esters and to facilitate the condensation. The choice of catalysts (0.1 equiv.) was crucial: the combined use of N-methylimidazole and TMEDA exhibited a dramatic synergistic effect. The catalytic amines have two different roles: (i) N-methylimidazole forms highly reactive ammonium intermediates with acid chlorides and (ii) TMEDA acts as an effective HCl binder. The production of these intermediates was rationally supported by a careful 1H NMR monitoring study. Related amide formation was also achieved between acid chlorides and primary or secondary amines, including less nucleophilic or water-soluble amines such as 2-(or 4-)chloroaniline, the Weinreb N-methoxyamine, and 2,2-dimethoxyethanamine.
- Nakatsuji, Hidefumi,Morita, Jun-Ichi,Misaki, Tomonori,Tanabe, Yoo
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p. 2057 - 2062
(2007/10/03)
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- A new method for the synthesis of carboxylic esters and lactones with di-2-thienyl carbonate (2-DTC) by the promotion of DMAP and iodine
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The esterification of carboxylic acids with alcohols by using di-2-thienyl carbonate (2-DTC) in the presence of a catalytic amount of 4-(dimethylamino) pyridine (DMAP) proceeded smoothly to afford the corresponding esters in good-to-high yields along with 2(5H)-thiophenone. This esterification was accelerated by the addition of an equimolar amount of iodine to afford the esters in higher yields within a shorter reaction time. Further, cyclization of ω-hydroxycarboxylic acids with an equimolar amount of 2-DTC in the presence of a catalytic amount of DMAP, followed by the addition of 1-4 equimolar amounts of iodine, afforded the corresponding lactones in good-to-high yields under mild conditions. This method was successfully employed in the synthesis of erythro-aleuritic acid lactone.
- Oohashi, Yoshiaki,Fukumoto, Kentarou,Mukaiyama, Teruaki
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p. 1508 - 1519
(2007/10/03)
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- Conversion of α,β-unsaturated aldehydes into saturated esters: An umpolung reaction catalyzed by nucleophilic carbenes
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(Chemical Equation Presented) N-Heterocyclic carbenes derived from benzimidazolium salts are effective catalysts for generating homoenolate species from α,β-unsaturated aldehydes. These nucleophilic intermediates can be protonated, and the resulting activated carbonyl unit is trapped with an alcohol nucleophile, thereby promoting a highly efficient conversion of an α,β-unsaturated aldehyde into a saturated ester. A kinetic resolution of secondary alcohols can be achieved using chiral imidazoylidene catalysts.
- Chan, Audrey,Scheidt, Karl A.
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p. 905 - 908
(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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- Conversion of α-haloaldehydes into acylating agents by an internal redox reaction catalyzed by nucleophilic carbenes
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Reactivity umpolung allows us to consider nontraditional bond disconnections. We report herein that treatment of an α-haloaldehyde with a nucleophile in the presence of catalytic amounts of nucleophilic carbenes results in an internal redox reaction giving rise to a dehalogenated acylating agent as an intermediate by a new reaction manifold. A brief illustration of the scope of this reaction is presented along with evidence supporting the direct intervention of the carbene in the acylation step. Copyright
- Reynolds, Nathan T.,De Alaniz, Javier Read,Rovis, Tomislav
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p. 9518 - 9519
(2007/10/03)
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- Simple, Mild, and Practical Esterification, Thioesterification, and Amide Formation Utilizing p-Toluenesulfonyl Chloride and N-Methylimidazole
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We have developed an efficient method for the esterification or thioesterification of equimolar amounts of carboxylic acids and alcohols or thiols using a novel reagent, p-toluenesulfonyl chloride (TsCl) together with N-methylimidazole. The present method is simple, mild, and reactive, uses readily available and economical reagents. The choice of amine is critical for the present method. The amine, N-methylimidazole, has two roles: (i) as an HCl scavenger for the initial smooth generation of mixed anhydrides between carboxylic acids and TsCl and (ii) successive formation of highly reactive ammonium intermediates from mixed anhydrides. This method could be applied to various types of carboxylic acids, alcohols, and thiols: a) several functionalities were tolerated; b) two N-Cbz amino acids were smoothly esterified without racemization; and c) the labile 1β-methylcarbapenem key intermediate and a pyrethroid insecticide, prallethrin, were successfully prepared. The related amide formation between carboxylic acids and primary or secondary amines was also performed. The proposed reaction mechanism involves a novel method for producing the reactive acylammonium intermediates. The production of these intermediates was rationally supported by a careful 1H NMR monitoring study.
- Wakasugi, Kazunori,Iida, Akira,Misaki, Tomonori,Nishii, Yoshinori,Tanabe, Yoo
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p. 1209 - 1214
(2007/10/03)
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- Novel and efficient method for esterification, amidation between carboxylic acids and equimolar amounts of alcohols, and amines utilizing Me2NSO2Cl and N,N-dimethylamines; Its application to the synthesis of coumaperine, a natural chemopreventive dieneamide
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Various carboxylic esters or amides were prepared in good to excellent yield between carboxylic acids and equimolar amounts of alcohols or amines under very mild conditions (0-45°C; within 3 h) using dimethylsulfamoyl chloride (Me2NSO2Cl; 1) combined with N,N-dimethylamines (Me2NR: 2a; R=Me, 2b; R=Bu). The choice of the sulfamoyl chloride and the amine is crucial for the reaction; that is, sterically uncrowded amines accelerated the present esterification and amidation. This agent had some advantages over methanesulfonyl chloride (3)/amines as for the atom-economy, avoidance of side reactions, and had very high chemoselectivity toward the carboxyl group vs the hydroxyl group; the experiment was performed by the addition of 1 to the mixture of carboxylic acids and alcohols. Application of this method to the synthesis of coumaperine, a chemopreventive natural product, was performed using the present amidation as a key step.
- Wakasugi, Kazunori,Nakamura, Atsushi,Iida, Akira,Nishii, Yoshinori,Nakatani, Nobuji,Fukushima, Shoji,Tanabe, Yoo
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p. 5337 - 5345
(2007/10/03)
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- Enantioselective synthesis of allenecarboxylates from phenyl acetates through C-C bond forming reactions
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A variety of optically active 4,4-disubstituted allenecarboxylic acid methyl esters were prepared from simple α,α-disubstituted phenyl acetate through base treatment of the esters to generate ketenes, followed by successive Horner-Wadsworth-Emmons reaction. The transformation was further developed as a one-pot procedure with satisfactory yields and high enantioselectivity.
- Yamazaki, Jiro,Watanabe, Toshiyuki,Tanaka, Kiyoshi
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p. 669 - 675
(2007/10/03)
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- Me2NSO2Cl and N,N-dimethylamines; a novel and efficient agent for esterification, amidation between carboxylic acids, and equimolar amounts of alcohols and amines
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Various carboxylic esters or amides were prepared in good to excellent yields between carboxylic acids and equimolar amounts of alcohols or amines under very mild conditions using dimethylsulfamoyl chloride (Me2NSO2Cl) combined with N,N-dimethylamines. The choice of the sulfamoyl chloride and the amine is crucial for the reactions.
- Wakasugi, Kazunori,Nakamura, Atsushi,Tanabe, Yoo
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p. 7427 - 7430
(2007/10/03)
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- Improved procedure for the reductive acetylation of acyclic esters and a new synthesis of ethers
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An optimized protocol for the DIBALH reductive acetylation of acyclic esters and diesters is described. This reductive acetylation procedure allows a wide variety of esters to be converted into the corresponding α-acetoxy ethers in good to excellent yields. It was found that, under mild acidic conditions, many α-acetoxy ethers can be further reduced to the corresponding ethers. This net two-step ester deoxygenation is an attractive alternative to the classical Williamson synthesis for certain ethers.
- Kopecky, David J.,Rychnovsky, Scott D.
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p. 191 - 198
(2007/10/03)
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- Structure-Activity Relationships in the Esterase-catalysed Hydrolysis and Transesterification of Esters and Lactones
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The Broensted exponents for the alkaline hydrolysis of alkyl esters are 1.3 and 0.4 for substitution in the acyl and alcohol portions, respectively, which is indicative of a transition state which resembles the anionic tetrahedral intermediate with a localised negative charge.By contrast, the rate of the pig liver esterase (PLE)-catalysed hydrolysis shows little dependence upon the electron-withdrawing power of substituents.The values of kcat are independent of the pKa of the leaving group alcohol suggesting rate-limiting deacylation.There is a small steric effect of α-substitution in both the alcohol and carboxylic acid residues for the enzyme-catalysed reactions but the enzyme rate enhancement factor remains high for most esters.There is no substantial ee observed for the hydrolysis of racemic esters although the kinetic data can be used for determining the regioselective hydrolysis of diesters.Unsubstituted lactones are poor substrates for PLE but derivatives with hydrophobic substituents show kcat/Km values similar to those for acyclic esters.Dihydrocoumarin undergoes transesterification catalysed by PLE, kcat increases with increasing alcohol concentration indicative of rate-limiting deacylation.There is enantioselectivity in the PLE-catalysed hydrolysis of some racemic lactones but little or none in the transesterification of racemic alcohols with dihydrocoumarin.
- Barton, Patrick,Laws, Andrew P.,Page, Michael I.
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p. 2021 - 2030
(2007/10/02)
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- A New and Efficient Esterification Reaction via Mixed Anhydrides by the Promotion of a Catalytic Amount of Lewis Acid
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In the presence of a catalytic amount of Lewis acid, various carboxylic esters or S-phenyl carbothioates are prepared in excellent yields by the respective reactions of equimolar amounts of silyl carboxylates and alkyl silyl ethers or phenyl silyl sulfides with 4-trifluoromethylbenzoic anhydride.
- Miyashita, Mitsutomo,Shiina, Isamu,Miyoshi, So,Mukaiyama, Teruaki
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p. 1516 - 1527
(2007/10/02)
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- A New and Efficient Method for the Preparation of S-Phenyl Carbothioates via Mixed Anhydrides Using Active Titanium(IV) Salts
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In the presence of a catalytic amount of titanium(IV) salt, various S-phenyl carbothioates are prepared in excallent yields by the reaction of nearly equimolar amounts of silyl derivatives of carboxylic acids and benzenethiols with p-trifluoromethylbenzoic anhydride.
- Mukaiyama, Teruaki,Miyashita, Mitsutomo,Shiina,, Isamu
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p. 1747 - 1750
(2007/10/02)
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- A Novel Transesterification of Thioesters with Alcohols by an Electrochemical Activation
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Esters were synthesized from thioesters and alcohols in high yields by an electrochemical activation.Different results were obtained by the use of n-Bu4N+ I- and LiBF4 as the electrolyte.
- Yamaguchi, Masahiko,Tsukamoto, Yukiharu,Minami, Toru
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p. 1223 - 1226
(2007/10/02)
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- Efficient acylation of alcohols with acylthiazolidine-2-thiones and cesium fluoride
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Primary alcohols are acylated in good yield under almost neutral conditions with 3-acylthiazolidine-2-thiones and cesium fluoride.For secondary alcohols, the yield is improved by the addition of zinc bromide. t-Butanol is not acylated.
- Yamada, M.,Yahiro, S.,Yamano, T.,Nakatani, Y.,Ourisson, G.
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p. 824 - 829
(2007/10/02)
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- Influence of the β-Substitution on the Photochemistry of α,2-Diacetoxystyrenes. Irradiatin of Phenyl, Vinyl, and Benzyl Derivatives
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β-Substitution shows a pronounced influence on the photochemistry of α,2-diacetoxystyrenes.As in the case of the parent compound, intramolecular cyclization with participation of the neighbouring 2-acetoxy group takes place upon irradiation of the enol esters 4a-c; however other processes are also observed, depending on the substrate.The phenyl derivative 4a gives the E isomer 7a and the phenanthrene 9.The vinyl derivative 4b also undergoes cis-trans isomerization and/or photooxidation, to afford 7b and 10.Finally, a 1,4-acyl migratin occurs in the benzyl derivative 4c, whereby the 1,4-diketone 12 is formed.
- Alvaro, Mercedes,Baldovi, Vicenta,Garcia, Hermenegildo,Miranda, Miguel, A.,Primo, Jaime
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p. 267 - 274
(2007/10/02)
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