3581-70-2Relevant articles and documents
The effect of solvent polarity on the rate of the Mitsunobu esterification reaction
Camp, David,Harvey, Peta J.,Jenkins, Ian D.
, p. 3932 - 3938 (2015)
The rate of the Mitsunobu esterification reaction of ethanol or isopropanol with benzoic acid was found to be much faster in non-polar solvents. The logarithm of the rate constant was inversely proportional to the solvent polarity, as defined by ET values. Typically, the rate constant for ethyl benzoate formation in THF was 100 times greater than that in MeCN. The presence of either sodium benzoate or excess benzoic acid resulted in a decrease in rate. Each of the main species involved in the Mitsunobu esterification reaction, the alcohol starting material, dialkoxyphosphorane, alkoxyphosphonium salt and ester product, was detected by proton NMR analysis. The possible role of ion pair aggregates or clusters, prior to rate-determining SN2 attack of carboxylate on the alkoxyphosphonium ion, is discussed. An explanation is provided as to why the yield in the Mitsunobu reaction is often higher in non-polar solvents.
Oxidative esterification of alcohols by a single-side organically decorated Anderson-type chrome-based catalyst
Wang, Jingjing,Jiang, Feng,Tao, Chaofu,Yu, Han,Ruhlmann, Laurent,Wei, Yongge
supporting information, p. 2652 - 2657 (2021/04/21)
The direct esterification of alcohols with non-noble metal-based catalytic systems faces great challenges. Here, we report a new chrome-based catalyst stabilized by a single pentaerythritol decorated Anderson-type polyoxometalate, [N(C4H9)4]3[CrMo6O18(OH)3C{(OCH2)3CH2OH}], which can realize the efficient transformation from alcohols to esters by H2O2oxidation in good yields and high selectivity without extra organic ligands. A variety of alcohols with different functionalities including some natural products and pharmaceutical intermediates are tolerated in this system. The chrome-based catalyst can be recycled several times and still keep the original configuration and catalytic activity. We also propose a reasonable catalytic mechanism and prove the potential for industrial applications.
Gram-Scale Preparation of Acyl Fluorides and Their Reactions with Hindered Nucleophiles
Barbasiewicz, Micha?,Tryniszewski, Micha?
, (2021/11/30)
A series of acyl fluorides was synthesized at 100 mmol scale using phase-transfer-catalyzed halogen exchange between acyl chlorides and aqueous bifluoride solution. The convenient procedure consists of vigorous stirring of the biphasic mixture at room temperature, followed by extraction and distillation. Isolated acyl fluorides (usually 7-20 g) display excellent purity and can be transformed into sterically hindered amides and esters when treated with lithium amide bases and alkoxides under mild conditions.
Palladium-Catalyzed Para-Selective Difluoromethylation of Arene Esters
Tu, Guangliang,Wang, Dongjie,Yuan, Chunchen,Zhang, Jingyu,Zhao, Yingsheng
, p. 10740 - 10749 (2020/09/18)
Highly efficient, palladium-catalyzed, para-selective difluoromethylation of arene esters has been developed using [1,1′-biphenyl]-2-dicyclohexylphosphine as the effective ligand. A wide variety of arene esters bearing various functional groups were all compatible with the reaction conditions, leading to para-difluoromethylated products in moderate to good yields. Moreover, benzoylamide and benzenesulfonamide were also well-tolerated, suggesting that this novel catalyst system has broad applications to a variety of substrates.
Synthesis of Sulfonimidamides from Sulfenamides via an Alkoxy-amino-λ6-sulfanenitrile Intermediate
Briggs, Edward L.,Tota, Arianna,Colella, Marco,Degennaro, Leonardo,Luisi, Renzo,Bull, James A.
supporting information, p. 14303 - 14310 (2019/09/06)
Sulfonimidamides are intriguing new motifs for medicinal and agrochemistry, and provide attractive bioisosteres for sulfonamides. However, there remain few operationally simple methods for their preparation. Here, the synthesis of NH-sulfonimidamides is achieved directly from sulfenamides, themselves readily formed in one step from amines and disulfides. A highly chemoselective and one-pot NH and O transfer is developed, mediated by PhIO in iPrOH, using ammonium carbamate as the NH source, and in the presence of 1 equivalent of acetic acid. A wide range of functional groups are tolerated under the developed reaction conditions, which also enables the functionalization of the antidepressants desipramine and fluoxetine and the preparation of an aza analogue of the drug probenecid. The reaction is shown to proceed via different and concurrent mechanistic pathways, including the formation of novel S≡N sulfanenitrile species as intermediates. Several alkoxy-amino-λ6-sulfanenitriles are prepared with different alcohols, and shown to be alkylating agents to a range of nucleophiles.
Aldehydes as potential acylating reagents for oxidative esterification by inorganic ligand-supported iron catalysis
Yu, Han,Wang, Jingjing,Wu, Zhikang,Zhao, Qixin,Dan, Demin,Han, Sheng,Tang, Jiangjiang,Wei, Yongge
supporting information, p. 4550 - 4554 (2019/08/21)
The oxidative esterification of various aldehydes with alcohols could be achieved by a heterogeneous iron(iii) catalyst supported on a ring-like POM inorganic ligand under mild conditions, affording the corresponding esters, including several drug molecules and natural products, in high yields. ESI-MS and control experiments demonstrated that POM-FeV(O) was the active catalytic species and the plausible mechanism was presented. More importantly, the 6th run of the iron catalyst recycles shows only a slight decrease in the yield.
ACYLATION REACTION OF HYDROXYL GROUP
-
Page/Page column 15-16, (2010/07/03)
Disclosed is a selective ester production process of an alcoholic hydroxyl group, which proceeds under chemically mild conditions, while having adequate environmental suitability, operability and economical efficiency. Specifically disclosed is a process for producing an ester compound, which is characterized in that an alcohol and a carboxylic acid ester compound are reacted in the presence of a compound containing zinc element, thereby selectively acylating a hydroxyl group of the alcohol.
Esterification of sterically hindered acids and alcohols in fluorous media
Gacem, Badra,Jenner, Gérard
, p. 1391 - 1393 (2007/10/03)
Sterically hindered esterification reactions are best performed in specific fluorous media in the presence of catalytic amounts of diphenylammonium triflate. Fluorous media, in addition to their positive effect on yields, have inherent favorable properties respecting environment and permitting simple work-up. Highly congested reagents, however, react only marginally.
Mixed Tishchenko reaction over solid base catalysts
Seki, Tsunetake,Kabashima, Hajime,Akutsu, Kazumasa,Tachikawa, Hiroto,Hattori, Hideshi
, p. 393 - 401 (2007/10/03)
Catalytic behaviors of solid base catalysts for mixed Tishchenko reactions were investigated to elucidate the activity- and selectivity-determining factors in active sites of the catalysts and molecular structures of the reactants. A mixture containing equal amounts of two kinds of aldehydes was allowed to react at 353 K. The aldehydes used were benzaldehyde, pivalaldehyde, and cyclopropanecar-baldehyde. For all the reactions, the catalytic activity of alkaline earth oxides increased in the order of BaO ? MgO 2O3, ZrO2, ZnO, γ-alumina, hydrotalcite, KF/alumina, and KOH/alumina, were all inactive for the mixed Tishchenko reaction of benzaldehyde and pivalaldehyde; not only crossed-condensation products but also self-condensation products hardly formed. Quantum chemical calculations of the positive charges on the carbonyl carbon atoms of aldehydes and the structure parameters of the active species for the ester formations account for the observed selectivities to four Tishchenko dimers. The selectivities to four Tishchenko dimers over MgO and CaO are determined primarily in the step of the nucleophilic addition of the active species (PhCH2O-, tBuCH2O-, and C3H5CH2O-) to the carbonyl carbon atoms of aldehydes. The reaction of the aldehyde having a more positively charged and sterically less-hindered carbonyl carbon atom with the active species having a less-hindered oxygen atom proceeds faster.
The invention of radical reactions. Part XXXVII. A convenient radical synthesis of dialkyl diselenides from carboxylic acids
Barton, Derek H. R.,Fontana, Giovanni
, p. 11163 - 11176 (2007/10/03)
A new and convenient synthesis of dialkyl diselenides from carboxylic acids by Barton PTOC ester based radical chemistry is described. This method was especially successful when O-cholestan-3β-yl-2,2,2-trichloroselenoacetate and O-neopentyl selenobenzoate
