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.
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.