13189-55-4Relevant academic research and scientific papers
Cu(II)-silsesquioxanes as efficient precatalysts for Chan-Evans-Lam coupling
Astakhov, G. S.,Bantreil, X.,Bilyachenko, A. N.,Dorovatovskii, P. V.,Khrustalev, V. N.,Lamaty, F.,Levitsky, M. M.,Shubina, E. S.,Zubavichus, Y. V.
, (2020)
Two cage copper(II)silsesquioxanes, namely, tricopper complex (PhSiO1.5)8(CuO)3(TMEDA)2*(MeCN)3 Cu-1 and hexacopper complex (MeSiO1,5)12(CuO)6(Py)6*TMEDA Cu
Studies of reactions within molecular complexes: Alkaline hydrolysis of substituted phenyl benzoates in the presence of xanthines
Pirinccioglu, Necmettin,Williams, Andrew
, p. 37 - 40 (1998)
Complexation with caffeine and theophylline-7-acetate depresses the rate of alkaline hydrolysis of substituted phenyl benzoates and is consistent with the formation of molecular complexes with 1:1 stoichiometry between the hosts and esters; stacking of the xanthines is excluded as an explanation in the range of concentrations studied. Bronsted-type correlations have been determined for the rate and complexation constants and for the transition-state binding constants. Development of effective charge in the transition state of the reactions in bulk solvent is slightly less than that in the host-ester complex, consistent with a similar electronic environment in both states. The negative Bronsted β values for Ks indicate that the interactions between ester and hosts involve electron donation to the host from the ester. Inhibition of hydrolysis is attributed to repulsion of the hydroxide ion from the host-ester complex by the extra hydrophobicity engendered by the xanthine host, as well as by the weaker binding of the transition state to the host compared with that in the host-ester complex.
Ligand-Controlled C?O Bond Coupling of Carboxylic Acids and Aryl Iodides: Experimental and Computational Insights
Li, Li,Song, Feifei,Zhong, Xiumei,Wu, Yun-Dong,Zhang, Xinhao,Chen, Jiean,Huang, Yong
supporting information, p. 126 - 132 (2019/11/28)
Palladium-catalyzed cross-coupling reactions between carboxylic acids and aryl halides have several possible competitive pathways. Decarboxylative C?C bond coupling and C?H arylation are well established in the literature. However, direct C?O bond coupling between carboxylic acids and aryl halides has received little success. In this report, we describe a protocol for exclusive C?O bond formation, enabled by a bidentate N,N-ligand such as 1,10-phenanthroline. The reaction is general for a broad range of carboxylic acids and iodoarenes. Experimental evidence and computational results suggest a high energy barrier for the alternative pathway of decarboxylative carbon-carbon bond coupling. (Figure presented.).
Enol Ester Intermediate Induced Metal-Free Oxidative Coupling of Carboxylic Acids and Arylboronic Acids
Xu, Xianjun,Feng, Huangdi,Li, Huiqiong,Huang, Liliang
, p. 3921 - 3928 (2019/06/24)
A facile, efficient and environmentally friendly methodology for the preparation of phenolic esters is realized via metal-free coupling of carboxylic acids and arylboronic acids. This sequential one pot reaction, employing methyl propiolate as an activating reagent, proceeds through the formation of enol ester intermediate, followed by a nucleophilic attack on the C-O bond under the oxidation of hydrogen peroxide. These studies display that enol esters, despite previously being overlooked as synthetic intermediates, would be the valuable building blocks for developing carbon–carbon and carbon–heteroatom bond-forming reactions.
Palladium-catalyzed non-directed C[sbnd]H benzoxylation of simple arenes with iodobenzene dibenzoates
Li, Li,Wang, Ying,Yang, Tingting,Zhang, Qian,Li, Dong
supporting information, p. 5859 - 5863 (2016/12/09)
A palladium-catalyzed non-directed C[sbnd]H benzoxylation of simple arenes with iodobenzene dibenzoates as both benzoxylate source and oxidant has been developed. The catalytic system was greatly promoted by a pyridine ligand. Good functional groups tolerance was showed in both hypervalent iodine reagents and arene substrates, which can be used for synthesis of aryl benzoates through simple aromatic compounds.
Nucleophilic substitution reactions of Y-Substituted-Phenyl Benzoates with Potassium Ethoxide in Anhydrous Ethanol: Reaction Mechanism and Role of K+ Ion
Kim, Song-I,Cho, Hyo-Jin,Um, Ik-Hwan
, p. 177 - 181 (2014/02/14)
Pseudo-first-order rate constants (kobsd) have been measured spectrophotometrically for the reactions of Ysubstituted-phenyl benzoates (5a-j) with potassium ethoxide (EtOK) in anhydrous ethanol at 25.0 ± 0.1 °C. The plots of kobsd vs. [EtOK] curve upward regardless of the electronic nature of the substituent Y in the leaving group. Dissection of kobsd into the second-order rate constants for the reactions with the dissociated EtOV and ion-paired EtOK (i.e., kEtO-and kEtOK, respectively) has revealed that the ion-paired EtOK is more reactive than the dissociated Et-V. The Bronsted-type plots for the reactions with the dissociated Et-V and ion-paired EtOK exhibit highly scattered points with βlg = -0.5 ± 0.1. The Hammett plots correlated with ao constants result in excellent linear correlations, indicating that no negative charge develops on the O atom of the leaving Ysubstituted-phenoxide ion in transition state. Thus, it has been concluded that the reactions with the dissociated EtOV and ion-paired EtOK proceed through a stepwise mechanism, in which departure of the leaving group occurs after the RDS, and that K+ ion catalyzes the reactions by increasing the electrophilicity of the reaction center through a four-membered cyclic TS structure.
17O NMR study of ortho and alkyl substituent effects in substituted phenyl and alkyl esters of benzoic acids
Nummert, Vilve,Maeemets, Vahur,Piirsalu, Mare,Vahur, Signe,Koppel, Ilmar A.
experimental part, p. 1737 - 1763 (2012/04/17)
17O NMR spectra for 44 ortho-, meta- and para-substituted phenyl and alkyl benzoates (C6H5CO2C 6H4-X, C6H5CO2R) at natural abundance in acetonitrile were re
Kinetics and mechanism of nucleophilic displacement reactions of Y-substituted phenyl benzoates with cyanide Ion
Kim, Song-I,Kim, Eun-Hee,Um, Ik-Hwan
experimental part, p. 689 - 693 (2010/08/19)
Second-order rate constants (kCN-) have been measured for nucleophilic substitution reactions of Y-substituted phenyl benzoates (1a-r) with CN- ion in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 °C. The Bronsted-type plot is linear with βlg = -0.49, a typical βlg value for reactions reported to proceed through a concerted mechanism. Hammett plots correlated with σo and σ-constants exhibit many scattered points. In contrast, the Yukawa-Tsuno plot for the same reaction exhibits excellent linearity with pY = 1.37 and r = 0.34, indicating that a negative charge develops partially on the oxygen atom of the leaving aryloxide in the rate-determining step (RDS). Although two different mechanisms are plausible (i.e., a concerted mechanism and a stepwise pathway in which expulsion of the leaving group occurs at the RDS), the reaction has been concluded to proceed through a concerted mechanism on the basis of the magnitude of βlg and pY values.
Aminolysis of Y-substituted phenyl X-substituted benzoates with piperidine: Effect of nonleaving group substituent
Um, Ik-Hwan,Lee, Ji-Youn,Ko, Seung-Hak,Bae, Sun-Kun
, p. 5800 - 5803 (2007/10/03)
The title reaction has been suggested to proceed through a zwitterionic tetrahedral intermediate with a change in the rate determining step on the basis of the curved Bronsted-type plots obtained. The curvature center of the curved Bronsted-type plots is at pKa = 6.4 regardless of the electronic nature of the substituent X in the benzoyl moiety.
Determination of aromaticity indices of thiophene and furan by nuclear magnetic resonance spectroscopic analysis of their phenyl esters
Lee, Chang Kiu,Yu, Ji Sook,Lee, Hye-Jin
, p. 1207 - 1217 (2007/10/03)
A series of m- and p-substituted phenyl benzoates, 2-thienoates, and 2-furoates were prepared and their 1H and 13C nmr spectroscopic characteristics were examined. In general, good correlations were observed between the chemical shift values of protons and carbons of the acyl aromatic rings and the Hammett σ. Plots of the chemical shift values of the carbonyl carbons of the benzoates against those of the 2-thienoates and 2-furoates gave an excellent correlation and the values of the slopes are 0.85 and 0.75, respectively, in dimethyl sulfoxide-d6 and 0.90 and 0.78, respectively, in chloroform-d. The values could be considered as a set of aromaticity indices.
