15024-12-1Relevant articles and documents
Pd-catalyzed C-H carbonylation of (Hetero)arenes with formates and intramolecular dehydrogenative coupling: A shortcut to indolo[3,2- c ]coumarins
Wu, Jie,Lan, Jingbo,Guo, Siyuan,You, Jingsong
supporting information, p. 5862 - 5865 (2015/01/08)
An efficient protocol for the synthesis of (hetero)aryl carboxylic esters has been achieved by Pd-catalyzed C-H carbonylation of (hetero)arenes with aryl formates. A relatively wide range of functional groups can be tolerated in this transformation, and the corresponding esters are obtained in good yields. On this basis, an intramolecular oxidative C-H/C-H coupling has been developed to prepare indolo[3,2-c]coumarins.
Palladium-catalyzed esterification of aryl halides using aryl formates without the use of external carbon monoxide
Fujihara, Tetsuaki,Hosoki, Tomoya,Katafuchi, Yuko,Iwai, Tomohiro,Terao, Jun,Tsuji, Yasushi
, p. 8012 - 8014 (2012/09/08)
Aryl formates are efficient carbon monoxide sources in palladium-catalyzed esterification of aryl halides. The carbonylation readily proceeds at ambient pressure without the use of external carbon monoxide to afford the corresponding esters in high yields.
N-heterocyclic carbene-catalyzed aerobic oxidative direct esterification of aldehydes with organoboronic acids
Meng, Jing-Jing,Gao, Min,Wei, Yu-Ping,Zhang, Wen-Qin
experimental part, p. 872 - 875 (2012/07/03)
A simple procedure affording benzoates through a NHC-catalyzed aerobic oxidative esterification of aldehydes with organoboronic acids has been disclosed. This process allows access to a wide variety of aromatic esters in good to excellent yields under simple, efficient, and sustainable reaction conditions (see scheme).
Rhodium-catalyzed cleavage reaction of aryl methyl ethers with thioesters
Arisawa, Mieko,Nihei, Yuri,Suzuki, Takaaki,Yamaguchi, Masahiko
supporting information; experimental part, p. 855 - 857 (2012/03/26)
A rhodium complex catalyzed the reaction of aryl methyl ethers and thioesters giving the corresponding aryl esters and methyl sulfides. S-(p-Chlorophenyl) p-(dimethylamino)benzothioate was used for the reaction of methyl aryl ethers with electron-withdrawing groups, and an S-(p-tolyl) derivative was used for those with electron-donating groups. Polymethoxybenzenes were converted to the esters in a regioselective manner.
Evidence of substituent-induced electronic interplay. Effect of the remote aromatic ring substituent of phenyl benzoates on the sensitivity of the carbonyl unit to electronic effects of phenyl or benzoyl ring substituents
Neuvonen, Helmi,Neuvonen, Kari,Pasanen, Paavo
, p. 3794 - 3800 (2007/10/03)
Carbonyl carbon 13C NMR chemical shifts δC(C=O) measured in this work for a wide set of substituted phenyl benzoates p-Y-C 6H4CO2C6H4-p-X (X = NO2, CN, Cl, Br, H, Me, or MeO; Y = NO2, Cl, H, Me, MeO, or NMe2) have been used as a tool to study substituent effects on the carbonyl unit. The goal of the work was to study the cross-interaction between X and Y in that respect. Both the phenyl substituents X and the benzoyl substituents Y have a reverse effect on δC(C=O). Electron-withdrawing substituents cause shielding while electron-donating ones have an opposite influence, with both inductive and resonance effects being significant. The presence of cross-interaction between X and Y could be clearly verified. Electronic effects of the remote aromatic ring substituents systematically modify the sensitivity of the C=O group to the electronic effects of the phenyl or benzoyl ring substituents. Electron-withdrawing substituents in one ring decrease the sensitivity of δC(C=O) to the substitution of another ring, while electron-donating substituents inversely affect the sensitivity. It is suggested that the results can be explained by substituent-sensitive balance of the contributions of different resonance structures (electron delocalization, Scheme 1).
Intramolecular charge transfer dual fluorescence of substituted-phenyl p-dimethylaminobenzoates with comparable electron acceptors
Huang, Wei,Zhang, Xuan,Li-Hua, Ma.,Wang, Chao-Jie,Jiang, Yun-Bao
, p. 401 - 407 (2007/10/03)
A series of substituted-phenyl p-dimethylaminobenzoates with para- or meta-substitution at the ester phenyl ring (p-OH, p-CH3, H, p-Br, m-Cl, and p-NO2) were synthesized and their fluorescence spectra were recorded. Intramolecular ch
Substituent effects on the base-catalysed hydrolysis of phenyl esters of para-substituted benzoic acids
Bauerova, Ingrid,Ludwig, Miroslav
, p. 1777 - 1790 (2007/10/03)
Seventeen model phenyl esters of 4-substituted benzoic acids were synthesised by the reaction of substituted benzoyl chlorides with phenol in aqueous alkaline solutions (Schotten-Baumann reaction), in pyridine (Einhorn reaction), or by the reaction of substituted benzoic acids with phosphorus oxychloride. Structures and purity of the model compounds were confirmed by 1H NMR and 13C NMR spectroscopy as well as by HPLC and elemental analysis. Phenyl 4-aminobenzoate was synthesised by reduction of phenyl 4-nitrobenzoate in methanol on palladium. Kinetics of base-catalysed hydrolysis of model phenyl esters occurring by the BAc2 mechanism were measured by UV spectrophotometry in 50% (v/v) aqueous dimethyl sulfoxide solutions at 25°C under pseudo-first-order conditions, (c[NaOH] = 0.001-1.0 mol l-1). The addition of OH- to phenyl benzoates was used to establish the kinetic J-E acidity scale. Linear relation between J-E and log kobs with the slope near unity was found for all the model compounds. The kinetic constants of hydrolysis of phenyl esters of 4-substituted benzoic acids precisely obey the Hammett relationship (σp) with ρ = 2.44. Quantitatively comparable results have been obtained by application of Alter-native Interpretation of Substituent Effects theory (AISE) using the σi set of substituent constants.
A STUDY OF TRANSMISSION EFFECTS OF SULFONYL AND CARBONYL GROUPS
Ludwig, Miroslav,Parik, Patrik,Kulhanek, Jiri
, p. 841 - 850 (2007/10/02)
Seventeen p-substituted N-phenylsulfonylbenzamides of general formulas XC6H4SO2NHCOC6H5 and C6H5SO2NHCOC6H4X have been synthesized and their structure has been confirmed by elemental analysis and 1H NMR spectra.The dissociation constants of all compounds have been measured by potentiometric titration in methanol, acetonitrile, dimethylformamide, dimethyl sulfoxide, and pyridine.The obtained pKHA values have been correlated with three sets of Hammett substituent constants using simple or double linear regression.The solvent and substituent effects are discussed on the basis of experimental results, and the difference between the substituent effects from sulfonamide and benzamide sections is evaluated.It has been found that due to extensive delocalization of negative charge in the conjugated base the transmission effects of carbonyl and sulfonyl groups on the transmission of substituent effect are roughly the same.The experimental data have been interpreted by the methods with latent variables: the principal component analysis (PCA), the conjugated deviation analysis (CDA), and the method of projection to latent structures (PLS).The results obtained by these procedures were similar.
