A simple and efficient transprotection of aryl methyl ether to aryl benzoate under microwave activation
摘要:
A simple and efficient method for the transprotection of aryl methyl ether to easily cleavable arylbenzoate mediated by microwave activation has been developed. One important feature of this method is its high tolerance towards sensitive functionalities and to some extent to bulky environment. (c) 2006 Elsevier Ltd. All rights reserved.
HF–Pyridine: A Versatile Promoter for Monoacylation/Sulfonylation of Phenolic Diols and for Direct Conversion of <i>t</i>-Butyldimethylsilyl Ethers to the Corresponding Acetates
Monoacylation and trifluoromethanesulfonylation of phenolic diols were achieved by the aid of HF–pyridine, whereas diacylation occurred with pyridine alone. Furthermore, HF–pyridine was found to promote the direct conversion of t-butyldimethylsilyl ethers to the corresponding acetates.
is commercially available, is a practical and useful Lewis acidcatalyst for acylation of alcohols with acidanhydrides or the esterification of alcohols by carboxylic acids in the presence of p-nitrobenzoic anhydrides. The remarkably high catalytic activity of scandium triflate can be used for assisting the acylation by acidanhydrides of not only primary alcohols but also sterically-hindered secondary
Electrostatic catalysis by ionic aggregates: scope and limitations of Mg(ClO4)2 as acylation catalyst
作者:Asit K Chakraborti、Lalima Sharma、Rajesh Gulhane、Shivani
DOI:10.1016/j.tet.2003.08.007
日期:2003.9
Alkali and alkaline earthmetal perchlorates exhibit electrostatic catalysis in the activation of anhydrides for the acylation reaction. Perchlorates with higher values of the charge-size function of the metal ion exhibit better catalytic activity following the order Mg(ClO4)2>Ba(ClO4)2>LiClO4. Acylation of structurally diverse phenols, thiols, alcohols, and amines have been carried out with stoichiometric
Magnesium Bistrifluoromethanesulfonimide as a New and Efficient Acylation Catalyst
作者:Asit K. Chakraborti、Shivani
DOI:10.1021/jo0605142
日期:2006.7.1
room temperature and in short times. Electron-deficient and sterically hindered phenols provided excellent yields. The catalyst was found to be general for acylation with other anhydrides, such as propionic, isobutyric, pivalic, chloroacetic, and benzoic anhydrides. The rate of acylation was influenced by the electronic and steric factors associated with the anhydride. The reaction with less electrophilic
Hydrogen-bond-assisted transition-metal-free catalytic transformation of amides to esters
作者:Changyu Huang、Jinpeng Li、Jiaquan Wang、Qingshu Zheng、Zhenhua Li、Tao Tu
DOI:10.1007/s11426-020-9883-3
日期:2021.1
interest in synthetic chemistry, biological process and pharmaceutical industry. Transition-metal, luxury ligand or excess base were always vital to the transformation. Here, we developed a transition-metal-free hydrogen-bond-assisted esterification of amides with only catalytic amount of base. The proposed crucial role of hydrogen bonding for assisting esterification was supported by control experiments