Cleavage of Carboxylic Esters by Aluminum and Iodine
Dayong Sang*, Huaxin Yue, Yang Fu and Juan Tian*
*College of Chemical Engineering and Pharmacy, Jingchu University of Technology, 33 Xiangshan Road, Jingmen, Hubei 448000, P. R. China,
Email: sangdy
jcut.edu.cn, tianjuanjcut.edu.cn
D. Sang, H. Yue, Y. Fu, J. Tian, J. Org. Chem., 2021, 86, 4254-4261.
DOI: 10.1021/acs.joc.1c00034
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Abstract
Aluminum powder and iodine in anhydrous acetonitrile mediate a one-pot deprotecting of alkyl carboxylates under nonhydrolytic conditions. Cleavage of lactones affords the corresponding ω-iodoalkylcarboxylic acids. This method enables the selective cleavage of alkyl carboxylic esters in the presence of aryl esters.
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proposed mechanism
anchimeric assistance
Note
An additional equivalent of Al (vs. iodine) will help shorten the time needed for the purple color of iodine to vanish to values below 0.5 h, whereas several hours would be needed if equimolar amounts of iodine and aluminium are used. Our explanation is that the aluminum powder contains aluminum oxide. The anhydrous MeCN (HPLC grade) contains less than 500 ppm of water. The water content is important, because water will hydrolyze AlI3.
Dayong Sang, December 12, 2021
Key Words
carboxylic acids, methyl esters
ID: J42-Y2021
