Selective Acylation of Phenols in Boron Trifluoride Diethyl Etherate Solution and the Mechanistic Implication
作者:Zhu-Ping Xiao、Wei Wei、Shen Huang、Xiao-Yi Lin、Bin Peng、Xu-Dong Wang、Lei Zhang
DOI:10.14233/ajchem.2014.17019
日期:——
In the presence of boron trifluoride diethyl etherate (BF3·OEt2), direct acylation of phenols with free carboxylic acid is chemoselective and regioselective and no demethylation, if any, was observed. The para-directing effect of BF3·OEt2 is attributed to the large steric hindrance of the boron trifluoride-phenolic hydroxyl group complex, which blocks the ortho-acylation from occurrence. Microwave irradiation could not change the regioselectivity of BF3·OEt2 except the reaction time being greatly shortened.
在三氟化硼二乙醚合物(BF3·OEt2)的存在下,酚类化合物直接与游离羧酸酰化反应具有化学选择性和区域选择性,并且没有观察到脱甲基化现象。BF3·OEt2的导向效应归因于硼三氟化物-酚羟基络合物的大位阻,这阻碍了邻位酰化的发生。微波照射不能改变BF3·OEt2的区域选择性,除了反应时间大大缩短。