Dependence of Aryl Ether Acylation upon Lewis Acid Stoichiometry

Article abstract of DOI:10.1021/ja00529a031

Acylation of alkyl aryl ethers has been observed to be uniquely dependent on the stoichiometry of the Friedel-Crafts catalyst.With 100 molpercent catalyst, acylation proceeds rapidly and in high yield; with large molar excesses of catalyst, the reaction is essentially completely arrested.This inhibition can be reversed by using sterically bulky alkyl groups which effectively prevent complexing between catalyst and aryl ether.Based on these observations, we have developed processes for regioselective intramolecular acylation of either a phenyl or an alkoxylated phenyl ring when both are present.