Microwave-assisted intramolecular Friedel–Crafts acylation of some aryl aliphatic acids using Gd(OTf)3/[BMI]BF4 catalytic system.

Abstract

Intramolecular Friedel–Crafts acylation of aryl acids is a “green” reaction and environmentally benign, generates some valuable intermediated compounds for pharmaceutical uses. In addition, metal triflates under microwave irradiation are efficient catalysts, solving many problems when using traditional Lewis acids. Gd(OTf)₃/[BMI]BF₄, a good catalyst for the intramolecular Friedel–Crafts acylation under mild condition with high yield, reduced the reaction time and pollution. Furthermore, Gd(OTf)₃ in [BMI]BF₄ was easily recovered and reused without significant loss of its activity.