Selective Friedel-Crafts Acylation Reactions of 2-Arylphenoxy-acetic Acids: A Simple and Efficient Methodology to Synthesize Dibenzoxepine and Arylcoumaranone Derivatives

摘要

Intramolecular Friedel-Crafts acylation reactions of 2-arylphenoxyacetic acids are accomplished using trifluoroacetic anhydride or trifluoromethanesulfonic acid at 0 degrees C or room temperature. Depending on the reaction conditions, dibenzoxepines or arylcoumaranones are obtained in good yields and with high selectivities (83-100%). Plausible mechanistic pathways for the selective formation of the different reaction products are discussed.