Cu-Catalyzed Consecutive Hydroxylation and Aerobic Oxidative Cycloetherification under Microwave Conditions: Entry to 2-Arylbenzofuran-3-carboxylic Acids

A convenient one-pot synthesis of 2-arylbenzofuran-3-carboxylic acids from (E)-2-(2-bromophenyl)-3-phenylacrylic acids via Cu-catalyzed consecutive hydroxylation and aerobic oxidative cycloetherification under microwave conditions has been developed. This protocol employed the reagent combination of Cu(OAc)(2), 1,10-phen, and KOH in DMSO/H2O (1:1), all of which are cost-effective, readily available, and easily removable from the reaction mixture. Utilizing this synthetic protocol, various 2-arylbenzofuran-3-carboxylic acids as well as the natural product moracin M have been synthesized in satisfactory yields under mild conditions.