Ligand-free copper(0) catalyzed direct C-H arylation of 1,2,4-triazoles and 1,3,4-oxadiazoles with aryl iodides in PEG-400

A ligand-free copper catalyzed approach has been developed to the synthesis of 3,4,5-triaryl-1,2,4-triazoles and 2,5-diaryl-1,3,4-oxadiazoles by the direct arylation of corresponding 3,4-diaryl-1,2,4-triazoles and 2-aryl-1,3,4-oxadiazoles with aryl iodides using PEG-400 as reaction medium. The procedure is experimentally simple and free from addition of external chelating ligands or co-catalysts. (C) 2014 Elsevier Ltd. All rights reserved.