I2/TBHP-mediated tandem cyclization and oxidation reaction: Facile access to 2,5-disubstituted oxazoles

A nonmetal-catalyzed oxidative cyclization sequence for the construction of 2,5-disubstituted oxazoles is presented. This procedure shows broad substrate scope. Compared with the traditional method of obtaining oxazoles, using substituted chalcones and ammonium oxalate can make the reaction milder and cheaper. Notably, the reaction proceeds smoothly under the system of I2/TBHP, which is very friendly to the environment.