Synthesis of 2,5-diaryloxazoles through van Leusen reaction and copper-mediated direct arylation

The direct arylation of 5-aryloxazoles, prepared by the van Leusen reaction, with various aryl iodides is effectively promoted by a system of CuI combined with PPh3 and Na2CO3 as a ligand and a base, respectively, in DMF to produce the corresponding 2,5-diaryloxazoles in good yields.