One-pot tandem synthesis of 2-arylbenzoxazole derivatives via copper-catalyzed C-N and C-O bond formation

The reaction of 2-(2-halophenyl)halobenzamides with a series of nitrogen nucleophiles resulted in the formation of benzoxazole derivatives. This procedure involves copper-catalyzed one-pot tandem C-N/C-O coupling reactions. No ligand was used in the reaction, even in the cases of primary or secondary amides, which were used as N-nucleophiles. However, L-proline was used as ligand in the case of N-aromatic heterocycles like indole, imidazole and pyrazole derivatives.