An efficient synthesis of 4-bromo-N-substituted oxindoles by an intramolecular copper-catalyzed amidation reaction

A highly efficient synthetic approach to novel 4-bromo-N-substituted oxindoles is described. The method involves a mild intramolecular copper-catalyzed amidation reaction of N-substituted 2,6-dibromophenylacetamides. In contrast to our recently published palladium-catalyzed amidation reaction, no concomitant dimerization on the 3-position of the formed oxindole occurs.