Phenyliodine Bis(trifluoroacetate)-Mediated Oxidative C-C Bond Formation: Synthesis of 3-Hydroxy-2-oxindoles and Spirooxindoles from Anilides

The reaction of phenyliodine bis(trifluoroacetate) (PIFA) with a series of anilides 1 (E = CO2Et) In CF3CH2OH was found to give 3-hydroxy-2-oxindole derivatives 2, while that with various anilides 1' (E = CON(R-4)Ar) afforded the C-2-symmetric or unsymmetric spirooxindoles 3. These processes feature a metal-free oxidative C(sp(2))-C(sp(3)) bond formation, followed by oxidative hydroxylation or spirocyclization.