Metal-free formal carbon-halogen bond insertion: facile syntheses of 3-halo 3,3'-disubstituted oxindoles and spirooxindole-γ-butyrolactones.

Metal-free formal carbon-halogen bond insertion: facile syntheses of 3-halo 3,3'-disubstituted oxindoles and spirooxindole-γ-butyrolactones.