Palladium-Catalyzed Chemoselective Oxygenation of C(sp 2 )-H and C(sp 3 )-H Bonds in Isatins.

The palladium-catalyzed chemoselective C(sp 2 )-H and C(sp 3 )-H bond oxygenation of substituted isatin derivatives is reported. This mild protocol exhibits the C5 C(sp 2 )-H oxygenation of isatins through electrophilic intermolecular C-H palladation in concentrated solutions using PhI(OAc) 2 or Selectfluor as an oxidant, whereas it exhibits-N-CH 3 C(sp 3 )-H oxygenation in dilute solutions via carbonyl-assisted intramolecular palladation in the presence of K 2 S 2 O 8 . This oxygenation reaction provides a direct and unified approach for synthesizing diverse oxygenated isatins with sensitive functionalities, including biorelevant compounds.