Palladium(II)-catalyzed allylic C-H oxidation of hindered substrates featuring tunable selectivity over extent of oxidation.

The use of Oxone and a palladium(II) catalyst enables the efficient allylic CH oxidation of sterically hindered α-quaternary lactams which are unreactive under known conditions for similar transformations. This simple, safe, and effective system for CH activation allows for unusual tunable selectivity between a two-electron oxidation to the allylic acetates and a four-electron oxidation to the corresponding enals, with the dominant product depending on the presence or absence of water. The versatile synthetic utility of both the allylic acetate and enal products accessible through this methodology is also demonstrated.