Palladium-Catalyzed C8-Oxygenation of Naphthalene Derivatives: Direct Access to Naphtholactone Skeleton

Herein, a direct C8-oxygenation of naphthalene derivatives is described. Different carbonyl groups were used as directing group to deliver corresponding naphthols via a palladium-catalyzed oxidation reaction using PhI(OAc)₂ in a TFA/TFAA mixture. Interestingly, when Weinreb amide was employed as the directing group, the naphtholactone skeleton was directly obtained. This methodology was applied to the synthesis of variously substituted naphtholactones. (Figure presented.).