Pd-catalyzed C-H oxygenation with TFA/TFAA: expedient access to oxygen-containing heterocycles and late-stage drug modification.

Acid brings the oxygen: a general method for palladium-catalyzed C-H oxygenation has been developed for the facile synthesis of a wide range of functionalized phenols with readily available aryl ketones, benzoates, benzamides, acetanilides, and sulfonamides. A trifluoroacetic acid/trifluoroacetic acid anhydride solvent system serves as the oxygen source and is the critical factor for C-H activation.