Palladium-catalyzed synthesis of aromatic acids from carbon monoxide and aromatic compounds via the aromatic CH bond activation

Various aromatic acids can be prepared from aromatic compounds and CO under mild conditions by Pd-based catalysts via direct aromatic CH bond activation. With PdII catalysts, the reaction is electrophilic and proceeds with ortho-para orientation when an electron-donating group is attached to the benzene ring; addition of t-BuOOH and allyl halides makes the reaction catalytic with respect to palladium(II). β-Naphthoic acid can be prepared from naphthalene and CO by the Pd/phenanthroline catalyst system in 421% yield based on Pd and in 92% selectivity.