Palladium-Catalyzed N-Acylation of Monosubstituted Ureas Using Near-Stoichiometric Carbon Monoxide

The palladium-catalyzed carbonylation of urea derivatives with aryl iodides and bromides afforded N-benzoyl ureas (20 examples) in yields attaining quantitative via the application of near-stoichiometric amounts of carbon monoxide generated from the decarbonylation of the CO precursor, 9-methylfluorene-9-carbonyl chloride. The synthetic protocol displayed good functional group tolerance. The methodology is also highly suitable for 13C isotope labeling, which was demonstrated through the synthesis of three benzoyl ureas, including the insecticide triflumuron, whereby 13CO was incorporated into the core structure.