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 C-13 isotope labeling, which was demonstrated through the synthesis of three benzoyl ureas, including the insecticide triflumuron, whereby (CO)-C-13 was incorporated into the core structure.