Palladium-Catalyzed N-Acylation of Monosubstituted Ureas Using Near-Stoichiometric Carbon Monoxide
Klaus Bjerglund, Anders T. Lindhardt and Troels Skrydstrup*
*Center for Insoluble Protein Structures, Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark, Email: tschem.au.dk
K. Bjerglund, A. T. Lindhardt, T. Skrydstrup, J. Org. Chem., 2012, 77, 3793-3799.
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A palladium-catalyzed carbonylation of urea derivatives with aryl iodides and bromides afforded N-benzoyl ureas in very good yields using near-stoichiometric amounts of carbon monoxide generated from the decarbonylation of 9-methylfluorene-9-carbonyl chloride as CO precursor. The synthetic protocol displayed good functional group tolerance. The methodology is also highly suitable for 13C isotope labeling.
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Release of carbon monoxide from COgen at temperatures higher than 50°C can be performed using both P(tBu)3 or the air stable precursor HBF4P(tBu)3 as ligand without change in results.
Anders T. Lindhardt, December 27, 2012
Palladium-Catalyzed Approach to Primary Amides Using Nongaseous Precursors
D. U. Nielsen, R. H. Taaning, A. T. Lindhardt, T. M. Gøgsig, T. Skrydstrup, Org. Lett., 2011, 13, 4454-4457.
Urea Derivatives, Aminocarbonylation