An efficient palladium-catalyzed synthesis of symmetrically disubstituted ureas via oxidative carbonylation of primary amines is described. The reactions are carried out in the presence of a large excess of carbon dioxide as reaction medium or under solvent-free conditions. The adopted catalyst such as potassium tetraiodopalladate, stable and easy to prepare, allows the use of air as a cheap oxidizing agent. The reactions yield urea and water as the ...