Unsymmetric Ureas via Palladium-Catalyzed Amidation

Significance

Bippyphos, a novel nonproprietary bipyrazole ligand, in combination with Pd₂(dba)₃ is demonstrated to be an efficient catalyst for the amidation of aryl and N-heterocyclic chlorides and bromides using monosubstituted phenyl, benzyl or alkyl ureas. The reaction proceeds in moderate to very good yields and tolerates a variety of functional groups using potassium phosphate as a mild base.