title: Pd(II)/Ag(I)-Promoted One-Pot Synthesis of Cyclic Ureas from (Hetero)Aromatic Amines and Isocyanates.
abstract: A simple and facile one-pot reaction has been developed to afford a diverse range of N,N'-disubstituted benzimidazolones and imidazopyridinones containing two differently substituted N atoms. A cooperative Pd(II)/Ag(I) system promotes the sequential addition/intramolecular C-H amidation reaction of (hetero)aromatic amines and isocyanates, leading to the formation of two C-N bonds. A mechanism involving radical intermediates generated by single-electron transfer (SET) in the presence of a Ag2CO3oxidant and Pd(OAc)2Lewis acid is proposed. This protocol offers an operationally easy, simple, and robust approach with the use of readily available starting materials, good functional group tolerance, and high efficiency.
authors.affiliation: Center for New Directions in Organic Synthesis, Department of Chemistry and Institute for Material Design, Hanyang University , Seoul 04763, Korea.
authors.forename: So Won
authors.initials: SW
authors.lastname: Youn
authors.affiliation: Center for New Directions in Organic Synthesis, Department of Chemistry and Institute for Material Design, Hanyang University , Seoul 04763, Korea.
authors.forename: Yi Hyun
authors.initials: YH
authors.lastname: Kim
mesh_terms: D000588:Amines / Q000737:chemistry*; D017953:Isocyanates / Q000737:chemistry*; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D014508:Urea / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000588:Amines; D017953:Isocyanates; D012834:Silver; D010165:Palladium; D014508:Urea