Palladium-Catalyzed Arylation of N-Aminoimidazol-2-ones towards Synthesis of Constrained Phenylalanine Dipeptide Mimics

N-Aminoimidazol-2-ones (e.g., 6) offer potential to serve as constrained amino amide components that can induce turn conformation in peptide sequences. To add side chain functionality onto this amino amide surrogate, mild conditions have now been developed for palladium-catalyzed arylation of N-aminoimidazol-2-ones. A diverse array of aryl iodides reacted at the 5-position of N-aminoimidazol-2-one dipeptides 7 and 10 in a general approach for making constrained arylalanine dipeptide turn mimics (e.g., 8 and 11).