Efficient Synthesis of Trifluoromethyl and Related Trisubstituted Alkene Dipeptide Isosteres by Palladium-Catalyzed Carbonylation of Amino Acid Derived Allylic Carbonates
A novel stereoselective synthetic approach to (Z)-trifluoromethylalkene dipeptideisosteres (CF3-ADIs) is described. Starting from readily available N-Boc-l-phenylalanine, Phe-Gly type CF3-ADIs were obtained through palladium-catalyzed carbonylation of allylic carbonates under CO. While the reaction of N-Boc derivatives proceeds in excellent yields but lower stereoselectivity (E:Z = 62:38–43:57), the