title: Synthesis of α-amino acid derivatives and peptides via enantioselective addition of masked acyl cyanides to imines.
abstract: A general, asymmetric synthesis of amino acid derivatives is reported. Masked acyl cyanide (MAC) reagents are shown to be effective umpolung synthons for enantioselective additions to N-Boc-aldimines. The reactions are catalyzed by a modified cinchona alkaloid, which can function as a bifunctional, hydrogen bonding catalyst, and afford adducts in excellent yields (90-98%) and high enantioselectivities (up to 97.5:2.5 er). Unmasking the addition products gives acyl cyanide intermediates that are intercepted by a variety of nucleophiles to afford α-amino acid derivatives. Notably, the methodology provides an alternative method for peptide bond formation.
authors.affiliation: Department of Chemistry, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Kin S
authors.initials: KS
authors.lastname: Yang
authors.forename: Viresh H
authors.initials: VH
authors.lastname: Rawal
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D060326:Chemistry Techniques, Synthetic; D002930:Cinchona Alkaloids / Q000737:chemistry; D004151:Dipeptides / Q000138:chemical synthesis* / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D009570:Nitriles / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D002930:Cinchona Alkaloids; D004151:Dipeptides; D007097:Imines; D009570:Nitriles