title: Catalytic enantioselective addition of propionate units to imines: an efficient synthesis of anti-alpha-methyl-beta-amino acid derivatives.
abstract: Optically active anti-alpha-methyl-beta-amino acid derivatives have been prepared based on catalytic enantioselective addition of propionate units to simple and inert imines using a chiral zirconium complex. High reactivity and selectivity with wide substrate scope were attained by using a new chiral ligand, (R)-6,6'-bis(pentafluoroethyl)-1,1'-bi-2-naphthol ((R)-6,6'-C(2)F(5)BINOL). The reactions using geometrically isomeric ketene silyl acetals gave excellent anti-selectivity with high enantiomeric excess in both cases. Synthetic utility of this reaction has been demonstrated by the preparation of various anti-alpha-methyl-beta-amino acid and trans-3,4-disubstituted beta-lactam derivatives.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. skobayas@mol.f.u-tokyo.jp
authors.forename: Shū
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Jun
authors.initials: J
authors.lastname: Kobayashi
authors.forename: Haruro
authors.initials: H
authors.lastname: Ishitani
authors.forename: Masaharu
authors.initials: M
authors.lastname: Ueno
authors.forename: Haruro
authors.initials: H
authors.lastname: Ishiani
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D007097:Imines / Q000737:chemistry*; D015394:Molecular Structure; D011422:Propionates / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D007097:Imines; D011422:Propionates