title: Synthesis of beta-substituted alpha-amino acids with use of iridium-catalyzed asymmetric allylic substitution.
abstract: The asymmetric synthesis of beta-substituted alpha-amino acids with use of iridium-catalyzed allylic substitution was described. The Ir-catalyzed allylic substitution of diphenylimino glycinate with allylic phosphates proceeded smoothly even at 0 degrees C and gave branch products with high enantioselectivity (up to 97% ee), when chiral bidentate phosphite bearing the 2-ethylthioethyl group was employed. In addition, both diastereomers of the branch products were synthesized stereoselectively by simply switching the base employed. These methods were also applied to the asymmetric synthesis of quaternary alpha-amino acids.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kanayama
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Yoshida
authors.forename: Hideto
authors.initials: H
authors.lastname: Miyabe
authors.forename: Tetsutaro
authors.initials: T
authors.lastname: Kimachi
authors.forename: Yoshiji
authors.initials: Y
authors.lastname: Takemoto
mesh_terms: D000478:Alkylation; D000498:Allyl Compounds / Q000138:chemical synthesis*; D000596:Amino Acids / Q000138:chemical synthesis*; D002384:Catalysis; D007495:Iridium / Q000737:chemistry*; D008968:Molecular Conformation; D017905:Phosphites / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000498:Allyl Compounds; D000596:Amino Acids; D017905:Phosphites; D007495:Iridium