title: Pd-catalyzed asymmetric allylic alkylation of glycine imino ester using a chiral phase-transfer catalyst.
abstract: Pd-catalyzed asymmetric allylic alkylation of the glycine imino ester 1a has been developed using a chiral quaternary ammonium salt 3d without chiral phosphine ligands. The proper choice of the achiral Pd ligand, P(OPh)3, is important to achieve high enantioselectivity. By this method with the dual catalysts, numerous enantiomerically enriched alpha-allylic amino acids 4a-h could be prepared with comparable to higher enantioselectivity than that of the conventional asymmetric alkylation of 1a. In addition, the Pd-catalyzed reaction of 1a with 1-phenyl-2-propenyl acetate 2i afforded the branch product 6 with high enantio- and diastereoselectivity (>95% de, 85% ee).
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Nakoji
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Kanayama
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Okino
authors.forename: Yoshiji
authors.initials: Y
authors.lastname: Takemoto
mesh_terms: D000478:Alkylation; D000498:Allyl Compounds / Q000737:chemistry; D002384:Catalysis; D004952:Esters; D005998:Glycine / Q000031:analogs & derivatives / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010165:Palladium; D013329:Structure-Activity Relationship
chemical_list: D000498:Allyl Compounds; D004952:Esters; C468561:tert-butyl (diphenylmethimino)acetate; D010165:Palladium; D005998:Glycine