title: Hydrogen-Bond Directed Regioselective Pd-Catalyzed Asymmetric Allylic Alkylation: The Construction of Chiral α-Amino Acids with Vicinal Tertiary and Quaternary Stereocenters.
abstract: A Pd-catalyzed asymmetric allylic alkylation of azlactones with 4-arylvinyl-1,3-dioxolan-2-ones was developed, providing "branched" chiral α-amino acids with vicinal tertiary and quaternary stereocenters, in high yields and with excellent selectivities. Mechanistic studies revealed that the formation of a hydrogen bond between the Pd-allylic complex and azlactone isomer is responsible for the excellent regioselectivities. This asymmetric alkylation can be carried out on a gram scale without a loss of catalytic efficiency, and the resulting product can be further transformed to a chiral azetidine in two simple steps.
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, P. R. China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Wei
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, P. R. China.
authors.forename: Delong
authors.initials: D
authors.lastname: Liu
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, P. R. China.
authors.forename: Qianjin
authors.initials: Q
authors.lastname: An
authors.affiliation: School of Pharmacy, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, P. R. China.|School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Wanbin
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000478:Alkylation; D000498:Allyl Compounds / Q000737:chemistry*; D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D004148:Dioxolanes / Q000737:chemistry*; D006860:Hydrogen Bonding; D007783:Lactones / Q000737:chemistry; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000498:Allyl Compounds; D000596:Amino Acids; D004148:Dioxolanes; D007783:Lactones; D010165:Palladium