title: Catalytic Enantioselective Electrophilic Aminations of Acyclic α-Alkyl β-Carbonyl Nucleophilies.
abstract: Highly enantioselective aminations of acyclic α-alkyl β-keto thioesters and trifluoroethyl α-methyl α-cyanoacetate (12) with as low as 0.05 mol % of a bifunctional cinchona alkaloid catalyst were established. This ability to afford highly enantioselectivity for the amination of α-alkyl β-carbonyl compounds renders the 6'-OH cinchona alkaloid-catalyzed amination applicable for the enantioselective synthesis of acyclic chiral compounds bearing N-substituted quaternary stereocenters. The synthetic application of this reaction is illustrated in a concise asymmetric synthesis of α-methylserine, a key intermediate previously utilized in the total synthesis of a small molecule immunomodulator, conagenin.
authors.affiliation: Department of Chemistry, Brandeis University, 415 South St., Waltham, MA 02454-9110, USA, Fax +01 781 736 2516; E-mail:  deng@brandeis.edu.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Liu
authors.forename: Bingfeng
authors.initials: B
authors.lastname: Sun
authors.forename: Li
authors.initials: L
authors.lastname: Deng