title: Dynamic kinetic asymmetric cross-benzoin additions of β-stereogenic α-keto esters.
abstract: The dynamic kinetic resolution of β-halo α-keto esters via an asymmetric cross-benzoin reaction is described. A chiral N-heterocyclic carbene catalyzes the umpolung addition of aldehydes to racemic α-keto esters. The resulting fully substituted β-halo glycolic ester products are obtained with high levels of enantio- and diastereocontrol. The high chemoselectivity observed is a result of greater electrophilicity of the α-keto ester toward the Breslow intermediate. The reaction products are shown to undergo highly diastereoselective substrate-controlled reduction to give highly functionalized stereotriads.
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: C Guy
authors.initials: CG
authors.lastname: Goodman
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Johnson
mesh_terms: D001573:Benzoin / Q000737:chemistry*; D004952:Esters; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D004952:Esters; D001573:Benzoin