title: An Asymmetric, bifunctional catalytic approach to non-natural alpha-amino acid derivatives.
abstract: A catalytic, asymmetric process for the synthesis of 1,4-benzoxazinones from o-benzoquinone imides and ketene enolates is reported. Addition of Lewis acids (Zn(OTf)2, In(OTf)3, and in particular Sc(OTf)3) creates a bifunctional catalytic system that dramatically increases the reaction rate and the yield of these non-natural amino acid precursors while preserving the remarkable enantioselectivity inherent to the reaction. Cocatalyst Sc(OTf)3 increases the yield by up to 42% while producing products in >99% ee.
authors.affiliation: Department of Chemistry, New Chemistry Building, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Paull
authors.forename: Ethan
authors.initials: E
authors.lastname: Alden-Danforth
authors.forename: Jamison
authors.initials: J
authors.lastname: Wolfer
authors.forename: Cajetan
authors.initials: C
authors.lastname: Dogo-Isonagie
authors.forename: Ciby J
authors.initials: CJ
authors.lastname: Abraham
authors.forename: Thomas
authors.initials: T
authors.lastname: Lectka
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis / Q000737:chemistry*; D001688:Biological Products / Q000737:chemistry; D002384:Catalysis; D008670:Metals / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D001688:Biological Products; D008670:Metals