title: Chiral Brønsted Acid-Catalyzed Asymmetric Synthesis of N-Aryl-cis-aziridine Carboxylate Esters.
abstract: We report a multi-component asymmetric Brønsted acid-catalyzed aza-Darzens reaction which is not limited to specific aromatic or heterocyclic aldehydes. Incorporating alkyl diazoacetates and, important for high ee's, ortho-tert-butoxyaniline our optimized reaction (i.e. solvent, temperature and catalyst study) affords excellent yields (61-98 %) and mostly >90 % optically active cis-aziridines. (+)-Chloramphenicol was generated in 4 steps from commercial starting materials. A tentative mechanism is outlined.
authors.affiliation: School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
authors.forename: Sean P
authors.identifier: 0000-0002-9087-9463
authors.initials: SP
authors.lastname: Bew
authors.affiliation: Department of Medicinal Chemistry, GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire, UK.
authors.forename: John
authors.initials: J
authors.lastname: Liddle
authors.affiliation: School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
authors.forename: David L
authors.initials: DL
authors.lastname: Hughes
authors.affiliation: School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
authors.forename: Paolo
authors.initials: P
authors.lastname: Pesce
authors.affiliation: School of Chemistry, Norwich Research Park, University of East Anglia, Norwich, NR4 7TJ, UK.
authors.forename: Sean M
authors.initials: SM
authors.lastname: Thurston
keywords: Brønsted acids; asymmetric catalysis; aziridine; multicomponent reactions