title: Pseudoephedrine-Directed Asymmetric α-Arylation of α-Amino Acid Derivatives.
abstract: Available α-amino acids undergo arylation at their α position in an enantioselective manner on treatment with base of N'-aryl urea derivatives ligated to pseudoephedrine as a chiral auxiliary. In situ silylation and enolization induces diastereoselective migration of the N'-aryl group to the α position of the amino acid, followed by ring closure to a hydantoin with concomitant explulsion of the recyclable auxiliary. The hydrolysis of the hydantoin products provides derivatives of quaternary amino acids. The arylation avoids the use of heavy-metal additives, and is successful with a range of amino acids and with aryl rings of varying electronic character.
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL (UK).
authors.forename: Rachel C
authors.initials: RC
authors.lastname: Atkinson
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL (UK).
authors.forename: Fernando
authors.initials: F
authors.lastname: Fernández-Nieto
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL (UK).
authors.forename: Josep
authors.initials: J
authors.lastname: Mas Roselló
authors.affiliation: School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL (UK). clayden@man.ac.uk.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Clayden
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D015394:Molecular Structure; D054199:Pseudoephedrine / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D054199:Pseudoephedrine
keywords: amino acids; arylation; chiral auxiliaries; enolates; pseudoephedrine