title: Highly diastereoselective nitrone cycloaddition onto a chiral ketene equivalent: asymmetric synthesis of cispentacin.
abstract: [reaction: see text] A highly diastereoselective intramolecular nitrone cycloaddition onto a chiral ketene equivalent, obtained by Horner-Wadsworth-Emmons olefination of either enantiomer of bis-sulfinyl phosphonate 6, is described. Cycloaddition gave 5,5-disubstituted isoxazolidine 10 in good yield as a single diastereomer. Catalytic hydrogenolysis of 10 furnished either enantiomer of optically pure cis-2-aminocyclopentane-1-carboxylic acid.
authors.affiliation: Department of Chemistry, University of Bristol, Cantock's Close, Bristol, and Celltech R+D Ltd, 216 Bath Road, Slough SL1 4EN, UK. v.aggarwal@bris.ac.uk
authors.forename: Varinder K
authors.initials: VK
authors.lastname: Aggarwal
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Roseblade
authors.forename: Juliet K
authors.initials: JK
authors.lastname: Barrell
authors.forename: Rikki
authors.initials: R
authors.lastname: Alexander
mesh_terms: D000935:Antifungal Agents / Q000138:chemical synthesis* / Q000737:chemistry; D001952:Bridged-Ring Compounds / Q000737:chemistry*; D002384:Catalysis; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry; D007202:Indicators and Reagents; D010084:Oxidation-Reduction; D013141:Spiro Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000935:Antifungal Agents; D001952:Bridged-Ring Compounds; D007202:Indicators and Reagents; D013141:Spiro Compounds; D003515:Cycloleucine; C065594:cispentacin