title: The 1,3-dipolar cycloaddition reaction of chiral carbohydrate-derived nitrone and olefin: towards long-chain sugars.
abstract: The thermal and microwave-activated 1,3-dipolar cycloadditions of several α,β-unsaturated esters derived from d-mannose and chiral nitrones derived from threitol have been studied as a model reaction en route to eleven carbon long chain carbohydrates. Very high facial selectivity is observed for the chiral nitrones whereas the olefin facial selectivity varies with the substrate. The presence of a dioxolane ring α to the olefinic bond is beneficial to the facial selectivity of the olefin whereas a pyranose ring is not. The combination of a d-mannose derivative and a l-threitol-derived nitrone is a matched pair suitable for the synthesis of long chain sugars with nine contiguous chiral centres. Finally complete facial selectivity was observed with exo-glycals which gave a single cycloadduct.
authors.affiliation: Université de Lorraine, UMR 7565 SRSMC, F-54506 Nancy, France; CNRS, UMR 7565 SRSMC, F-54506 Nancy, France.
authors.forename: Hassan
authors.initials: H
authors.lastname: Oukani
authors.forename: Nadia
authors.initials: N
authors.lastname: Pellegrini-Moïse
authors.forename: Olivier
authors.initials: O
authors.lastname: Jackowski
authors.forename: Françoise
authors.initials: F
authors.lastname: Chrétien
authors.forename: Yves
authors.initials: Y
authors.lastname: Chapleur
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002241:Carbohydrates / Q000138:chemical synthesis* / Q000737:chemistry*; D003500:Cyclization; D004952:Esters / Q000737:chemistry*; D008872:Microwaves; D008968:Molecular Conformation; D009589:Nitrogen Oxides / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D002241:Carbohydrates; D004952:Esters; D009589:Nitrogen Oxides; C015388:nitrones
keywords: 1,3-Dipolar cycloaddition; Chiral nitrone; Chiral olefin; Long-chain sugar