title: N-vinyl-2-oxazolidinones: efficient chiral dienophiles for the [4 + 2]-based de novo synthesis of new N-2-deoxyglycosides.
abstract: Under smooth Eu(fod)(3)-catalyzed conditions, the inverse-electron demand hetero-Diels-Alder reactions between enantiopure N-vinyl-2-oxazolidinones 1a-f and representative beta,gamma-unsaturated alpha-ketoesters proceed with a high degree of endo and facial diastereoselectivity. The elucidation of the stereostructure of these adducts, performed by X-ray analysis or chemical correlation, shows that the endo-selective cycloaddition process is facially controlled in favor of the (2S,4S)-adduct when starting from a (4S)-dienophile or vice versa. The specific interest of the adducts 10a-e, derived from (E)-4-tert-butoxymethylene pyruvic acid methyl ester 9, has been exemplified by the two-step and highly stereoselective transformation of these adducts into the new and valuable N-2-deoxyglycosyl-oxazolidinones 12a-e, isolated in a pure diastereo- and enantiomeric form.
authors.affiliation: Unité de Chimie Organique Moléculaire et Macromoléculaire (UMR CNRS 6011) et Laboratoire des Oxydes et Fluorures (UMR CNRS 6010), Université du Maine F-72085 Le Mans Cedex 9, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Gaulon
authors.forename: Robert
authors.initials: R
authors.lastname: Dhal
authors.forename: Teddy
authors.initials: T
authors.lastname: Chapin
authors.forename: Vincent
authors.initials: V
authors.lastname: Maisonneuve
authors.forename: Gilles
authors.initials: G
authors.lastname: Dujardin