title: Rigid spacer-mediated synthesis of bis-spiroketal ring systems: stereoselective synthesis of nonsymmetrical spiro disaccharides.
abstract: The application of the "rigid spacer-mediated linkage between nonreacting centers" concept to the preparation of nonsymmetrical bis-spiroketal structures is demonstrated by the stereoselective synthesis of the bis-spiro fructodisaccharide 1, a minor component of industrial caramels. An o-xylylene bridge has been used to limit the conformational space during the intramolecular glycosylation-spirocyclization reaction of a difructopyranose precursor, thus controlling both the ring size and the stereochemistry at the spiro centers. [Structure: see text]
authors.affiliation: Instituto de Investigaciones Químicas, CSIC, Américo Vespucio s/n, Isla de la Cartuja, E-41092 Seville, Spain.
authors.forename: Enrique M
authors.initials: EM
authors.lastname: Rubio
authors.forename: M Isabel
authors.initials: MI
authors.lastname: García-Moreno
authors.forename: Patricia
authors.initials: P
authors.lastname: Balbuena
authors.forename: Carmen Ortiz
authors.initials: CO
authors.lastname: Mellet
authors.forename: José M
authors.initials: JM
authors.lastname: García Fernández
mesh_terms: D002236:Carbohydrate Conformation; D004187:Disaccharides / Q000138:chemical synthesis*; D008958:Models, Molecular; D015394:Molecular Structure; D013141:Spiro Compounds / Q000737:chemistry*
chemical_list: D004187:Disaccharides; D013141:Spiro Compounds