Rigid spacer-mediated synthesis of bis-spiroketal ring systems: stereoselective synthesis of nonsymmetrical spiro disaccharides.
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]
Rubio
Enrique M
EM
Instituto de Investigaciones Químicas, CSIC, Américo Vespucio s/n, Isla de la Cartuja, E-41092 Seville, Spain.
García-Moreno
M Isabel
MI
Balbuena
Patricia
P
Mellet
Carmen Ortiz
CO
García Fernández
José M
JM
D002236:Carbohydrate Conformation; D004187:Disaccharides / Q000138:chemical synthesis*; D008958:Models, Molecular; D015394:Molecular Structure; D013141:Spiro Compounds / Q000737:chemistry*
D004187:Disaccharides; D013141:Spiro Compounds