title: Stereocontrolled synthesis of four diastereomeric C-aryl manno- and talofuranosides.
abstract: In a chiral-pool synthesis starting from D-mannono-1,4-lactone 1a, the four diastereomeric C-aryl furanosides (1S,4R)-4a, (1S,4S)-4b, (1R,4R)-4c, and (1R,4S)-4d were obtained in a stereocontrolled manner. The key steps of the synthetic pathway comprise a stereoselective reduction of the diastereomeric hemiketals (4R)-2a and (4S)-2b as well as a stereospecific cycloetherification of the resulting diols (1R,4R)-5a, (1S,4R)-5c, and (1S,4S)-5d. This ring closure which led to the desired C-glycosides was achieved by a Mitsunobu reaction or by preparing the 1-O-benzoyl-4-O-methylsulfonyl derivative 7 which was then treated with sodium methoxide. Final hydrolysis of the 5,6-O-isopropylidene protecting group led to the diastereomeric diols (1S,4R)-4a, (1S,4S)-4b, (1R,4R)-4c, and (1R,4S)-4d, representing versatile building blocks for further synthetic transformations.
authors.affiliation: Institut für Pharmazeutische und Medizinische Chemie der Universität Münster, Hittorfstraße 58-62, D-48149 Münster, Germany.
authors.forename: Elisa
authors.initials: E
authors.lastname: Ravarino
authors.forename: Sunit Kumar
authors.initials: SK
authors.lastname: Jana
authors.forename: Roland
authors.initials: R
authors.lastname: Fröhlich
authors.forename: Ralph
authors.initials: R
authors.lastname: Holl
mesh_terms: D005630:Fructans / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D013237:Stereoisomerism
chemical_list: D005630:Fructans