title: Synthesis of 4,4-difluoroglycosides using ring-closing metathesis.
abstract: 4-Deoxy-4,4-difluoro-glycosides have been synthesised for the first time via a direct sequence involving ring-closing metathesis and indium-mediated difluoroallylation with 1-bromo-1,1-difluoropropene in water. Two protecting group strategies were explored, one to allow protection of the primary C-6 hydroxyl group throughout the sequence, while the second was intended to allow deprotection after RCM and before dihydroxylation. The benzyl ether could be used in the first role, and pivaloyl is effective in the second. Dihydroxylations were highly stereoselective and controlled by the orientation of the glycosidic C-O bond.
authors.affiliation: Department of Chemistry, University of Leicester, University Road, Leicester, UK.
authors.forename: Christophe
authors.initials: C
authors.lastname: Audouard
authors.forename: John
authors.initials: J
authors.lastname: Fawcett
authors.forename: Gerry A
authors.initials: GA
authors.lastname: Griffiths
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Percy
authors.forename: Stéphane
authors.initials: S
authors.lastname: Pintat
authors.forename: Clive A
authors.initials: CA
authors.lastname: Smith
mesh_terms: D017611:Fluorine Compounds / Q000138:chemical synthesis*; D006027:Glycosides / Q000138:chemical synthesis*; D008958:Models, Molecular; D015394:Molecular Structure
chemical_list: D017611:Fluorine Compounds; D006027:Glycosides