Synthesis of 4,4-difluoroglycosides using ring-closing metathesis
2004; Royal Society of Chemistry; Volume: 2; Issue: 4 Linguagem: Inglês
10.1039/b313731g
ISSN1477-0539
AutoresChristophe Audouard, John Fawcett, Gerry A. Griffiths, Jonathan M. Percy, Stéphane Pintat, Clive A. Smith,
Tópico(s)Fluorine in Organic Chemistry
Resumo4-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.
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