Synthesis of α-CF₂-mannosides and Their Conversion to Fluorinated Pseudoglycopeptides

Abstract

A methodology allowing the synthesis alpha-CF(2)-mannosides, based on the addition of a difluoroenoxysilane to a glycal followed by a dihydroxylation reaction, is described. The resulting 2,2-difluoro-2-mannosylacetate is converted into two pseudoglycopeptides which may act as E- and P-selectin inhibitors.

Recent Developments in the Ferrier Rearrangement

“…Similar chemistry with difluoroenoxysilanes has recently been employed in the preparation of fluorinated C ‐glycosidic analogues of 2‐deoxy‐2‐acetamido‐ D ‐altrose198 and pseudo‐glycopeptides 199…”

Fluorinated enol ethers: their synthesis and reactivity

“…108 A similar procedure was used by Leclerc for the addition of difluoroketene ethyl trimethylsilyl acetals to tri-O-acetylglucal (Scheme 88). 109 The addition of 2,2-difluoro-1-trimethylsilyloxyacrylate 82 to aldehyde-derived methyl acetals was also reported by Shi and Uneyama (Scheme 89). 110 Nucleophilic substitution reactions were also investigated, mostly using "activated" electrophiles.…”

Synthetic efforts towards the synthesis of fluorinated C-glycosidic analogues of α-galactosylceramides

“…had little influence on the outcome of the reaction (Scheme 7). The addition to glycal 19 proved to be much more rewarding since the S N 2 0 products 20 could be isolated in 72% yield under optimized reaction conditions [21]. The diastereoselectivity was however disappointing (6:4 a:b ratio) and could not be improved despite our efforts.…”