Towards novel difluorinated sugar mimetics; syntheses and conformational analyses of highly-functionalised
Gerry A Griffith1, Jonathan M Percy, Stéphane Pintat
1Department of Chemistry, University of Leicester, University Road, Leicester, UK LE1 7RH.
Abstract:
Highly-functionalised difluorinated cyclooctenones were synthesised from trifluoroethanol using either metallated difluoroenol acetal or carbamate chemistry, followed by a [2,3]-Wittig rearrangement or aldol reaction. Efficient RCM reactions afforded the title compounds which showed rather restricted fluxional behaviour by VT (19)F NMR. Topological characterisation by molecular modelling and NOESY/ROESY experiments offered a number of challenges, but allowed the identification of two favoured boat-chair conformers which interconverted by pseudorotation with relatively large activation barriers.
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