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Updated: Dec 6, 2025

Characterizing Lewis Pairs Using Titration Coupled with In Situ Infrared Spectroscopy
Published on: February 20, 2020
Insight into the Ferrier Rearrangement by Combining Flash Chemistry and Superacids
Naresh Bhuma1, Ludivine Lebedel1, Hiroki Yamashita2
1IC2MP UMR CNRS 7285, Equipe "Synthèse Organique", Université de Poitiers, 4 rue Michel Brunet, 86073, Poitiers cedex 9, France.
Abstract:
The transformation of glycals into 2,3-unsaturated glycosyl derivatives, reported by Ferrier in 1962, is supposed to involve an α,β unsaturated glycosyl cation, an elusive ionic species that has still to be observed experimentally. Herein, while combination of TfOH and flow conditions failed to observe this ionic species, its extended lifetime in superacid solutions allowed its characterization by NMR-based structural analysis supported by DFT calculations. This allyloxycarbenium ion was further exploited in the Ferrier rearrangement to afford unsaturated nitrogen-containing C-aryl glycosides and C-alkyl glycosides under superacid and flow conditions, respectively.
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