First o-glycosylation from unprotected 1-thioimidoyl hexofuranosides assisted by divalent cations.
The preparation of O-hexofuranosides was accomplished from unprotected 1-thioimidoyl furanosides as donors. The present methodology was first used for the synthesis of octyl galactofuranoside and further extended to D-galactofuranose-containing disaccharides. Within this study, we emphasized the need for additional complexing cations to maintain the furanose ring in its initial size. After experimentation, calcium ion was first used concomitantly with trimethylsilyl trifluoromethanesulfonate, the latter being able to activate the thioimidate and the former being likely to inhibit ring expansion. Moreover, an improvement was performed by using copper(II) trifluoromethanesulfonate which could then meet the requirements as both promoter and complexing agent.
Euzen
Ronan
R
Sciences Chimiques de Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, Avenue du Général Leclerc, F-35700 Rennes, France.
Guégan
Jean-Paul
JP
Ferrières
Vincent
V
Plusquellec
Daniel
D
D002413:Cations, Divalent; D006031:Glycosylation; D007094:Imides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry
D002413:Cations, Divalent; D007094:Imides