Stereochemical features of the [1,2]-Wittig rearrangement of O- glycosides derived from D-galactono- and D-xylono-γ-lactones: A new approach to the core part of zaragozic acids

The Wittig rearrangement of D-galactono-γ-lactone derived β-O- glycoside is shown to afford β-C-glycoside (retention product), a potentially useful intermediate for zaragozic acid synthesis. By contrast, the rearrangement of the D-xylonolactone-derived counterpart was found to violate the retention principle to yield an inversion product as the major product.