Remarkable high-pressure enhancement of enantiopure nitrone cycloadditionsto glycals: General access to (1 -> 2)-linked pseudo aza-C-disaccharides

1,3-Dipolar cycloadditions of enantiopure hydroxylated nitrones to glycals are strongly accelerated under high pressure. Under 10 Kbar pressure the pr ocess gains generality and broad scope and allows a direct access, in goad to excellent yields, to stereodifferentiated tricyclic isoxazolidines, key intermediates for the synthesis of a new class of (1 --> 2)-linked pseudo a za-C-disaccharides.