Acyloxonium-lon-Umlagerungen an Polyol- und Monosaccharid-Systemen

Abstract

Acyloxonium ions of glycerol 7 or 1,2/3-cyclopentanetriol 10 show an acyloxonium rearrangement effected by fast valence isomerism. There can be observed a cyclo-rearrangement, by total valence isomerism of 1,2,4/3,5-cyclopentanepentol acyloxonium ion 20. A cyclo-rearrangement will be found at the pivaloxonium ion of pentaerythrol 26, too. Monosaccharide esters show acyloxonium rearrangements which always give equilibria of the corresponding acyloxonium ions. The respective equilibrium is influenced by the stabilities of the individual ions. D-Idose and D-talose are easily obtainable by acyloxonium rearrangement. The influence of other substituents in the monosaccharide molecule on the acyloxonium-ion-equilibrium is discussed.