STEREOSELECTIVE SYNTHESIS OF HIGHER SUGAR DIALDOSES VIA COUPLING OF TERMINAL C-ATOMS OF SIMPLE MONOSACCHARIDES

Different methods of the preparation of the precursors of higher carbo n sugars via the coupling of monosaccharide sub-units are presented. T he ''economic'' synthesis of such precursor is exemplified by the prep aration of enone 11. Functionalization of the allylic fragment of high er sugar allylic alcohols (S-cis, R-cis, R-trans and S-trans: 23a, 23b , 24a, and 24b respectively) was achieved by the cis-hydroxylation of the double bond what afforded all possible stereoisomeric triols 27-33 . The osmylation reaction followed the empirical Kishi's rule.