Asymmetric synthesis of amino sugars. Part 2. A novel versatile approach to the chiral non-racemic synthesis of 2-amino-2-deoxy sugars. Preparation of L-glucosamine, L-mannosamine and L-talosamine derivatives

A novel methodology for asymmetric synthesis of 2-amino-2-deoxy sugars is d eveloped, starting from readily available chiral building block 1 and 2,3-O -isopropylideneglyceraldehyde 2, via Julia olefination and subsequent dihyd roxylation as key steps. The versatility of this approach is exemplified by the preparation of L-glucosamine, L-mannosamine and L-talosamine derivativ es in highly diastereometrically pure forms.