The stereoselective syntheses of the four aminodiol precursors of the diastereomers of lincosamine are reported. The procedure is based on the initial two‐carbon elongationof 1,2;3,4‐di‐O‐isopropylidene‐α‐D‐galactohexodialdo‐1,5‐pyranose, followed by the stereocontrolled introduction of the amino group by nucleophilic amination. Two complementary approaches have been investigated and compared: The first one is the direct transformation of α‐chloroglycidic ester into β‐amino‐α‐keto ester. The second strategy is a three‐step synthesis that is based on the treatment of the β‐iodo‐α‐keto ester with dibenzylamine. Subsequent reduction of the β‐amino‐α‐keto ester provides the pure D‐erythro, L‐threo, L‐erythro, and D‐threo aminodiols after chromatographic purification. Further classical transformations afford the N‐acetyl derivatives, which are key precursors of the lincosamine diastereomers.

Durch O‐Acylierung (in siedendem Benzol, 24‐75 h) der entsprechenden Alkohole mit dem betreffenden Säurechlorid (Cl‐BPA) werden die Ester (I)‐(VI) dargestellt [bei der Darstellung von (III) und (IV) findet als Neben‐ 141R reaktion N‐Acylierung statt (Ausb. in g angegeben)].

In search for new antibiotics we have developed a novel route leading to direct precursors of the carbohydrate moieties of new promising antibacterial agents 6-epi-VIC-105555 and 6-epi-VIC-II. The presented synthetic strategy consists of using as starting material the readily available β-dibenzylamino-α-ketoester and application of a sequence of chemical transformations on C-7: olefination or methylation, reduction, deoxygenation of the terminal alcohol, and finally hydrogenation. The desired molecules were obtained in a stereoselective fashion and with good overall yields.