Synthesis of 2-Amino-2-deoxy-β-d-mannosides via Stereoselective Anomeric O -Alkylation of 2 N ,3 O -Oxazolidinone-Protected d-Mannosamine: Synthesis of the Trisaccharide Repeating Unit of Streptococcus pneumoniae 19F Polysaccharide.

Cesium carbonate-mediated stereoselective anomeric O -alkylation of a 2 N ,3 O -oxazolidinone-protected d-mannosamine with sugar-derived primary or secondary alkyl triflates afforded the corresponding 2-amino-2-deoxy-β-d-mannosides in moderate to good yields and excellent stereoselectivity. The oxazolidinone ring can be opened with aqueous alkali hydroxide to liberate the amine functionality. This method has been successfully applied to the synthesis of the trisaccharide repeating unit of Streptococcus pneumoniae 19F polysaccharide.