Compound 5 (598 mg 2.7 mmole) was dissolved in dry CH3CN(60 ml) and 97% NaH (80 mg, 3 mmole) was added. The mixture was stirred under N2 for 1 hour at room temperature. Then 2,3,5-tri-O-benzyl-D-arabinofuranosyl chloride (prepared from 2,3,5-tri-O-benzyl-1-O-p-nitrobenzoyl-D-arabinofuranose) (1.83 g, 3 mmole)) dissolved in dry CH3CN (20 ml) was added dropwise. The mixture was stirred under N2 for overnight at room temperature. The reaction solution was filtered through Celite. The filtrate was evaporated to give a syrup and this syrup was subjected to flash column chromatography on silica gel (Kieselgel 60, 230-400 mesh) and eluted with CH2Cl2. The fractions containing 133 were combined and evaporated to give 1.6 g (95.0%) of 133. (IR KBr cm-1 : 1140-1060 (C--O--C)).
