To a solution of phenyl 6-O-(4-azido-3-chlorobenzyl)-1-thio-β-D-glucopyranoside (10) (580 mg, 1.32 mmol) in pyridine (5 ml) was added benzoyl chloride (609 μl, 5.28 mmol) at 0° C., and the resulting mixture was stirred at room temperature for 2 hr. Thereto was added water, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure to give phenyl 6-O-(4-azido-3-chlorobenzyl)-2,3,4-tri-O-benzoyl-1-thio-β-D-glucopyranoside (11) as slightly yellow crystals (934 mg, yield 94%).
