Imidazole (32 g) is added to a solution of 3 (30 g) in DMF (225 mL). After cooling to 0° C., tert-butyldiphenylsilyl chloride (34 g) is added. The reaction is allowed to come to room temperature overnight, whereupon TLC analysis (silica, 10% MeOH in CH2Cl2) indicates that the reaction is complete. MeOH (30 mL) is added and the reaction is stirred for an additional 30 minutes. The solvents are then removed in vacuo (40° C., 10 mm Hg). The residue is dissolved in EtOAc (500 mL) and washed successively with water (2×100 mL) and brine (2×100 mL). The EtOAc solution is then dried (MgSO4) and filtered. Removal of the EtOAc in vacuo provides a syrup which is subjected to flash column chromatography (silica, 5% EtOAc in hexane) to provide phenyl 6-O-(tert-butyldiphenylsilyl)-1-thio-β-D-glucopyranoside (4, 51 g).
