Noncatalytic selective 6-O-acetylation of methyl 2,3-di-O-benzoyl-α-d-glucopyranoside with acetic acid and acetic anhydride

Noncatalytic acetylation of methyl 2,3-di- O -benzoyl-α- d -glucopyranoside with acetic acid or acetic anhydride proceeds regioselectively at the primary hydroxyl group and affords methyl 6- O -acetyl-2,3-di- O -benzoyl-α- d -glucopyranoside in good yield. The possibility of 6- O -acetylation should be taken into account when removing a 4,6- O -benzylidene protecting group with aqueous acetic acid at elevated temperature.