D-glucose is treated with an excess of acetic anhydride in the presence of pyridine. Identity the products formed

Options

A.
B.
C.
D. Both (2) and (3)

Answer

D

Explanation

Treating a monosaccharide such as `D-`glucose with excess acetic anhydride and a weak base (such as pyridine or sodium acetate) converts all of the hydroxyl groups, including the anomeric hydroxyl, to ester groups.
If the reaction is carried out at a low temperature (e.g., `0^(@)C`), the reaction occurs stereospecifically, the `alpha`-another gives the `alpha`-acetate while the `beta`-anomer gives the `beta`-acetate