Question

Draw a stepwise mechanism for the following reaction.

Short answer

Answer

The mechanism of the above reaction is followed by resonance and nucleophilic attack of H₂O to form anomers.

Step-by-step solution

Glycoside

Glycoside is the molecule formed from monosaccharide, which undergoes condensation with a hydroxyl group and eliminates water.Glycosides have hemiacetal and hydroxyl groups, which on hydrolysis gives two anomers.

Formation of carbocation

Glycoside is hydrolyzed and forms an intermediate by the loss of H₂O , which on resonance gives carbocation.

Formation of anomers

Carbocation was attacked by H₂O on both sides (above and below). The carbocation forms an intermediate that undergoes nucleophilic attack to form $\alpha and\beta$anomers, as shown below: