Question

Mutarotation involves:

• A. Racemisation.
• B. Diastereomerisation.
• C. Optical resolution.
• D. Conformational inversion.

Answer 1

The correct option is B Diastereomerisation.

Mutarotation involves diastereomerisation. Mutarotation is the change in the optical rotation because of the change in the equilibrium between two anomers, when the corresponding stereocenters interconvert. Cyclic sugars show mutarotation as $\alpha$ and $\beta$ anomeric forms interconvert. The optical rotation of the solution depends on the optical rotation of each anomer and their ratio in the solution. The $\alpha$ and $\beta$ anomers are diastereomers of each other and usually have different specific rotations.