Chapter 25: Carbohydrates
Mutarotation : interconversion of α-
and β- anomers
The α- and β- anomers of carbohydrates are typically stable solids.
However, in aqueous solution, they quickly equilibrate to an equilibrium
mixture of the two forms.
For example, in aqueous solution, glucose exists as a mixture of 36% α-
and 64% β- (>99% of the pyranose forms exist
The equilibration occurs via the ring opening of the cyclic sugar at the
anomeric center with the acyclic form as the intermediate.
Or, in a simplified form with all the "extra" hydroxy groups removed:
The curly arrow mechanism involved here is essentially the same as that
for acetal formation (review ?)