Acetalization
Abstract
Acetalization is an organic reaction in which an aldehyde (or a ketone) reacts with an alcohol under acidic conditions to form an acetal, enabling the protection of the carbonyl toward nucleophiles.
Keywords
Aldehyde, Ketone, Alcohol, Acetal
Category
Aldehyde/Ketone
Mechanism
First, the acid catalyst promotes the nucleophilic addition of an alcohol to the aldehyde (or ketone), yielding a hemiacetal. Then, the hydroxyl group of the hemiacetal is protonated and water is eliminated, resulting in the formation of an oxocarbenium ion. The latter is then attacked by another alcohol molecule, followed by deprotonation to generate the acetal functional group. Note that this reaction is fully reversible, meaning the carbonyl group can be deprotected by simple acidic hydrolysis.
