Aldol Condensation: Making Enals by Dehydration

Aldol condensation can turn a β-hydroxy aldehyde into an enal when the mixture is heated in the presence of base. An enal is an unsaturated carbonyl product. The β-hydroxy aldehyde first forms during a base-catalyzed aldol addition reaction.

The reaction follows a two-step mechanism. First, the b...

In an aldol addition reaction, the β-hydroxy aldehyde formed contains mildly acidic hydrogens at the α carbon.

The heating of the aldol product in a strong base shifts the equilibrium forward, enabling a dehydration reaction to form an enal.

As for the dehydration mechanism, it occurs in two distinct steps: enolization and eliminat...