Aldol reaction

Aldol Addition
Reaction type Coupling reaction
Reaction
Ketone or Aldehyde
+
Ketone or Aldehyde
β-hydroxy Aldehyde
or
β-hydroxy Ketone
Conditions
Temperature
−Δ, ~−70 °C
Catalyst
OH or H+
Identifiers
Organic Chemistry Portal aldol-addition
RSC ontology ID RXNO:0000016

The aldol reaction (aldol addition) is a reaction in organic chemistry that combines two carbonyl compounds (e.g. aldehydes or ketones) to form a new β-hydroxy carbonyl compound. Its simplest form might involve the nucleophilic addition of an enolized ketone to another:

These products are known as aldols, from the aldehyde + alcohol, a structural motif seen in many of the products. The use of aldehyde in the name comes from its history: aldehydes are more reactive than ketones, so that the reaction was discovered first with them.

The aldol reaction is paradigmatic in organic chemistry and one of the most common means of forming carbon–carbon bonds in organic chemistry. It lends its name to the family of aldol reactions and similar techniques analyze a whole family of carbonyl α-substitution reactions, as well as the diketone condensations.