is an organic reaction
in which a chemical compound
containing a carbonyl
group acts both as the electrophile
and the nucleophile
in an aldol condensation
. It is also called a symmetrical aldol condensation
as opposed to a mixed aldol condensation
in which the electrophile and nucleophile are different species.
For example, two molecules of acetone condense to a single compound mesityl oxide in the presence of an ion exchange resin:
- 2 CH3COCH3 → (CH3)2C=CH(CO)CH3 + H2O
For synthetic uses, this is generally an undesirable, but spontaneous and favored side-reaction of mixed aldol condensation, and special precautions are needed to prevent it.