Intramolecular aldol reaction

Molecules which contain two carbonyl functionalities have the possibility of forming a ring through an intramolecular aldol reaction.  This is where the “head” of the molecule “bites its own tail”.  In most cases two sets of α hydrogens need to be considered. As with most ring forming reaction five and six membered rings are preferred.

As with other aldol reactions, the addition of heat causes an aldol condensation to occur.