Kostanecki acylation
The Kostanecki acylation is a method used in organic synthesis to form chromones or coumarins by acylation of O-hydroxyaryl ketones with aliphatic acid anhydrides, followed by cyclization. If benzoic anhydride is used, a particular type of chromone called a flavone is obtained. It was named after Polish chemist Stanisław Kostanecki.
Mechanism
The mechanism consists of three well-differentiated reactions:- Phenol O-acylation with formation of a tetrahedral intermediate
- Intramolecular aldol condensation to cyclize and to form a hydroxydihydrochromone
- Elimination of the hydroxyl group to form the chromone