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 (or benzoyl chloride) 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:Ellis, G. P. (1977) Chromenes, Chromanones, and Chromones from The Chemistry of Heterocyclic Compounds, Weissberger, A. and Taylor, E. C., eds.; Wiley & Sons: New York, vol. 31, p. 495. 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 (or coumarin)
Examples Alvocidib (flavopiridol) Dimefline Flavoxate
See also Allan–Robinson reaction Baker–Venkataraman rearrangement
References