Kostanecki acylation

The Kostanecki acylation is a method used in organic synthesis to form chromones^[1] or coumarins^[2] by acylation of O-hydroxyaryl ketones with aliphatic acid anhydrides, followed by cyclization.^[3] 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:^[4][5]

1. Phenol O-acylation with formation of a tetrahedral intermediate
2. Intramolecular aldol condensation to cyclize and to form a hydroxydihydrochromone
3. Elimination of the hydroxyl group to form the chromone (or coumarin)

Examples

• Alvocidib (flavopiridol)
• Dimefline
• Flavoxate

See also

• Allan–Robinson reaction
• Baker–Venkataraman rearrangement