Isomerization of Estragole to Anethole

Abstract

Anethole (trans-isomer, I) is an industrially significant organic which has found use predominantly as a flavor and fragrance (licorice) chemical. I is a component of many essential oils, e.g., fennel oils, from which it is isolated for application. Rather than depending on natural sources in toto, in its wisdom the chemical industry has chosen to fortify availability through chemical synthesis. An accepted route¹ involves the isomerization of estragole (II) to I with strong base at 200° for an extended² time period.