Algar-Flynn-Oyamada reaction

What is Algar-Flynn-Oyamada reaction?

In 1934, the synthesis of flavones through oxidative cyclization of 2-oxychalcones with hydrogen peroxide under alkaline conditions was first reported by Algar and Flynn, and concurrently by Oyamada. This reaction is commonly known as the Algar-Flynn-Oyamada reaction, and has been referred to by several other names such as the Algar-Flynn oxidation, Algar-Flynn-Oyamada oxidation, AFO reaction, Algar-Flynn-Oyamada condensation, and AFO cyclization.

Algar-Flynn-Oyamada - reaction scheme - flavone - chalcone - hydrogen peroxide H2O2 - Algar-Flynn oxidation - Algar-Flynn-Oyamada oxidation - AFO reaction - Algar-Flynn-Oyamada condensation - AFO cyclization
Algar-Flynn-Oyamada reaction

The Algar-Flynn-Oyamada reaction involves the alkaline oxidation of o-hydroxyphenyl styryl ketones (chalcones) using hydrogen peroxide, H2O2 as a reactant. This reaction results in the formation of flavonols via the intermediate dihydroflavonols.

Various 2-hydroxychalcones with methoxy groups in different positions in the two aromatic nuclei have been found to smoothly undergo the AFO oxidation.