The oxidation of 2′-hydroxychalcones 1 with alkaline hydrogen peroxide, commonly known as the Algar, Flynn and Oyamada (AFO) reaction is a convenient method for the synthesis of 2-aryl-3-hydroxy-4H-1-benzopyran-4-ones (flavonols), 2-aryl-2, 3-dihydro-3-hydroxy-4H-1- benzopyran-4-ones (2, 3-dihydroflavonols), 2-arylidenebenzo [b] furan-3 (2H)-ones (aurones) and other flavonoid compounds. Oxidation of substrates bearing a 6′- ...
