3988-94-1Relevant academic research and scientific papers
Aspects of the Algar-Flynn-Oyamada (AFO) reaction
Bennett, Michael,Burke, Anthony J.,O'Sullivan, W. Ivo
, p. 7163 - 7178 (2007/10/03)
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-arylidenobenzo[b]furan-3(2H)-ones (aurones) and other flavonoid compounds. Oxidation of substrates bearing a 6'-substituent was initially believed to proceed through an epoxide intermediate, giving aurones or benzofuran-3(2H)-one derivatives as the chief reaction products. This was disputed when it was observed that AFO oxidation of (Z)-2'-hydroxy-α,4',6'-trimethoxychalcone gave the erythro-α-methoxybenzofuran-3-one 7 instead of the threo-isomer, which is expected if an epoxide were an intermediate. Evidence to suggest that an epoxide can be an intermediate in this reaction when 2'-hydroxy-6'-substituted substrates are employed, is described herein.
Flavonoid Epoxides. Part 18. Solvolysis Products of 2-Arylmethylenebenzofuran-3(2H)-one (Aurone) Epoxides
Brady, Brian A.,Geoghegan, Michael,O'Sullivan, W. Ivo
, p. 1557 - 1562 (2007/10/02)
Aurone epoxides readily undergo solvolysis with aqueous acetone, methanol, and ethanol under neutral conditions, and also with acetic acid to give α,β-dihydroxy, α-hydroxy-β-alkoxy, and α-hydroxy-β-acetoxy aurones, which equilibrate in solution, through r
