Georg Thieme Verlag, Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, 20(29), p. 2633-2637, 2018
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The uncatalyzed reaction of hydrogen peroxide with (E)-3-[3-(2-hydroxyaryl)-3-oxoprop-1-en-1-yl]chromones resulted in a regioselective epoxidation of the chromone intracyclic C(2)=C(3) double bond to afford unique isomeric (E)-7a-[3-(2-hydroxyphenyl)-3-oxoprop-1-en-1-yl]-1aH-oxireno[2,3-b]chromen-7(7aH)-ones in high yields. 2D NMR and single-crystal X-ray diffraction were used to elucidate the structures of the chromanone epoxides. Density functional theoretical studies demonstrated a high electrophilicity of the starting chromones.