A straightforward oxidation of dienones to 2-acetylfurans by selenium dioxide

Article abstract of DOI:10.1016/S0040-4039(98)01272-6

Direct oxidation of (E)-4-(6-substituted-1-cyclohexenyl)-3-buten-2-ones (4a-7a) by selenium dioxide afforded 2-acelyltetrahydrobenzofurans (4b-7b) in moderate to good yields. An inverse, stepwise [2+4] cycloaddition mechanism of the intermediate formation was proposed from conformational and electronic requirements of conjugated dienones and solvent effects of SeO₂ oxidation.