The unusual alcohol mediated formation of 4-oxo-2-aryl-4H-chromene-3-carboxylate (flavone-3-carboxylate) derivatives from 4-hydroxycoumarins and β-nitroalkenes in an alcoholic medium is described. The transformation occurs via the in situ formation of a Michael adduct, followed by the alkoxide ion mediated rearrangement of the intermediate. The effect of the different alcohol and nonalcohol media on
这种不寻常的醇介导的4-氧代-2-芳基-4-的形成ħ色烯-3-
羧酸甲酯(
黄酮-3-
羧酸)衍
生物由
4-羟基
香豆素和β-硝基烯烃在醇介质进行说明。该转化通过原位形成迈克尔加合物而发生,随后是醇盐离子介导的中间体重排。研究了不同醇和非醇介质对反应的影响。