Ethyl cyclohexene-1-carboxylate (1) undergoes reaction with various aromatic substrates in presence of concentrated sulfuric acid to give cis-1,2,3, 4,4a,9a-hexahydrofluoren-9-ones 3a-f which on dehydrogenation afforded the corresponding fluoren-9-ones 4a-f in good yield. Fluorenones with an alkoxy group in the meta-orientation with respect to carbonyl group have also been prepared.
乙基
环己烯-1-
羧酸酯 (1) 在浓
硫酸存在下与多种芳香基底发生反应,生成 cis-1,2,3, 4,4a,9a-六氢
芴-9-酮 3a-f,经过脱氢后得到相应的
芴-9-酮 4a-f,产率良好。还合成了相对于羰基在邻位的烷氧基取代的
芴酮。