Lithiated methoxyallene 1 and aldehydes 2 provided after base- or gold-catalyzed cyclization dihydrofurans 3 which were oxidatively cleaved giving α,β-unsaturated γ-ketoaldehydes 4 as key intermediates. These smoothly underwent intramolecular aldol addition to furnish highly substituted cyclopentene derivatives 5 in good yields. Due to their dense pattern of functional groups compounds 5 are versatile
在碱或
金催化环化二氢
呋喃 3 后提供
锂化甲氧基
丙二烯 1 和醛 2,它们被氧化裂解,得到 α,β-不饱和 γ-酮醛 4 作为关键中间体。这些顺利地进行了分子内醛醇加成,以良好的产率提供高度取代的
环戊烯衍
生物 5。由于其官能团的密集模式,化合物 5 是通用中间体,适用于后续加工。这通过 5e 转化为烯醇
磷酸酯 8 和 5c 转化为四环硝酮环加合物 13 来证明。