Addition of Indole to Methyl 2-Chloro-2-cyclopropylideneacetate en Route to Spirocyclopropanated Analogues of Demethoxyfumitremorgine C and Tadalafil
作者:Michael Limbach、Suryakanta Dalai、André Janssen、Mazen Es-Sayed、Jörg Magull、Armin de Meijere
DOI:10.1002/ejoc.200400617
日期:2005.2
Indole readily added across the double bond of the highly reactive Michael acceptor methyl 2-chloro-2-cyclopropylideneacetate (4) to yield 2-chloro-2-(3′-indolylcyclopropyl)acetate 5 (85%) which was converted in two steps into the racemic tryptophan analogue 7 in 90% yield. This in turn was transformed by a condensation and Pictet−Spengler sequence into the spirocyclopropane analogues, 11, 13 and 15
吲哚很容易通过高反应性迈克尔受体甲基 2-氯-2-环亚丙基乙酸酯 (4) 的双键添加,以产生 2-氯-2-(3'-吲哚基环丙基)乙酸酯 5 (85%),其分两步转化外消旋色氨酸类似物 7 的产率为 90%。这反过来又通过缩合和 Pictet-Spengler 序列转化为天然产物(脱甲氧基)fumitremorgine C(3b,3 步,11% 产率)和有效 PDE-5 的螺环丙烷类似物 11、13 和 15抑制剂他达拉非(2, 3 步,71% 产率)以及带有乙内酰脲骨架的原始先导结构(1, 2 步,79% 产率)。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)