Development of Enantioselective Synthetic Routes to the Hasubanan and Acutumine Alkaloids
作者:Nicholas A. Calandra、Sandra M. King、Seth B. Herzon
DOI:10.1021/jo401889b
日期:2013.10.18
reduction–aza-Wittig sequence. The latter serves as a universal precursor to the targets. Key carbon–carbon bond constructions include highly diastereoselective acetylide additions to the N-methyliminium ion derived from 39 and Friedel–Crafts and Hosomi–Sakurai cyclizations to construct the carbocyclic skeleton of the targets. Initially, this strategy was applied to the syntheses of (−)-acutumine (4), (−)-dechloroacutumine
我们描述了一种制备Hasubanan和Acutumine生物碱的一般策略,该生物碱是显示抗肿瘤,抗病毒和增强记忆作用的一大类植物天然产物。靶标的绝对立体化学是通过5-(三甲基甲硅烷基)环戊二烯(36)与5-(2-叠氮基乙基)-2,3-二甲氧基苯醌(24)之间的对映选择性Diels-Alder反应建立的。Diels-Alder加合物38通过Staudinger还原-aza-Wittig序列转化为四环亚胺39。后者是目标的普遍先驱。关键的碳-碳键结构包括对衍生自39的N-甲基亚胺离子的高度非对映选择性乙炔化物以及Friedel–Crafts和Hosomi–Sakurai环化来构建目标的碳环骨架。最初,这种策略应用于的合成( - ) - acutumine(4),( - ) - dechloroacutumine(5),和四个hasubanan生物碱(1,2,3,和8)。在此,合成路线适于六个附