Formal Synthesis of (-)-Perhydrohistrionicotoxin Using a Thorpe-Ziegler Cyclization Approach. Synthesis of Functionalized Aza-Spirocycles
作者:Van Ha Vu、Christelle Bouvry、Thierry Roisnel、Stéphane Golhen、Jean-Pierre Hurvois
DOI:10.1002/ejoc.201801604
日期:2019.2.14
based on the anodic cyanation of (S)‐1‐(1‐phenylethyl)‐piperidine (–)‐1 to afford α‐aminonitrile 2 in 85 % yield in a 53:47 dr. The presence of the α‐phenylethyl group as the chiral auxiliary ensured the control of the absolute configuration of the future C6 spiro‐center during the alkylation step of 2, which was carried out with 1‐bromo‐4‐chlorobutane. Next, elaboration of the 1‐azaspiro[5,5]undecane‐7‐one
描述了 (-)-PHTX 的正式合成。我们的方法基于 (S)-1-(1-苯乙基)-哌啶 (-)-1 的阳极氰化,以 53:47 的速度以 85% 的产率提供 α-氨基腈 2。α-苯乙基作为手性助剂的存在确保了在用 1-溴-4-氯丁烷进行的 2 烷基化步骤中控制未来 C6 螺中心的绝对构型。接下来,1-氮杂螺[5,5]十一烷-7-one环系统的构建分两步完成,包括(a)Thorpe-Ziegler环化和(b)烯氨基腈的水解-脱羧( –)-5 以 >99:1 dr 提供螺酮 (+)-6。最后,