β-elimination. The stereochemistry of 1,4-addition of cyanide to the resulting enone is discussed with supporting molecular modelling calculations. N-Deprotection is shown to be accompanied by cyclisation onto the nitrile group, resulting in a tricyclic lactam with a twisted amide functionality. Elaboration of this lactam afforded four of the five rings present in lycopladine D with just the C(8) carbon lacking
本文报道了呋塞迪明
生物碱石杉碱Q和
番茄红素D的
呋喃氧化N-螺环化方法的开发进展。描述了关键的中间体环pentaindolizidine的简短合成,随后通过N-酰化和β-消除作用进行了片段化。讨论了支持的分子模型计算,讨论了将1,4-加成
氰化物加成生成的烯酮的立体
化学。N-脱保护被显示伴随环化到腈基上,产生具有扭曲的酰胺官能度的
三环内酰胺。对该内酰胺的精加工提供了
番茄红素D中存在的五个环中的四个,而仅缺少C(8)碳。