Li Wei-Dong Z, Wang Xin-Wei
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, China.
Org Lett. 2007 Mar 29;9(7):1211-4. doi: 10.1021/ol070024b. Epub 2007 Mar 10.
[structure: see text]. A novel formal synthesis of cephalotaxine (CET), the parent structure of the antileukemia Cephalotaxus alkaloids, was achieved via a facile Friedel-Crafts cyclization of the amino (or amido) spiro-cyclopentenone precursor (A) mediated by a protic acid leading to tetracyclic ketone B. A remarkable stereoelectronic effect of the methylenedioxy substituent (R) and an interesting skeletal isomerization of the CET core ring system (B, X = H2) were observed.
[结构：见正文]。通过质子酸介导的氨基（或酰胺基）螺环戊烯酮前体（A）的简便傅克环化反应，实现了抗白血病三尖杉生物碱的母体结构——三尖杉碱（CET）的新型形式合成，得到四环酮B。观察到亚甲二氧基取代基（R）具有显著的立体电子效应以及CET核心环系（B，X = H2）有趣的骨架异构化现象。
