State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University Lanzhou 730000, P. R. China.
Org Lett. 2014 Apr 4;16(7):1996-9. doi: 10.1021/ol500553x. Epub 2014 Mar 26.
The first enantioselective total synthesis of the structurally unique nortriterpenoid (-)-walsucochin B has been accomplished through the cationic polyolefin cyclization initiated by chiral epoxide. The core framework and the stereocenters in the natural product were all constructed in this step. A site-selective, late-stage free-radical halogenation and Seyferth-Gilbert homologation was adopted to install the acetylene moiety to synthesize the phenylacetylene. The absolute configuration of walsucochin B was confirmed through enantioselective total synthesis.
通过手性环氧化物引发的阳离子聚烯烃环化反应，首次完成了结构独特的北三萜（-）-瓦苏考辛 B 的对映选择性全合成。该天然产物的核心骨架和立体中心均在此步构建。采用选择性的、晚期的自由基卤化和 Seyferth-Gilbert 同系化反应，引入乙炔部分来合成苯乙炔。通过对映选择性全合成确定了瓦苏考辛 B 的绝对构型。
