Total Synthesis of (+)-Isatisine A

Total synthesis of (+)-isatisine A is described based on the application of a silyl-directed Mukaiyama-type [3 + 2]-annulation for the preparation of a fully substituted furan core. The indole branch forming the quaternary carbon center at C2 was constructed by addition to an intermediate N-acyliminium ion derived from aminal 4. In addition, the fused tetracyclic framework including furan core was built up using modified Buchwald amidation conditions.

本文报道了(+)-菘蓝碱A的全合成策略：采用硅基导向的Mukaiyama型[3+2]环加成反应制备完全取代的呋喃环核心；通过与由缩醛胺4衍生得到的中间体N-酰基亚胺离子发生加成反应，构建位于C2位的季碳中心吲哚侧链；此外，包含呋喃环核心的稠合四环骨架可通过改良的Buchwald酰胺化反应条件搭建完成。