A Racemic Synthesis of an AB-Ring System of Hexacyclinic Acid

An AB-ring system of the polyketide natural product hexacyclinic acid has been synthesized in racemic form. The key steps were an intramolecular
Diels−Alder cyclization of an ester tethered 1,3-nonadiene-8-yne, which generated the B-ring, and a samarium diiodide mediated reductive
annulation, which was used to form the A-ring.

本研究以外消旋形式完成了聚酮类天然产物六环酸（hexacyclinic acid）的AB环系合成。核心关键步骤包含两项：一是通过带有酯基连接臂的1,3-壬二烯-8-炔发生分子内Diels-Alder环化反应构建B环；二是利用二碘化钐介导的还原环化反应构筑A环。