Laboratory of Applied Bioorganic Chemistry, Graduate School of Agricultural Science , Tohoku University , 468-1 Aramaki Aza-Aoba , Aoba-ku , Sendai 980-8572 , Japan.
Research and Analytical Center for Giant Molecules, Graduate School of Science , Tohoku University , 6-3 Aramaki Aza-Aoba , Aoba-ku , Sendai 980-8578 , Japan.
Org Lett. 2018 Aug 3;20(15):4645-4648. doi: 10.1021/acs.orglett.8b01932. Epub 2018 Jul 13.
A bioinspired seven-step total synthesis of delitschiapyrone A was accomplished in 32% overall yield from commercially available 4-bromo-3,5-dimethoxybenzoic acid. The key step of the synthesis is an exclusively regioselective and diastereoselective reaction cascade consisting of the Diels-Alder reaction, α-ketol rearrangement, and cyclic hemiacetalization, achieved by simply stirring a heterogeneous mixture of two Diels-Alder substrates (putative biosynthetic intermediates) and water at 35 °C, directly furnishing the pentacyclic natural product in 75% yield.
受生物启发，以商业可得的 4-溴-3,5-二甲氧基苯甲酸为起始原料，经 32%的总收率，我们实现了 delitschiapyrone A 的仿生全合成。该合成的关键步骤是一个立体选择性的 Diels-Alder 反应、α-酮醇重排和环半缩醛化的串联反应，通过简单搅拌两种 Diels-Alder 底物（假定的生物合成中间体）和水的非均相混合物，在 35°C 下进行，直接以 75%的产率得到了五元环天然产物。
