Graduate School of Pharmaceutical Sciences , Kyoto University , Yoshida, Sakyo-ku, Kyoto 606-8501 , Japan.
J Org Chem. 2019 Sep 6;84(17):11014-11024. doi: 10.1021/acs.joc.9b01589. Epub 2019 Aug 12.
Stereocontrolled total syntheses of allelopathic 4-oxyprotoilludane sesquiterpenes, melleolide, melleolide F, and echinocidins B and D were achieved. The curved 5/6/4 tricyclic system with an angular hydroxy group was built via three key transformations: (1) MeAl-catalyzed [2 + 2] cycloaddition of a ketene silyl acetal with a propiolate, (2) reductive ring-opening of a cyclic hemiketal, and (3) the intramolecular Morita-Baylis-Hillman reaction. This synthetic route represents a new and reliable strategy to obtain protoilludanes with several oxy-functional groups.
通过三种关键转化，实现了具有角羟基的弯曲 5/6/4 三环系统的立体控制全合成：（1）MeAl 催化的烯酮硅缩醛与丙二酸盐的[2+2]环加成，（2）环状半缩醛的还原开环，和（3）分子内 Morita-Baylis-Hillman 反应。这条合成路线代表了获得具有多个氧官能团的 protoilludanes 的一种新的可靠策略。
