Divergent Total Synthesis of Euphoranginol C, Euphoranginone D, <i>ent</i>‐Trachyloban‐3β‐ol, <i>ent</i>‐Trachyloban‐3‐one, Excoecarin E, and <i>ent</i>‐16α‐Hydroxy‐atisane‐3‐one
Zejun Xu, Yan Zong, Yanan Qiao, Jiao‐Zhen Zhang, Xuyuan Liu, Ming‐Zhu Zhu, Yuliang Xu, Hongbo Zheng, Liyuan Fang, Xiao‐ning Wang, Hong‐Xiang Lou
Abstract
Abstract A divergent synthetic approach to biogenetically related diterpenoids such as ent‐kauranes, ent‐trachylobanes, ent‐beyerane, and ent‐atisane has been developed. The unified synthetic route involves the De Mayo reaction to rapidly generate the bicyclo[3.2.1]‐octane moiety of ent‐kaurane. The key reactions also include bioinspired nucleophilic cyclopropanation generating the [3.2.1.0 2,7 ]‐tricyclic core of ent‐trachylobane and regioselective cyclopropane fragmentation furnishing ent‐beyerane and ent‐atisane through the nucleophilic attack and protonation of the cyclopropane ring. This strategy enables the asymmetric total syntheses of six diterpenoids from the commercially available geraniol.