A Bifunctional Lewis Acid Induced Cascade Cyclization to the Tricyclic Core of <i>ent</i>-Kaurenoids and Its Application to the Formal Synthesis of (±)-Platensimycin
作者:Lizhi Zhu、Yejian Han、Guangyan Du、Chi-Sing Lee
DOI:10.1021/ol3033412
日期:2013.2.1
A mild and efficient bifunctional Lewis acid induced cascade cyclization reaction has been developed for construction of the tricyclic core of ent-kaurenolds. With ZnBr2 as the bifunctional Lewis acid, a series of substituted enones and dienes underwent cascade cyclization smoothly at room temperature and provided the tricyclic products in one pot with good yields (75-91%) and high diastereoselectivity. The cyclized product has been successfully employed for the formal synthesis of (+/-)-platenslmycln.