Formal Syntheses of (卤)-Platensimycin and (卤)-Platencin via a Dual-Mode Lewis Acid Induced Cascade Cyclization Approach

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• 作者：Lizhi Zhu ; Congshan Zhou ; Wei Yang ; Shuzhong He ; Gui-Juan Cheng ; Xinhao Zhang ; Chi-Sing Lee
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：August 16, 2013
• 年：2013
• 卷：78
• 期：16
• 页码：7912-7929
• 全文大小：852K
• 年卷期：v.78,no.16(August 16, 2013)
• ISSN：1520-6904

文摘

A mild and efficient dual-mode Lewis acid induced Diels鈥揂lder (DA)/carbocyclization cascade cyclization reaction has been developed for construction of the tricyclic core of ent-kaurenoids in one pot with the aid of a theoretical study on the 蟺,蟽-Lewis acidities of a variety of Lewis acids. With ZnBr₂ as the dual-mode Lewis acid, a series of substituted enones and dienes underwent DA/carbocyclization cascade cyclization reaction smoothly at room temperature and provided the tricyclic cyclized products in one pot with good yields and high diastereoselectivity. The tricyclic cyclized product has been successfully utilized as a common intermediate for formal syntheses of (卤)-platensimycin and (卤)-platencin.