Formal syntheses of (±)-platensimycin and (±)-platencin via a dual-mode Lewis acid induced cascade cyclization approach.
Formal syntheses of (±)-platensimycin and (±)-platencin via a dual-mode Lewis acid induced cascade cyclization approach.
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DOI：
10.1021/jo401105q
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发表时间：
2013-08
期刊：
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通讯作者：
Lizhi Zhu;Congshan Zhou;Wei Yang;Shuzhong He;G. Cheng;Xinhao Zhang;Chi-Sing Lee
中科院分区：
文献类型：
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作者：
Lizhi Zhu;Congshan Zhou;Wei Yang;Shuzhong He;G. Cheng;Xinhao Zhang;Chi-Sing Lee
通过对各种刘易斯酸的π，σ-刘易斯酸性的理论研究，提出了一种温和有效的双模式刘易斯酸诱导的Diels-Alder（DA）/碳环化级联环化反应，用于一锅法构建对映贝壳杉烯类化合物的三环核.以ZnBr 2为双模式刘易斯酸，一系列取代烯酮和二烯在室温下顺利进行DA/碳环级联环化反应，一锅法得到三环环化产物，产率高，非对映选择性高。三环环化产物已成功地用作（±）-platensimycin和（±）-platencin的形式合成的通用中间体。
A mild and efficient dual-mode Lewis acid induced Diels-Alder (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 π,σ-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 (±)-platensimycin and (±)-platencin.