Total Synthesis of (+)-7,11-Helianane and (+)-5-Chloro-7,11-helianane through Stereoselective Aromatic Claisen Rearrangement
作者:Francesca Quartieri、Laura Elisabetta Mesiano、Daniela Borghi、Viviana Desperati、Cesare Gennari、Gianluca Papeo
DOI:10.1002/ejoc.201100706
日期:2011.11
concise, stereoselective route. By capitalizing on a palladium-catalyzed asymmetric allylic alkylation (Pd-AAA) reaction, followed by a thermal (uncatalyzed) aromatic Claisen rearrangement, which allowed for the installation of the required benzylic stereocenter, the aforementioned natural products were secured in 80 % ee, with almost complete transfer of stereochemical information during the [3,3] sigmatropic
海洋来源的芳香红没药烯倍半萜 (+)-7,11-helianane (1) 及其具有中等细胞毒性的卤代相关物 (+)-5-chloro-7,11-helianane (3) 已通过简洁的立体选择性路线合成. 通过利用钯催化的不对称烯丙基烷基化 (Pd-AAA) 反应,然后进行热(未催化)芳族克莱森重排,安装所需的苄基立体中心,上述天然产物的 ee 含量为 80%,在 [3,3] sigmatropic 过程中几乎完全转移了立体化学信息。对映选择性全合成证实了最近证明的 (+)-7,11-helianane (1) 的 (S) 绝对构型,并首次在 (+)-5-chloro-7 的情况下证明了相同的构型,11-氦烷 (3)。