Synthesis of Alkaloid (−)-205B via Stereoselective Reductive Cross-Coupling and Intramolecular [3+2] Cycloaddition
作者:Dexi Yang、Glenn C. Micalizio
DOI:10.1021/ja306362m
日期:2012.9.19
nitrone. The utility of this latter cycloaddition process for the assembly of the stereochemically dense piperidine core of 205B is noteworthy, as this method enables direct [3+2] cycloaddition of an intermediate homoallylic (E)-nitrone via a pathway that is stereochemically unscathed by competitive [3,3]-sigmatropic rearrangement processes. Overall, the synthesis is asymmetric, concise, and highly
生物碱 (-)-205B 是一种从新热带毒蛙皮肤中分离出的结构多样的天然产物家族的三环成员,其不对称合成被描述为通过两种最近开发的立体选择性合成方法进行:(1)Ti 介导的烯丙基醇-亚胺还原交叉偶联和(2)基于乙醛酸酯的高烯丙基硝酮的分子内 [3+2] 环加成。后一种环加成过程用于组装 205B 立体化学致密的哌啶核的效用值得注意,因为该方法能够通过在立体化学上不受竞争性影响的途径使中间同烯丙基 (E)-硝酮直接 [3+2] 环加成[3,3]-sigmatropic 重排过程。总的来说,合成是不对称的,简洁的,