Desymmetrization of<i>meso</i>-2,5-Diallylpyrrolidinyl Ureas through Asymmetric Palladium-Catalyzed Carboamination: Stereocontrolled Synthesis of Bicyclic Ureas
作者:Nicholas R. Babij、John P. Wolfe
DOI:10.1002/anie.201302720
日期:2013.8.26
Lost symmetry: Fused bicyclic ureas are enantioselectively obtained through Pd‐catalyzed desymmetrizing carboaminations of meso‐2,5‐diallylpyrrolidinyl ureas (see scheme). The reactions generate a CN and a CC bond, and afford products with three stereocenters. One of these products was transformed to a tricyclic guanidine and then to 9‐epi‐batzelladine K over several steps.
失去对称性:通过 Pd 催化的内消旋-2,5-二烯丙基吡咯烷基脲的去对称碳胺化反应对映选择性地获得稠合双环脲(参见方案)。反应生成 C N 和 C C 键,并提供具有三个立体中心的产物。其中一个产物经过几个步骤转化为三环胍,然后转化为 9- epi- batzelladine K。
Synthesis of Cyclohexenylamines by Ring Closing Metathesis
作者:Martin E. Maier、Tzvetelina Lapeva
DOI:10.1055/s-1998-1789
日期:1998.8
Starting from 5-pentenaldehyde 1, the 1-allyl-4-pentenylamines 2a-d were prepared. The ring closing metathesis reaction of these dienes using the Grubbs catalyst 3 gave the corresponding cyclohexenylamines 4a, b and 4d in high yield. The secondary amine 2c was recovered unchanged. This route to compound 4d represents a formal total synthesis of the alkaloid epibatidine. In additon, 4b was transformed by electrophilic transannular cyclization to the bicyclic urethanes 5a and 5b.