Enantioselective Total Syntheses of (−)-Taiwaniaquinone H and (−)-Taiwaniaquinol B by Iridium-Catalyzed Borylation and Palladium-Catalyzed Asymmetric α-Arylation
作者:Xuebin Liao、Levi M. Stanley、John F. Hartwig
DOI:10.1021/ja110215b
日期:2011.2.23
We report a concise, enantioselective total synthesis of (-)-taiwaniaquinone H and the first enantioselective total synthesis of (-)-taiwaniaquinol B by a route that includes asymmetric palladium-catalyzed α-arylation of a ketone with an aryl bromide that was generated by sterically controlled halogenation via iridium-catalyzed C-H borylation. This asymmetric α-arylation creates the benzylic quaternary
我们报告了 (-)-台湾醌 H 的简明对映选择性全合成,以及 (-)-台湾醌醇 B 的第一个对映选择性全合成,其路线包括用生成的芳基溴对酮进行不对称钯催化 α-芳基化通过铱催化的 CH 硼化反应进行空间控制卤化。这种不对称 α-芳基化产生了台湾醌类中存在的苄基四元立体中心。通过开发路易斯酸促进的级联来构建许多台湾醌类化合物合成中常见的中间体的[6,5,6]三环核心,有效地完成了合成。通过这些化合物的制备,我们证明了通过不对称α-芳基化构建苄基四级立体中心的实用性,即使是那些在α-位缺乏羰基的中心。