A Photochemical Organocatalytic Strategy for the α‐Alkylation of Ketones by using Radicals
作者:Davide Spinnato、Bertrand Schweitzer‐Chaput、Giulio Goti、Maksim Ošeka、Paolo Melchiorre
DOI:10.1002/anie.201915814
日期:2020.6.8
Reported herein is a visible‐light‐mediated radical approach to the α‐alkylation of ketones. This method exploits the ability of a nucleophilic organocatalyst to generate radicals upon SN2‐based activation of alkyl halides and blue light irradiation. The resulting open‐shell intermediates are then intercepted by weakly nucleophilic silyl enol ethers, which would be unable to directly attack the alkyl
本文报道了一种可见光介导的自由基对酮进行α-烷基化的方法。该方法利用了亲核有机催化剂在S N上生成自由基的能力基于2的烷基卤化物的激活和蓝光照射。然后,所得的开壳中间体被弱亲核的甲硅烷基烯醇醚截获,它们将无法通过传统的双电子路径直接攻击卤代烷。温和的反应条件使酮的α位置具有与经典阴离子策略不兼容的官能团。此外,该方法的氧化还原中性性质使其与基于金鸡纳酮的伯胺催化剂兼容,该催化剂被用于开发酮的对映选择性有机催化自由基α-烷基化的罕见实例。