Metal‐Free Allylic C−H Amination of Vinylsilanes and Vinylboronates using Silicon or Boron as a Regioselectivity Switch
Metal‐Free Allylic C−H Amination of Vinylsilanes and Vinylboronates using Silicon or Boron as a Regioselectivity Switch
复制标题
使用硅或硼作为区域选择性开关对乙烯基硅烷和乙烯基硼酸酯进行无金属烯丙基 C-H 胺化
DOI：
10.1002/anie.202210109
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Michael, Forrest E.
中科院分区：
文献类型：
--
作者：
Maloney, T. Parker;Berman, Janna L.;Michael, Forrest E.
乙烯基硅烷和乙烯基硼酸酯是有机合成中常见的结构单元，但在没有C=C或C−Si/B键参与的情况下，这些物质的直接官能化是罕见的。在这里，我们报告了这些乙烯基类金属物种的无金属烯丙基C-H胺化反应，该反应在没有竞争性transmethalide或烯烃加成的情况下安装了新的C-N键。在这种转化中，硅或硼取代基反转了通常的区域选择性，将胺化作用引导到远离该基团的位点。随后的交叉偶联或去甲基化允许获得互补的区域异构产物。密度泛函理论计算表明，观察到的区域选择性是由于电子和反直觉的空间因素的微妙组合，这些因素有利于硒在含硅碳原子上的初始攻击。
Vinylsilanes and vinylboronates are common building blocks for organic synthesis, but direct functionalization of these species without the participation of either the C=C or C−Si/B bonds is rare. Herein, we report a metal‐free allylic C−H amination reaction of these vinylmetalloid species that installs a new C−N bond without competing transmetallation or alkene addition. In this transformation, the silicon or boron substituent inverts the usual regioselectivity, directing amination to the site distal to that group. Subsequent cross‐coupling or demetallation allows access to complementary regioisomeric products. Density Functional Theory computations revealed that the observed regioselectivity is due to a subtle combination of electronic and counterintuitive steric factors that favor initial attack of selenium at the silicon‐bearing carbon atom.