Development of Quinoline-Derived Chiral Diaminocarbene Ligands and Their Transition Metal Complexes: Synthesis, Structural Characterization, and Catalytic Properties
作者:Cong Xu、Yu Feng、Li-Ren Wang、Wen-Peng Ma、Yan-Mei He、Qing-Hua Fan
DOI:10.1021/acs.organomet.0c00141
日期:2020.5.26
and steric environment of these new chiral tricyclic NHCs were systematically evaluated by determining the Tolman electronic parameter (TEP) and the percent buried volumes (%Vbur) of the corresponding metalated complexes. It was revealed that these new ligands possess strong electron-donating properties and high steric demands. Additionally, these chiral NHC ligands have been successfully employed in
最近已经开发出带有稠合三环骨架的N-杂环卡宾(NHC)作为新型的有前途的配体,用于不对称过渡金属催化。在本文中,通过直接不对称氢化合成策略制备了两种具有部分还原的2,2'-双喹啉-和2-(哌啶-2--2-基)喹啉骨架的手性三环NHC。合成了它们的Rh和Pd复合物,并通过NMR和高分辨率质谱以及X射线晶体学对其进行了表征。通过确定托尔曼电子参数(TEP)和掩埋体积百分比(%V bur),系统地评估了这些新的手性三环NHC的电子效应和空间环境。)的相应金属化配合物。揭示了这些新的配体具有强的供电子性和高空间要求。另外,这些手性NHC配体已以高收率和良好的对映选择性(高达80%ee)成功地用于对映选择性钯催化的分子内α-芳基化反应。值得注意的是,刚性稠合的三环和庞大的邻位取代基可以极大地改善这些手性NHC配体的供电子性和手性诱导能力。