An Improved Class of Phosphite-Oxazoline Ligands for Pd-Catalyzed Allylic Substitution Reactions
作者:Maria Biosca、Joan Saltó、Marc Magre、Per-Ola Norrby、Oscar Pàmies、Montserrat Diéguez
DOI:10.1021/acscatal.9b01166
日期:2019.7.5
for generation of Pd/phosphite-oxazoline catalysts containing an alkyl backbone chain has been successfully applied to Pd-catalyzed allylic substitution reactions. By carefully selecting the substituents at both the alkyl backbone chain and the oxazoline of the ligand, as well as the configuration of the biaryl phosphite group, high activities (TOF > 8000 mol substrate × (mol Pd × h)−1) and excellent
包含烷基主链的Pd /亚磷酸酯-恶唑啉催化剂的制备方法已成功地应用于Pd催化的烯丙基取代反应。通过仔细选择配体的烷基主链和恶唑啉上的取代基以及亚磷酸亚芳基酯的构型,可获得高活性(TOF> 8000 mol底物×(mol Pd×h)-1)和具有多种C-,O-和N-亲核试剂(总共73个取代产物)的许多受阻和不受阻底物均实现了出色的对映选择性(ee高达99%)。此外,对关键的Pd-烯丙基配合物的DFT和NMR研究使我们能够更好地了解实验观察到的优异对映选择性的起源。Pd /亚磷酸酯-恶唑啉催化剂的有用应用已通过许多具有手性立体中心的手性碳环的合成,通过涉及Pd-烯丙基取代和1,6-烯炔环化或Pauson-Khand烯炔环化的简单顺序反应得到了证明。