Chiral Electron-Rich PNP Ligand with a Phospholane Motif: Structural Features and Application in Asymmetric Hydrogenation
作者:Heng Wang、Yao Zhang、Tilong Yang、Xiaochong Guo、Quan Gong、Jialin Wen、Xumu Zhang
DOI:10.1021/acs.orglett.0c03159
日期:2020.11.20
catalysts with a PNP type ligand, the electron-rich chiral PNP ligands have still been rarely reported because of the difficulties in synthesis and the nature of air-sensitivity. Herein, we report a novel chiral PNP ligand (Heng-PNP) with both a rigid backbone and a bulky tert-butyl group on the phospholane motif. We successfully obtained its divalent iron complex. The chiral environment of its Ir(III) complex
尽管通过一系列具有PNP型配体的过渡金属催化剂实现了显着的反应性,但由于合成困难和对空气敏感的性质,富电子手性PNP配体仍然很少报道。在本文中,我们报道了一种新颖的手性PNP配体(Heng-PNP),其磷骨架上具有刚性骨架和庞大的叔丁基。我们成功获得了其二价铁配合物。还通过象限分析讨论了其Ir(III)配合物的手性环境。该三齿配体用于挑战性二芳基酮的铱催化不对称氢化反应:ee最高可达98%达到500吨。计算研究表明,底物中共轭芳基的扭曲(由Ir / Heng-PNP络合物的特殊手性口袋诱导)导致对映体确定步骤中的能量差。