Synthesis of <scp>Planar‐Chiral</scp> [2.2]<scp>Paracyclophane‐Based Oxazole‐Pyrimidine</scp> Ligands and Application in <scp>Nickel‐Catalyzed</scp> 1,<scp>2‐Reduction</scp> of α,<scp>β‐Unsaturated</scp> Ketones
作者:Juan Wang、Qing‐Xian Xie、Xiang Li、Chang‐Bin Yu、Yong‐Gui Zhou
DOI:10.1002/cjoc.202300575
日期:2024.4
structure and large steric hindrance performed successfully in nickel-catalyzed asymmetric 1,2-reduction of α,β-unsaturated ketones, affording the chiral allylic alcohols with up to 99% yield and 99% ee. Meanwhile, this reduction reaction could be conducted on gram-scale without loss of activity and enantioselectivity, and the chiral ligand could be conveniently recovered with high yield.
平面手性配体作为一类独特且重要的配体在不对称催化中得到了广泛的应用。其中,手性[2.2]对环芳烷已成为一种特殊类型的平面手性框架,并由于其结构稳定性而被用作重要的工具箱。在此,我们设计并合成了[2.2]对环芳烷衍生的恶唑嘧啶配体(缩写为PYMCOX)。这些性质稳定、结构刚性和位阻大的N , N-配体成功地进行了镍催化的α,β-不饱和酮的不对称1,2-还原反应,得到了手性烯丙醇,收率高达99%,产率高达99% ee。同时,该还原反应可以在克级水平上进行,而不损失活性和对映选择性,并且可以方便地高收率地回收手性配体。