Dalian Institute of Chemical Physics, Chinese Academy of Sciences , 457 Zhongshan Road, Dalian 116023, China.
School of Light Industry and Chemical Engineering, Dalian Polytechnic University , Dalian 116034, China.
Org Lett. 2016 Nov 4;18(21):5592-5595. doi: 10.1021/acs.orglett.6b02828. Epub 2016 Oct 21.
A new class of sterically hindered chiral ferrocenyl P,N,N-ligands have been prepared through a two-step transformation from (S,R)-PPFNH, in which a new (R)-stereogenic center at the pyridinylmethyl position was generated in high diastereoselectivity. With these newly developed P,N,N-ligands, Ir-catalyzed asymmetric hydrogenation of various α-alkyl-substituted β-aryl-β-ketoesters via dynamic kinetic resolution has been realized in high diastereo- and enantioselectivities for the first time, which led to a variety of optically active anti-β-hydroxyesters in up to 99% ee. The study indicated that the additional stereocenter at the pyridinylmethyl position of these ligands is crucial to realize this hydrogenation.
一类新型位阻手性二茂铁基 P,N,N-配体通过（S,R）-PPFNH 的两步转化得到，其中在吡啶甲基位置生成了一个新的（R）手性中心，具有高的非对映选择性。利用这些新开发的 P,N,N-配体，首次通过动态动力学拆分实现了 Ir 催化的各种α-烷基取代的β-芳基-β-酮酯的不对称氢化反应，具有高的非对映和对映选择性，最高可获得 99%ee 的各种光学活性反式-β-羟基酯。研究表明，这些配体中吡啶甲基位置的额外手性中心对于实现这种氢化反应至关重要。
