Complementing Pyridine‐2,6‐bis(oxazoline) with Cyclometalated N‐Heterocyclic Carbene for Asymmetric Ruthenium Catalysis
作者:Long Li、Feng Han、Xin Nie、Yubiao Hong、Sergei Ivlev、Eric Meggers
DOI:10.1002/anie.202004243
日期:2020.7.20
6‐bis(oxazoline) (pybox) ligands for asymmetric transition metal catalysis is introduced by adding a bidentate ligand to modulate the electronic properties and asymmetric induction. Specifically, a ruthenium(II) pybox fragment is combined with a cyclometalated N‐heterocyclic carbene (NHC) ligand to generate catalysts for enantioselective transition metal nitrenoid chemistry, including ring contraction
通过添加双齿配体来调节电子性质和不对称诱导,提出了扩大手性吡啶-2,6-双(恶唑啉)(pybox)配体在不对称过渡金属催化中的应用的策略。具体来说,钌 (II) pybox 片段与环金属化 N-杂环卡宾 (NHC) 配体结合,生成用于对映选择性过渡金属氮烯化学的催化剂,包括环收缩为手性 2H-氮丙啶(2000 TON 时高达 97% ee)和对映选择性 C(sp 3 )−H 胺化(50 TON 时高达 97 % ee)。