钌
化学
立体中心
分子内力
对映选择合成
非对映体
催化作用
卡宾
立体化学
手性(物理)
反应性(心理学)
药物化学
有机化学
手征对称性
病理
替代医学
夸克
物理
医学
量子力学
Nambu–Jona Lasinio模型
作者
Zijun Zhou,Shuming Chen,Yubiao Hong,Erik Winterling,Yuqi Tan,Marcel Hemming,Klaus Harms,K. N. Houk,Eric Meggers
摘要
A new class of chiral ruthenium catalysts is introduced in which ruthenium is cyclometalated by two 7-methyl-1,7-phenanthrolinium heterocycles, resulting in chelating pyridylidene remote N-heterocyclic carbene ligands (rNHCs). The overall chirality results from a stereogenic metal center featuring either a Λ or Δ absolute configuration. This work features the importance of the relative metal-centered stereochemistry. Only the non-C2-symmetric chiral-at-ruthenium complexes display unprecedented catalytic activity for the intramolecular C(sp3)-H amidation of 1,4,2-dioxazol-5-ones to provide chiral γ-lactams with up to 99:1 er and catalyst loadings down to 0.005 mol % (up to 11 200 TON), while the C2-symmetric diastereomer favors an undesired Curtius-type rearrangement. DFT calculations elucidate the origins of the superior C-H amidation reactivity displayed by the non-C2-symmetric catalysts compared to related C2-symmetric counterparts.
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