Chiral Arene Ligand as Stereocontroller for Asymmetric C−H Activation**

Abstract

Development of chiral ligands is the most fundamental task in metal-catalyzed asymmetric synthesis. In the last 60 years, various kinds of ligands have been sophisticatedly developed. However, it remains a long-standing challenge to develop practically useful chiral η 6 -arene ligands, thereby seriously hampering the asymmetric synthesis promoted by arene-metal catalysts. Herein, we report the design and synthesis of a class of readily tunable, C 2 -symmetric chiral arene ligands derived from [2.2]paracyclophane. Its ruthenium(II) complexes have been prepared and successfully applied in the enantioselective CÀ H activation to afford a series of axially chiral isoquinolones (up to 99 % yield and 96 % ee). This study not only lays chemists' longstanding doubts about whether it is possible to use chiral arene ligands to stereocontrol ruthenium(II)-catalyzed asymmetric CÀ H activation, but also opens up a new avenue to achieve asymmetric CÀ H activation.

Study on Chiral Arene Ruthenium(II)-Catalyzed Asymmetric C—H Activation

“…最近, 中山大学化学学院汪君团队开发了一类结 构新颖、易于调节的[2.2]对环番手性芳烃配体, 并将其 成功地应用于钌(II)催化的不对称 C-H 键活化反应 [8] . 该类手性芳烃配体的设计主要基于以下考虑:…”

Ru(II)/Chiral Carboxylic Acid-Catalyzed Asymmetric [4 + 3] Annulation of Sulfoximines with α,β-Unsaturated Ketones

“…9 Nevertheless, the development of enantioselective versions of ruthenium(II)-catalyzed C−H activation has lagged far behind the same periodic palladium and rhodium. 4,10 Significant breakthroughs were achieved recently by taking advantage of the chiral transient directing group, 11 the chiral Ru(II) catalyst bearing the chiral η 6 -arene ligand, 12 the cooperative chiral amine ligand, 13 or the CCA ligand. 7,14 However, the development of efficient Ru(II)-catalyzed enantioselective C−H functionalizations is still in high demand, considering their specific features.…”

“…In the past decades, a great deal of attention have been paid for ruthenium­(II) catalysts in transition metal-catalyzed C–H activation owing to their cost efficiency and versatile reactivity . Nevertheless, the development of enantioselective versions of ruthenium­(II)-catalyzed C–H activation has lagged far behind the same periodic palladium and rhodium. , Significant breakthroughs were achieved recently by taking advantage of the chiral transient directing group, the chiral Ru­(II) catalyst bearing the chiral η 6 -arene ligand, the cooperative chiral amine ligand, or the CCA ligand. , However, the development of efficient Ru­(II)-catalyzed enantioselective C–H functionalizations is still in high demand, considering their specific features. Herein, we reported the Ru­(II)-catalyzed enantioselective [4 + 3] annulation of sulfoximines with α,β-unsaturated ketones (Scheme b) .…”

Ruthenium(II)/Imidazolidincarbonsäure‐katalysierte C−H‐Alkylierung für zentrale und axiale Doppelenantioinduktion

“…[1,2] So zeigten bahnbrechende Beiträge zu ruthenium(II)-katalysierten CÀ H-Transformationen durch Oi und Inoue, [2] Ackermann, [2d] sowie Bruneau und Dixneuf, [2e] die ausgeprägte Reaktivität und Selektivität. Trotz unbestreitbarer Fortschritte ist die vollständige Selektivitätskontrolle für ruthenium(II)-katalysierte enantioselektive CÀ H-Aktivierungen weiterhin unterentwickelt, [3][4][5][6][7][8][9][10] zumal bisher nur wenige Beispiele beschrieben wurden. Daher entwickelten Cui [4] und Wang [5] eine ruthenium(II)-katalysierte enantiose-lektive intramolekulare CÀ H-Aktivierung/Hydroarylierung unter Verwendung einer chiralen transienten dirigierenden Gruppe (cTDG), wenn auch nur intramolekular Transformationen möglich waren (Schema 1A).…”