180272-45-1Relevant articles and documents
Low-Temperature Nickel-Catalyzed C?N Cross-Coupling via Kinetic Resolution Enabled by a Bulky and Flexible Chiral N-Heterocyclic Carbene Ligand
Hong, Xin,Shi, Shi-Liang,Wang, Zi-Chao,Xie, Pei-Pei,Xu, Youjun
supporting information, p. 16077 - 16084 (2021/06/17)
The transition-metal-catalyzed C?N cross-coupling has revolutionized the construction of amines. Despite the innovations of multiple generations of ligands to modulate the reactivity of the metal center, ligands for the low-temperature enantioselective amination of aryl halides remain a coveted target of catalyst engineering. Designs that promote one elementary reaction often create bottlenecks at other steps. We here report an unprecedented low-temperature (as low as ?50 °C), enantioselective Ni-catalyzed C?N cross-coupling of aryl chlorides with sterically hindered secondary amines via a kinetic resolution process (s factor up to >300). A bulky yet flexible chiral N-heterocyclic carbene (NHC) ligand is leveraged to drive both oxidative addition and reductive elimination with low barriers and control the enantioselectivity. Computational studies indicate that the rotations of multiple σ-bonds on the C2-symmetric chiral ligand adapt to the changing needs of catalytic processes. We expect this design would be widely applicable to diverse transition states to achieve other challenging metal-catalyzed asymmetric cross-coupling reactions.
A through halogen bond activation isoquinoline asymmetric hydrogenation method
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Paragraph 0031-0040; 0062, (2019/03/26)
A through halogen bond activation isoquinoline asymmetric hydrogenation method, the catalyzing system is [...] complex, the activator is a halide. The reaction can be carried out under the following conditions, temperature: 25 - 100 °C; solvent: tetrahydr
Asymmetric Transfer Hydrogenation in Thermomorphic Microemulsions Based on Ionic Liquids
Hejazifar, Mahtab,Pálv?lgyi, ádám Márk,Bitai, Jacqueline,Lanaridi, Olga,Bica-Schr?der, Katharina
, p. 1841 - 1851 (2019/10/11)
A thermomorphic ionic-liquid-based microemulsion system was successfully applied for the Ru-catalyzed asymmetric transfer hydrogenation of ketones. On the basis of the temperature-dependent multiphase behavior of the targeted microemulsion, simple product separation as well as catalyst recycling could be realized. The use of water-soluble ligands improved the immobilization of the catalyst in the microemulsion phase and significantly decreased the catalyst leaching into the organic layer upon extraction of the product. Eventually, the optimized microemulsion system could be applied to a wide range of aromatic ketones that were reduced with good isolated yields (up to 98%) and enantioselectivities (up to 97%), while aliphatic ketones were less successful.