Low‐Temperature Nickel‐Catalyzed C−N Cross‐Coupling via Kinetic Resolution Enabled by a Bulky and Flexible Chiral
<i>N</i>
‐Heterocyclic Carbene Ligand
作者:Zi‐Chao Wang、Pei‐Pei Xie、Youjun Xu、Xin Hong、Shi‐Liang Shi
DOI:10.1002/anie.202103803
日期:2021.7.12
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 arylhalides remain a coveted target of catalyst engineering. Designs that promote one elementary reaction often create bottlenecks at
A new electronically deficient atropisomeric diphosphine ligand (S)-CF3O-BiPhep was synthesized from 1-bromo-3-(trifluoromethoxy)benzene in high yield. The key steps included oxidative coupling with anhydrousferricchloride and optical resolution by (+)-DMTA. The ligand afforded high performance for Ir-catalyzed asymmetric hydrogenation of quinolines with ee up to 92% and TON up to 25,000. It was
A New Class of Versatile Chiral-Bridged Atropisomeric Diphosphine Ligands: Remarkably Efficient Ligand Syntheses and Their Applications in Highly Enantioselective Hydrogenation Reactions
作者:Liqin Qiu、Fuk Yee Kwong、Jing Wu、Wai Har Lam、Shusun Chan、Wing-Yiu Yu、Yue-Ming Li、Rongwei Guo、Zhongyuan Zhou、Albert S. C. Chan
DOI:10.1021/ja0602694
日期:2006.5.1
A series of chiral diphosphineligands denoted as PQ-Phos was prepared by atropdiastereoselective Ullmann coupling and ring-closure reactions. The Ullmann coupling reaction of the biaryl diphosphine dioxides is featured by highlyefficient central-to-axial chirality transfer with diastereomeric excess >99%. This substrate-directed diastereomeric biaryl coupling reaction is unprecedented for the preparation
atropisomeric bisphosphine ligands have been synthesized from (S)-MeO-BiPhep. The introduction of electron-withdrawing groups in the ligands had a dramatic influence on both the enantioselectivity and the activity of catalyst. The iridium complex of the MeO-BiPhep-based ligand bearing a trifluoromethanesulfonyl group was successfully applied in the asymmetrichydrogenation of quinolines with ee values of up
Synthesis of Sulfoximine-Derived P,N Ligands and their Applications in Asymmetric Quinoline Hydrogenations
作者:Sheng-Mei Lu、Carsten Bolm
DOI:10.1002/adsc.200800068
日期:2008.5.5
A series of naphthalene-bridged P,N-type sulfoximine ligands and their iridium complexes have been synthesized. They were applied in the enantioselective hydrogenation of quinoline derivatives, and enantioselectivities up to 92% ee have been achieved in the hydrogenation of 2-methylquinoline.