42070-92-8Relevant articles and documents
Synthesis, coordination behavior, and structural features of chiral amino-, pyrazolyl-, and phosphino-substituted ferrocenyloxazolines and their application in asymmetric hydrogenations
Schuecker, Raffael,Zirakzadeh, Afrooz,Mereiter, Kurt,Spindler, Felix,Weissensteiner, Walter
, p. 4711 - 4719 (2011)
A highly flexible and modular synthesis of 15 chiral nonracemic ferrocenyloxazolines-all based on a ferrocenylethyl backbone-is described. Starting from N,N-dimethylaminoethyl ferrocene a range of oxazoline derivatives with various oxazoline substituents were prepared in a three-step sequence. After reaction with methyl iodide, the quaternized dimethylamino group was replaced by different amino, pyrazolyl, and phosphinyl groups. Subsequent reduction of the phosphinyl groups gave phosphinooxazoline derivatives. The molecular structures of three palladium [PdCl2(L)] and three ruthenium [RuCl(p-cymene)(L)]PF6 complexes of representative ferrocenyloxazoline ligands were studied by X-ray diffraction. In addition, five ruthenium complexes [RuCl2(PPh3)(L)] were prepared. These complexes were tested, using a high-throughput screening system, in the asymmetric hydrogenation of three ketones. Enantioselectivities of up to 99% ee were obtained.
Cinchona-Alkaloid-Derived NNP Ligand for Iridium-Catalyzed Asymmetric Hydrogenation of Ketones
Zhang, Lin,Zhang, Ling,Chen, Qian,Li, Linlin,Jiang, Jian,Sun, Hao,Zhao, Chong,Yang, Yuanyong,Li, Chun
supporting information, p. 415 - 419 (2022/01/12)
Most ligands applied for asymmetric hydrogenation are synthesized via multistep reactions with expensive chemical reagents. Herein, a series of novel and easily accessed cinchona-alkaloid-based NNP ligands have been developed in two steps. By combining [Ir(COD)Cl]2, 39 ketones including aromatic, heteroaryl, and alkyl ketones have been hydrogenated, all affording valuable chiral alcohols with 96.0-99.9% ee. A plausible reaction mechanism was discussed by NMR, HRMS, and DFT, and an activating model involving trihydride was verified.
Chiral Yolk-Shell MOF as an Efficient Nanoreactor for Asymmetric Catalysis in Organic-Aqueous Two-Phase System
Shi, Shunli,Zhong, Yicheng,Hu, Zhuo,Wang, Lei,Yuan, Mingwei,Ding, Shunmin,Wang, Shuhua,Chen, Chao
supporting information, p. 12714 - 12718 (2021/09/11)
It remains a great challenge to introduce large and efficient homogeneous asymmetric catalysts into MOFs and other microporous materials as well as retain their degrees of freedom. Herein, a new heterogeneous strategy of homogeneous chiral catalysts is proposed, that is, to construct a yolk-shell MOFs-confined, large-size, and highly efficient homogeneous chiral catalyst, which can be used as a nanoreactor for asymmetric catalytic reactions.
Dynamic Kinetic Resolution of Alcohols by Enantioselective Silylation Enabled by Two Orthogonal Transition-Metal Catalysts
Oestreich, Martin,Seliger, Jan
, p. 247 - 251 (2020/10/29)
A nonenzymatic dynamic kinetic resolution of acyclic and cyclic benzylic alcohols is reported. The approach merges rapid transition-metal-catalyzed alcohol racemization and enantioselective Cu-H-catalyzed dehydrogenative Si-O coupling of alcohols and hydrosilanes. The catalytic processes are orthogonal, and the racemization catalyst does not promote any background reactions such as the racemization of the silyl ether and its unselective formation. Often-used ruthenium half-sandwich complexes are not suitable but a bifunctional ruthenium pincer complex perfectly fulfills this purpose. By this, enantioselective silylation of racemic alcohol mixtures is achieved in high yields and with good levels of enantioselection.
