4208-64-4Relevant articles and documents
A novel route to stereoselective synthesis of (4R,5S)-O- acetylosmundalactone and (4S,5R)-O-acetylosmundalactone
Yonghong, Gan,Fangning, Zhang,Xinfu, Pan
, p. 488 - 489 (1999)
A route has been developed for the enantioselective synthesis of (4R,5S)-O-acetylosmundalactone 1 and (4S,5R)-O-acetylosmundalactone 2 by using sharpless kinetic resolution of the racemic 1-(2-furyl)ethanol 6 as a key step.
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.
Cationic Ru complexes anchored on POM via non-covalent interaction towards efficient transfer hydrogenation catalysis
Chen, Manyu,Cui, Kai,Hou, Zhenshan,Peng, Qingpo,Wang, Jiajia,Wei, Xinjia,Zhao, Xiuge
, (2021/12/22)
The ionic materials consisting of cationic Ru complexes and Wells-Dawson polyoxometalate anion (POM, K6P2W18O62) have been constructed via a non-covalent interaction. The as-synthesized catalysts have been characterized thoroughly by NMR, XRD, FESEM, and FT-IR, etc. The characterization suggested that a hydrogen bond interaction occurred between the proton of the amine ligand in the cationic Ru complexes and the oxygen atom of the POM anion. The hydrogen bond played an important role in enhancing catalytic activity for the transfer hydrogenation of methyl levulinate (ML) to γ-valerolactone (GVL) under very mild conditions. Especially, the transfer hydrogenation reaction proceeded via a heterogeneous catalysis approach and the heterogenized catalysts even afforded much better catalytic performance than homogeneous analogs. Notably, the catalysts can be recycled without an obvious loss of activity, and further extended to highly selective transfer hydrogenation of α,β-unsaturated ketones and aldehydes, etc. into the corresponding α,β-unsaturated alcohols without any base external additives. The high catalytic performance of these anchored catalysts was highly related to the hydrogen bond interaction and the basicity of the polyanion. The obtained knowledge from this work could lead us to a new catalysis concept of tethering active homogeneous complexes for constructing highly active anchored Ru complex catalysts for hydrogenation reaction.
Dynamic Kinetic Resolution of Alcohols by Enantioselective Silylation Enabled by Two Orthogonal Transition-Metal Catalysts
Oestreich, Martin,Seliger, Jan
supporting information, 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.
