1280591-49-2Relevant academic research and scientific papers
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.
A Cobalt(II) Complex Bearing the Amine(imine)diphosphine PN(H)NP Ligand for Asymmetric Transfer Hydrogenation of Ketones
Huo, Shangfei,Chen, Hong,Zuo, Weiwei
supporting information, p. 37 - 42 (2020/10/21)
Novel chiral cobalt complex a containing amine(imine)diphosphine PN(H)NP ligand and complex b containing bis(amine)diphosphine PN(H)N(H)P ligand were synthesized. The structures of two complexes were characterized by X-ray crystallography and high resolution mass spectrometry. The catalytic performances of cobalt complexes a and b for asymmetric transfer hydrogenation (ATH) of ketones under mild conditions were evaluated using 2-propanolisopropanol as solvent and hydrogen source after being activated by 8 equivalents of base. Complex a showed a good reactivity for reduction of ketones, with a turnover number (TON) of up to 555, and a maximum enantiomeric excess (ee) value of up to 91 %. Complex b exhibited inertness for hydrogenation of ketones. Electronic structure studies on a and b were conducted to account for the function of ligands on the catalytic performances.
Synthesis and catalytic applications of an extended range of tethered ruthenium(II)/η6-arene/diamine complexes
Hodgkinson, Roy,Jurk, Vclav,Zanotti-Gerosa, Antonio,Nedden, Hans Günter,Blackaby, Andrew,Clarkson, Guy J.,Wills, Martin
supporting information, p. 5517 - 5524 (2015/02/19)
A series of novel enantiopure Ru(II) complexes containing a chiral diamine and η6-arene connected by a tethering group have been prepared and were evaluated in the asymmetric reductions of a range of ketones. Changes to the level of steric hindrance and the addition of an electron-withdrawing functionality on the sulfonyl group have a significant effect on the reactivity and enantioselectivity of the catalysts.
An efficient diphosphine/hybrid-amine combination for ruthenium(II)- catalyzed asymmetric hydrogenation of aryl ketones
Li, Yuehui,Zhou, Yougui,Shi, Qixun,Ding, Kuiling,Noyori, Ryoji,Sandoval, Christian A.
supporting information; scheme or table, p. 495 - 500 (2011/04/16)
Readily available and modular hybrid amine/benzimidazole-based 1H-benzimidazole-2-methanamine (BIMA) ligands in combination with 2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane (DIOP) afford efficient catalytic systems for the ruthenium(II)-catalyzed asymmetric hydrogenation (AH) of a number of aryl ketones. The AH proceeds smoothly with substrate-to-catalyst (S/C) molar ratios of up to 100,000 (TOF of 6500ah -1, 8aatm) giving chiral alcohols in up to 99% ee.
