Even alkyl methyl ketones undergo asymmetric hydrogenation with high enantioselectivity when a rhodium complex of the conformationally rigid chiral ligand 1 (Me-PennPhos; R=CH3 ) is used as the catalyst. Basic additives such as 2,6-lutidine contribute to the achievement of high enantiomeric excesses.
当使用构象刚性手性配体1的铑配合物(Me-PennPhos; R = CH 3)作为催化剂时,即使烷基甲基酮也经历高对映选择性的不对称氢化。碱性添加剂(例如2,6-二甲基吡啶)有助于实现高对映体过量。
Chiral Bicyclo[2.2.2]octane‐Fused CpRh Complexes: Synthesis and Potential Use in Asymmetric C−H Activation
作者:Guozhu Li、Xiaoqiang Yan、Jijun Jiang、Hao Liang、Chao Zhou、Jun Wang
DOI:10.1002/anie.202010489
日期:2020.12.7
A new class of chiral cyclopentadienyl rhodium(I) complexes (CpRhI) bearing C2‐symmetric chiral bridged‐ring‐fused Cp ligands was prepared. The complexes were successfully applied to the asymmetric C−H activation reaction of N‐methoxybenzamides with quinones, affording a series of chiral hydrophenanthridinones in up to 82 % yield with up to 99 % ee. Interestingly, structure analysis reveals that the
Asymmetric synthesis catalyzed by transition metal complexes with rigid chiral ligands
申请人:The Penn State Research Foundation
公开号:US20010047113A1
公开(公告)日:2001-11-29
This invention is to develop novel transition metal catalysts for the practical synthesis of important chiral molecules. The invention emphasizes asymmetric catalysis based on chiral bidentate phosphine ligands with cyclic ring structures which could be used to restrict conformational flexibility of the ligands and thus the efficiency of chiral transfer can be enhanced through the ligand rigidity.
Syntheses of Novel Chiral Monophosphines, 2,5-Dialkyl-7-phenyl-7-phosphabicyclo- [2.2.1]heptanes, and Their Application in Highly Enantioselective Pd-Catalyzed Allylic Alkylations
C2-Symmetric nitroxides and their potential as enantioselective oxidants
作者:Benjamin Graetz、Scott Rychnovsky、Wen-Hao Leu、Patrick Farmer、Rong Lin
DOI:10.1016/j.tetasy.2005.09.016
日期:2005.10
The synthesis and evaluation of four C-2-symmetric nitroxides are presented. The nitroxides were evaluated for their ability to mediate the oxidation of several alcohols and found to have good catalytic activity. One enantioenriched nitroxide was found to kinetically resolve selected secondary alcohols with very modest selectivities. (c) 2005 Elsevier Ltd. All rights reserved.