Supramolecular chiral dendritic monophosphites assembled by hydrogen bonding and their use in the Rh-catalyzed asymmetric hydrogenation
作者:Yong Li、Yan-Mei He、Zhi-Wei Li、Feng Zhang、Qing-Hua Fan
DOI:10.1039/b823047a
日期:——
A new type of supramolecular chiral dendritic monophosphite ligands has been prepared via a hydrogen-bonding assembly. The Rh complexes of these supramolecular ligands have been successfully applied in the asymmetric hydrogenation of enamides and dehydroamino acid derivatives with good enantioselectivities, which are comparable to those obtained from the free monophosphite ligands. The supramolecular catalyst could be easily recycled viasolvent precipitation.
Modular chiral dendrimers with monodentatephosphoramiditeligands located at the core were synthesized and applied in the Rh-catalyzed asymmetric hydrogenations, afforded unprecedented enhancement of enantioselectivity.
Design and synthesis of a novel three-hindered quadrant bisphosphine ligand and its application in asymmetric hydrogenation
作者:Kexuan Huang、Xiaowei Zhang、Thomas J. Emge、Guohua Hou、Bonan Cao、Xumu Zhang
DOI:10.1039/c0cc02620d
日期:——
A novel three hindered quadrant bisphosphine ligand has been synthesized. The ligand shows excellent enantioselectivities and reactivities for rhodium-catalyzed hydrogenations of various functionalized olefins.
Enantioselective Hydrogenation of α-Dehydroamino Acid Esters Catalyzed by Rhodium Complexes with Chiral Bisaminophosphine Ligands
作者:Xianfeng Sun、Wei Li、Le Zhou、Xumu Zhang
DOI:10.1002/adsc.201000038
日期:——
A highly efficient strategy for the synthesis of a series of chiral bisaminophosphine ligands was well established with several remarkable features. The synthetic utility of these ligands was explored for rhodium‐catalyzed asymmetric hydrogenations of α‐dehydroamino acidesters. Up to 98% ee values were achieved for the enantioselectivesynthesis of aminocarboxylic acids and their derivatives, which
A supramolecularly tunable chiral bisphosphine ligand bearing two pyridyl-containing crown ethers was synthesized and applied in Rh or Ir-catalyzed asymmetric hydrogenations in high yields with excellent ee values (90-99% ee).