Modular Monodentate Phosphoramidite Ligands for Rhodium-Catalyzed Enantioselective Hydrogenation
作者:Yan Liu、Kuiling Ding
DOI:10.1021/ja052749l
日期:2005.8.1
A new class of monodentate phosphoramidite ligands (DpenPhos) has been developed on the basis of the modular concept for Rh(I)-catalyzed asymmetric hydrogenations of a variety of olefin derivatives, affording the corresponding optically active compounds in excellent yields and enantioselectivities. The ligands have the advantages of facile preparation, tunable structure, and broad scope of substrates
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
Supramolecular chiral phosphorous ligands based on a [2]pseudorotaxane complex for asymmetric hydrogenation
作者:Yong Li、Yu Feng、Yan-Mei He、Fei Chen、Jie Pan、Qing-Hua Fan
DOI:10.1016/j.tetlet.2008.03.039
日期:2008.4
A new type of supramolecular chiral phosphorus-based ligands was prepared from easily available monodentate ligands through complexationbetween dibenzylammonium salt and dibenzo[24]crown-8 macrocycle. Rhodium complexes with these supramolecular ligands were prepared, and the supramolecular bidentate ligand-containing catalyst has demonstrated better catalytic activity for all substrates, and higher
An efficient and highly stereoselective synthesis of new P-chiral 1,5-diphosphanylferrocene ligands and their use in enantioselective hydrogenation
作者:Weiping Chen、Stanley M. Roberts、John Whittall、Alexander Steiner
DOI:10.1039/b601952h
日期:——
An efficient and highly stereoselective synthesis of P-chiral 1,5-diphosphanylferrocene ligands has been developed, and the introduction of P-chirality in ferrocene-based phosphineligands enhances the enantioselective discrimination produced by the corresponding catalyst when matching of the planar chirality, the chirality at carbon and the chirality at phosphorus occurs.
Cation-Triggered Switchable Asymmetric Catalysis with Chiral Aza-CrownPhos
作者:Guang-Hui Ouyang、Yan-Mei He、Yong Li、Jun-Feng Xiang、Qing-Hua Fan
DOI:10.1002/anie.201411593
日期:2015.3.27
AbstractAn aza‐crown ether, modified phosphoramidite ligand, has been designed and synthesized. The ON/OFF reversible switch of catalytic activity for its rhodium catalyst was thoroughly investigated in the asymmetric hydrogenation of dehydroamino acid esters modulated by host–guest interactions. In the OFF state, the catalyst is almost inactive (less than 1 % conversion) because of the formation of an intermolecular sandwich complex by two aza‐crown ether moities and the cationic rhodium metal center. In using alkali‐metal‐cations as the trigger, the catalytic activity was turned ON and consequently resulted in full conversions and excellent enantioselectivities (up to 98 % ee).