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
Conjugate addition of potassiumtrifluoro(organo)borates 2 to dehydroalanine derivatives 1, mediated by a chiral rhodium catalyst and in situ enantioselective protonation, afforded straightforward access to a variety of protected alpha-amino esters 3 with high yields and enantiomeric excesses up to 95%. Among the tested chiral ligands and proton sources, Binap, in combination with guaiacol (2-methoxyphenol)
An<i>Atropos</i>Chiral Biphenyl Bisphosphine Ligand Bearing Only 2,2′-Substituents and Its Application in Rh-Catalyzed Asymmetric Hydrogenation
作者:Jia Jia、Zheng Ling、Zhenfeng Zhang、Ken Tamura、Ilya D. Gridnev、Tsuneo Imamoto、Wanbin Zhang
DOI:10.1002/adsc.201701281
日期:2018.2.15
19.9 kcal/mol). This ligand avoids the time‐consuming optical resolution generally needed for the preparation of axially chiral ligands and shows high reactivity and enantioselectivity in Rh‐catalyzedasymmetric hydrogenations.
A series of chiral bisphosphine ligands were designed and synthesized based on single-handed quinoline oligoamidefoldamers. The bisphosphine ligands can coordinate with Rh(cod)2BF4 in a 1 : 1 stoichiometry and the resulted chiral Rh(I) catalysts were applied in the asymmetric hydrogenation of α-dehydroamino acid esters, in which excellent conversions and promising levels of enantioselectivity were