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).
More electron donating, more rigid: A new highly electron‐donating P‐stereogenic bisphospholaneligand (ZhangPhos) was synthesized in a practical and highlyenantioselective manner from a commercially available chiral source. Better or comparable enantioselectivities and reactivities than TangPhos were achieved in rhodium‐catalyzed hydrogenation of various functionalized olefins (see scheme; nbd=3
High performance of Me-BIPAM for enantioselective hydrogenation of α-dehydroamino esters, enamides, and dimethyl itaconate was demonstrated. [Rh(Me-BIPAM)(diene)]X (diene = cod, nbd; X = BF4, PF6, SbF6) gave optically active β-aryl α-amino esters up to 99% ee, 1-arylethylamines up to 97% ee, methyl 2-acetylaminobutanoate with 90% ee, and dimethyl 2-methylsuccinate with 97% ee under 0.3−0.8 MPa dihydrogen