Novel atropisomeric aminophosphine ligands with a bridge across the 5,5′-position of biphenyl for Rh(I)-catalyzed asymmetric hydrogenation
摘要:
A new type of atropisomeric bisaminophosphine ligands 2 with a bridge across the 5,5'-position of biphenyl has been developed. The axial chirality of this type of ligands can be retained by macro-ring strain produced from 5,5'-linkage of biphenyl even without 6,6'-substituents on biphenyls. The ligand (R)-2a showed high catalytic activities and enantioselectivities (up to 95.3% ee and quantitative yields) for Rh(I)-catalyzed asymmetric hydrogenation of a variety of methyl (Z)-2-acetamido-3-arylacrylates, (C) 2008 Elsevier Ltd. All rights reserved.
Novel atropisomeric aminophosphine ligands with a bridge across the 5,5′-position of biphenyl for Rh(I)-catalyzed asymmetric hydrogenation
摘要:
A new type of atropisomeric bisaminophosphine ligands 2 with a bridge across the 5,5'-position of biphenyl has been developed. The axial chirality of this type of ligands can be retained by macro-ring strain produced from 5,5'-linkage of biphenyl even without 6,6'-substituents on biphenyls. The ligand (R)-2a showed high catalytic activities and enantioselectivities (up to 95.3% ee and quantitative yields) for Rh(I)-catalyzed asymmetric hydrogenation of a variety of methyl (Z)-2-acetamido-3-arylacrylates, (C) 2008 Elsevier Ltd. All rights reserved.
A new type of atropisomeric bisaminophosphine ligands 2 with a bridge across the 5,5'-position of biphenyl has been developed. The axial chirality of this type of ligands can be retained by macro-ring strain produced from 5,5'-linkage of biphenyl even without 6,6'-substituents on biphenyls. The ligand (R)-2a showed high catalytic activities and enantioselectivities (up to 95.3% ee and quantitative yields) for Rh(I)-catalyzed asymmetric hydrogenation of a variety of methyl (Z)-2-acetamido-3-arylacrylates, (C) 2008 Elsevier Ltd. All rights reserved.
Synthesis of atropisomeric 5,5′-linked biphenyl bisaminophosphine ligands and their applications in asymmetric catalysis
作者:Yong Jian Zhang、Hao Wei、Wanbin Zhang
DOI:10.1016/j.tet.2008.12.056
日期:2009.2
Atropisomeric 5,5'-linked biphenyl bisaminophosphine ligands 2 has been synthesized. The axial chirality of this type of ligands can be retained by macro ring strain produced from 5,5'-linkage of biphenyl even without 6,6'-substituents on biphenyls. The Rh complex of bisaminophosphine 2a as a catalyst is effectively working in the asymmetric hydrogenation of methyl (Z)-2-acetamido-3-arylacrylates, however, for hydrogenation of arylenamide, the low enantioselectivity was observed. When the ligands applied to Pd-catalyzed allylic alkylation, it is found that ligand 2b having a longer backbone linkage is a better ligand for enantioselection in the reaction. (C) 2008 Elsevier Ltd. All rights reserved.