Self‐Assembly of a Chiral Bis‐phosphine Ligand Bearing Pyridyl Crown Ethers and Chiral Primary Ammoniums: Application to Catalytic Asymmetric Hydrogenation Reactions. Issue 20 (20th May 2022)

• Record Type: Journal Article
• Authors: Lu, Ying‐Bo; Chen, Chuan‐Fu; Hu, Yi‐Hu; Zhang, Xi‐Chang; Fang, Qiang; Yang, Li‐Yao; Xie, Lin‐Jie; Wu, Jing; Li, Shijun
• Is Part Of: ChemistrySelect. Volume 7:Issue 20(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-20
• Subjects: asymmetric catalysis -- crown ethers -- host-guest chemistry -- self-assembly -- supramolecular catalysts; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202200912
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: A chiral bis‐hosphine ligand bearing two pyridyl crown ethers was complexed with primary ammonium salts of different absolute configuration to form supramolecular chiral catalysts, which were successfully applied in the Rh‐catalyzed asymmetric hydrogenation of α‐dehydroamino acid esters and Ir‐catalyzed asymmetric hydrogenation of quinoxalines. By comparison with the non‐assembled catalysts, the complexation between the chiral catalysts and primary ammoniums obviously improved enantioselectivities. Up to 11 % enhancement in ee values in asymmetric hydrogenation of α‐dehydroamino acid esters and 30 % enhancement in ee values in asymmetric hydrogenation of quinoxalines were achieved. Abstract : A bis‐phosphine ligand bearing pyridyl crown ethers was applied to the asymmetric hydrogenation of α ‐dehydroamino acid esters and quinoxaline derivatives, in which the presence of primary ammonium salts as guests could significantly improve the enantioselectivities.