Water‐Promoted Heterogeneous Asymmetric Hydrogenation of Quinolines over Ordered Macroporous Poly(ionic liquid) Catalyst

Abstract

The development of air stable solid chiral catalysts for asymmetric hydrogenation is very attractive for the largescale production of chiral compounds. Herein, we reported the synthesis of an ordered macroporous poly(ionic liquid) catalyst integrated with VDPEN-RuOTf as air stable chiral catalyst for asymmetric hydrogenation of quinoline derivatives. Under ambient conditions, the solid catalyst afforded 97% conversion with 90% ee in the asymmetric hydrogenation of 2-methylquinoline in water. It was found that the activity and enantioselectivity of poly(ionic liquid) catalyst decreases with surface hydrophobicity increasing, suggesting the important role of surface hydrophilicity in obtaining high activity and enantioselectivity in water. Control experiment suggests that water promotes the anti-air stability of the poly (ionic liquid) catalyst. The combination of poly(ionic liquid) catalyst and water may provide a new approach for designing heterogeneous chiral catalyst with anti-air stability.

Development of efficient solid chiral catalysts with designable linkage for asymmetric transfer hydrogenation of quinoline derivatives

“…Using SBA-ILBF4-TsDPEN50 as a representative sample, the characteristic peaks for C=C vibrations of the phenyl ring at ~1450-1550 cm -1 and the S=O stretching peak at 1157 cm - 13 C NMR spectrum of imidazole-TsDPEN-N-Boc in CDCl3; (d) 13 C CP/TOSS NMR spectrum of SBA-ILBF4-TsDPEN50. [27][28][29], demonstrating the successful incorporation of the chiral ligands with IL linkages into SBA-15 by this one-pot method. In comparison with imidazole-TsDPEN-N-Boc, the characteristic peak of the C=O stretching vibration at 1710 cm -1 shifted slightly to 1700 cm -1 for SBA-ILBr-TsDPENx-N-Boc (Fig.…”