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

Abstract

Developing chiral solid catalysts for asymmetric catalysis is desirable for the elimination of homogeneous catalysis flaws but remains an immense challenge. Herein, we report the immobilization of TsDPEN on SBA-15 with an ionic liquid (IL) linkage via the one-pot reaction of imidazole-TsDPEN-N-Boc with 3-(trimethoxysilyl)propyl bromide in the SBA-15 mesopores. After coordination to Rh, the chiral solid catalysts could efficiently catalyze quinoline transfer hydrogenation, achieving 97% conversion with 93% ee, which was comparable to their homogeneous counterparts. The chiral solid catalyst with the IL linkage afforded much higher turnover frequency than that without the IL linkage (93 h -1 vs. 33 h -1 ), attributed to the phase transfer and formate-enriching ability of the IL linkage. Furthermore, the effect of the pH on the reaction rate of the solid catalyst was investigated, preventing reaction rate retardation during the catalytic process. The tuning of the linkage group is an efficient approach for catalytic activity improvement of immobilized chiral catalysts.

Supramolecular Catalysis with Chiral Mono- and Bis-(Thio)Urea-Derivatives

“…In "Artificial Enzymes" published in 1982, Breslow [1] envisioned that simple catalysts constituted by small organic molecules can reach performances of natural systems such as selectivity, efficiency, geometric control, and velocity. Since then, very important results have been obtained in the field of supramolecular organocatalysis [2][3][4][5][6][7][8][9][10][11][12][13][14] thanks to the design of catalysts inspired by the efficiency of natural enzymes. In supramolecular organocatalysis, different substrate activation modes have been reported [3][4][5][6][7][8][9][10][11][12][13][14] including iminium catalysis, enamine catalysis, and acid-base organocatalysis [2].…”

FePO4supported Rh subnano clusters with dual active sites for efficient hydrogenation of quinoline under mild conditions

“…Generally, active metal sites with incomplete filled d-electron orbitals in the catalyst are beneficial to adsorb reactants and exhibit moderate strength for this interaction, which are good for the formation of active intermediates. 4 Recently, various catalysts have been developed for the hydrogenation of quinoline, such as noble metals (Pd, Ru, Pt, Rh, Au and Ir) 5–16 and bimetallic catalysts (AuPd, RuCu and PdNi), 17–19 as well as non-noble metal catalysts (Co, Ni, Fe and Cu). 20–23 Strategies for the design of highly efficient catalysts include the tuning of particle size and the modulation of electronic state for the metal active species.…”

Nanocatalysts Derived from Copper Phyllosilicate for Selective Hydrogenation of Quinoline

“…Recently, many homogeneous and heterogeneous catalysts that are based on conventional precious metals (e.g., Pd, Pt, Ru, Rh, etc.) have been developed for selective hydrogenation. − However, high prices and limited availability hinder their further applications . Although non-noble metal catalysts like Fe, Co, and Ni have significant cost advantages, their low hydrogenation selectivity limits their application in the hydrogenation of quinoline.…”