Asymmetric reduction of imines with trichlorosilane catalyzed by valine-derived formamide immobilized onto magnetic nano-Fe₃O₄

Abstract

Magnetic nano-Fe 3 O 4 -supported organocatalysts were synthesized by anchoring valine-derived formamide onto the surface of Fe 3 O 4 magnetic nanoparticles, which were applied in the asymmetric reduction of imines with trichlorosilane at room temperature in toluene. The high level of yield and enantioselectivity catalyzed by magnetic nano-Fe 3 O 4 -supported organocatalysts was obtained. In the immobilization process, Cu I -catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) "click chemistry" was used as the anchored bridge. The magnetic nanoparticles can simplify the recovery of the organocatalyst and its separation from the reaction system. By an external magnet, the catalyst can be recycled and reused five times without a remarkable activity decline.

Fe3O4@vitamin B1 as a sustainable superparamagnetic heterogeneous nanocatalyst promoting green synthesis of trisubstituted 1,3‐thiazole derivatives

“…As a part of our ongoing research and in continuation of earlier work, herein we report Fe 3 O 4 @vitamin B 1 MNPs as a catalyst in the one‐pot reaction between arylglyoxals monohydrate ( 1 ), cyclic 1,3‐dicarbonyls ( 2 ) and thiobenzamides ( 3 ) under aqueous conditions at 80°C for the preparation of trisubstituted thiazole derivatives (Scheme ).…”

The Development of Organocatalytic Asymmetric Reduction of Carbonyls and Imines Using Silicon Hydrides

“…Magnetic nano-Fe 3 O 4 -supported catalysts were synthesized through anchoring L-valine derived formamide onto the surface of Fe 3 O 4 magnetic nanoparticles. [34] The main advantage of this system is that the magnetic nanoparticles can be easily recovered from the liquid phase reaction through magnet-driven force. By an external magnet, the catalyst 14 can be easily recycled and reused five times without a remarkable loss of activity.…”

“…Cheaper nanoparticle system was also developed. Magnetic nano‐Fe 3 O 4 ‐supported catalysts were synthesized through anchoring L ‐valine derived formamide onto the surface of Fe 3 O 4 magnetic nanoparticles [34] . The main advantage of this system is that the magnetic nanoparticles can be easily recovered from the liquid phase reaction through magnet‐driven force.…”

Rational Design of Simple Organocatalysts for the HSiCl3 Enantioselective Reduction of (E)-N-(1-Phenylethylidene)aniline

“…Thus, the catalyst role was mainly analyzed through the observed enantioselectivity. The low degree of induction achieved with Cbz-L-Val was surprising, since a variety of catalysts have been reported based on this amino acid [4][5][6][7][47][48][49]. Only appreciable asymmetric induction (62% ee) was observed for Cbz-L-Pro, probably due to its cyclic structure that can reduce the conformational freedom at the transition state, favoring an efficient chirality transfer [50].…”