Filtration‐Free Recyclable Catalytic Asymmetric Dihydroxylation Using a Ligand Immobilized on Magnetic Mesocellular Mesoporous Silica

Abstract

A new magnetic mesocellular mesoporous silica support featuring a 3D open-pore structure has been developed for highly efficient, filtration-free recycling of chiral ligands for catalytic asymmetric dihydroxylation. Reactions using the ligand immobilized on this magnetic silica system exhibited almost the same reactivity and enantioselectivity as those obtained in the homogeneous reaction. Magnetically recovered ligand could be recycled eight times with good to excellent conservation of reaction rates and enantioselectivities.

Magnetically Separable Base Catalysts: Heterogeneous Catalysis vs. Quasi-Homogeneous Catalysis

“…The supported catalysts proved to be effective and easily separated from the reaction media by applying an external magnetic field. Moreover, the ability of magnetic nanoparticles to serve efficiently as nano-support for organocatalytic systems has been recently reported [22][23][24][25][26][27][28][29][30][31][32]. We have described the highly selective hydroformylation reaction using rhodium catalysts supported on dendronized magnetic nanoparticles [33].…”

Recyclable Stereoselective Catalysts

“…1.12 ) [52] . This ligand was tested for AD reaction using K 3 Fe(CN) 6 as cooxidant (1 mol% catalyst).…”

DBU Derived Ionic Liquids and Their Application in Organic Synthetic Reactions

“…Thus, novel supports that ensure both good recyclability and catalytic activity are still desirable. MNP have recently appeared as a new type of catalyst support because of their easy preparation and functionalization, large surface area ratio, facile separation via magnetic force as well as low toxicity and price (Yoon et al, 2003;Stevens et al, 2005;Lee et al, 2006;Abu-Reziq et al, 2006;Luo et al, 2008). These features have made MNP a promising alternate of porous/mesoporous catalyst supports.…”