The First Magnetic Nanoparticle‐Supported Chiral DMAP Analogue: Highly Enantioselective Acylation and Excellent Recyclability

Abstract

Recyclable organocatalysts: The first chiral DMAP analogue immobilized on magnetic nanoparticles is a highly active catalyst that is capable of the acylation of racemic sec-alcohols under convenient, process-scale friendly conditions (room temperature, 5 mol % loading, with acetic anhydride as the acylating agent) with excellent enantiodiscrimination. The catalyst is easily recovered and possesses unprecedented recyclability-in this study it was demonstrated to retain excellent activity and selectivity over 32 iterative cycles.

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].…”

Fe3O4 Nanoparticles-Supported Palladium-Bipyridine Complex: Effective Catalyst for Suzuki Coupling Reaction

“…Additionally, as MNPs have a high surface area, MNPs-supported catalysts also show high dispersion and reactivity with a high degree of chemical stability. The various types of organic reactions using the MNPs-supported catalysts that have emerged recently include C-C coupling reactions [17][18][19][20][21][22][23][24], hydroformylation [25,26], hydrogenation [27][28][29][30][31][32][33][34][35], C-N coupling reaction [36,37], oxidation [38][39][40][41][42][43], cleavage of allyl esters and ethers (deallylation catalyst) [44], enantioselective acylation [45], multicomponents Aza-Sakurai reaction [46], the Paal-Knorr reaction [47], CO 2 cycloaddition reactions [48], asymmetric hydrosilylation of ketones [49], and esterification [50]. Other reports of MNPs-supported catalysts include O-Alkylation reaction [51], halogen exchange reaction [52], polymerization reactions [53], enzymes for carboxylate resolution [54], amino acids for ester hydrolysis [55], organic amine catalysts promoting Knoevenagel [56], one-pot reaction cascades [57], and the various acidcatalyzed reactions (deprotection reaction of benzaldehyde ...…”

Magnetic nanoparticle-supported organocatalysis

“…The Connon group also reported the preparation of cat-4 via the reaction of Fe 3 O 4 -supported N-methyl dopamine hydrochloride with (S)-α,α-diphenylprolinolcatalyst (Scheme 7) [22]. This catalyst promoted acylative kinetic resolution of racemic mono-protected cis-diol (Scheme 8).…”