Unmodified Nano‐Powder Magnetite Catalyzes a Four‐ Component Aza‐Sakurai Reaction

Abstract

A new catalyst for an old material: magnetite is an excellent Lewis acid catalyst for the four-component aza-Sakurai reaction. The process could be repeated up to 15-times without losing effectiveness, with the catalyst recycling being as easy as the use of a simple magnet. The catalyst is selective and could discriminate between aldehyde and ketone functionalities, catalyzing first the reaction with the higher electrophilic aldehyde.

Application of Nanocatalysts in Multi-Component Reactions

“…Between 21 Results pointed out that the reaction performed at room temperature took longer times in order to obtain similar results and the reaction using different substituted chloroformates gave practically the same results. In addition, the nature of the carbonyl compound has a certain impact on the results.…”

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 ...…”

Byproduct‐Catalyzed Four‐Component Reactions of Aldehydes with Hexamethyldisilazane, Chloroformates, and Nucleophiles in Acetonitrile Leading to Protected Primary Amines, β‐Amino Esters, and β‐Amino Ketones

“…(1)], [2] which was found later by Ramón and Yus to proceed smoothly in the presence of unmodified nanopowder magnetite at 110 8C. [3] The products resulting from these multicomponent reactions are alkoxycarbonyl-protected primary amines (carbamates), which are widely used as synthetic intermediates for biologically important molecules. In addition, the alkoxycarbonyl groups Abstract: Multicomponent reactions are a very powerful tool for the construction of complex organic molecules by using readily available starting materials.…”

“…[4] Mechanistic studies indicate that the above four-component reaction proceeds through a pathway of tandem nitrogen protection/imine formation/imine addition. [2,3] While the first step can occur in the absence of catalysts, the last two steps are promoted by acidic species. Importantly, byproduct chlorotrimethylsilane (TMSCl), a silicon Lewis acid generated by the reaction of HMDS with a chloroformate, [5] plays a vital role in combination with an iron species in promoting the imine formation/imine addition.…”