To address the obstacles facing the use of palladium-based homogeneous and heterogeneous catalysts in C─C cross-coupling reactions, a novel semi-heterogeneous support was developed based on hyperbranched poly(ethylene glycol)-blockpoly(citric acid)-functionalized Fe 3 O 4 magnetic nanoparticles (Fe 3 O 4 @PCAb-PEG). Because of the surface modification of the Fe 3 O 4 nanoparticles with amphiphilic and hyperbranched polymers (PCA-b-PEG), these hybrid materials are not only soluble in a wide range of solvents (e.g. water, ethanol and dimethylformamide) but also are able to trap Pd 2+ ions via complex formation of free carboxyl groups of the PCA dendrimer with metal ions. The reduction of trapped palladium ions in the dendritic shell of Fe 3 O 4 @PCA-b-PEG leads to immobilized palladium nanoparticles. The morphology and structural features of the catalyst were characterized using various microscopic and spectroscopic techniques. The catalyst was effectively used in the palladium-catalysed Mizoroki-Heck coupling reaction in water as a green solvent. In addition, the catalyst can be easily recovered from the reaction mixture by applying an external magnetic field and reused for more than ten consecutive cycles without much loss in activity, exhibiting an example of a sustainable and green methodology.

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Reactions of benzoic acid derivatives and (E)-cinnamic acid derivatives with N, N-dialkyl carbodiimide proceed smoothly at room temperature and in neutral conditions to afford N-acylurea derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions and no side reactions were observed.

Tetramethylguanidine-functionalized silica-coated iron oxide magnetic nanoparticles as a productive and reusable catalyst have been applied for the one-pot three-component synthesis of furanone derivatives (4a-o). In addition to the characterization of all products by FT-IR, 1 HNMR and 13 CNMR spectroscopy, single-crystal X-ray analysis of ethyl 5-oxo-2-phenyl-4-(phenylamino)-2,5-dihydrofuran-3carboxylate product has been made. Easy recrystallization and good-to-excellent yields (81-92%) of furanone derivatives are notable characteristics of this procedure. The catalyst identification was performed using FT-IR, XRD, SEM, TEM and TGA techniques. It is worth noting that the nanocatalyst can be recycled with an external magnet and reused for several times.

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