A heterogeneous and reusable nanopolymer-supported palladium catalyst for the copper- and phosphine-free Sonogashira coupling reaction under aerobic conditions in water

Palladium nanoparticles immobilized on sepiolite–cyclodextrin nanosponge hybrid: Efficient heterogeneous catalyst for ligand‐ and copper‐free C─C coupling reactions

“…[26,27] Development of copper-and ligand-free protocols [28] with the use of heterogeneous catalysts in aqueous media is considered as a turning point in this field and can facilitate the applications of such processes for industrials purposes. [26,[29][30][31][32][33][34][35][36][37][38][39][40] As an example, immobilization of Pd on cellulose-aluminium oxide composite [41] and biopolymers [42][43][44][45] can be mentioned. In this context, use of biopolymers such as wool, chitosan and cellulose as catalyst supports has attracted much attention due to their biodegradability, biocompatibility, chemical and physical versatility, availability and relatively low cost.…”

Solid-Supported Palladium Catalysts in Sonogashira Reactions: Recent Developments

“…After filtration, the catalyst was recovered and reused ten times, showing a certain decrease in the reactivity after the sixth run. Moreover, the tetrazole-supported complex 13 catalyzes the Sonogashira process of aryl iodides and bromides in water as solvent, using triethylamine as base and TBAB as additive, the catalyst being recovered and reused up to five times in the reaction between 4-methyliodobenzene and phenylacetylene with decreasing in the observed final yield from 94% to 89% (Figure 4) [29]. Furthermore, a poly(styrene-co-maleic anhydride) modified with 2-aminothiazole moieties has been reported for the immobilization of palladium(II) dichloride, the resulting material 14 being suitable as catalyst for the coupling of aryl iodides, bromides and chlorobenzene with terminal acetylenes, using pyridine as base and in the absence of solvent ( Figure 4) [30].…”

Palladium nanoparticles immobilized on cyclodextrin‐decorated halloysite nanotubes: Efficient heterogeneous catalyst for promoting copper‐ and ligand‐free Sonogashira reaction in water–ethanol mixture

“…To circumvent these problems, the development of heterogeneous catalysts for Sonogashira reactions has been suggested . Moreover, the use of green procedures, especially use of aqueous media, for promoting C–C coupling reactions has been a focus …”