Copper- and ligand-free Sonogashira reaction catalyzed by palladium in microemulsion

Sonogashira reactions catalyzed by water-soluble, β-cyclodextrin-capped palladium nanoparticles

“…In addition, the reaction still offered a satisfactory yield ($90%) when it was carried out at room temperature (25°C) for 20 h (table 1). It should be noted that the Sonogashira reaction catalyzed by supported Pd nanoparticles under the ligand free condition was also found by other researchers [12,17,22,29,30,42,43]. In addition, several groups reported that some Sonogashira reactions could be successfully carried out under the copper free condition [12,[16][17][18][19]21,22,30,43,44].…”

“…It should be noted that the Sonogashira reaction catalyzed by supported Pd nanoparticles under the ligand free condition was also found by other researchers [12,17,22,29,30,42,43]. In addition, several groups reported that some Sonogashira reactions could be successfully carried out under the copper free condition [12,[16][17][18][19]21,22,30,43,44]. Stimulated by these results and the attempt to further simplify the reaction condition, we took one more step.…”

Copper- and ligand-free Sonogashira reaction catalyzed by palladium in microemulsion: Effects of surfactant and alcohol

“…In our study, nano-Pd could be in situ formed in a five-component microemulsion of heptane/butanol/water/ propylene glycol/TX100 microemulsion [23,24]. The palladium nanoparticles were in situ formed by heating the palladium salt in the microemulsion in absence of any other reducing agent (Fig.…”

“…The microemulsion here may act as the palladium nanoparticle reducing agent and stabilizer [23]. In situ-formed palladium nanoparticles in the microemulsion have higher reactivities than the pre-prepared palladium nanoparticles [24]. And the nano-Pd can be preserved for months without changes of properties.…”

Sonogashira Reactions Using Nanocatalysts

“…41 In addition, oil-in-water microemulsions formed by the mixture Triton R X-100/n-heptane/nbutanol/water/PEG at 80 • C have been employed in the fast cross-coupling of very activated aryl iodides, such as 10, with phenylacetylene (5 min) catalyzed by Pd-NPs generated by combining PdCl 2 (0.5 mol%) and sodium hydroxide, yielding the corresponding alkynes such as 11 (Scheme 4.4). 42,43 However, aryl bromides performed poorly under these conditions. Catalytically active Pd-NPs have been synthesized in water by reduction of Na 2 PdCl 4 with a Fisher carbene complex in the presence of PEG as nanoparticle stabilizers.…”