Copper-free, recoverable dendritic Pd catalysts for the Sonogashira reaction

Abstract

Three generations of bidentate phosphinated Pd(II) dendrimers are efficient catalysts in the absence of copper co-catalyst for the Sonogashira reaction and are, with two cyclohexyl substituents on the phosphorus atoms, recovered by precipitation and re-used.

Sulphonated “Click” Dendrimer‐Stabilized Palladium Nanoparticles as Highly Efficient Catalysts for Olefin Hydrogenation and Suzuki Coupling Reactions Under Ambient Conditions in Aqueous Media

“…This efficient ligandless catalysis under ambient conditions in an aqueous solvent compares favourably with other more classic approaches of dendritic palladium catalysis. [16] Experimental Section…”

Palladium–Poly(3‐aminoquinoline) Hollow‐Sphere Composite: Application in Sonogashira Coupling Reactions

“…To avoid the formation of this undesired byproduct, several Cu-free methods of the palladium-catalyzed Sonogashira coupling have been developed. [24][25][26][27][28] We report here on the synthesis of a palladium-polymer supramolecular system by using the IPCF approach. We paid special attention to characterize the polymer product by using optical techniques.…”

Metallodendritic Catalysis for Redox and CarbonCarbon Bond Formation Reactions: A Step towards Green Chemistry.

“…The Cy series of catalysts proved easier to recover than the t-Bu ones for solubility reasons, however, and kept the same catalytic efficiency after five recycling operations. [29,30] These dendritic palladium catalysts showed a negative dendritic effect, i.e., not only are the metallodendritic catalysts slower than the monomer model, but also the efficiency decreased as the dendrimer generation increased from 1 to 3. The two first generations containing respectively 4 and 8 catalytic palladium centers had about the same activity (the decrease was very weak from the first to the second generation), but the conversion yields dropped by half from the first to the third generation.…”