Copper- and Ligand-Free Sonogashira Reaction Catalyzed by Pd(0) Nanoparticles at Ambient Conditions under Ultrasound Irradiation

Abstract

The Sonogashira reaction proceeds at ambient temperature (30 degrees C) in acetone or room-temperature ionic liquid, 1,3-di-n-butylimidazolium tetrafluoroborate ([bbim]BF4), as solvent under ultrasound irradiation to give enhanced reaction rates, excellent chemoselectivity, and high yields in the absence of a copper cocatalyst and a phosphine ligand. TEM analysis showed the formation of stable, crystalline, and polydispersed Pd(0) nanoparticles as catalyst for the reaction.

Development of a Sulfur-Modified Glass-Supported Pd Nanoparticle Catalyst for Suzuki–Miyaura Coupling

“…For example, it has recently reported that traditional palladiumcatalyzed reactions that require a zero valent/divalent palladium catalyst and a suitable ligand (i.e., phosphine ligands and nitrogen-containing heterocyclic carbenes), can progress under ligand-free conditions using PdNPs. [3][4][5][6][7][8] There are therefore numerous advantages associated with the use of PdNP catalysts, including reduced processing costs, shorter reaction times and cleaner reaction profiles, which can have a positive impact on product purification. Based on their many attractive qualities, it is envisaged that PdNPs will become increasingly important for the synthesis of pharmaceutical agents and functional materials.…”

A Simple and Efficient One‐Pot Synthesis of Substituted Benzo[b]furans by Sonogashira Coupling–5‐endo‐dig Cyclization Catalyzed by Palladium Nanoparticles in Water Under Ligand‐ and Copper‐Free Aerobic Conditions

“…We also studied the normal Sonogashira coupling [13] of aryl iodides with aryl/alkylacetylenes by using this catalyst system. It was found that sodium hydroxide was equally effective as triethylamine for this reaction (Table 3, Entry 2).…”

Sonochemistry (Applications of Ultrasound in Chemical Synthesis and Reactions): A Review Part I

“…Deshmukh and co-workers reported ligand-free Pd-catalyzed coupling between aryl halides and terminal alkyne (Deshmukh, R.R., et al, 2001 ) as shown in Figure (18) Fig. (18) i-Heck reaction Sonogashira reaction or terminal acetylenes (Gholap, A.R., et al, 2005) (Heck reaction) in ionic liquids using a cleaning bath. (Ambulgekur, G. V., et al, 2005) investigated the leaching of Pd off support during the reaction, by examining the Heck reaction under ultrasound.…”