The Sonogashira Reaction in Water via an Amphiphilic Resin-supported Palladium-Phosphine Complex under Copper-free Conditions

The Sonogashira reaction of aryl halides with terminal alkynes was catalyzed by an amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin-supported palladium-phosphine complex in water to give the corresponding aryl-substituted alkynes in high yields under copper-free conditions.Reaction of o-iodophenol with terminal alkynes under Sonogashira conditions gave benzofuran derivatives in one step.The palladium-catalyzed coupling of an aryl halide with a terminal alkyne promoted by CuI and an amine base, the so-called Sonogashira reaction, 1 is recognized not only as the most successful method for producing arylacetylene derivatives but is also a key step in the preparation of benzofurans or indoles. 2