PALLADIUM-CATALYZED 3-COMPONENT COUPLING - POLYMERIZATION OF DIYNE, ARYL DIHALIDE, AND HYDRIDE

The palladium-catalyzed three-component coupling reaction of acetylene s, aryl halides, and hydride and it's application to polymer synthesis are described. The coupling reaction of 1,2-diphenylacetylene, iodobe nzene, and sodium diethyl benzylmalonate was carried out at 80 degrees C for 48 h in 1,4-dioxane with Pd(OAc)(2)/tri-o-tolylphosphine, from which triphenylethylene was obtained in 71% isolated yield. The benzyl ic hydrogen of sodium diethyl benzylmalonate was supposed to be a hydr ide source in the present reaction by detecting diethyl benzalmalonate in the reaction system. Based on the results, the coupling polymeriza tion of 1,2-bis(4-phenylethynylphenyl)ethane, 4,4'-diiodobiphenyl, and sodium diethyl benzylmalonate was carried out at 80 degrees C for 48 h to produce a polymer (M-n=8500, M-W/M-n=3.0) in high yield. Using va rious aryl dihalides, the corresponding polymers having trisubstituted ethylene units were also obtained in high yields.