Three-component coupling polymerization of bisallene, aryl dihalide, and nucleophiles via pi-allylpalladium complex

A novel palladium(0)-catalyzed three-component coupling polymerization of a bisallene (1,2,-10,11-dodecatetraene, 1), aryl dihalides (2a-e), and a nucleophile (sodium diethyl malonate, 3) is described. By the reaction of 1, 4,4'-diiodobiphenyl (2a), and 3 in the presence of a palladium catalyst in 1,4-dioxane at 80 degrees C for 2 days, a polymer (4a) was obtained in high yield (97%, (M) over bar(n) = 11 100). The structure of the resulting polymer (4a) was confirmed by C-13-, H-1-NMR, and IR spectra, from which the double bonds in the polymer backbone were detected quantitatively and were found to be mainly composed of E-isomer. The concentration of the palladium catalyst was found to affect the degree of polymerization. By using some aryl dihalides (2b-e), the corresponding polymers were also obtained in high yield.