Synthesis of polyethers containing viologen moiety and their application to electron-transfer catalyst

Polyethers containing viologen moieties were prepared by the reaction of tosylated polyethers with bipyridine. Viologen moieties of these polymers having ? ((CH₂)₂? O? )_n ? chains were reduced into the cation radicals by sodium dithionite in dichloromethane, methanol, and benzene. The reduction of vicinal dibromide, ethyl 2,3-dibromo-3-phenylpropionate using these polymers as electron-transfer catalyst (ETC) was performed in dichloromethane to obtain ethyl cinnamate in good yield.