Synthesis of fluorinated dienes by palladium-catalyzed coupling reactions.

The synthesis of partly fluorinated 1,3- and 1,4-dienes by palladium-catalyzed coupling makes these compounds available on the laboratory scale. Several catalyst systems were tested to maximize the yields and minimize the by-products. The molecular structures of 1,1,2,4,4-pentafluorobutadiene, chloro(N,N'-tetramethylethylenediamine)(trifluorovinyl)zinc, PCy(2)R, and P(O)Cy(2)R (Cy=cyclohexyl, R=2-(1-naphthyl)phenyl) were elucidated by X-ray crystallography.