GENERAL-METHOD FOR THE PREPARATION OF FUNCTIONALIZED FLUORINATED PHENYL ALKYNES

In the presence of cuprous iodide, the palladium-catalyzed coupling re action of 4-substituted tetrafluorophenyl iodides 1 with terminal alky nes proceeds readily in diisopropylamine or triethylamine to afford th e corresponding fluorinated phenylalkynes in excellent yields under mi ld conditions. A variety of substituents on F-benzenes such as methoxy , dimethylamino, hydro, acyl, piperidino, and morpholino do not interf ere with the coupling reaction. The reaction works well with 1-alkynes containing functional groups, including alkyl, alkenyl, phenyl, vinyl ether, alkoxy, phenoxy, hydroxy, amino, trimethylsilyl, and cyano, to give the corresponding (fluorophenyl)alkynes. With dialkynes, 2 equiv of the fluorinated phenyl iodide give bis(fluorophenyl)dialkynes in g ood yields. When 1,4-dibromotetrafluorobenzene reacts with an excess o f alkyne in diisopropylamine, the bis-alkynylated tetrafluorobenzenes are obtained in good yields. However, in triethylamine the reaction gi ves a mixture of mono- and bis-alkynylated products. This method provi des a practical approach to fluorinated phenyl functionalized alkynes.