Highly regioselective cyclotrimerization of 1-perfluoroalkylenynes catalyzed by nickel.

We report the highly regioselective cyclotrimerization of the 1-perfluoroalkylenynes in the presence of Ni(PPh3)4. The substituent effects on the reactivity of the enynes were investigated. We also succeeded in the nickel-catalyzed cocyclization of the 1-perfluoroalkylenynes with (trimethylsilyl)-acetylene. The possible structures of the intermediates of the cyclotrimerization and the reasons for the observed high regioselectivity were discussed.