1-(perfluoroheptyl)heptane and 1-(perfluoroheptyl)-2-heptene and of 1-(perfluoroheptyl)dodecane and 1-(perfluoroheptyl)-2-dodecene, respectively. In similar reactions cyclohexene and cycloheptene yield only the (perfluoroalkyl)cycloalkane whereas cyclopentene yields only the olefin. Reaction with allyl bromide proceeds with double bond migration and loss of bromine. A mild copper-catalysed addition of perfluoroalkyliodides