This "polymeric iodide" has been oxidized to yield iodosyl compounds such as the iodosyl acetate (M.L.Hallensleben). Being an excellent leaving group, iodine may also be replaced with a metal (e.g. lithium). A broad range of resin derivatives can be obtained via metallated polymer (see e.g. M.J.Farrall and J.M.J.Fréchet).