act as a one-electron oxidant, producing radical cations from olefins and promoting the
efficient radical cation [2+ 2] and [2+ 4] cycloaddition reactions. Subsequent chain
propagation afforded trisubstituted cyclobutane or cyclohexene derivatives, and this facile
route enables the replacement of rare metals with sustainable, green, and inexpensive iron
in radical cation cycloadditions.