While lesser steps and higher yield look attractive at first sight, this approach had to be given up due to high cost and restricted availability of the dioxide. Several derivatives are available, such as the diketone (melting point about 322 °C). Both [1.1.1.1]pagodane and [2.2.1.1]pagodane form divalent cations in /. In these cations the electron deficiency is spread over the central cyclobutane ring. These dications were the first examples to show the phenomenon of σ-bishomoaromaticity which was subsequently studied by the Prinzbach group to great length. Pagodane is an isomer of dodecahedrane and can be chemically converted to it.