 This is confirmed by theoretical and practical work by Hogeveen.In contrast to the monocation, which is described with several patterns of substitution, the dication is mainly studied by its hexamethyl derivative.The synthesis starts at hexamethyl Dewar benzene (compound I in table 4) reacting with Cl2 into 5,6-dichloro-1,2,3,4,5,6-hexamethylbicyclo[2.1.1]hex-2-ene (compound II in table 4).