Edge-polyhalogenation of PAHs has attracted considerable interest because the resulting halogenated derivatives exhibit characteristics that are notably different from those of the parent hydrocarbons. Nevertheless, direct and selective halogenation of polycyclic frameworks remains challenging. We herein report controlled multichlorination and annulation of 5helicene enabled by using Carborane-SMe catalyst to efficiently furnish decachlorobenzoghiperylene. The remaining C-H bonds can be used for the downstream functionalization via direct lithiation.
Sakamoto et al. (Mon,) studied this question.