SEARCH Articles Figures Tables Cycloaddition 1,3-dipolar-electrophilic ring closur Electrophiles cycloaddition Electrophiles cycloaddition Electrophilic cycloaddition Electrophilic cycloaddition Polar Cycloadditions in Which Cationic Aromatic Systems Act as Electrophiles Polar Cycloadditions in Which the Electrophilic System Contains Two Atoms of an Aromatic Ring