An effective system to synthesize methanofullerenes: substrate–ionic liquid–ultrasonic irradiation

Dehalogenation of the polyhalides, CHCl3, C60(CCl2), CH2I2, and 7,7-dibromobicyclo(4,1,0)heptane, by treatment with zinc, magnesium or NaOH powder, followed by the in situ reaction with fullerene in the presence of ultrasonic irradiation and in the ionic liquid solvents, [bmim][PF4] or [omim][BF4], provided [6,6]-junction cycloaddition products in 53–79% yields. Only single isomers of the products were detected in the reaction solutions.