Synthesis of a Difullerenopyrrole

The synthesis and spectroscopic characterization of a difullerenopyrrole is described. The synthesis starts from the easily accessible 2,3,6,7-tetramethylanthracene, and its final step involves treatment of the pyrrole derivative 2,3,6,7-tetrakis(bromomethyl)-9,10-dihydro-9,10-[3,4]epipyrroloanthracene with iodide in the presence of excess [60]-fullerene. The difullerenopyrrole is directly assembled in this key step and is thought to arise from the in situ generation of an o-quino-dimethane intermediate followed by a regiocontrolled cycloaddition at one of the thirty (6,6)-bonds of [60]-fullerene. This symmetric difullerenopyrrole represents a versatile building block for a variety of pyrrolic molecules, such as fullerenoporphyrins.