Ring Expansion of the Fullerene Core by Highly Regioselective Formation of Diazafulleroids

Fullerenes with enlarged openings such as diazafulleroid 1 are obtained by twofold addition of azides to C60. Even after cleavage of the two 5–6 bonds and introduction of the imino bridges, the π‐electron system of C60 remains intact. Compound 1 contains three seven‐membered rings and one eleven‐membered ring, and may hold the key to the synthesis of endohedral fullerenes under mild conditions.