A synthetic methodology is reported that functionalizes C60 and C70 fullerenes with dihydroazepine rings by a cascade reaction encompassing a rhodium‐catalyzed cycloisomerization of 1,5‐bisallenes and a [4+2] cycloaddition. This transition metal‐catalyzed cascade reaction provides a versatile and step‐economical approach to the synthesis of 6,7‐membered polyheterocyclic fullerene adducts. Electrochemical characterization of the products obtained ventures their application in organic and perovskite photovoltaic devices.

Open-cage fullerenes, fullerenes with orifices created by breaking some of the C-C bonds in a fullerene such as C60, are molecules that allow chemical access to both the external and the internal surfaces of the carbon cage. We have found such molecules to be challenging to crystallize and thereby fully structurally characterize through single crystal X-ray diffraction studies. We have also found that the reactivity of these open cage fullerenes can differ significantly from that of the parent fullerene (see A. Aghabali, S. Jun, M. M. Olmstead, A. L. Balch, Silver(I)-Mediated Modification, Dimerization, and Polymerization of an Open-Cage Fullerene. J. Am. Chem. Soc. 2016, 138, 16459-16465.) This talk will report recent studies of the crystallographically determined structures and reactivities of several open-cage fullerenes with particular attention given to the accessibility of the cage opening to chemical reactions.

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