Functionalization of Fullerenes: Addition Reactions

Abstract

This chapter begins with the nucleophilic reactions of fullerenes, in which Grignard reagents, alkyllithium, and other carbon nucleophiles, as well as silicon and phosphorous nucleophiles, have been employed for the synthesis of a variety of fullerene adducts. In some cases, multiple adducts have been synthesized regioselectively. The second part deals with electrophilic reactions, although reported examples of these reactions are still limited. The third part is devoted to addition–elimination reactions, which have been recognized as one of the most powerful methodologies to construct methanofullerenes. Other types of cycloadducts can also be obtained by modifying the substrates. Carbenes and silylenes are also reactive toward fullerenes; this reactivity is described in the fourth part. A variety of 1,3-dipolar cycloadditions, including the well-known Prato reactions, are summarized in the fifth part. The sixth part deals with nitrene additions, as these are relevant to 1,3-dipolar cycloadditions. The seventh part is devoted to phosphine-mediated reactions. Notably, azafulleroids and azamethanofullerenes have also been prepared via 1,3-dipolar cycloadditions followed by N2 extrusion. Several examples of [2 + 2] cycloadditions are described in the eighth part. Finally, a variety of Diels–Alder reactions are summarized in the final part. Noteworthily, some Diels–Alder cycloadducts obtained from the reactions of fullerenes with nitrogen-containing aromatic compounds provide useful precursors for the preparation of open-cage fullerenes and endohedral fullerenes. In addition, the reversibility of the Diels–Alder reaction of C60 with 9,10-dimethylanthracene has been applied to achieve the regioselective synthesis of hexaadducts.KeywordsNucleophilic additionElectrophilic additionAddition–elimination reactionCarbene additionSilylene addition1,3-Dipolar cycloadditionNitrene additionPhosphine-mediated reaction[2 + 2] CycloadditionDiels–Alder reaction