Azafullerene formation

Since heterofullerene chemistry began, as well as 8, 17 and 18 various further derivatives formed during the formation of azafullerenes or from (C59N)2 (2) itself have been synthesized. Heterofullerene transformation of the ketolactam 6 in the presence of a 15-fold excess of hydroquinone leads to the parent hydroaza[60]-fullerene 25 [14]. The hydroquinone is assumed to reduce the C59N radical intermediate (Scheme 12.6). 

Fig. 17. More trapping products of the reaction 22 28. Trapping of azafullerenyl radical intermediate 1 by hydroquinone leads to the formation of hydroaza[60]fullerene 34. Trapping of intermediate azafulleronium 2 by anisole yields arylated azafullerene 35...

Thermal treatment of the dimer with anisole, toluene, and 1-chloronaphtha-lene in the presence of a large excess of pTsOH and air leads to the formation of mono-arylated azafullerenes in 78-90% isolated yields [68]. The reaction with anisole and toluene yield para-substitution products 35 and 39, while 1-chloro-naphthalene is substituted at various positions (Fig. 21). The reaction does not take place in the absence of air or pTsOH. The reaction is presumed to proceed through electrophilic aromatic substitution by C59N, which was proposed as being formed via thermal homolysis of the dimer, followed by oxidation with O2. 

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