The [2+1] cycloaddition of singlet oxycarbonylnitrenes to C-60

Semiempirical and density functional calculations have been carried out to discuss the origin of the closed [5,6]-aza-bridged adduct obtained as a min or product in the reaction of singlet nitrenes with C-60. The results indic ated that the most likely source is the direct addition of singlet nitrenes to a [5,6]-bond of C-60, in contradiction to the common belief that the [5 ,6]-bonds are not attacked in cycloaddition reactions to C-60.