New norbornadiene-tethered fulleropyrrolidines

N-Methyl-3,4-fulleropyrrolidine–norbornadiene conjugates with or without (CH₂)_n (n=0–3) spacers were synthesized by the Prato reaction from the corresponding norbornadiene aldehydes. The influence of the spacer length on the diastereomer composition of the conjugates with two chiral centres studied by ¹³C NMR revealed a pronounced diastereotopic splitting of the fullerene carbon signals relating to four diastereomers in the case when the norbornadiene substituent was directly attached to the pyrrolidine moiety. When norbornadiene moiety was separated from the pyrrolidine one by three methylene units, the diastereotopic difference was lower and some of the signals were grouped.