A Protocol for the Preparation of 2,5-Diaryl Fulleropyrrolidines: Thermal Reaction of [60]Fullerene with Aromatic Aldehydes and Arylmethanamines.

Thermal reaction of [60]fullerene with various arylmethanamines in the presence of aromatic aldehydes under air conditions afforded a series of rare 2,5-diaryl fulleropyrrolidines. Intriguingly, the obtained fulleropyrrolidines exhibited different stereoselectivity. N-unsubstituted arylmethanamines exclusively produced 2,5-diaryl fulleropyrrolidines as cis isomers, while N-substituted arylmethanamines with rare exceptions always gave 2,5-diaryl fulleropyrrolidines as trans isomers. Theoretical calculations at the level of B3LYP/6-31G (d,p) were employed to elucidate the stereoselectivity of N-substituted 2,5-diaryl fulleropyrrolidines as trans isomers by investigating the transition-state structures of different cycloaddition pathways.