Manganese(iii) acetate-mediated synthesis of N-substituted fulleropyrrolines via the reaction of [60]fullerene with α-monosubstituted acetaldehydes and primary amines

Abstract

The simple one-step reaction of [60]fullerene with α-monosubstituted acetaldehydes and primary amines in the presence of Mn(OAc)₃·2H₂O under air conditions afforded a series of novel N-substituted fulleropyrrolines with trisubstituted CC bonds in moderate to good yields. The addition of Mn(OAc)₃·2H₂O played a crucial role in the successful synthesis of N-aryl fulleropyrrolines with trisubstituted CC bonds, which would be extremely difficult to prepare by known methods as a result of the decreased nucleophilicity of arylamines due to the p–π conjugation effect. Intriguingly, arylamines displayed abnormally higher reactivity as compared with non-arylamines in the current reaction system by the observation of obviously decreased equivalent of Mn(OAc)₃·2H₂O, higher product yields, and lower reaction temperature probably due to the radical reaction mechanism initiated by Mn(OAc)₃·2H₂O. On the basis of experimental observations, a plausible formation pathway for N-substituted fulleropyrrolines with trisubstituted CC bonds was proposed to elucidate the above-mentioned reaction process.