Multicomponent Synthesis of 2‐Arylvinyl‐Substituted Fulleropyrrolidines from [60]Fullerene, Amines and Aldehydes

Abstract

The three‐ and four‐component reactions of [60]fullerene with triethylamine/diethylamine and aldehydes affording 2‐arylvinyl‐substituted fulleropyrrolidines in high stereoselectivity have been achieved. Depending on the reaction conditions, cis‐ and trans‐fulleropyrrolidines can be stereoselectively synthesized. The thermodynamically stable cis‐fulleropyrrolidines can be obtained by rearrangement of the kinetically formed trans‐fulleropyrrolidines. A plausible reaction mechanism is proposed to elucidate the formation of fulleropyrrolidines.

Alternative Access to Cyclopentafullerenes through the Reaction of [60]Fullerene with Aldehydes and Secondary Amines

“…Finally, the reactions of C 60 with β-methoxyphenyl-substituted propionaldehyde 4c and 2a – c generated products 3ca – cc in 21–35% yields. It should be noted that the reaction of C 60 with 4c and 2a required 20 equiv of 4c and 2a and a higher temperature of 220 °C, otherwise the undesired fulleropyrrolidine derivative would be formed. , …”

“…In these cases, the addition of CH 3 OH and the utilization of a lower reaction temperature could avoid byproduct formation of fulleropyrrolidines. 6,11 It should be pointed out that when 2b was used as the secondary amine, the reactions for the formation of 3ab, 3bb, and 3cb proceeded rapidly, and a significant amount of residues was formed. Therefore, these reactions were carried out at a lower temperature of 130 °C, and neutralization of the unreacted 2b by hydrochloric acid (HCl) was required to eliminate its detrimental side effect after the reactions were completed.…”

“…It should be noted that the reaction of C 60 with 4c and 2a required 20 equiv of 4c and 2a and a higher temperature of 220 °C, otherwise the undesired fulleropyrrolidine derivative would be formed. 6,11 Moreover, a scale-up reaction by employing butanal and diethylamine as representative substrates was examined. The reaction of C 60 (360.0 mg, 0.50 mmol) with 4a (2.20 mL, 25.00 mmol) and 2a (2.58 mL, 25.00 mmol) at 180 °C for 40 min gave a slightly higher yield (60% vs 58%) of 3aa (255.0 mg).…”