One-Pot Method for the Synthesis of 2,5-Unsubstituted Pyrrolidino[3′,4′:1,9]fullerenes

Abstract

A new, efficient process has been developed for the preparation of 2,5-unsubstituted pyrrolidino[3',4':1,9]fullerenes by the Ti(O-i-Pr)-promoted reaction of fullerene C with 1,3,5-perhydrotriazines generated in situ upon the reaction of primary alkyl- and benzylamines with paraformaldehyde and EtMgBr.

Metal-Free Synthesis of N-Alkyl-2,5-Unsubstituted/Monosubstituted Fulleropyrrolidines: Reaction of [60]Fullerene with Paraformaldehyde and Amines

“…In summary, the simple one-step thermal reaction of C 60 with paraformaldehyde and primary/secondary amines in the absence of metal salts successfully afforded a series of scarce N -alkyl-2,5-unsubstituted/monosubstituted fulleropyrrolidines in moderate to excellent yields. The current method for the preparation of fulleropyrrolidines by using inexpensive and easily available paraformaldehyde and primary/secondary amines is obviously more straightforward and practical than the previous ones . Furthermore, the current synthetic protocol also displays a broad substrate scope and excellent functional group tolerance, providing a good opportunity for researchers to design and synthesize a large variety of novel organic photovoltaic materials.…”

“…Although many synthetic strategies, including cycloadditions, nucleophilic additions, radical additions, and asymmetric catalysis, have been developed to functionalize fullerenes, , the known protocols still meet a great challenge in preparing N -alkyl-2,5-unsubstituted/monosubstituted fulleropyrrolidines. Fulleropyrrolidines are a kind of important fullerene compound ,− and have attracted extensive attention among the scientific community due to their promising applications in many fields, such as modern drug synthesis, organic solar cells, and light-controlled field effect transistors . Generally speaking, fulleropyrrolidines were synthesized by two main strategies, that is, the best-known Prato reaction , together with the newly developed reaction based on aldehydes and amines. , However, these known methods still have great difficulty in the preparation of fulleropyrrolidines with specific structural motifs.…”

“…For example, N -alkyl-2,5-unsubstituted/monosubstituted fulleropyrrolidines is not easy to obtain by Prato reaction due to the very limited substrate scope of N -substituted amino acids . To the best of our knowledge, only a few N -alkyl-2,5-unsubstituted/monosubstituted fulleropyrrolidines were reported by different groups . Nevertheless, these reported methods have their own limitations, including hardly available starting materials, poor product selectivity, low product yields, and a complex reaction system.…”

Synthesis and Electrochemical Properties of Fullerenylstyrenes

“…11,12 These reactions provided diverse cyclopropane, aziridine, and pyrrolidinofullerene derivatives, which were useful as components of modern solar cells, 13 organic electronic devices, 14 oil additives, 15,16 and compounds with various types of biological activity. 17 In continuation of these investigations aimed at developing new methods for the efficient functionalization of fullerenes, we have designed and developed an original and universal reaction, which allows preparation of diverse hard to reach and not previously described cyclic and acyclic C 60 derivatives from carboxylic acid esters, 18 nitriles, 19,20 isonitriles, 21,22 and triazines 23,24 in one preparative stage in the presence of the catalytic system EtMgBr-Ti(Oi-Pr) 4 . While proceeding with the fundamental and applied studies along this line, in order to develop new classes of aryl-substituted carbon clusters, we planned the reaction between fullerene C 60 and aromatic acetylenes and EtMgBr catalyzed by Ti(OiPr) 4 , hoping to obtain aromatic π-conjugated compounds linked with the fullerene core, which could be useful as materials for the development of solar cells.…”

“…Considering published data, − we proposed a probable mechanism of formation of monoarylalkene fullerene derivatives in the reaction of C 60 with terminal arylacetylenes and EtMgBr in the presence of Ti­(O i -Pr) 4 (Scheme ).…”