Ring-Opening Reaction of Cyclopropanated [60]Fullerenes:  Unexpected Transformation of Methano[60]fullerenes Having an Electron-Donating Group on the Methano-Bridge Carbon

Abstract

A series of novel transformations of [60]fullerene derivatives were found, starting from methano[60]fullerenes with an electron-donating group on the methano-bridge carbon. Aminomethano[60]fullerenes, in situ generated by the treatment of their trifluoromethanesulfonic acid salts with a base, were readily converted into 1-acyl-1,2-dihydro[60]fullerenes via the ring opening of the cyclopropane moiety. The aldehyde/ketones thus obtained were easily hydrolyzed to give 1,2-dihydro[60]fullerene in the presence of hydroxide anions.

One-step Synthesis of Fullerene Hydride C60H2 via Hydrolysis of Acylated Fullerenes

“…Acylated fullerenes represent a novel class of fullerene compounds, and their chemical properties are of fundamental interest. Our present studies on their reactivity revealed, in accordance with earlier studies reported by Mattay et al and Saigo et al, that these compounds could be converted into C 60 H 2 under mild conditions. This result prompted us to conduct further investigations for addressing this reactivity and explore potential applications.…”

Reactions of [60]Fullerene with Acetone under Basic Condition: Nucleophilic Ring Opening of the [5,6]-Cyclopropane in C60 and Formation of the Substituted Methano[60]Fulleroids

“…The nucleophilic ring-opening reactions of electrophilic cyclopropanes are important for fragmenting the three-membered ring and well recorded in literature . However, nucleophilic ring-opening reactions of the cyclopropanated [60]­fullerenes (methano[60]­fullerenes) are very limited, where only methano[60]­fullerenes with an electron-donating amino group on the methano-bridge carbon have been shown to undergo ring-opening reactions initiated by the nucleophilic attack of the amino group, even though the C 60 -fused cyclopropanes are typically electrophilic due to the strong electron deficiency of fullerenes . Methano[60]­fullerenes are a type of fullerene derivatives with a cyclopropane ring fused at the [6,6]-bond between two six-membered rings (Figure a) .…”

Synthesis of Imino[60]fullerenes Using Nitriles and Trimethylsilylmethyl Triflate

“…The imine product 3a was hydrolytically rather unstable and was quickly purified on triethylamine-impregnated silica gel column chromatography or by precipitation by addition of methanol. Some attempts to remove the imine group under acidic conditions resulted in partial scission of the C-acyl bond and did not afford the expected ketone …”