DMSO: An Efficient Catalyst for the Cyclopropanation of C60, C70, SWNTs, and Graphene through the Bingel Reaction

Dimethyl sulfoxide (DMSO) with sodium carbonate (Na2CO3) is an effective catalyst system for C-60 cyclopropanation through the Bingel reaction. Various bromomalonic esters, brominated beta-keto esters, brominated 1,3-diketones, and other bromo-substituted active methylene compounds can react with C-60 in the presence of DMSO and Na2CO3 to achieve excellent yields of the corresponding metharmfullerenes at 10 degrees C. Moreover, this proposed methodology has been also employed successfully to fundtionalize [70]fullerene, single-walled carbon nanotubeS (SWNTs), and graphene. This protocol is beneficial because it involves short reaction time, high yield, and a simple procedure. Additionally, this method does not need a strong base, such as sodium hydride and 1,8-diazabicydo[5,4,0]undec-7-ene, because inexpensive Na2CO3 can be the catalyst.