Heterocyclization of [60]fullerene with isocyanides

Abstract

Isocyanides cycloadded to a doable bond of [60]fullerene to give various [60]fullero-1-pyrrolines. While the reaction with unsubstituted ethyl isocyanoacetate occurred slowly even without a catalyst, it was facilitated with NEt3, and use of DBU was more effective for α-monosubstituted isocyanoacetates. Alternatively, copper(I) oxide was found to be an expedient catalyst, which allowed the possible use of an unactivated isocyanide such as PhCH2NC as well as other activated isocyanides.