Ferric perchlorate-promoted reaction of [60]fullerene with β-keto esters

The ferric perchlorate-promoted reaction of [60]fullerene (C60) with ethyl 2-methylacetoacetate generates fullerenyl hemiketal as a mixture of trans and cis isomers, while the reaction with ethyl acetoacetate gives a C60-fused dihydrofuran derivative. A possible reaction mechanism for the formation of these products is proposed.