N-Unsubstituted fulleropyrrolidine derivatives: reinvestigation, structural reassignment and new insight

The reaction of [60]fullerene with α-amino acids and aldehydes affording N-unsubstituted 2,5-disubstituted fulleropyrrolidines was reinvestigated. The previously reported stereochemistry should be reassigned. A reversible interconversion between the cis and trans stereoisomers of fulleropyrrolidines was observed for the first time.