Tether-directed remote functionalization of fullerenes C60 and C70

Unexpected Isomerism in cis‐2 Bis(pyrrolidino)[60]Fullerene Diastereomers

“…[14] Also, selective tether-controlled tandem additions of nitrile oxides and azomethine ylides to yield cis-1 bis(adduct)s were reported by Prato et al [15] Herein we report the one-step synthesis and characterization of three pure [60]fullerene bis(adduct)s, including the X-ray crystal structure of two cis-2 bisadducts (1 and 2; see Scheme 1 for structures) which are individual meso forms. Although there are multiple reports of chirality for fullerene derivatives, [16,4] the isomerism reported here is unprecedented. These meso bis(adduct)s, easily isolable by silica gel chromatography, show a unique isomerization and the proposed mechanism is supported by computational studies.…”

Regioselectivity in Tether‐Directed Remote Functionalization – The Addition of a Cyclotriveratrylene‐Based Trimalonate to C60 Revisited

“…[15] Stepwise cyclopropanation of C 60 with chiral and enantiopure diisoxazolinylmethanes, partly in combination with malonates, provided diastereoisomeric tris-adducts of C 60 with enantiomeric functionalization patterns, which were separated and chiroptically investigated. [11,12] A very efficient strategy for the selective synthesis of fullerene bis-and multi-adducts with a defined functionalization pattern is the tether-directed remote functionalization, [16][17][18] which was first applied to fullerene chemistry by Diederich and co-workers. [19] The generation of specific fullerene functionalization patterns results from the size and the geometry of the tether that interconnects the individual reactive groups.…”

Prediction of the experimental regioselectivity of C60 fullerene bis‐adducts

“…This theoretical calculation indicates that these regiochemical outcomes are dependent on the nature of the first and second addend, the electronic nature of the mono‐adduct, and the thermodynamic stabilities of the bis‐adducts. The general outcome of the reported study can be used as a guide for future assignments on regioisomeric structure of observed bis‐adducts, as has been carried out in other reports . Future investigations are expected to improve the prediction of specific regioisomers in C 60 fullerene bis‐functionalization and will provide useful information for the synthesis and study of these important macrocyclic C 60 bis‐adducts.…”