Anomalous Cis‐Conformation Regioselectivity of Heterocycle‐Fused Sc₃N@D_3h‐C₇₈ Derivatives

Abstract

Endohedral clusterfullerenes exhibit unique chemical properties due to intramolecular electron transfer of the encaged metal cluster to the outer fullerene cages.Wereport the synthesis of two Sc 3 N@D 3h-C 78 monoadducts 2a and 2b through the 1,3-dipolar reaction of Sc 3 N@D 3h-C 78 with carbonyl ylide bearing anomalous cis-conformation regioselectivity.T he molecular structures of these monoadducts are unambiguously confirmed by single-crystal X-ray crystallography,r evealing that both 2a and 2b have cis-conformations with the furan moiety grafted via [6,6]-closed addition patterns. Under the same conditions,t he control reaction of C 60 with carbonyl ylide affords two monoadducts 3a and 3b,w hich exhibit cis-and trans-conformations,r espectively,w ith [6,6]closed addition patterns.Accordingtotheoretical calculations, the exclusive formation of the cis-only Sc 3 N@D 3h-C 78 monoadducts is aconsequence of conjunct effects of thermodynamic stability of adducts,t he reactivity of the addition site,a nd the cis-dipole intermediate from trans 1.

Unexpected Formation of Metallofulleroids from Multicomponent Reactions, with Crystallographic and Computational Studies of the Cluster Motion

“…With notable exceptions, [16][17][18][19][20] most reactions of the NCFs with well-characterized derivatives are from cycloadditions, including the Bingel-Hirsch reaction, [21] Prato reaction, [22,23] Diels-Alder reaction, [24] diazo addition, [25,26] benzyne addition, [27,28] and reaction with azide [29] or ylide. [30] Overall, the pool of viable reactions on NCFs remains very limited; new reactions, and especially those not directly inspired from an analogous C 60 reaction, are still in strong demand.…”