Inherently chiral fullerenes, structures

Figure 1.7. A selection of inherently chiral higher fullerenes, for which certain or confident structural assignments have been made. In the case of D2-C76, the absolute configuration as well as a characteristic CD (circular dichroism) maximum of the shown enantiomer are indicated.

I>2-C76, >3-C78, and D2-Cu are the inherently chiral higher fullerenes of which defined derivatives have been isolated and in part structurally characterized.17,60 As a consequence of their inherent chirality, all derivatives of these fullerenes are chiral, except for as yet unknown me so type combinations of both optical antipodes of a given constitution. 

Irradiation of the pyrazoline mixture 12, 13, and ( )-14 yielded methanofullerenes 15 and 16 (7 1) with a closed transannular 6 - 6 bond besides minor amounts of a third constitutional isomer (17), whereas thermolysis of the same mixture gave 17 and inherently chiral ( )-18 (4 l),both constituting core-modified fullerenes [76] (Scheme l).With open transannular 6-5 bonds , the functionalized regions of 17 and ( )-18 resemble methanoannulene sub-structures. [3 + 2]Cycloaddition of alkyl azides to C70 affords triazolines which are isolable when the temperature does not exceed ca. 50 °C. Similar to the reaction with diazomethane, three constitutionally isomeric adducts were observed [77,113], and the regioisomer of type 19 [113] with the substituent of the heterocycle located above the apex of C70, predominated over its regioisomer of type 20 in two in-... 

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