Higher Adducts with the Addends Bound in Octahedral Sites

1 Higher Adducts with the Addends Bound in Octahedral Sites 

As pointed out by Diederich [77] it is important to investigate fullerene properties as a fimction of addition pattern and the nature of the addend. Various pronoimced correlations and trends can be deduced. In general, with increasing reduchon in the conjugated fullerene re-chromophore, (1) the HOMO-LUMO gap increases  

Each macrocycHzahon could, in principle, lead to a mixture of diastereoisomers, depending on how the EtOOC residues at the two methano bridge C atoms are oriented with respect to each other (in-in, in-out, and out-out stereoisomerism) [92]. Usually, only out-out stereoisomerism has been observed so far. One exception is the in-out isomer 81. 

Transesterification of the fullerene crown ether conjugate (+)-89 allowed for the removal of the tether, leading to the D2fj-symmetrical bisadduct 94 (34%) [93], which is a very useful building block for further addition chemistry. 

Determination of the absolute configurations of these optically active fullerene derivatives was possible by comparison of their experimental and calculated circular dichroism (CD) spectra [96]. Tether controlled bis-cyclopropanation reactions have been extensively used to synthesize extended fimctional architectures such as dyads. 

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