The Addition Patterns of C60 Trisadducts Involving the Positional Relationshipse andtrans-n (n = 2–4): Isolation, Properties, and Determination of the Absolute Configuration of Tris(malonates) and Tris[bis(oxazolines)]

A series of regioisomeric trisadducts of C60 (5–11, 14–18) having the positional relationships e and trans-n (n = 2–4) resulting from successive additions of malonates or bis(oxazolines) to [6,6]-double bonds of the fullerene framework has been isolated and characterized. The new adducts 8–11 and 15–17 represent examples of unprecedented addition patterns. The addition patterns of the new trisadducts with C2, Cs or C1 symmetry have been assigned on the basis of the known positional relationships of the addends in their precursor bisadducts, and those of the C2- or Cs-symmetric representatives have been verified by analysis of their NMR spectra. The absolute configurations of the adducts with inherently chiral addition patterns could be determined either by comparison of the calculated and experimental CD spectra of the bis(oxazoline) adducts or with knowledge of the absolute configurations of the chiral bisadduct precursors containing bis(oxazoline) addends. The CD spectra of the pairs of diastereomers with an enantiomeric addition pattern fA -15/fC -15, fA -16/fC -16, and fA -18/fC -18 show mirror image behavior and pronounced Cotton effects.