The addition patterns of C-60 trisadducts involving the positional relationships e and trans-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 C-60 (5-11, 14-18) having the posi tional relationships e and trans-n (n = 2-4) resulting from successive addi tions of malonates or bis(oxazolines) to [6,6]-double bonds of the fulleren e framework has been isolated and characterized. The new adducts 8-11 and 1 5-17 represent examples of unprecedented addition patterns. The addition pa tterns of the new trisadducts with C-2, C-s or C-1 symmetry have been assig ned on the basis of the known positional relationships of the addends in th eir precursor bisadducts, and those of the C-2- or C-s-symmetric representa tives have been verified by analysis of their NMR spectra. The absolute con figurations of the adducts with inherently chiral addition patterns could b e determined either by comparison of the calculated and experimental CD spe ctra of the bis(oxazoline) adducts or with knowledge of the absolute config urations of the chiral bisadduct precursors containing bis(oxazoline) adden ds. The CD spectra of the pairs of diastereomers with an enantiomeric addit ion pattern (f)A-15/C-f-15, (f)A-16/C-f-16, and (f)A-18/C-f-18 show mirror image behavior and pronounced Cotton effects.