A New Method to prepare an e,e,e Trisadduct of C60 Using a ProtectionDeprotection Sequence

A racemic mixture of the e,e,e Bingel-trisadduct, tris[di(ethoxycarbonyl)methano][60]fullerene 3 was synthesized by malonate additions (Bingel reaction) following by retro Diels-Alder reactions using a C60 tris-e,e,e adduct of anthracene 1 as precursor. Using this approach, the anthracenes act as protective groups and help orient the new additions so that poly-adducts with particular geometries are obtained. From the e,e,e anthracene-trisadduct 1 we also obtained the mono[di(ethoxycarbonyl)methano][60]fullerene 6 and bis [di(ethoxycarbonyl)methano][60]fullerene 7. This approach exhibits a total yield of 4,2 % for the e,e,e tris malonate adduct, gives rise to less complex reaction mixtures and makes it easier to separate and characterize the compounds than other methods. The compounds obtained where characterized by UV/VIS, FT-IR, 1H NMR, and MALDI-TOF.