The di-t-butylsilylene protecting group as a bridging unit in linear and macrocyclic bis-malonates for the regioselective multifunctionalization of C60

Fullerene equatorial bis-adducts have been prepared with high regioselectivity by a double Bingel reaction between [60]fullerene and di-t-butylsilylene-tethered bis-malonates. Macrocyclic bis-malonates incorporating di-t-butylsilylene moieties have also been prepared and used to functionalize C60 in multiple Bingel cyclopropanations. Fullerene bis-adducts with a cis-2 addition pattern and tris-adducts with an e,e,e addition pattern have been thus obtained. Finally, the bridging di-t-butylsilylene is not only a directing group for the cyclization step, it is also a protecting group that can be readily cleaved to afford the corresponding acyclic fullerene polyols.