Si-Tethered Bis- and Tris-Malonates for the Regioselective Preparation of Fullerene Multi-Adducts

Bis- and tris-malonates constructed around a silicon atom have been prepared by reaction of malonate derivatives bearing an alcohol function with di-tert-butylsilyl bis(trifluoromethanesulfonate) and tert-butyl(trichloro)silane, respectively. These compounds have been used for the regioselective bis- and tris-functionalization of C-60 under Bingel conditions. By changing the nature of the linker between the central Si atom and the reactive malonate groups, the malonate precursors have been optimized to produce specific bis- and tris-adducts with excellent regioselectivity. A complete understanding of the electronic and stereochemical factors governing the regioselectivity has been obtained by combining computational studies with a complete analysis of the by-products formed during the reactions of the Si-tethered tris-malonates with C-60. Finally, desilylation reactions of the resulting fullerene bis- and tris-adducts have been carried out to generate the corresponding acyclic fullerene bis- and tris-adducts bearing alcohol functions.

Automated summary

Bis- and tris-malonates were synthesized by reacting malonate derivatives with alcohol groups with di-tert-butylsilyl bis(trifluoromethanesulfonate) and tert-butyl(trichloro)silane, respectively. These compounds were used for regioselective bis- and tris-functionalization of C-60 under Bingel conditions. By optimizing the malonate precursors with different linkers between the central Si atom and the malonate groups, specific bis- and tris-adducts with excellent regioselectivity were obtained. A complete understanding of the factors governing the regioselectivity was achieved through computational studies and analysis of the by-products. Desilylation reactions of the resulting fullerene adducts yielded acyclic fullerene adducts with alcohol functions.