We report an “inversed” Arbuzov reaction of the fullerene derivatives C₆₀Ar₅Cl with trialkyl phosphites P(OR)₃ producing alkylated fullerene derivatives C₆₀Ar₅R (R = Me, Et, iPr, nBu) with almost quantitative yields. This reaction provides a convenient synthetic route for the preparation of a large variety of functionalized fullerene derivatives with tailored properties, e.g. water-soluble compounds demonstrating promising antiviral activities against HCMV, HSV1, HIV and several influenza virus strains.