Triflic Anhydride-Mediated Cycloacylation of [60]Fullerene with 1-Naphthoic Acids: Synthesis and Derivatization of [60]Fullerene-Fused Dihydrophenalenones.

An efficient triflic anhydride-mediated synthesis of [60]fullerene (C60)-fused dihydrophenalenones from C60 and 1-naphthoic acids has been developed, representing the first one-step construction of C60-fused polyaromatic ketones under metal-free conditions. In addition, the C60-fused dihydrophenalenones can be reduced to C60-fused dihydrophenalenes and C60-fused dihydrophenalenols. The structures of the products were unambiguously established by single-crystal X-ray diffraction. A possible reaction mechanism is proposed based on control experiments. Furthermore, a representative C60-fused dihydrophenalenone was employed as a third component in organic solar cells, leading to improved device performance.