A copper-promoted synthesis of epoxy-bridged [60]fullerene-fused lactones and further derivatization

Abstract

A facile copper-promoted decarboxylative annulation of [60]fullerene (C₆₀) with two identical α-oxocarboxylic acids via an unprecedented cascade addition pathway has been exploited to synthesize the unique epoxy-bridged C₆₀-fused lactones for the first time. Further transformations into the rare epoxy-bridged C₆₀-fused hemiacetals and bicyclic-fused 1,2,3,4-adducts as well as application in a perovskite solar cell device of the obtained products have also been demonstrated. The structures of the epoxy-bridged C₆₀-fused lactones and derived reductive products have been unequivocally established by single-crystal X-ray crystallography. Plausible reaction mechanisms leading to the observed products are proposed.