Palladium-Catalyzed Heteroannulation of Indole-1-carboxamides with [60]Fullerene and Subsequent Electrochemical Transformations.

A highly efficient heteroannulation between [60]fullerene (C60) and N-methoxy-1H-indole-1-carboxamides has been successfully achieved via the palladium-catalyzed C-H activation and subsequent cyclization. This protocol has remarkable functional group tolerance for the synthesis of C60-fused 3,4-dihydropyrimido[1,6-a]indol-1(2H)-ones. Furthermore, the electrochemically generated dianionic C60-fused 3,4-dihydropyrimido[1,6-a]indol-1(2H)-ones can be regioselectively transformed into 1,2,3,4-, 1,2,3,16-, and 1,4,9,25-adducts of C60.