Asphaltene oxide promotes a broad range of synthetic transformations

Abstract

Carbocatalysts, which are catalytically-active materials derived from carbon-rich sources, are attractive alternatives to metal-based analogs. Graphene oxide is a prototypical example and has been successfully employed in a broad range of synthetic transformations. However, its use is accompanied by a number of practical and fundamental drawbacks. For example, graphene oxide undergoes explosive decomposition when subjected to elevated temperatures or microwaves. We found that asphaltene oxide, an oxidized collection of polycyclic aromatic hydrocarbons that are often discarded from petroleum refining processes, effectively overcomes the drawbacks of using graphene oxide in synthetic chemistry and constitutes a new class of carbocatalysts. Here we show that asphaltene oxide may be used to promote a broad range of transformations, including Claisen-Schmidt condensations, C–C cross-couplings, and Fischer indole syntheses, as well as chemical reactions which benefit from the use of microwave reactors.