Carbon Dioxide as the C1 Source for Direct C-H Functionalization of Aromatic Heterocycles

A simple and straightforward method has been developed for the direct carboxylation of aromatic heterocylces such as oxazoles, thiazoles, and oxadiazoles using CO(2) as the C1 source. The reactions require no metal catalyst and only Cs(2)CO(3) as the base. A good functional group tolerance is achieved.