Recent Progress in Metal Catalyzed Direct Carboxylation of Aryl Halides and Pseudo Halides Employing CO2: Opportunities for 11C Radiochemistry

Carbon dioxide (CO2) as a synthon in organic transformations is very useful, especially when combined with transition metal catalysts. CO2 insertion on carbon(Aryl)‐metal is are an elegant route to construct carbon–carbon bonds. A limited number of reports have been published to date on the direct conversion of aryl halides (or pseudo halides) to aryl carboxylic acids using transition metal catalysts. These reactions place great demand on the choice of catalyst, starting material, and reducing agent. However, these approaches could be of interest for the synthesis of a wide range of biologically active small molecules. Such transformations have already been applied for the synthesis of radiolabeled compounds for imaging with positron emission tomography (PET) using cyclotron produced [11C]CO2 and may be applicable to the production of a diverse range of PET tracers. Please read the label: This Minireview describes an overview of recent progress in transition metal catalyzed reactions with CO2 as a synthon for direct addition on aryl halides and aryl boronates. New radiolabeling methods using 11CO2 are also discussed, owing to the demand for a diverse array of new positron emission tomography (PET) tracers.