Transition Metal-Mediated Direct C-H Arylation of Heteroarenes Involving Aryl Radicals

This review gives an overview of the generation of aryl radicals, mediated by transition metals, and their use for the CH arylation of heteroarenes. The different sources of aromatic derivatives able to generate aryl radicals via a metal-assisted reduction or oxidation are discussed, with a critical view of the developed systems. The radical arylations of nitrogen-, oxygen- or sulfur-containing heterocycles are then described and mechanistic considerations are discussed as well.