Phenyl Hydrazine as Initiator for Direct Arene C–H Arylation via Base Promoted Homolytic Aromatic Substitution

A simple and efficient direct radical arylation of unactivated arenes is described which uses cheap and commercially available phenyl hydrazine as an initiator. The reaction occurs through a base promoted homolytic aromatic substitution (BHAS) mechanism involving aryl radicals and aryl radical anions as intermediates and offers a practical approach for preparation of an array of substituted biaryls.