Ascorbic Acid as an Initiator for the Direct C-H Arylation of (Hetero)arenes with Anilines Nitrosated In Situ

Ascorbic acid (vitaminC) has been used as a radical initiator in a metal-free direct CH arylation of (hetero)arenes. Starting from an aniline, the corresponding arenediazonium ion is generated in situ and immediately reduced by vitaminC to an aryl radical that undergoes a homolytic aromatic substitution with a (hetero)arene. Notably, neither heating nor irradiation is required. This procedure is mild, operationally simple, and constitutes a greener approach to arylation.