2-(Fluorophenyl)pyridines by the Suzuki–Miyaura method: Ag2O accelerates coupling over undesired ipso substitution (SNAr) of fluorine

Problematic ipso substitution was observed in the Suzuki–Miyaura coupling of pentafluorophenylboronic acid to make 2-pentafluorophenylpyridine. Strong bases favored coupling, but under these conditions fluorine in the product tended to undergo nucleophilic substitution. Inclusion of Ag2O accelerated coupling over ipso substitution.