Facile one-pot transformation of phenols into o-cyanophenols

Article abstract of DOI:10.1002/ejoc.201402817

The treatment of phenols with paraformaldehyde in the presence of MgCl₂ and Et₃N in THF at 80 C, followed by reaction with molecular iodine and aq. ammonia at room temperature provided the corresponding o-cyanophenols in moderate to good yields. The present reaction is a one-pot transformation of phenols into o-cyanophenols using much less expensive reagents than are typically used; the reaction is free of both transition-metals and cyanide. The utility of this reaction was highlighted during our preparation of Febuxostat from p-bromophenol.