Selective reactions in the triazene series. Part 2. Protodediazoniation of arenediazonium salts with formamide
Treatment of preformed arenediazonium tetrafluoroborates or arenediazonium trifluoroacetates (formed in situ) with formamide and base effects reduction to the corresponding arene in moderate to good yield in cases where an electron-withdrawing substituent is present on the aromatic ring. Other functionalities remain unaffected. The mechanism of the protodediazoniation is shown to involve transfer of the formyl hydrogen atom to the substrate and may proceed via a 1-aryl-3-formyltriazene.