A Convenient Approach to Fused Indeno-1,4-diazepinones through Hypervalent Iodine Chemistry

Indenocarboxamides, resulting from the sequential addition of two arylamine equivalents to indanedione ketene dimer, are oxidized by [bis(trifluoroacetoxy)iodobenzene] to fused indeno-1,4-diazepinones in yields depending on the substituents on both aromatic rings. A plausible reaction pathway explaining the formation of the title compounds, as well as the formation of the two other minor products of the reaction, through a common intermediate, is suggested.