N1-(4-Oxo-2,5-cyclohexadien-1-ylidene)-N2-substituted-2,2,2-trifluoroethanimidamides (p-Benzoquinone Imine Derivatives): Syntheses of Trifluoromethylated 6-Hydroxybenzimidazoles and Spiro Dienone Diazacarbocycles

Article abstract of DOI:10.1021/jo00125a028

Lewis acid-catalyzed intramolecular cyclization of N¹-(4-oxo-2,5-cyclohexadien-1-ylidene)-N²-substituted-2,2,2-trifluoroethanimidamides (p-benzoquinone imine derivatives, 1) prepared by electrooxidation of N-(4-methoxyphenyl)-N'-substituted-2,2,2-trifluoroethanimidamides 2 occurred to give 1-substituted-2-(trifluoromethyl)-6-hydroxybenzimidazoles 3.Alternatively, thermal cyclization of 1 gave spiro dienone diazacarbocycles 9 and 10, which converted into diazepine 12 via a dienone-phenol rearrangement.