Synthesis of <i>ortho</i>-Nitrophenols with an Ester Functionality via Nitro Rearrangement

Although sigmatropic rearrangements have been widely reported, nitro group shifts have rarely been investigated. In this study, we investigated the synthesis of 4-ethoxycarbonyl-2-nitrophenols via the [1,3]-nitro shift. 4-Ethoxycarbonyl-4-nitrocyclohexanone, when subjected to I₂-DMSO system, gave the 4-nitrocyclohexa-2,5-dienenone intermediate that undergoes [1,3]-nitro shift followed by aromatization to afford 4-ethoxycarbonyl-2-nitrophenols. Although there is a room for improvement in product yield and selectivity, the development of a reaction system that facilitates [1,3]-nitro shift from readily available starting materials is noteworthy.