Fe(NO <sub>3</sub> ) <sub>3</sub> ·9H <sub>2</sub> O-mediated visible-light photocatalysis for the nitration of cyclobutanols: access to functionalized nitrocyclobutenes
O as the nitro source and RFTA as the photocatalyst, showing good functional group tolerance and furnishing the desired products in moderate to excellent yields. Preliminary mechanistic studies suggested that the nitro radical was involved in the reaction process.