A fast and mild method for the nitration of aromatic rings

The use of N2O5 and a Fe(III) catalyst for the nitration of aromatic rings is described. This methodology is compatible with most functional groups and results in near quantitative yields in 4 min. The reaction conditions are non-oxidising: benzaldehyde and benzyl alcohols are readily nitrated with little or no oxidation (<4%) occurring. The addition of the iron catalyst activates the system to such an extent that nitration of an activated aromatic ring, such as toluene, occurs quantitatively at −100°C. This high activity allows compounds with sensitive functional groups such as alkenes to be smoothly nitrated.