PEG-N2O4: An Efficient Nitrating Agent for the Selective Mono- and Dinitration of Phenols Under Mild Conditions

Electrochemical Nitration with Nitrite

Aromatic nitration has tremendous importance in organic chemistry as nitroaromatic compounds serve as versatile building blocks. This study represents the electrochemical aromatic nitration with NBu₄ NO₂ , which serves a dual role as supporting electrolyte and as a safe, readily available, and easy-to-handle nitro source. Stoichiometric amounts of 1,1,1-3,3,3-hexafluoroisopropan-2-ol (HFIP) in MeCN significantly increase the yield by solvent control. The reaction mechanism is based on electrochemical oxidation of nitrite to NO₂ , which initiates the nitration reaction in a divided electrolysis cell with inexpensive graphite electrodes. Overall, the reaction is demonstrated for 20 examples with yields of up to 88 %. Scalability is demonstrated by a 13-fold scale-up.