A directing group-assisted ruthenium-catalyzed approach to access meta-nitrated phenols

Abstract

meta-Selective C–H nitration of phenol derivatives was developed using a Ru-catalyzed σ-activation strategy. Cu(NO₃)₂·3H₂O was employed as the nitrating source, whereas Ru₃(CO)₁₂ was found to be the most suitable metal catalyst for the protocol. Mechanistic studies suggested involvement of an ortho-C_Ar–H metal intermediate, which promoted meta-electrophilic aromatic substitution and silver-assisted free-radical pathway.