Ru-Catalyzed δ-Arylation of para-Quninone Methides with Aryl Diazonium Salts to Synthesize Fuchsones

A novel reaction mode and efficient ruthenium-catalyzed Matsuda-Heck-type arylation of para-quinone methides (p-QMs) with aryl diazonium salts has been developed for the synthesis of symmetrical or unsymmetrical delta,delta'-diaryl quinone methides (fuchsones). Aryl groups are introduced at the delta-position of p-QMs via tandem olefin insertion reaction/beta-H elimination processes. This reaction features advantages such as mild and green conditions, broad reactant scope, and high yields.