Mechanochemical Palladium‐Catalyzed Cross‐Coupling of Thianthrenium Salts and Arylboronic Acids

Abstract Cross‐coupling reactions are indispensable for the construction of complex molecular scaffolds. In this work, we developed a sustainable methodology for the cross‐coupling reaction of arene thianthrenium salts with aryl boronic acids, which can be effectively realized under mechanochemical conditions. Liquid‐assisted grinding (LAG) enabled fast and high‐yielding synthesis of a range of biaryls via Pd/RuPhos‐catalyzed cross‐coupling. The transformation works under ambient temperature and on air. Environmentally friendly solvent 2‐methyltetrahydrofurane (Me‐THF) was used as a LAG additive. Moreover, the major by‐product of the cross‐coupling reaction, thianthrene, can be recovered and reused.