Synthesis of Sulfones via Ru(II)-Catalyzed Sulfination of Boronic Acids

Ruthenium(II) complexes catalyze the insertion of sulfur dioxide into (het)aryl and alkenyl boronic acids. The transmetalation-sulfination process proceeds with DABSO in the presence of 5 mol % RuCl2(PPh3)(3) in methanol at 100 degrees C. The intermediate sulfinate salt can be quenched with various electrophiles such as alkyl halides, epoxides, Michael acceptors, and lambda(3)-iodanes in moderate to good yields. The reported sulfone synthesis can be performed either as a direct one-pot or one-pot two-step procedure depending on the reactivity of the electrophile.