Palladium(II)-Catalyzed Synthesis of Sulfinates from Boronic Acids and DABSO: A Redox-Neutral, Phosphine-Free Transformation

A redox-neutral palladium(II)-catalyzed conversion of aryl, heteroaryl, and alkenyl boronic acids into sulfinate intermediates, and onwards to sulfones and sulfonamides, has been realized. A simple Pd(OAc) 2 catalyst, in combination with the sulfur dioxide surrogate 1,4-diazabicyclo[ 2.2.2] octane bis(sulfur dioxide) (DABSO), is sufficient to achieve rapid and high-yielding conversion of the boronic acids into the corresponding sulfinates. Addition of C-or N-based electrophiles then allows conversion into sulfones and sulfonamides, respectively, in a one-pot, two-step process.