Thianthrenium Salts Enable Regio- and Stereoselective C(sp2)-H Arylation of Enamides with Simple Arenes.

We report a palladium(II)-catalyzed regio- and stereoselective β-C(sp2)-H arylation of enamides with simple arenes under base- and ligand-free conditions via thianthrenium salts, affording a broad array of geometrically defined β-arylated enamides with an exquisite Z configuration. This transformation is characterized by operational simplicity, readily available and bench-stable aryl surrogates, broad substrate scope, and extraordinary compatibility with diverse functionalities. The utility of this approach has been demonstrated by the late-stage diversification of biologically active molecules.