Palladium-catalyzed direct ortho-sulfonylation of azobenzenes with arylsulfonyl chlorides via C-H activation

A highly efficient and practical procedure to direct ortho-sulfonylation of azobenzenes' C-H bond with arylsulfonyl chlorides has been developed. The method was applicable to both electron-rich and electron-deficient substrates and delivered good yields for 21 examples. This reaction provides a convenient access to ortho-sulfonylated azobenzenes under mild conditions.