Imino-λ 3 -iodane-Triggered Oxidative Ring-Opening of 2 H -Indazoles to ortho - N -Acylsulfonamidated Azobenzenes.

An iminoiodane-enabled oxidative ring-opening of 2 H -indazoles via C-N bond cleavage has been developed under metal-free reaction conditions. This methodology afforded a new array of unsymmetrical ortho - N -acylsulfonamidated azobenzenes with a wide functional group tolerance in good yields. The reaction potentially proceeds through the formation of a zwitterionic adduct, which is formed by the reaction between 2 H -indazoles and iminoiodane.