Metal-Free Bisamidation of N -Tosylhydrazones with Carboxylic Acids Promoted by Tetrabutylammonium Iodide and tert -Butyl Hydroperoxide.

A versatile reaction between N -tosylhydrazones and carboxylic acids to access bisamides is reported. This metal-free, room-temperature reaction was catalyzed by TBAI, while TBHP served as the oxidant. Broad substrate scope and good functional group tolerance are the key features of the strategy. Subsequent intramolecular N-arylation of suitably substituted bisamides readily afforded functionalized 3-indazolones.