Synthesis of 1H-indole-3-sulfonates via palladium-catalyzed tandem reactions of 2-alkynyl arylazides with sulfonic acids

An efficient method for the synthesis of 1H-indole-3-sulfonates via palladium-catalyzed tandem reactions of 2-alkynyl arylazides with sulfonic acids has been developed. The desired products were obtained in good to excellent yields under mild reaction conditions. The reactions were shown to proceed very fast, in most cases, within 10 min.