Convenient KI-catalyzed regioselective synthesis of 2-sulfonylindoles using water as solvent

A convenient procedure is developed for the preparation of 2-sulfonylindoles from indoles and sodium sulfinates catalyzed by KI in water. This environmentally benign 2-sulfonylation of indoles proceeds efficiently under mild conditions, affording the products with high regioselectivity and in moderate to good yields.