Gold-catalyzed intramolecular hydroamination of terminal alkynes in aqueous media: efficient and regioselective synthesis of indole-1-carboxamides

Using [Au(PPh3)]Cl/Ag2CO3-catalyzed 5-endo-dig cyclization in water under microwave irradiation, we developed a fast and green route to prepare indole-1-carboxamides from N'-substituted N-(2-alkynylphenyl)ureas. The described method is tolerant to a variety of functional groups, including N'-aryl, alkyl, heterocyclic, various N-(substituted-2-ethynylphenyl) and N-(2-ethynylpyridin-3-yl) ureas and affords moderate to high yields of the desired products.