Palladium-Catalyzed Indole and Azaindole Synthesis by Direct Annulation of Electron-Poor<i>o</i>-Chloroanilines and<i>o</i>-Chloroaminopyridines with Aldehydes
for the synthesis of 2-unsubstituted indolesand azaindoles has been developed by the palladium-catalyzed directannulation of electron-poor O-chloro/bromoanilines and O-chloroaminopyridines with aldehydes.Coupled with the previous results of Jia and Zhu, this allows rapidaccess to a variety of 2-unsubstituted indoles and azaindoles startingfrom simple and easily accessible precursors.