From PtCl2‐ and Acid‐Catalyzed to Uncatalyzed Cycloisomerization of 2‐Propargyl Anilines: Access to Functionalized Indoles

On the move: PtCl2-catalyzed electrophilic activation of an alkyne moiety triggers a heterocyclization accompanied by migrations of both an allyl group and an acetate group to produce an indole (see scheme). Variation of the reaction conditions (particularly the temperature) as well as substituents at the propargylic position and on the nitrogen atom allows easy and versatile access to a myriad of indole substrates.