Lewis Acid‐Catalyzed or Base‐Promoted Regioselective Cycloisomerization of N‐Imidoyl‐o‐alkynylanilines for Synthesis of N‐Imidoyl‐(1 H)‐indoles and 4‐Alkylidene‐3,4‐dihydroquinazolines

Product selectivity control for the synthesis of imidoylindoles and 4‐alkylidenedihydroquinazolines from N‐imidoyl‐o‐alkynylanilines via silver triflate‐catalyzed cycloisomerization or tetrabutylammonium fluoride‐promoted cyclization is described. The product selectivity depends mainly on the catalyst/promoter used, and on the substituents on the alkyne and amidine functions of the substrates.