Chemoselective Cascade Synthesis of N‐Fused Heterocycles via Silver(I) Triflate‐Catalyzed Friedel–Crafts/N‐C Bond Formation Sequence

Abstract An efficient cascade methodology toward chemoselective synthesis of N‐fused heterocycles including 9 H ‐pyrrolo[1,2‐ a ]indole, 3 H ‐pyrrolo[1,2‐ a ]indole and 1 H ‐pyrrolo[1,2‐ a ]indole derivatives has been developed. This transformation proceeds via a silver(I) triflate‐catalyzed consecutive Friedel–Crafts reaction/NC bond formation sequence between readily available propargyl alcohols and 3‐substituted 1 H ‐indoles. Not only is excellent chemoselectivity observed according to the substitution patterns of propargyl alcohols, but also the Lewis acid‐catalyzed NC bond formation process can be carried out under base‐ and ligand‐free conditions.