Interrupted Barton–Zard Reaction/Friedel–Crafts Alkylation Telescoped Reaction for the Synthesis of Pyrrolo[3,4‐ <i>b</i> ]indole Cores

Abstract A dearomatization reaction between electron‐deficient indoles and α,α‐diaryl‐substituted methyleneisocyanides, followed by in situ Friedel–Crafts alkylation, is described. In a telescoped reaction mediated by a Brønsted base in the first step and a Brønsted acid in the second step, aryl‐substituted pyrrolo[3,4‐b]indole cores are generally obtained in moderate‐to‐good yields and with high diastereoselectivity. The reaction tolerates a wide range of 3‐nitroindoles and aryl nucleophiles; however, the substrate scope of isocyanide derivatives is limited. The developed methodology offers a modular approach for the synthesis of multi‐substituted polycyclic cores.