Copper‐Catalyzed Sequential C(sp2)−H/C(sp3)−H Annulation of Indoles with Propargylic Alcohols to Access Hydrobenzo[b]carbazoles.

Herein, we describe a copper‐catalyzed sequential C(sp2)−H/C(sp3)−H annulation of indoles with propargylic alcohols for the synthesis of diversely functionalized hydrobenzo[b]carbazole scaffolds. The reaction involves a Friedel‐Crafts addition, 1,5‐H shift, 6π electrocyclization, and dearomatization‐aromatization cascade. Importantly, this is a report of the use of 2‐(diarylmethyl)indoles as three‐carbon synthons in a (3+3) annulation reaction involving C(sp3)−H indole functionalization under oxidant‐free conditions. [ABSTRACT FROM AUTHOR]