Rh(III)‐Catalyzed (Benz)imidazole‐Directed [4+2] Cyclization of Indoles With Maleimides: Facile Access to C6‐Fused Indole Polyheterocyclic Compounds

We report the first rhodium (III)‐catalyzed, (benz)imidazole‐directed site‐ selective [4+2] cyclization of indoles with maleimides, enabling the efficient synthesis of C6‐fused polyheterocyclic indoles. This strategy features with wide substrate scope and excellent functional group tolerance. Mechanistic insights were gained through control experiments, deuterium‐labeling, and competitive studies. Application of this methodology produced novel heterocycles via simple postsynthetic chemical transformations, showcasing the synthetic utility of this approach.