MDPI Acta Medica Okayama 2624-8549 5 1 2023 Aluminum-Catalyzed Cross Selective C3-N1′ Coupling Reactions of N-Methoxyindoles with Indoles 452 462 EN Keisuke Tokushige Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Toshiki Yamashiro Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Seiya Hirao Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Takumi Abe Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University C3–N1′ bond formation of bisindoles has been a great challenge due to the intrinsic reactivity of indoles as both C3 and N1-nucleophilic character. Herein, we demonstrate an C3–N1′ cross-coupling reaction of indoles using N-methoxyindoles as N-electrophilic indole reagents in the presence of Lewis acid. The bisindoles generated in this transformation are latent C3-nucleophile, allowing them to be used as strategic intermediates in sequential C3–N1′–C3′–N1″ triindole formations. The potential synthetic usefulness of this sequential transformation was highlighted upon application to the construction of C3–N1 looped polyindoles. No potential conflict of interest relevant to this article was reported.