Construction of 3,3'‐Bicarbazoles and Indolocarbazoles by Using Visible Light

Abstract A synthetic and mechanistic study of novel iterative double cyclization intramolecular S RN 1 reactions from diarylamines bearing two aryl halide moieties was carried out. This cyclization affords symmetric and unsymmetric 3,3'‐bicarbazoles and indolocarbazoles compounds in regular to very good yields. The synthetic strategy employed for their preparation was a Buchwald‐Hartwig arylation of anilines followed by an intramolecular S RN 1 reaction, in the presence of base and visible light, at room temperature. The mechanism is non‐trivial and it was studied using spectroscopy and computational calculations, employing the DFT method, with B3LYP and M06‐2X functionals and 6‐31+G*, def2SVP and def2TZVP as bases and radicals are proposed as intermediates.