Metal-Free C–H Functionalization and Aromatization Sequence for the Synthesis of 1-(Indol-3-yl)carbazoles and Total Synthesis of 7-Bromo-1-(6-bromo-1H-indol-3-yl)-9H-carbazole

Abstract

An operationally simple, metal-free, costeffective, and mild oxidative cross-coupling protocol for the synthesis of 1-indolyl tetrahydrocarbazoles to afford 1-(indol-3-yl)carbazoles is developed. N-Chlorosuccinimide is used as a mild oxidant for the functionalization of the 1-position of tetrahydrocarbazoles, aromatization of which furnished 1-(indol-3-yl)carbazoles in good to moderate yields without employing protection/deprotection strategy. A naturally rare dibromo 1-(indol-3-yl)carbazole alkaloid was synthesized for the first time in two steps with an overall yield of 64% by applying the same methodology.

Trends in carbazole synthesis – an update (2013–2023)

“…There is a significant body of work on the conversion of tetrahydrocarbazoles and tetrahydrocarbazol-1-ones to carbazoles. [122][123][124][125][126][127][128][129][130][131][132] Over several publications, Lokhande developed iodine-and copper-mediated oxidations of tetrahydrocarbazoles. [133][134][135] Iodine was used to produce carbazoles, such as glycozoline and a, or 3-iodocarbazoles by varying the stoichiometry.…”

“…125 Later, Ertürk employed Pd/C or DDQ to convert tetrahydrocarbazoles to key intermediates on route natural products, including Olivacine and Ellipticine, 136,137 while Nagarajan used DDQ to form indolesubstituted carbazoles. 138 Scheme 16 Mal's synthesis of mafaicheenamine E.…”

Synthesis and theoretical activity of three steroid-derivatives on both aromatase and 17β-hydroxysteroid dehydrogenase Type 1 enzymes

“…In this study, three steroid derivatives were prepared using some chemical strategies: First stage. This step involved the preparation of an indol-steroid derivative (compound 2); it is noteworthy that several indol analogs have been synthesized using some reagents such as Nchlorosuccinimide [28], gold [29], rhodium [30], CuBr [31] and others. In this study, the compound 2 was prepared from formestane and diphenylhydrazine ( Figure 1).…”