I₂-mediated regioselective C-3 azidation of indoles

Abstract

An unprecedented synthesis of novel 3-azido indoles has been developed using I2 and NaN3 in high yields and excellent regioselectivity. The reaction proceeds under metal-free conditions at room temperature. Essentially, an umpolung in reactivity at the C-3 position of indole has been achieved by the activation of indoles with I2.

Copper-Catalyzed Regioselective sp3 C–H Azidation of Alkyl Substituents of Indoles and Tetrahydrocarbazoles

“…For example, Prabhu et al developed a copper-catalyzed azidation of indoles at the C-2 position (Scheme a) . Suna and Sudalai’s group reported the regioselective azidation at the C-3 position (Scheme b) . Jiao et al and our group found tryptophols and tryptamines could undergo C-3 azidation followed by cyclization cascade (Scheme c) .…”

Methods for direct C(sp2)–H bonds azidation

“…In 2016, Sudalai and colleagues reported an efficient I 2 -mediated regioselective C3 azidation of indole derivatives 15 with NaN 3 under metal-free conditions at room temperature. 22 1.0 equiv. molecular iodine and 1.0 equiv.…”

Cu-Catalyzed Oxidative 3-Amination of Indoles via Formation of Indolyl(aryl)iodonium Imides Using o-Substituted (Diacetoxyiodo)arene as a High-Performance Hypervalent Iodine Compound

“…Regarding previous work on the 3-selective amination of indole derivatives, the nitration of protecting-group-free and N -protected indoles with metal nitrate or nitric acid is well known (Scheme 1A) [7,8,9,10,11,12]. Sudalai and coworkers reported an azidation of indole derivatives with a stoichiometric amount of I 2 and NaN 3 to give 3-azide indole derivatives (Scheme 1B) [13]. Wang and coworkers developed an electrophilic amidation of indoles with N -[(benzenesulfonyl)oxy]amide as the electrophilic nitrogen agent in the presence of ZnCl 2 (Scheme 1C) [14].…”