Recent Studies of Bifunctionalization of Simple Indoles

Abstract

Indole structures are extremely important and widely employed in organic synthesis. This review will focus on direct bifunctionalizations of simple indoles in tandem reactions. Recent studies have been divided into four types by trigger mechanisms: (1) nucleophilic C3; (2) nucleophilic NH for cyclization; (3) reduction; (4) oxidation. Reactions with carbocations, pyridines, alkenes, alkynes, aldehydes, imines, halogenated compounds et al were discussed. We hope this review will promote future research in the use of indoles.

Synthesis, characterization, and crystal structure of 2-(2-azidophenyl)-3-oxo-3H-indole 1-oxide

“…2,2-Disubstituted indolin-3-ones play a crucial role as fundamental structural motifs in various natural alkaloids and bioactive molecules (Dhote, Patel et al, 2021;Ji et al, 2019;Gu et al, 2014). Thus, substantial research efforts have been dedicated to the synthesis of these essential compounds (Dhote, Patel et al, 2021;Wang et al, 2021;Liu & McWhorter, 2003;Wetzel & Gagosz, 2011;Liu et al, 2003). These synthetic methods can be broadly sorted into three main strategies, viz.…”

“…These synthetic methods can be broadly sorted into three main strategies, viz. oxidative dearomatization of indoles (Wang et al, 2021;Liu et al, 2020), cyclization reactions (Dhote, Pund & Ramana, 2021;Xie et al, 2021;Fu & Song, 2018) and nucleophilic additions to 3H-indol-3-ones or indolone-N-oxides (Zhang et al, 2017;Liu et al, 2003;Berti et al, 1975). Notably, indolone-N-oxides, also known as isatogens, hold substantial importance in medicinal chemistry and serve as intermediates in the synthesis of natural alkaloids and bioactive compounds (Nepveu et al, 2010).…”

Brønsted Acid-Catalyzed Synthesis of 4-Functionalized Tetrahydrocarbazol-1-ones from 1,4-Dicarbonylindole Derivatives

“…On the other hand, the indole core is ubiquitous in numerous biologically active compounds, and therefore the development of methodologies for direct indole functionalization is an open challenge in organic synthesis, in which its FC reaction through the nucleophilic C3 position is one of the most useful approaches. 7 …”

Recent Advances of Three‐component Reactions of Simple Indoles

“…Recently, Gaich, [1m] Eycken [1n] have reported the light‐induced chemistry of indoles, while the Ye [1o] summarized the electrochemical transformations. Since our research team is very interested in indoles, we have also reviewed bifunctionalization of simple indoles [1p] …”