Synthesis of Indole Derivatives from 2‐Alkynylanilines by Means of Gold Catalysis

Abstract

The peculiar features of gold(III) and gold(I) species include exceptional carbophilicity and, at the same time, lone pair affinity. Such a combination offers many advantages for the development of more sustainable approaches to the synthesis of indole derivatives from readily available 2‐alkynylanilines. This mini‐review critically summarizes the literature reports in this field, with the aim to encourage further research activities in this promising area.

Gold‐Catalyzed Functionalization Reactions of Indole

“…[1][2][3][4] Therefore, since its discovery and characterization in 1866, [5] enormous efforts have been dedicated to the development of efficient methods for its preparation [6][7][8][9][10][11][12] and functionalization. Indole is probably one of the most important and intensively studied heterocyclic systems in different research areas, including pharmaceutical, agrochemical, and materials sciences.…”

A theoretical investigation on palladium-catalyzed one-pot coupling of aryl iodides, alkynes, and amines through CN bond cleavage for the synthesis of indole derivatives

“…As the reports of N‐substituted indoles are relatively small, the synthesis of N‐substituted indole derivatives are of special interest to us . As to the transition metal catalysts, not only expensive such as Au, Ag, Rh, or Pd complexes but the naturally more abundant Cu and Ni have been utilized for indole synthesis in recent years. In the construction of indole skeleton, there are Ackermann's oxidative alkyne annulation through CH/NH bond functionalization, Xia's improved one‐pot tandem Leimgruber–Batcho indole synthesis, Sun's annulation of α‐substituted diazoacetates with 2‐ethynylanilines and so forth.…”

“…[1][2][3][4] Therefore, the synthesis of various substituted indoles has attracted significant attention of chemists. [5][6][7][8] Although more and more methods for the construction and functionalization of indole ring have been developed, [9,10] the multistep one-pot synthesis [8,11] and especially the transition-metal-catalyzed synthesis [12][13][14][15] have drawn and will continue to attract much attention.…”

Gold‐Catalyzed Indole Ring Synthesis

“…Given several reviews in the period 2011 through 2014 on gold-catalyzed indole synthesis [1][2][3][4], this chapter focuses on a few seminal papers and then very recent work.…”

“…A common feature is that gold salts have an enormous affinity for multiple bonds and they behave as soft carbophilic Lewis acids, thus triggering subsequent chemistry. For excellent discussions of these mechanisms, see references [42][43][44][45][46][47][48]. …”