Gold(I)‐Catalyzed Post‐Ugi Hydroarylation: An Approach to Pyrrolopyridines and Azepinoindoles

Kumar, Amit; Vachhani, Dipak D.; Modha, Sachin G.; Sharma, Sunil K.; Parmar, Virinder S.; Eycken, Erik V. Van der

doi:10.1002/ejoc.201300132

Cited by 40 publications

(23 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[63] For example, C-4-functionalized indoles 47 were employed to synthesize azocinoindolones 48 through direct C-3 nucleophilic attack of indole on the gold-activated alkyne systems (Scheme 19). [63] For example, C-4-functionalized indoles 47 were employed to synthesize azocinoindolones 48 through direct C-3 nucleophilic attack of indole on the gold-activated alkyne systems (Scheme 19).…”

Section: Scheme 16 Synthesis Of Indoloazepinones 41mentioning

confidence: 99%

Gold‐Catalyzed Functionalization Reactions of Indole

Pirovano

2018

Eur J Org Chem

View full text Add to dashboard Cite

This review summarizes the progress achieved in the last fifteen years by application of homogeneous gold catalysis in the field of indole functionalization. Several electrophilic species obtained through gold‐catalyzed π‐activation have in fact been found to react with the nucleophilic positions of indole, thus allowing its efficient manipulation. In order to furnish a complete and clear overview on the role of the catalyst, the review is organized from the perspective of the gold‐activated substrate that is reacting with the indole. In addition, in view of the ability of gold to catalyze tandem and cascade reactions, a separate section describes tandem/cascade protocols useful for the synthesis of complex polycyclic indole derivatives. Finally, gold catalysis has also been employed for the synthesis of indole‐based natural products. For this reason, a dedicated section collects all the work in which the key step to obtain these complex indoles is represented by a gold‐catalyzed reaction.

show abstract

Section: Scheme 16 Synthesis Of Indoloazepinones 41mentioning

confidence: 99%

Gold‐Catalyzed Functionalization Reactions of Indole

Pirovano

2018

Eur J Org Chem

View full text Add to dashboard Cite

show abstract

“…The highly investigated Ugi four‐component reactions about arylacetic acids have been widely employed to generate multifunctionalized acyclic adducts for a myriad of intramolecular cyclizations –. Adjusting the structure of aldehydes (R 1 position) or amines (R 2 position)– achieved different one‐pot applications (Scheme ).…”

Section: Electrophilic Acidsmentioning

confidence: 99%

Arylacetic Acids in Organic Synthesis

et al. 2019

View full text Add to dashboard Cite

Arylacetic acids are widely used in organic reactions and their recent advances are summarized in six categories according to their triggered pathways: (1) the acid as directing group in ortho-or meta-CÀ H activation; (2) decarboxylation; (3) deprotonation; (4) nucleophilic methylenes; (5) nucleophilic acids; (6) electrophilic acids. Reactions with alkenes, alkynes, aldehydes, amines, water, Grignard reagents, silanes and so forth are discussed. We hope this Minireview will promote future research in this area. Recently, the Zeng group [3g] reported a weakly coordinationassisted alkynylation of arylacetic acids with iridium catalysis under air atmosphere (Eq. 2-2). It was supported the sixmembered ring cycloiridiated 2.5 acted as the key intermediate. The alkynylation of indole, thiophene, pyrrole, and benzo[b] thiophene afforded better yields than phenylacetic acids. The acid moiety could also participated in the intramolecular ortho-CÀ H activation, which was developed by the Shi group to obtain lactonization 2.6 (Eq. 2-3) (Scheme 2). Meta-CÀ H ArylationThe study of Yu group [3e] in 2017 revealed a successful control of meta selectivity 3.1 of arylation from aryl iodides (Eq. 3-1). The use of mono-protected 3-amino-2-hydroxypyridine (as ligand) and 2-carbomethoxynorbornene (NBE-CO 2 Me) were crucial. In the absence of NBE-CO 2 Me, only ortho-arylated product was obtained. This method was still efficient in a gramsale (Scheme 3). Decarboxylation Decarboxylative CouplingAs shown in Scheme 4, the decarboxylation could generate benzyl radicals 4.1. Then, direct couplings of 4.1 with diverse [ + ] These authors contributed equally. Scheme 1. Six categories based on triggered mechanism. 2 3 4 5 6 7 8 . Passerini Three-Component ReactionThe Passerini reaction was the oldest multicomponent reaction (MCR) [37d] in which isocyanides, carboxylic acids and aldehydes were used. It was powerful for the rapid construction of complex molecules. The tactic to expand the scope of Passerini reaction was to use surrogates of the carbonyl partners. As described in Scheme 51, syn-chlorooximes, [37b] diazoketones, [37c] alcohols, [37d,e] azirines [37f] and isatins [37g] could be employed instead of aryl or alkyl aldehydes [37a] (Scheme 51). Besides, in 2018, Zhang and co-workers [37] have firstly reported asymmetric phosphoric acid-catalyzed four-component Ugi reaction, which Scheme 45. BTM-catalyzed cycloaddition. Scheme 46. HBTM-catalyzed cycloaddition. Scheme 47. TFA-catalyzed reaction. Scheme 48. Friedel-Crafts triggered tandem reactions. Scheme 49. C-acylation of 1,3-diones. Scheme 50. C-acylation of 1,3-indandiones.

show abstract

“…A wide range of substituents related to the isocyanide (R 2 ) and the carboxylic acid (R 1 ) were tolerated. Furthermore, when indole alkynamide‐bearing phenyl‐substituted alkynes (R 3 = Ph) were treated under the optimized conditions, endo‐ cyclized azepinoindoles 31 were exclusively formed …”

Section: Intramolecular Hydroarylation (C–c Bond) Reactionmentioning

confidence: 99%

Gold-Catalyzed Cyclization Processes: Pivotal Avenues for Organic Synthesis

Kumar

Singh

Sharma

et al. 2015

The Chemical Record

Self Cite

View full text Add to dashboard Cite

Over the years, gold catalysis has materialized as an incredible synthetic approach among the scientific community. Due to the trivial reaction conditions and great functional compatibility, these progressions are synthetically expedient, because practitioners can implement them to build intricate architectures from readily amassed building blocks with high bond forming indices. The incendiary growth of gold catalysts in organic synthesis has been demonstrated as one of the most prevailing soft Lewis acids for electrophilic activation of carbon-carbon multiple bonds towards a great assortment of nucleophiles. Nowadays, organic chemists consistently employ gold catalysts to carry out a diverse array of organic transformations to build unprecedented molecular architectures. Despite all these achievements and a plethora of reports, many vital challenges remain. In this account, we describe the reactivity of various gold catalysts towards cyclization processes developed over the years. These protocols give access to a wide scope of polyheterocyclic structures, containing different medium-sized ring skeletons. This is interesting, as the quest for highly selective reactions to assemble diversely functionalized products has attracted much attention. We envisage that these newly developed chemo-, regio-, and diastereoselective protocols could provide an expedient route to architecturally cumbersome heterocycles of importance for the pharmaceutical industry.

show abstract

Gold(I)‐Catalyzed Post‐Ugi Hydroarylation: An Approach to Pyrrolopyridines and Azepinoindoles

Cited by 40 publications

References 56 publications

Gold‐Catalyzed Functionalization Reactions of Indole

Gold‐Catalyzed Functionalization Reactions of Indole

Arylacetic Acids in Organic Synthesis

Gold-Catalyzed Cyclization Processes: Pivotal Avenues for Organic Synthesis

Contact Info

Product

Resources

About