Solvent- and ligand-induced switch of selectivity in gold(I)-catalyzed tandem reactions of 3-propargylindoles

Álvarez, Estela; Miguel, Delia; García‐García, Patricia; Fernández‐Rodríguez, Manuel A.; Rodríguez, Félix; Sanz, Roberto

doi:10.3762/bjoc.7.89

Cited by 18 publications

(13 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Through these investigations, a combined effect of the electronic/steric properties of the aryl substituent at the propargylic position, auxiliary ligand and solvent was reasoned to the preponderance of Nazarov over the iso-Nazarov selectivity. [204] Gold catalysts in different oxidation state were shown to influence the cyclization of bromoallenylketones 183 to afford regiodivergent halofurans 184 and 185 (Scheme 42). The mechanistic insights of this ligand-controlled selectivity indicate that AuCl 3 favors the formation of 3-bromofuran 184 which is likely to be initiated by the activation of carbonyl group followed by 1,2-Br shift.…”

Section: Alkyl/aryl and Hydride Migrationsmentioning

confidence: 99%

“…Later, an in‐depth investigation regarding the factors influencing the regioselectivity such as reaction conditions, counter‐anion and ligand effects of the Au(I)‐catalyzed selective 1,2‐indole migrations were established. Through these investigations, a combined effect of the electronic/steric properties of the aryl substituent at the propargylic position, auxiliary ligand and solvent was reasoned to the preponderance of Nazarov over the iso‐Nazarov selectivity [204] …”

Section: Alkyl/aryl and Hydride Migrationsmentioning

confidence: 99%

See 1 more Smart Citation

Regio‐ and Site‐selective Molecular Rearrangements by Homogeneous Gold Catalysis

Praveen

2020

Asian J Org Chem

View full text Add to dashboard Cite

Homogeneous gold catalysis for connection and disconnection of carbon-carbon (CÀ C) as well as carbonheteroatom (CÀ X) bond constitutes an important zone in molecular chemistry, since all new or existing organic synthesis relies on the transformation of these chemical bonds. Among the diaspora of molecular transformations, rearrangement and shift reactions occupy a special place in organic chemistry, as they enable the synthesis of molecules of increased complexity from simple precursors. However, the rearrangement in substrates possessing more than one potential reaction site produce more than one isomer and could result in regioselective issues. This challenge of selective synthesis of one regisomer over the other was fairly addressed by gold catalysis on various occasions. To this end, the prowess of homogeneous gold catalysis towards regioselective molecular rearrangement reactions and the contributing parameters are comprehensively reviewed. Also, synthetic applicability of regioselective rearrangements by gold catalysis in total and formal synthesis of several natural products was emphasized.This review also covers the emergence of gold catalyzed migratory/shift selective reactions and could be beneficial for synthetic and medicinal chemists.

show abstract

Section: Alkyl/aryl and Hydride Migrationsmentioning

confidence: 99%

Section: Alkyl/aryl and Hydride Migrationsmentioning

confidence: 99%

Regio‐ and Site‐selective Molecular Rearrangements by Homogeneous Gold Catalysis

Praveen

2020

Asian J Org Chem

View full text Add to dashboard Cite

show abstract

“…In their early works, Echavarren and co-workers reported that C-3 alkynylindole 33 could be transformed either into indoloazocine 34 or into azepino [4,5-b]indole 35, depending on the nature of the employed gold catalyst. [54][55][56][57] Interestingly, for both products the reaction took place through initial coordination of the triple bond of the starting indole (intermediates XIX), followed by intramolecular attack of indole C-3 on XIX to give vinyl gold complexes XX. In both cases the first reaction step is an intramolecular cyclization, leading to spirocyclic intermediates XVII and XVIII, which further evolve to the final products after 1,2-migration of the vinyl group (Scheme 14).…”

Section: Intramolecular Hydroarylation Of Alkynesmentioning

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

“…In a latter report, in 2011, it was showcased that by altering the electronic and steric properties of ligands and reaction conditions (solvent, temperature, and counteranion) it is possible to switch the reactivity of gold(I)-carbene intermediate 95e (generated after a 1,2-indole shift) to follow the Nazarov cyclization pathway and furnish the products 95b. 276 Hence, divergent reaction pathways were accessed from the same substrate to achieve either 1,2-indole shift/Nazarov cyclization product 95b or alternative 1,2-indole shift/iso-Nazarov cyclization product 95c.…”

Section: Ligand-dependent Divergent Gold Catalysis (Ldgc)mentioning

confidence: 99%

Divergent Gold Catalysis: Unlocking Molecular Diversity through Catalyst Control

et al. 2021

View full text Add to dashboard Cite

The catalyst-directed divergent synthesis, commonly termed as “divergent catalysis”, has emerged as a promising technique as it allows chartering of structurally distinct products from common substrates simply by modulating the catalyst system. In this regard, gold complexes emerged as powerful catalysts as they offer unique reactivity profiles as compared to various other transition metal catalysts, primarily due to their salient electronic and geometrical features. Owing to the tunable soft π-acidic nature, gold catalysts not only evolved as superior contenders for catalyzing the reactions of alkynes, alkenes, and allenes but also, more intriguingly, have been found to provide divergent reaction pathways over other π-acid catalysts such as Ag, Pt, Pd, Rh, Cu, In, Sc, Hg, Zn, etc. The recent past has witnessed a renaissance in such examples wherein, by choosing gold catalysts over other transition metal catalysts or by fine-tuning the ligands, counteranions or oxidation states of the gold catalyst itself, a complete reactivity switch was observed. However, reviews documenting such examples are sporadic; as a result, most of the reports of this kind remained scattered in the literature, thereby hampering further development of this burgeoning field. By conceptualizing the idea of “Divergent Gold Catalysis (DGC)”, this review aims to consolidate all such reports and provide a unified approach necessary to pave the way for further advancement of this exciting area. Based on the factors governing the divergence in product formation, an explicit classification of DGC has been provided. To gain a fundamental understanding of the divergence in observed reactivities and selectivities, the review is accompanied by mechanistic insights at appropriate places.

show abstract

Solvent- and ligand-induced switch of selectivity in gold(I)-catalyzed tandem reactions of 3-propargylindoles

Cited by 18 publications

References 29 publications

Regio‐ and Site‐selective Molecular Rearrangements by Homogeneous Gold Catalysis

Regio‐ and Site‐selective Molecular Rearrangements by Homogeneous Gold Catalysis

Gold‐Catalyzed Functionalization Reactions of Indole

Divergent Gold Catalysis: Unlocking Molecular Diversity through Catalyst Control

Contact Info

Product

Resources

About