Synthesis of substituted anilines via a gold-catalyzed three-component reaction

Abstract

A three-component reaction for the synthesis of substituted anilines by a gold(I)-catalyzed domino reaction was developed. Cationic gold catalysts selectively and sequentially activated two different alkynes, which were involved in...

Gold-catalyzed multicomponent reactions

“…40 Later, Tokuyama and co-workers demonstrated the goldcatalyzed domino reactions for the synthesis of substituted anilines 14d using terminal alkynes 14a, acetal amide 14b and internal alkynes 14c (Scheme 14). 41 The same group reported the synthesis of pyrroles 14e using terminal alkynes 14a and acetal 14b under gold catalysis. 42 In this transformation, pyrrole intermediate 14e further undergoes a gold-catalyzed Diels-Alder reaction with internal alkynes 14c to afford anilines 14d.…”

Gold Nanoparticle-Catalyzed Multicomponent Reactions

“…Propargylamines are building blocks, key intermediates, and synthetically versatile components for the synthesis of N- containing biological active structures including oxotremorine analogues, β-lactams, peptides, natural products, and therapeutics drug molecules . Gold, including GNPs, salts, and complexes, being a class of efficient catalysts, has garnered widespread attention in A 3 -coupling reactions. − In this perspective, we focus on the preparation of propargylamines via a transition metal-catalyzed A 3 -coupling reaction in the presence of GNPs. − In this context, the first paper concerning GNP-catalyzed greener preparation of propargylamines was explored by Kidwai and colleagues via an A 3 -coupling reaction of 3CR amine, alkyne, and aldehyde; products were obtained in the presence of 10 mol % GNPs in 67%–96% yield. The particle size of the catalyst was a key issue in this reaction, and the maximum reaction rate has been achieved when the particles of average size were ∼20 nm …”

Switching Mechanistic Pathways by Micellar Catalysis: A Highly Selective Rhodium Catalyst for the Hydroaminomethylation of Olefins with Anilines in Water

“…Secondary aromatic amines are valuable products and synthetic intermediates for the synthesis of heterocyclic compounds and Active Pharmaceutical Ingredients (API). , Different strategies are available for their synthesis, including aromatic ring nitration followed by the reduction of the nitro group using different metal catalysts, , Cu-catalyzed and photoredox Ullmann coupling reactions of aryl halides and tosylates with amines, − nucleophilic aromatic substitution reactions of properly designed substrates − such as diaryliodonium salt electrophiles, and the Pd catalyzed Buchwald–Hartwig amination. − Significant efforts have been devoted toward the development of more efficient approaches for the preparation of aryl amines by using ecofriendly media such as water in Fe-catalyzed reductive aminations, applying micellar catalysis in the alkylation of amines by alcohols using a hydrogen borrowing process (HB), in Ullmann type reactions, − and in Buchwald–Hartwig amination. − Despite these reaction improvements, the purposed methodologies still suffer from low atom-economy (Ullmann and Buchwald aminations), use nonsuitable catalysts for API preparation (e.g., Pd), and usually involve the introduction of the aromatic moiety into the beforehand formed aliphatic amines, mostly obtained by manipulation of the products obtained from derivatives prepared by the hydroformylation (HF) of olefins. − , In this context, the tandem HF and reductive amination process commonly called hydroaminomethylation (HAM) can be considered as an elegant and ecofriendly approach to the synthesis of substituted amines (Scheme ), as it is intrinsically atom-economic being able to incorporate all atoms of the starting materials and gaseous reagents inside the final product with water as the sole byproduct, yet, and important to note, it has found only very limited application in aromatic amine synthesis so far. − …”

“…33−36 Despite these reaction improvements, the purposed methodologies still suffer from low atom-economy (Ullmann and Buchwald aminations), use nonsuitable catalysts for API preparation (e.g., Pd), 37 and usually involve the introduction of the aromatic moiety into the beforehand formed aliphatic amines, mostly obtained by manipulation of the products obtained from derivatives prepared by the hydroformylation (HF) of olefins. [28][29][30][31][32][33][34][35][36]38 In this context, the tandem HF and reductive amination process commonly called hydroaminomethylation (HAM) can be considered as an elegant and ecofriendly approach to the synthesis of substituted amines (Scheme 1), as it is intrinsically atom-economic being able to incorporate all atoms of the starting materials and gaseous reagents inside the final product with water as the sole byproduct, yet, and important to note, it has found only very limited application in aromatic amine synthesis so far. 39−42 Despite the different improvements in HAM protocols as recently reviewed by Kalck and Urrutigoi ̈ty, 40 the use of water as a reaction medium is usually avoided considering its negative impact on the formation of the imine reaction intermediate.…”