CuPy2Cl2: A Novel and Efficient Catalyst for Synthesis of Propargylamines Under the Conventional Method and Microwave Irradiation

CuPy₂Cl₂ is an efficient catalyst for the preparation of propargylamines via three-component coupling reaction of aromatic aldehydes, amines, and aromatic alkynes stirred at 95 °C without using any solvent to afford the corresponding products in good yields. The reaction mixture was irradiated at 450 W in a microwave oven to furnish the expected products in excellent yields.     

New 1,2-dithioether based 2D copper(I) coordination polymer: from synthesis to catalytic application in A3-coupling reaction

Abstract

A new 2D copper(I) coordination polymeric complex has been synthesized from CuI and 1-(1-{4-chlorophenylthio}propan-2-ylthio)-4-chlorobenzene ([(CuI)₂{ArSCH₂CH(CH₃)SAr}₂]_n, Ar = 4-ClC₆H₄) and characterized by high resolution mass spectrometry (HRMS) and single crystal X-ray diffraction techniques. The complex has been employed as a suitable catalyst for a solvent-free, one-pot, three-component A³-coupling reaction. A variety of aromatic and aliphatic aldehydes, terminal alkynes and aliphatic cyclic secondary amines have been used to prepare a library of propargylamines using the 2D-Cu complex at significantly low concentration (0.2?mol%).     

Expeditious and highly efficient synthesis of propargylamines using a Pd‐Cu nanowires catalyst under solvent‐free conditions

A heterogeneous Pd‐Cu NWs‐catalyzed expeditious and solvent‐free synthesis of propargylamines via A³‐coupling of aldehydes, alkynes, and amines has been proposed. A wide range of aldehydes, alkynes and amine substrates undergo A³‐coupling to produce propargylamines in good to excellent yields with good functional tolerance, such as that towards alkoxy, hydroxy, C‐X (X = F, Cl, Br) as well as amide and C=C bonds. Furthermore, the catalyst could be recovered easily and reused for at least 5 cycles without showing significant loss of catalytic activity.     

Single and double A3-coupling (aldehyde-amine-alkyne) reaction catalyzed by an air stable copper(I)-phosphole complex

An air stable copper(I)-phosphole complex, [CuCl{2,5-bis(2-thienyl)-1-phenylphosphole}₂] (1), was utilized as a catalyst in single and double A³-coupling reactions for preparing mono- and bi-propargylamines. A variety of aldehydes, amines and terminal alkynes were tested. Most of these reactions led to formation of the expected propargylamines in good yields using low amounts catalyst and obviating both the use of purified reagents as employ of a glovebox.     

Direct Enantioselective Three‐Component Synthesis of Optically Active Propargylamines in Water

An enantioselective three‐component reaction of aldehydes, amines, and alkynes in water by using a bis(imidazoline)–Cu^I catalysts having a hydrophobic substituent and sodium dodecyl sulfate as a surfactant was developed. The reaction was applied to a broad range of aldehydes and alkynes to give optically active propargylamines with excellent yields (up to 99 %) and enantiomeric excesses (up to 99 % ee).     

Ag2CO3-catalyzed efficient synthesis of internal or terminal propargylicamines and chalcones via A3-coupling under solvent-free condition

Several simple, fast and practical protocols have been developed to synthesize internal or terminal propargylamines and chalcones via A³-coupling reaction of aldehydes, amines, and alkynes catalyzed by an easily available catalyst Ag₂CO₃ under solvent-free condition. The reaction proceeded smoothly to deliver various products in good-to-excellent yields with good functional group tolerance. Gram-scale preparation, bioactive molecule synthesis and asymmetric substrates have been demonstrated. Furthermore, plausible mechanisms for the synthesis of different products have been proposed.     

An efficient synthesis of propargylamines via three-component coupling of aldehydes, amines and alkynes catalyzed by nanocrystalline copper(II) oxide

An efficient three-component coupling of aldehydes, amines and alkynes to prepare propargylamines, in nearly quantitative yields using nanocrystalline CuO as a catalyst is described. Structurally divergent aldehydes and amines were converted to the corresponding propargylamines. The reaction does not require any co-catalyst. After completion of the reaction, the catalyst was recovered by centrifugation and reused several times with only a slight decrease of activity observed under the same reaction conditions.     

Caffeine gold complex supported on magnetic nanoparticles as a green and high turnover frequency catalyst for room temperature A3 coupling reaction in water

A new heterogeneous catalyst derived from gold (III) and supported on caffeine‐coated magnetic nanoparticles, Fe₃O₄@Caff‐Au, has been prepared and characterized using different techniques. This magnetic gold composite shows high catalytic activity in A³ coupling reactions of terminal alkynes, aldehydes and secondary amines. Using this green catalyst, propargylamines are obtained in high turnover frequency in short reaction times using water as solvent at room temperature. This stable and ready accessible catalyst can be easily recycled magnetically for at least nine consecutive runs without significant loss of activity and with slight aggregation of Au species.     

Magnetic CuO nanoparticles supported on graphene oxide as an efficient catalyst for A3-coupling synthesis of propargylamines

Magnetically separable CuO nanoparticles supported on graphene oxide (Fe₃O₄ NPs/GO-CuO NPs) is synthesized and characterized for the preparation of propargylamines in EtOH, at 90℃. Fe₃O₄ NPs/GO-CuO NPs is found to be an efficient catalyst for the A³-coupling of aldehydes, amines, and alkynes through C-H activation. Both aromatic and aliphatic aldehydes and alkynes are combined with secondary amines to provide a wide range of propargylamines in moderate to excellent yields.     

Highly efficient three-component (aldehyde-alkyne-amine) coupling reactions catalyzed by a reusable PS-supported NHC-Ag(I) under solvent-free reaction conditions

The development of a highly efficient, polystyrene-supported NHC-Ag(I) catalyst for the three-component coupling reactions of aldehydes, alkynes, and amines (A³-coupling) was described. In the presence of PS-NHC-Ag(I) (2 mol %), the A³-reactions were carried out at room temperature under solvent-free reaction conditions and the corresponding propargylamines were generated in good to excellent yields. Furthermore, the catalyst could be reused at least 12 times without a significant loss of its catalytic activity.     

An efficient synthesis of propargylamines via C-H activation catalyzed by copper(I) in ionic liquids

A readily available copper(I) catalyst, in an ionic liquid, can effect three-component coupling of aldehydes, amines and alkynes to generate propargylamines in high yields.     

Nano‐Fe3O4@TiO2/Cu2O Core‐shell Composite: A Convenient Magnetic Separable Catalyst for A3 and KA2 Coupling

An eco‐efficient one‐pot three component reaction between different aldehydes or ketones with alkynes and amines for the synthesis of propargylamines was performed using Fe₃O₄@TiO₂/Cu₂O as a nano‐magnetic composite under solvent free condition. The catalyst showed remarkable catalytic activity by decreasing the time of the reaction in comparison of other reported magnetic catalysts. In addition, the Fe₃O₄@TiO₂/Cu₂O can be easily recycled and reutilized for five times without apparent loss of catalytic activity.     

Ultrasound-assisted rapid and efficient synthesis of propargylamines

Ultrasound was used for the addition of metal acetylides to in situ generated imines to generate propargylamines in good to excellent yields using copper iodide in water at ambient temperature. This process is an efficient alternative to traditional heated reactions. A variety of aldehydes and amines were used for this reaction.     

Magnetically separable Fe3O4 nanoparticles: an efficient catalyst for the synthesis of propargylamines

Magnetically separable Fe₃O₄ nanoparticles endow with an efficient and economic route for the synthesis of propargylamines by the three-component coupling of aldehyde, amine, and alkyne through C-H activation. The reaction is especially effective for reactions involving aliphatic aldehydes and no additional co-catalyst or activator is required. High catalytic activity and ease of recovery using an external magnetic field are additional eco-friendly attributes of this catalytic system. The catalyst was recycled for five times without a significant loss of catalytic activity.     

Identifying a Highly Active Copper Catalyst for KA2 Reaction of Aromatic Ketones

The well‐established A³ coupling reaction of terminal alkynes, aldehydes, and amines provides the most straightforward approach to propargylic amines. However, the related reaction of ketones, especially aromatic ketones, is still a significant challenge. A highly efficient catalytic protocol has been developed for the coupling of aromatic ketones with amines and terminal alkynes, in which Cu^I, generated in situ from the reduction of CuBr₂ with sodium ascorbate, has been identified as the highly efficient catalyst. Since propargylic amines are versatile synthetic intermediates and important units in pharmaceutical products, such an advance will greatly stimulate research interest involving the previously unavailable propargylic amines.     

Porous triazine polymer: A novel catalyst for the three-component reaction

A new porous triazine-based covalent organic polymer (Triazine-COP) was prepared through the Schiff-base condensation of 2,4,6-tris(4-formyl phenoxy)-1,3,5-triazine and 4,4′-oxydianiline, under sonication. The synthesized Triazine-COP with a high surface area was stable in water and other organic solvents. In the next step, Au (III) ions were immobilized on the nitrogen-rich Triazine-COP that on the reduction with NaBH₄ produced the heterogeneous catalyst of gold clusters in nanosize (Au-NCs@Triazine-COPs). It was applied as an efficient catalyst for the A³ coupling reaction of alkynes, aldehydes with and amines. Both electron-withdrawing/releasing groups produced the corresponding propargylamines with high yields. The high activity of the Au-NCs@Triazine-COPs in this reaction was because of the nanoporous structure of the support that enables the high dispersion and an unhindered open environment for the NCs. The catalyst was reused up to 7 times without significant loss in activity.     

The silver salt of 12-tungstophosphoric acid: an efficient catalyst for the three-component coupling of an aldehyde, an amine and an alkyne

A three-component coupling of an aldehyde, an alkyne and an amine to prepare propargylamines was performed using the silver salt of 12-tungstophosphoric acid (Ag₃PW₁₂O₄₀) as a heterogeneous catalyst under mild reaction conditions in the absence of any co-catalyst. A variety of aldehydes and amines were converted to the corresponding propargylamines demonstrating the versatility of the reaction. The Ag₃PW₁₂O₄₀ (AgTPA) catalyst was recovered quantitatively by a simple filtration and reused several times.     

Synthesis of enantiomerically enriched propargylamines by copper-catalyzed addition of alkynes to enamines

The first copper(I) bromide/Quinap-catalyzed synthesis of enantiomerically enriched propargylamines by addition of alkynes to enamines is reported. Various functionalized terminal alkynes add smoothly to Nprotected enamines to afford the corresponding amines in good to high yields and moderate to good enantiomeric excesses. The influence of the metal salt, the ligand, and the protecting group on the conversion, the reaction rate, and the stereoselectivity of the reaction are investigated. The scope of the reaction and further transformations of the resulting propargylamines (deprotection, Pauson-Khand reaction) are also described.     

Practical highly enantioselective synthesis of propargylamines through a copper-catalyzed one-pot three-component condensation reaction

The one-pot three-component reaction of terminal alkynes, aldehydes and secondary amines in the presence of copper(I) bromide/quinap is reported. The reaction scope has been determined and a broad variety of all three components has been used, which afforded the corresponding propargylamines in good to excellent yields and moderate to very good enantioselectivities. The reaction showed a strong positive nonlinear effect. The transformation of a propargylamine intermediate into the alkaloid (S)-(+)-coniine has also been described.     

One-pot synthesis of α-aminophosphonates catalyzed by antimony trichloride adsorbed on alumina

SbCl₃ adsorbed on Al₂O₃ is found to be an efficient and recyclable catalyst in promoting three-component coupling reactions of aldehydes (aromatic and aliphatic), amines (aryl amines, aliphatic amines and esters of S-α-amino acids) and dialkylphosphites to afford the corresponding α-aminophosphonates in high yields. The ethyl ester of S-phenylalanine was observed to yield the corresponding α-aminophosphonate with S,S-diastereoisomer formed in dominance over the S,R-diastereoisomer.