Alkynes In Water Research Articles

Au(III) catalyst supported on a thermoresponsive hydrogel and its application to the A-3 coupling reaction in water

Poly(NIPAM-co-4-VP), synthesized from N-isopropylacrylamide and 4-vinylpyridine with a 1:1 monomer ratio, exhibits a temperature-dependent phase transition in water with a low critical solution temperature (LCST) of 47°C. Coordination of Au(III) with the polymer results in material with metal catalytic activity combined with the inverse solubility phenomenon of the polymer, which catalyzes the three-component coupling reaction of aldehydes, amines, and alkynes in water with excellent yields. The polymer not only functions as a supporter for Au(III) but also accelerates the catalysis by undergoing a coil-to-globule phase transition above the LCST. The catalyst is efficient, is stable in air, and tolerates a variety of substrates. Moreover, the recyclability of the catalyst makes it eco-friendly and economical to use.

A Palladium Nanoparticle–Nanomicelle Combination for the Stereoselective Semihydrogenation of Alkynes in Water at Room Temperature

AbstractThe addition of NaBH4to Pd(OAc)2in water containing nanomicelles leads to the generation of H2and Pd nanoparticles. Subsequent reduction of disubstituted alkynes affordsZ‐alkenes in high yields. These reactions are general, take place in water at ambient temperatures, and offer recycling of the aqueous reaction mixture along with low overall E Factors.

A palladium nanoparticle-nanomicelle combination for the stereoselective semihydrogenation of alkynes in water at room temperature.

The addition of NaBH4 to Pd(OAc)2 in water containing nanomicelles leads to the generation of H2 and Pd nanoparticles. Subsequent reduction of disubstituted alkynes affords Z-alkenes in high yields. These reactions are general, take place in water at ambient temperatures, and offer recycling of the aqueous reaction mixture along with low overall E Factors.

ChemInform Abstract: Reaction of Tri(2‐pyridyl)phosphine with Electron‐Deficient Alkynes in Water: Stereoselective Synthesis of Functionalized Pyridylvinylphosphine Oxides.

AbstractTreatment of electron‐deficient alkynes with phosphine (II) in water is found to result in unusual formation of pyridylvinylphosphine oxides.

ChemInform Abstract: Stereoselective Silylcupration of Conjugated Alkynes in Water at Room Temperature.

AbstractOptimized conditions allow the silylcupration of various electron‐deficient alkynes to give the corresponding products with high E‐selectivity.

ChemInform Abstract: Copper(II)‐Catalyzed Silylation of Activated Alkynes in Water: Diastereodivergent Access to E‐ or Z‐β‐Silyl‐α,β‐Unsaturated Carbonyl and Carboxyl Compounds.

AbstractAn operationally simple and mild protocol is developed for the hydrosilylation of α,β‐alkynyl carbonyl compounds.

Immobilized silver on surface-modified ZnO nanoparticles: As an efficient catalyst for synthesis of propargylamines in water

Silver nanoparticles were immobilized on ionic liquid modified zinc oxide nanoparticles leading to a ZnO-IL/Ag NPs catalyst, which exhibits high catalytic performance in the synthesis of propargylamines through one-pot three-component condensation reaction of aldehydes, amines, and alkynes in water. The as-prepared catalyst was characterized by ICP-AES, FT-IR, XRD, SEM, and TEM. The catalyst was easily recycled and reused at least five times without significant loss of its catalytic activity.

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).

Stereoselective Silylcupration of Conjugated Alkynes in Water at Room Temperature

AbstractMicellar catalysis enables copper‐catalyzed silylcupration of a variety of electron‐deficient alkynes, thereby providing access to isomerically pure E‐ or Z‐β‐silyl‐substituted carbonyl derivatives. These reactions take place in minutes, afford high yields and stereoselectivity, and are especially tolerant of functional groups present in the substrates. The aqueous reaction medium has been successfully recycled several times, and a substrate/catalyst ratio of 10,000:1 has been documented for this methodology.

Stereoselective Silylcupration of Conjugated Alkynes in Water at Room Temperature

Micellar catalysis enables copper-catalyzed silylcupration of a variety of electron-deficient alkynes, thereby providing access to isomerically pure E- or Z-β-silyl-substituted carbonyl derivatives. These reactions take place in minutes, afford high yields and stereoselectivity, and are especially tolerant of functional groups present in the substrates. The aqueous reaction medium has been successfully recycled several times, and a substrate/catalyst ratio of 10,000:1 has been documented for this methodology.

An environmentally benign synthesis of isoxazolines and isoxazoles mediated by potassium chloride in water

An effective and environmentally benign procedure for the synthesis of isoxazolines and isoxazoles has been developed by a cycloaddition of nitrile oxides with alkenes or alkynes in water. In this approach, potassium chloride is first oxidized into chlorine in water by the environmentally friendly oxidant Oxone®, then aldoximes are oxidized into nitrile oxides by the in situ generated hypochlorous acid, finally a 1,3-dipolar cycloaddition between nitrile oxides and alkenes or alkynes occurs to provide the corresponding isoxazolines and isoxazoles in good yields.

Copper(II)‐Catalyzed Silylation of Activated Alkynes in Water: Diastereodivergent Access to E‐ or Z‐β‐Silyl‐α,β‐Unsaturated Carbonyl and Carboxyl Compounds

AbstractCopper(II)‐catalyzed silylation of substituted alkynylcarbonyl compounds was investigated. Through the activation of Me2PhSiBpin in water at room temperature and open atmosphere, vinylsilanes conjugated to carbonyl groups are synthesized in high yield. A surprising diastereodivergent access to olefin geometry was discovered using a silyl conjugate addition strategy: aldehydes and ketones were Z selective while esters and amides were exclusively transformed into the E products.

Microwave-assisted palladium-catalyzed highly regio- and stereoselective head to head dimerization of terminal aryl alkynes in water

A highly regio- and stereoselective oxime palladacycle/imidazolinium-catalyzed head to head dimerization of terminal aryl alkynes in water is presented.

Metal-free synthesis of 1,3,5-trisubstituted benzenes by the cyclotrimerization of enaminones or alkynes in water

The trimeric cyclization reactions of enaminones proceed efficiently in water to provide C3 symmetric benzenes in the presence of lactic acid.

Reaction of Tri(2‐pyridyl)phosphine with Electron‐Deficient Alkynes in Water: Stereoselective Synthesis of Functionalized Pyridylvinylphosphine Oxides

AbstractThe reaction of tri(2‐pyridyl)phosphine with electron‐deficient alkynes in water proceeds under mild conditions (40–45 °C, without catalyst, 4–5 h) with liberation of pyridine to give (E)‐pyridylvinylphosphine oxides in 45–56 % yields, the only exception being the reaction with cyanophenylacetylene, which affords the corresponding vinylphosphine oxide of Z‐configuration in 40 % yield. The reaction is likely triggered by the zwitterion, the adduct of tri(2‐pyridyl)phosphine to the electrophilic acetylenes, the carbanionic center of which is then neutralized by a proton from water. The intermediate phosphonium hydroxide finally decomposes to the product.

ChemInform Abstract: Preparation of Substituted Pyrroles via Ru(II)‐Catalyzed Coupling of Alkynes with Enamides.

AbstractThe optimized conditions can be used in DME or water.

Nanoporous Titania-Supported Gold Nanoparticle-Catalyzed Green Synthesis of 1,2,3-Triazoles in Aqueous Medium

Nanoporous titania-supported gold nanoparticles have been synthesized through the deposition–precipitation method, and the synthesized nanoparticles have been characterized by XRD, SEM, HRTEM, EDAX, BET adsorption isotherm, and IR and UV–vis spectral techniques. The efficiency of this catalyst toward green organic synthesis has been studied by carrying out the 1,3-dipolar cycloaddition of organic azides with a variety of terminal alkynes in water. The reaction proceeds regioselectively yielding the corresponding 1,4-disubstituted-1,2,3-triazole derivative in good to excellent yield.

ChemInform Abstract: Catalytic Nucleophilic Additions of Alkynes in Water

AbstractReview: 98 refs.

2-Ethynylpyridine-Promoted Rapid Copper(I) Chloride Catalyzed Azide-Alkyne Cycloaddition Reaction in Water

The copper(I) chloride catalyzed reaction of azides with alkynes in water at room temperature was promoted by the addition of a catalytic amount of 2-ethynylpyridine, affording the corresponding 1,4-disubstituted 1,2,3-triazoles in good yields after a specific reaction time. The catalytic system could be successfully applied to electron-rich, electron-poor, and sterically crowded substrates. A study of the additive effect of pyridine derivatives revealed that alkynyl and 2-pyridyl groups were essential for activating the copper catalyst.

Preparation of substituted pyrroles via Ru(II)-catalyzed coupling of alkynes with enamides

An efficient ruthenium-catalyzed oxidative cyclization of enamides with alkynes in water or dimethoxyethane leading to the pyrrole derivatives is reported. Typically, a mixture of ethyl 2-(acetylamino)acrylate, diphenylacetylene, [Ru(p-cymene)Cl2] (2mol%), KPF6, and Cu(OAc)2 in water was heated under refluxing conditions providing the N-acetylated pyrrole product in 95% yield.