Stereoselective synthesis of 2-iodo-1-perfluoroalkyl-2(Z)-alkenes and E or Z-4-perfluoroalkylmethyl-4-en-2-ynol via Na2S2O4-promoted radical addition reaction of perfluoroalkyl iodides with allenes and the palladium-catalyzed kinetic resolution with Sonogashira coupling reaction

A Na₂S₂O₄-promoted radical addition reaction of perfluoroalkyl iodides with allenes has been studied in which a Z/E mixture of 2-iodo-1-perfluoroalkyl-2-alkenes 3 were afforded in 52-69% yields. A kinetic resolution using Sonogashira coupling reaction in MeCN using Et₂NH as the base was developed to synthesize the 2-iodo-1-perfluoroalkyl-2(Z)-alkenes (Z-3) and E-4-perfluoroalkylmethylalk-4-en-2-ynols (E-5) stereoselectively. A complete Sonogashira coupling procedure in Et₂NH at 40 °C was also developed affording a mixture of E and Z-4-perfluoroalkylmethyl-4-en-2-ynols (E-5 and Z-5), which may be easily separated by chromatography on silica gel.     

Studies on the radical addition reaction of perfluoroalkyl iodides with 2,3-allenols and the Pd-catalyzed kinetic resolution via Sonogashira coupling reaction

A radical addition reaction promoted by Na₂S₂O₄ of perfluoroalkyl iodides with 2,3-allenols affording E/Z mixtures of 3-iodo-4-perfluoroalkyl-substituted allylic alcohols has been studied. Kinetic resolution with Sonogashira coupling reaction was applied to afford the Z isomer of 3-iodo-4-perfluoroalkyl-substituted allylic alcohol (Z-3) and the E isomer of conjugated enynic diols (E-5) in 39-52% and 22-40% yields, respectively.     

CuI/PPh3‐catalyzed Sonogashira coupling reaction of aryl iodides with terminal alkynes in water in the absence of palladium

The Sonogashira cross‐coupling of aryl iodides with terminal alkynes catalyzed by a simple and inexpensive catalyst system of CuI/PPh₃ in water as the sole solvent has been reported. In the presence of CuI/PPh₃, with KOH used as a base, a number of aryl iodides were treated with alkynes to afford the corresponding products in moderate to excellent yields. Copyright © 2008 John Wiley & Sons, Ltd.     

Copper-free PdCl2/PPh3-catalyzed Sonogashira coupling reaction of aryl bromides with terminal alkynes in water

A simple, copper-free and efficient catalytic system for the Sonogashira coupling reaction of aryl bromides with terminal alkynes in pure water has been developed. The use of PdCl₂/PPh₃ in the presence of pyrrolidine allows the coupling reaction to proceed at 120 °C in moderate to excellent yields.     

The thermoregulated ligand–palladium‐catalyzed carbonylative Sonogashira coupling of aryl iodides with terminal alkynes in water

The carbonylative Sonogashira coupling of aryl iodides with terminal alkynes was studied by using thermoregulated ligand–palladium as an efficient and reusable catalyst at 80 °C in water. The corresponding alkynone products were obtained in good to excellent yields under 1 atm of carbon monoxide. The isolation of the products was readily achieved by extraction with ethyl acetate, and the catalyst recovered in water can be reused and recycled up to four times without significant loss in catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.     

Facile synthesis of fluorinated α-imino alkynes by the coupling reaction of imidoyl iodides with terminal alkynes

A series of N-arylbromodifluoroacetimidoyl iodides and 1-alkynes were converted into α-imino alkynes by using Pd(Ph₃)₂Cl₂/CuI as the catalyst under mild conditions. The reaction proceeded smoothly to give the coupling products in good to excellent yields.     

FeCl3/PPh3-catalyzed Sonogashira coupling reaction of aryl iodides with terminal alkynes

Conditions for a FeCl₃/PPh₃-catalyzed and palladium-, copper-, amine free-Sonogashira coupling reaction of aryl halides with terminal alkynes are reported. The protocol was applicable to a wide variety of substituted aryl iodides and alkynes with different steric and electronic properties and gave excellent yields of the desired coupling products.     

A convenient access to furo[3,2-c]pyridin-6(5H)-ones by the reaction of 5-iodo-4-methoxy-2-pyridones with terminal alkynes under microwave-enhanced Sonogashira conditions

N-Alkyl-3-aryl-5-iodo-4-methoxypyridin-2(1H)-ones readily undergo sequential acetylide cross-coupling, demethylation, and furan annulation under classical Sonogashira reaction conditions to furnish 7-arylfuro[3,2-c]pyridin-4(5H)-ones, a class of hitherto unknown compounds, in a one-pot operation. Microwave irradiation was found to significantly reduce reaction times and to allow lower catalysts and reagent loadings.     

The first heterogeneous Sonogashira coupling reaction of aryl halides with terminal alkynes catalyzed by diatomite‐supported palladium(II) salophen complex

We report here our observation that, using appropriate reaction conditions, the Sonogashira reaction can be performed without the need for copper catalyst and solvent. Our approach involves the use of diatomite‐supported palladium(II) salophen complex as a catalyst and triethylamine as a base. The methodology works, to differing extents, for aryl iodides and bromides. This heterogeneous catalyst can be reused at least five times without any decrease in activity. Copyright © 2011 John Wiley & Sons, Ltd.     

Pd-catalyzed cross-coupling reaction of (Z)- and (E)-bromoenyne: unusual stereochemical outcome

Pd-catalyzed cross-coupling reaction of (E)-bromoenyne 1Z with 1-alkyne and tributylvinyl-stannane occurs with retention of the configuration in benzene but with an inversion of the configuration in DMF or CH₂Cl₂. On the other hand, that of (Z)-bromoenyne 1E occurs with retention of the configuration in these solvents.     

Regio- and stereo-specific preparation of (E)-1-aryl-3,3,3-trifluoro-1-iodo-propenes and their palladium-catalyzed reaction with terminal alkynes

A new type of iodo-containing trifluoromethylated building blocks were synthesized. The reaction of 1-aryl-3,3,3-trifluoropropynes 1 with lithium iodide in acetic acid at 75 °C gave (E)-1-aryl-3,3,3-trifluoro-1-iodo-propenes 2 in high yield, which undergo the palladium-catalyzed Sonogashira reaction with terminal alkynes afforded trifluoromethyl-containing 1,3-enynes in high yield.     

A new synthesis of 2-aryl/alkylbenzofurans by visible light stimulated intermolecular Sonogashira coupling and cyclization reaction in water

A visible light induced rapid one pot intermolecular Sonogashira coupling and 5-endo-dig cyclization in water of ortho-halophenols and terminal alkynes catalyzed by [Pd] have been developed to furnish 2-aryl/alkyl benzofurans in good yields sans Ru or Ir complexes or any other additives.     

Recyclable and reusable NiCl2(PPh3)2/CuI/PEG‐400/H2O system for the sonogashira coupling reaction of aryl iodides with alkynes

A stable and highly efficient NiCl2(PPh₃)₂/CuI/PEG‐400/H₂O catalytic system for the Sonogashira reaction has been developed. In the presence of NiCl₂(PPh₃)₂ and CuI, the coupling reaction of aryl iodides with terminal alkynes was carried out smoothly in a mixture of poly(ethylene glycol) (PEG‐400) and water at 100°C with K₂CO₃ as base to afford a variety of arylacetylenes in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether, and the NiCl₂(PPh₃)₂/CuI/PEG‐400/H₂O system could be easily recycled and reused six times without significant loss of catalytic activity. Our system not only avoids the use of easily volatile organic solvents but also solves the basic problem of catalyst reuse. Copyright © 2015 John Wiley & Sons, Ltd.     

Copper- and phosphine-free Sonogashira coupling reactions of aryl iodides catalyzed by an N,N-bis(naphthylideneimino)diethylenetriamine-functionalized polystyrene resin supported Pd(II) complex under aerobic conditions

A polymer-supported palladium(II) N,N-bis(naphthylideneimino)diethylenetriamine complex is found to be a highly active catalyst for Sonogashira coupling reactions. The reactions are performed under copper- and phosphine-free conditions in an air atmosphere. The palladium catalyst is easily separated, and can be reused several times without significant loss in catalytic activity.     

Microwave assisted copper-free Sonogashira coupling/5-exo-dig cycloisomerization domino reaction: access to 3-(phenylmethylene)isoindolin-1-ones and related heterocycles

An efficient microwave assisted one-pot synthesis of substituted 3-(phenylmethylene)isoindolin-1-ones is reported via a copper-free Sonogashira coupling and a regioselective 5-exo-dig cycloisomerization. This domino reaction was also extended to other related heterocycles.     

Effect of addition of iron on morphology and catalytic activity of PdCu nanoalloy thin film as catalyst in Sonogashira coupling reaction

Palladium‐supported catalysts are complex assemblies with a challenging preparation. Minor changes in their preparation conditions can affect the activity, selectivity and lifetime of these catalysts. PdCuFe nanoparticle (NP) thin films were supported on reduced graphene oxide (RGO) by the reduction of the organometallic complex [PdCl_2‌(cod)] (cod = cis ,cis ‐1,5‐cyclooctadiene), and [Cu(acac)₂] and [Fe(acac)₃] (acac = acetylacetonate) complexes at a toluene–water interface. We have investigated the application of the liquid–liquid interface method for preparing ultrathin films of catalysts and have evaluated the catalytic activity of the prepared NPs for the Sonogashira coupling reaction in micelle media. Also, we have investigated the effect of the addition of iron on the morphology, size and catalytic activity of PdCu/RGO NPs. Our study shows that both of the prepared catalysts (PdCu/RGO and PdCuFe/RGO) are efficient and recoverable catalysts for the Sonogashira carbon–carbon coupling reaction. This method has advantages compared to other routes, such as short reaction times, high to excellent yields, facile and low‐cost method for the preparation of the catalysts, and easy separation and reusability of the catalysts.     

A facile approach to 6-amino-2H-pyrano[2,3-g]isoquinolin-2-ones via a sequential Sonogashira coupling of 6-cyanoumbelliferone triflate and annulations with amines

Palladium-catalyzed synthesis of 2H-pyrano[2,3-g]isoquinolinones have been described from easily accessible precursor 6-cyanoumbelliferone triflate via sequential of Sonogashira coupling and the following annulations with several primary alkylamines under basic conditions The so obtained 6-propargylamino-2H-pyrano[2,3-g]isoquinolinones were involved in the CuAAC reaction with 2-azidobenzoic acid for obtaining 2H-pyrano[2,3-g]isoquinoline-benzoic acid hybrid compounds containing a 1,2,3-triazole linker.     

Synthesis of homo-propargylic ethers: A domino ring opening/coupling reaction of oxiranes with terminal alkynes and aryl iodides

A domino ring opening/cross-coupling reaction of oxiranes with terminal alkynes and aryl iodides has been developed. This transformation serves as a protocol for the synthesis of homo-alkyne ether skeletons from the readily available starting materials. The success of the reaction has dependence on catalyst/ligand system of choice. The synthesis utility of the alkyne ether skeletons in formation of chromane skeleton has also been studied.     

Pd-catalyzed copper-free carbonylative Sonogashira reaction of aryl iodides with alkynes for the synthesis of alkynyl ketones and flavones by using water as a solvent

The Pd-catalyzed copper-free carbonylative Sonogashira coupling reaction to synthesize alkynyl ketones from terminal alkynes and aryl iodides was achieved by using water as a solvent. The reaction was carried out at room temperature under balloon pressure of CO with Et(3)N as a base. The developed method was successfully applied to the synthesis of flavones.     

Pd-catalyzed regiocontrolled Sonogashira and Suzuki cross-coupling reaction of 3,6-dihalogenoimidazo[1,2-a]pyridines: one-pot double-coupling approach

New and efficient regioselective Sonogashira and Suzuki-Miyaura palladium-catalyzed coupling reactions of 3,6-dihalogenoimidazo[1,2-a]pyridines followed by another cross-coupling has been successfully developed. Various solvents, palladium species and bases were tested. Scope and limitations of this regiocontrolled palladium-catalyzed reaction were investigated. The synthesis of 3,6-disubstituted imidazo[1,2-a]pyridine derivatives using one-pot regioselective double-coupling approach was developed. This procedure affords convergent syntheses of polysubstituted compounds in high yields in a very few steps.