An approach for quinolines via palladium-catalyzed Heck coupling followed by cyclization

2-Iodoaniline reacts with α,β-unsaturated carbonyl compounds in DMF at 100 °C in the presence of a catalytic amount of a palladium catalyst along with a base to afford the corresponding quinolones or quinolines in moderate to good yields.     

Synthesis of indolequinones via a Sonogashira coupling/cyclization cascade reaction

A mild strategy for constructing indolequinone motifs is described on the basis of the Sonogashira reaction and a copper-catalyzed intramolecular cyclization cascade reaction. The first step involves the palladium- and copper-catalyzed reaction between halogenated naphthoquinone and terminal acetylene to generate a coupling product, which then reacts in a copper-catalyzed intramolecular cyclization with the nitrogen functional group adjacent to the carbon-carbon triple bond.     

Cross-linked polymer supported palladium catalyzed carbonylative Sonogashira coupling reaction in water

A cross-linked polymer-supported ionic liquid immobilized palladium catalyst, which is prepared by reaction of the Pd(OAc)₂ with copolymer of 3-butyl-1-vinylimidazolium iodide and divinylbenzene, was well characterized and employed as an effective heterogeneous catalyst for carbonylative Sonogashira coupling reaction of aryl iodides with terminal alkynes in water, affording the corresponding α,β-alkynyl ketones in good to excellent yields. The catalytic system not only solves the basic problem of homogeneous palladium catalyst recovery and reuse but also avoids the use of toxic phosphine ligands. The stability of supported palladium was also discussed.     

Synthesis of new 2-substituted pyrazolo[5,1-b][1,3]oxazoles via Sonogashira coupling reactions in water

New 2-substituted pyrazolo[5,1-b][1,3]oxazoles are synthesized through the Sonogashira coupling reaction of 2-iodomethyl-6-methylpyrazolo[5,1-b][1,3]oxazole with terminal alkynes in the presence of a palladium catalyst. This process is carried out in the absence of any copper salt, and provides an eco-friendly and efficient method for the synthesis of the products in water in good-to-high yields. Some of the compounds synthesized were screened for their in vitro anti-oxidant activity using the DPPH (2,2-diphenyl-2-picrylhydrazyl) assays.     

Regioselective synthesis of substituted pyrrolopyridines based on Pd(II)-mediated cross coupling and base induced heteroannulation

Novel pyrrolopyridines have been synthesized by an efficient, regioselective and catalytic method from commercially available and inexpensive 3-aminopyridine or 2-aminopyridine.     

Facile synthesis of palladium nanoclusters and their catalytic activity in Sonogashira coupling reactions

This work reports a facile synthesis of palladium nanoclusters (PdNCs) in MeCN/MeOH mixture without any stabilizer. The PdNCs were found to be effective catalysts for copper-free, amine-free and ligand-free Songashira coupling reactions under ambient conditions.     

Heterogeneous copper-free Sonogashira coupling reaction catalyzed by a reusable palladium Schiff base complex in water

Heterogeneous Sonogashira coupling of terminal alkynes with aryl halides was studied over a polymer-supported macrocyclic Schiff base palladium complex. The cross-coupling reaction proceeded smoothly by adding a piperidine in water medium. The catalyst exhibited effective catalytic activities to afford the corresponding products in good to excellent yields under copper-free conditions. Furthermore, the catalyst could be easily recovered and reused for several times without a significant loss of its activity.     

Copper-free Sonogashira reaction using 7-chloro camptothecins

We studied copper-free Sonogashira reaction using 7-chloro camptothecins, and determined that rac-BINAP/Pd(OAc)₂ was an efficient catalyst for the coupling reaction. With this process, a number of 7-substituted camptothecins with a wide range of functional groups are potentially accessible. Besides, two drugs, SN-38 and BNP-1350, could be prepared by this method.     

Microwave-enhanced Sonogashira coupling reaction of substituted pyrimidinones and pyrimidine nucleosides

Direct microwave-enhanced Sonogashira coupling of several pyrimidinones and uridine with alkynes, PdCl₂(PPh₃)₂, Et₃N and CuI to give the corresponding 5-alkynyl derivatives is described.     

Palladium-catalyzed cyclization of vinyl iodide-tethered allensulfonamide

This Letter describes a palladium-catalyzed cyclization of vinyl iodide-tethered allensulfonamide in the presence of alkylol, which provides a facile access to 2-alkoxy-3-methylene-tetrahydropyridine. The asymmetric version of this reaction has also been preliminarily realized with up to 81% enantioselectivity when chiral bisphosphine ligands were used.     

A copper- and amine-free Sonogashira coupling reaction promoted by a ferrocene-based phosphinimine-phosphine ligand at low catalyst loading

A palladium(II) complex containing a ferrocene-based phosphinimine-phosphine ligand was applied to the amine- and copper-free Sonogashira coupling of aryl iodides and aryl bromides with terminal alkynes using 1 equiv of tetrabutylammonium acetate as an activator. The corresponding disubstituted alkynes were obtained in high yields and TONs using 0.1 mol % Pd-catalyst.     

The first palladium-catalyzed Sonogashira coupling of unactivated secondary alkyl bromides

A palladium-carbene catalyzed Sonogashira coupling of unactivated alkyl bromides with alkyl substituted alkynes is reported. For the first time, unactivated secondary alkyl halides were successfully employed in Sonogashira reactions.     

Copper-free Sonogashira coupling in amine-water solvent mixtures

Extensive study of different amine-water solvent mixtures was carried out for copper free Sonogashira coupling of aryl iodides. The influence of the palladium sources, ligands, amine-water ratio and further additives was also evaluated. Application of sec-butylamine-water mixture proved to be an excellent medium for rapid and efficient coupling of aryl-iodides at ambient temperature in the presence of PdCl₂(PPh₃)₂ as catalyst.     

Recyclable heterogeneous palladium-catalyzed carbonylative Sonogashira coupling under CO gas-free conditions

Abstract

A convenient, efficient and practical heterogeneous palladium-catalyzed carbonylative Sonogashira coupling of aryl iodides with terminal alkynes under CO gas-free conditions has been developed by using an MCM-41-supported bidentate phosphine palladium acetate complex as catalyst. Here, formic acid was used as the CO source with dicyclohexylcarbodiimide (DCC) as the activator and a wide variety of alkynyl ketones were generated in moderate to high yields. This heterogeneous palladium catalyst can be easily recovered via a simple filtration process and recycled up to 8 times without apparent loss of activity.     

A new strategy for the synthesis of coumarin- and quinolone-annulated pyrroles via Pd(0) mediated cross-coupling followed by Cu(I) catalyzed heteroannulation

The sequential coupling and cyclization reactions between aryl halides and (trimethylsilyl)acetylene (TMSA) with concurrent elimination of the TMS substituent, allows a straightforward synthesis of substituted pyrano[3,2-e]indolone and pyrrolo[3,2-f]quinolone derivatives in excellent yields.     

New nonlinear optical polyurethanes with adjusted subtle structure through Sonogashira coupling reaction

In this paper, four new nonlinear optical (NLO) polyurethanes ( P1 – P4 ) were designed and synthesized, and according to the concept of “suitable isolation group,” the subtle structure of the obtained polymers were modified by the introduction of isolation groups in different sizes to adjust their properties via Sonogashira coupling reaction. All the polymers were well characterized and the second harmonic generation (SHG) experiment results demonstrated that BOP groups were the suitable isolation groups in this system, and the corresponding polymer P2 exhibited a larger d₃₃ value than other polymers. Thus, the obtained results further confirmed our original idea and were consistent with the concept of “suitable isolation group.” Copyright © 2009 John Wiley & Sons, Ltd.     

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.     

有机高分子负载的Sonogashira反应的研究进展

综述了有机高分子负载钯催化剂或反应底物的Sonogashira反应的研究进展;天然高分子壳聚糖负载钯(CS-Pd)作为非均相催化剂,表现出较高的催化活性,可以实现无碱水相反应,正被人们广泛关注.     

Development of environmental friendly synthetic strategies for Sonogashira cross coupling reaction: An update

Sonogashira cross coupling is a well-known reaction for the formation of carbon–carbon bond. It involves the coupling of aryl halides with terminal alkynes to synthesize versatile functionalized alkyne scaffolds having diverse applications. Many of the natural products and important pharmaceutical drugs can be obtained through this reaction. In this regard, hectic progress has been put by the synthetic chemists to make this cross coupling more effective. This review article discloses mild and environmental friendly reaction conditions of Sonogashira cross coupling developed during 2013–2018.