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In this project, para‐carboxamidostilbene derivatives were synthesized using the Heck coupling reaction, confirmed through various analytical techniques such as FT‐IR, HRMS, and NMR analyses, and tested in vitro to evaluate their α‐amylase inhibitory activity. In silico molecular docking was employed to model the binding interactions of compounds with α‐amylase. Pharmacokinetic properties (ADME) and drug‐likeness were also examined. Structure activity relationship (SAR) analysis was conducted to establish the relationship between the chemical structure and α‐amylase inhibitory activity. The synthesized compounds exhibited significant α‐amylase inhibitory activity with IC50 values ranging from 15.0 to 37.5 µM in comparison with acarbose (IC50 = 30.2 ± 1.9 µM). Among them, compounds 6d–6f and 7c–7f demonstrated promising inhibitory activity. Furthermore, molecular docking studies revealed strong interactions between the studied molecules and the α‐amylase binding pocket. The drug‐likeness prediction results indicated that all synthesized compounds adhered to Lipinski's rule of five, suggesting their suitability as drug‐like molecules. Additionally, the assessment of ADMET properties indicated favorable absorption profiles, particularly in terms of human intestinal absorption (HIA). Overall, this study successfully identified several para‐carboxamidostilbene derivatives as potential α‐amylase inhibitors for the treatment of T2DM. [ABSTRACT FROM AUTHOR]

The key skeleton that could allow to access structurally intriguing mohangic acids A−E has been synthesized in stereoselective manner. The salient features of this synthesis include Evans syn‐aldol reaction to construct the C‐11 and C‐12 centers, HWE olefination to construct C14−C15 bond, Evans asymmetric methylation to install C‐14 center and Crimmins acetate aldol to generate C‐15 center whereas Wittig and Takai olefinations to prepare the C8–C9 & C6–C7 alkenes, respectively, and Heck reaction to couple C1–C5 & C6–C17 segments of the molecules. The developed route is highly modular and useful for accessing diverse natural product like molecules for future investigations. [ABSTRACT FROM AUTHOR]

A novel protocol facilitated by Na2SO3 that enhances the efficiency of palladium-catalyzed Heck coupling and the homo-coupling reactions of arylhydrazines. This innovative method enables the effective construction of a diverse array of cinnamate derivatives and biphenyl compounds. Notably, these transformative reactions proceed smoothly at room temperature, leveraging the activation of C-N bonds. This technique not only streamlines the synthesis process but also expands our understanding and expertise in the realm of coupling reactions. [ABSTRACT FROM AUTHOR]

Herein we report the use of a supported Pd3P catalyst for Heck coupling reactions. For the stabilisation of Pd3P and Pd, as reference system, the silica support material was modified via phosphorus doping (0.5 and 1 wt % P). Through this so‐called support engineering approach, the catalytic activity of Pd3P was clearly enhanced. Whereas an iodobenzene conversion of 79 % was witnessed for Pd3P@SiO2 in the coupling of styrene and iodobenzene in 1 h, 90 % conversion could be achieved using Pd3P@1P‐SiO2. This improved catalytic activity probably stems from an electronic modulation of the support surface via the introduction of phosphorus. Simultaneously, the recyclability was boosted and the Pd3P@1P‐SiO2 catalyst has shown to maintain its catalytic activity over several recovery tests. Hereby, metal leaching could almost be suppressed completely to 3 % by the use of a P‐modified silica support. [ABSTRACT FROM AUTHOR]

Due to the recent emergence of drug-resistance of antidiabetic drugs and the increase in the number of diabetes cases around the world, the search for and discovery of more effective a-amylase inhibitors is of great interest. In the present study, a new series of eighteen ortho-carboxamidostilbene derivatives were synthesized via Heck coupling reaction. The structures of the synthesized compounds were identified by various spectroscopic techniques, including HREIMS, FTIR and 1D-NMR. In addition, the compounds were evaluated in vitro for their potential a-amylase inhibitory potency using acarbose as the reference drug. Compounds 5e, 5f and 6e showed remarkably moderate to good inhibitory activity with IC50 values ranging from 13.3 - 28.2 µM. These compounds showed potent IC50 values compared to the reference drug acarbose (IC50 = 30.2 ± 0.1 µM). The in silico molecular docking studies revealed the binding interactions of the most active ortho-carboxamidostilbene derivatives (5e and 6e) with binding energies of -8.7 ± 0.0 and -8.6 ± 0.2 kcal/mol, respectively. Based on the structure-activity relationship (SAR) analysis, it was established that variations in the inhibitory activities of a-amylase enzymes were attributed to distinct types of substituents at the amide group of the aryl ring A along with the number and position of methoxy groups attached to the aryl ring B. These findings highlight the a-amylase inhibitory properties of orthocarboxamidostilbene containing cyclohexane and phenyl moieties, serving as potential lead compounds in antidiabetic drug development for the treatment of type II diabetes mellitus. [ABSTRACT FROM AUTHOR]

Asymmetric total synthesis of (2 E)-macrolactin 3 has been accomplished in a highly convergent manner utilizing our earlier developed tandem isomerization followed by C–O and C–C bond-forming reaction, Sharpless asymmetric dihydroxylation, and a late-stage intramolecular Heck coupling reaction. Comparison of the NMR spectra of the coupled product and thorough analysis of the 2D NMR data of the final compound led to the conclusion that the Z -double bond at C2 was isomerized during the coupling reaction. [ABSTRACT FROM AUTHOR]

In the present work, quinoxaline‐bridged bis(benzimidazolium) salts were prepared by the reaction of 2,3‐bis(bromomethyl) quinoxaline and 1‐substituted benzimidazole. The structures of the bis(benzimidazolium) salts were characterized by NMR, FT‐IR, and elemental analysis techniques. Also, the photophysical properties of salts were investigated by UV–Vis absorption and fluorescence emission spectroscopy. Next, these quinoxaline bridged bis(benzimidazolium) salts were used as bidentate benzimidazol‐2‐ylidene ligand precursors in the palladium‐catalyzed Suzuki‐Miyaura and Mizoroki‐Heck cross‐couplings. These salts exhibited moderate‐to‐high activity in the palladium‐catalyzed cross‐coupling reactions. [ABSTRACT FROM AUTHOR]

The palladium incorporated amine-functionalized dendronized polymer was synthesized by the addition of palladium acetate to dendronized polymer in methanol at room temperature. Palladium species are immobilized onto the dendritic structure by their coordination with amino functional groups. The newly developed dendritic system showed high palladium content in the low generation level itself, which was found to be 4.19 mmol/g. This was fairly higher than, the other palladium-based catalysts. Energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, UV–Visible spectroscopy, and X-ray photoelectron spectroscopy were used to confirm the successful synthesis of the new catalyst. It was used as a homogeneous palladium catalyst for Heck coupling reaction between olefins and differently substituted aryl halides and the products were isolated in high yield. The products isolated were in trans configuration, which indicated the selectivity of the newly developed catalytic system. Also, this catalyst system was reused up to nine times without a significant decrease in its catalytic activity. The easy accessibility of catalytic sites, stability, resistance to metal leaching, high catalytic activity and remarkable stereoselectivity with a low amount of catalyst are all due to the dendritic support. The docking study was carried out for all the stilbene derivatives obtained by the Heck coupling reaction against DprE1 protein to study its potential antitubercular activity. All the compounds displayed superior docking score values over the range − 6.5 to − 8.2 kcal/mol, compared to the standard drug isoniazid with docking score of − 6.1 kcal/mol against DprE1. [ABSTRACT FROM AUTHOR]

Addressed herein is the effective catalytic performance of palladium nanoparticles supported on mesoporous graphitic carbon nitride (mpg-CN/Pd) for the Heck coupling reaction of alkenes with various aryl halides. The presented catalytic C–C bond formation reaction was carried out in a high-pressure glass tube for 4 hours in an aqueous solution EtOH/H2O (v/v 2/1). The corresponding alkene products were obtained in relatively high yields as E-selective under the optimized conditions. The catalyst's utility in the Suzuki cross-coupling reaction was also investigated under almost identical conditions. Moreover, these reactions proceeded smoothly with both electron-rich and electron-deficient aryl iodides and aryl bromides. The nanocatalyst can be recovered from the reaction medium by centrifugation. It can be reused by preserving approximately 92% of its initial catalytic activity after the five consecutive reactions. [ABSTRACT FROM AUTHOR]

Aromatic triangular tri‐palladium cations 1–3, abbreviated as [Pd3]+, have shown interesting photoelectric properties, Lewis basic character, and excellent activities in catalytic hydrogenation. Herein, we report the highly efficient and C−I selective Sonogashira and Heck coupling reactions catalyzed by these tri‐palladium complexes. Benefiting from the moderate C−I bond association energy, these tri‐palladiums presented exclusive reactivities to aryl iodides over the brominated aromatics in coupling reactions. In the Sonogashira pathway, good to excellent isolated yields (71–95 %) were achieved. Gram‐scale reaction reached 93 % of yield with palladium loading as few as 0.06 mol %. We also explored the electronic and steric effects for phenyl alkynes and aryl iodides including heteroaromatics like thiophene, pyridine, pyrazole, and pyrazine. Similarly, yields of 71–96 % were obtained for palladium loading of 1.5 mol% through catalyzed Heck coupling of aryl iodides and alkenes. The HRMS monitoring revealed that [Pd3]+ maintained as whole entity during the catalytic process due to its robusness. [ABSTRACT FROM AUTHOR]

In this report, chitin and chitosan nanocrystals were used as biomass-based supports for Pd nanoparticles (NPs) used as a heterogeneous catalyst for the Heck coupling reaction. By using a one-pot fabrication method, a Pd salt precursor was directly reduced and deposited onto these nanocrystal catalysts. Characterization of these nanocomposites showed disperse Pd NPs on the surfaces of the chitinous nanocrystals. Heck coupling model reactions revealed full product yield in relatively benign conditions, outcompeting the use of other catalysts supported on biomass-based nanomaterials, including cellulose nanocrystals. These initial results show the potential for using chitinous nanomaterials as effective catalyst supports in cross-coupling reactions.

Heck reaction is a synthetically important C−C bond forming coupling reaction happening between alkenes and aryl or vinyl halides catalyzed by palladium complexes to form substituted alkenes. This review focusses on the recent advancements in the development of various types of N‐heterocyclic carbene (NHC) ligands coupled with palladium catalyst that can catalyze Mizoroki‐Heck reactions. NHC ligands have unique characteristic nature, and hence widely used in homogeneous catalysis. Generally, they have good σ‐donating and sparingly π‐accepting properties. It is more stable and shows superior π‐accepting properties when compared to phosphine ligands that is under prominent studies. Thus, they can stabilize large extend of metal oxidation states and have high thermal stability. Most of the catalysts outlined here provide efficient and green synthetic route for the development of C−C coupled bond formations. The review encompasses literature from 2017 to 2021. [ABSTRACT FROM AUTHOR]

An efficient, one-pot, domino synthesis of quinolines via the coupling of iodoanilines with allylic alcohols facilitated by palladium catalysis is described. The overall synthetic process involves an intermolecular Heck coupling between 2-iodoanilines and allylic alcohols, intramolecular condensation of in situ generated ketones with an internal amine functional group, and a dehydrogenation sequence. Notably, this protocol occurs in water as a green solvent. Significantly, the method exhibits broad substrate scope and is applied for the synthesis of deuterated quinolines through a deuterium-exchange process. [ABSTRACT FROM AUTHOR]

A highly stereoselective Pd‐catalyzed Heck‐type reaction of allenes in which the stereochemistry of both olefins is set simultaneously was developed. The ligand CyJohnPhos was crucial to achieving stereoselectivity, while minimizing isomerization of the starting material through hydropalladation. The stereodetermining factors were proposed to be A1,3 strain between the catalyst and allene substituent, which influences the σ‐π‐σ equilibrium of the coupled allene intermediate, as well as eclipsing interactions of R groups in the β‐hydride elimination. Good functional group tolerance and stereoselectivities for formation of the Z,E isomer were demonstrated. The methodology was further expanded to include the regioselective formation of 2,4‐dienoates and 2,4‐dienamides with a variety of substitution patterns, albeit in reduced stereoselectivities favoring the E,E isomer. A plausible mechanism is proposed to account for the observed selectivities and substituent effects. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of alkyl benzoyl indanones via a simple intermolecular Heck coupling followed by intramolecular condensation, and alkylation is presented. Notably, the strategy exhibited good substrate scope and enabled the synthesis of diverse alkyl substituted 1,3‐dicarbonyl products. Significantly, this protocol was successful using a single‐column purification technique. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new palladium(II) immobilized MCM-41 based catalyst Pd(II)-L 1 –S. • propylsilyl@MCM-41 (Pd(II)-MS2) was prepared an amide-based ligand (L 1). • The synthesized mesoporous material Pd(II)-MS2 was used as an efficient and recyclable heterogeneous catalyst for Suzuki-Miyaura and Heck coupling reaction under mild reaction conditions. • The catalyst Pd(II)-MS2 can be easily separated from the reaction mixture by simple filtration and efficiently reused up to seven consecutive catalytic cycles for both Suzuki and Heck coupling reactions without loss of catalytic activity. • The synthesized catalyst Pd(II)-MS2 shows excellent catalytic activity even for less reactive aryl chlorides with a decent substrate conversion up to 73–100% yield. A new palladium(II) immobilized MCM-41 based catalyst Pd(II)-MS2 was prepared via a facile and straightforward post-modification method. Initially, 3-(trimethoxysilyl)propane-1-thiol was incorporated into the mesoporous matrix MCM-41 to produce SH-propylsilyl@MCM-41 (MS1), which on treatment with an amide-based ligand (L1) yielded a periodic mesoporous silica material L1-S-propylsilyl@MCM-41(MS2) having suitable binding sites where Pd(II) ion can easily accumulate. The resulting material MS2 on treatment with Pd(OAc) 2 produces the desired mesoporous material Pd(II)-L1-S-propylsilyl@MCM-41 (Pd(II)-MS2) under reflux reaction condition in MeCN. The synthesized mesoporous materials were successfully characterized by various spectroscopic techniques and analyses such as FT-IR, TGA, XPS, TEM, UV–Vis, PXRD, ICP, N 2 adsorption–desorption isotherm. The synthesized mesoporous material Pd(II)-MS2 was used as an efficient and recyclable solid catalyst for Suzuki-Miyaura and Heck coupling reaction under mild reaction conditions. Further, the resulting catalyst can be easily separated from the reaction mixture by simple filtration and efficiently reused up to seven consecutive catalytic cycles for both Suzuki and Heck coupling reactions without loss of catalytic activity. Importantly, synthesized catalyst Pd(II)-MS2 shows excellent catalytic activity even for less reactive aryl chlorides with a decent substrate conversion up to 73–100% yield. [ABSTRACT FROM AUTHOR]

The Pd nanoparticles generated in situ from Pd–pincer complexes catalyzed Heck coupling reaction. For this purpose, new Pd(II)–ONO pincer complexes (1–4) containing acylthiourea ancillary ligand were obtained by treating [Pd(ONO)(CH3CN)] with the respective N-substituted carbamothioyl benzamide ligand (L1–L4). Formation of these complexes was confirmed by UV–Visible, FT-IR, NMR and mass spectroscopic techniques. The sizes of in situ formed Pd nanoparticles were greatly affected by the substituent in ancillary ligand, which in turn influenced their catalytic activity towards Heck coupling reaction. The in situ formed Pd nanoparticles during Heck reaction were removed from the reaction medium and analyzed using HR-TEM to estimate the sizes of the Pd nanoparticles. Complex [Pd(ONO)((N-benzylcarbamothioyl)benzamide)] (1) which does not possess any substituent on the benzyl moiety of acylthiourea produced the smallest Pd nanoparticles with the average particle size of 3.7 nm. Hence, complex 1 showed the utmost catalytic activity. With complex 1, 51–99% of conversion was observed during Heck coupling reaction of styrene with various aryl halides. XPS results confirmed that the recovered black particles were Pd(0). A reasonable recyclability results were achieved by these in situ generated Pd nanoparticles. [ABSTRACT FROM AUTHOR]

Palladium catalysts, obtained by the impregnation of Pd(OAc)2 on aminopropyl‐ or pyridine‐functionalized polysiloxane microspheres, were used in the Heck reaction of iodobenzene with 3‐buten‐2‐one and 3‐buten‐2‐ol at 120°C using an oil bath or microwave heating. The synthesis of 4‐phenyl‐3‐buten‐2‐one was one‐step arylation of ketone while 4‐phenyl‐2‐butanone was formed in two‐step arylation–isomerization sequential transformation of alcohol. A very low palladium loading, 0.05 mol%, was sufficient to obtain a yield of ketones higher than 90%. In recycling experiments, an effect of the functional group present in polysiloxane was observed and much better results were obtained for the aminopropyl‐modified polymer. The catalyst was easily retrieved and reused in eight consecutive runs in the reaction of 3‐buten‐2‐one, while with 3‐buten‐2‐ol 11 subsequent cycles were performed with practically the same yield. [ABSTRACT FROM AUTHOR]

A new and practical method for the preparation of high molecular weight polycinnamamides has been developed through a heterogeneous palladium-catalyzed Heck coupling polycondensation of bis(acrylamide)s with aromatic diiodides. The polymerization proceeded smoothly in DMF at 100 °C in the presence of a magnetic nanoparticles-anchored bidentate phosphine-palladium(II) acetate complex [Fe3O4@SiO2-2P-Pd(OAc)2] and tributylamine, yielding a series of polycinnamamides with inherent viscosities up to 0.89 dL/g and a low level of palladium residue (below 10 ppm). The polycinnamamides obtained were quite soluble in dipolar aprotic solvents and had glass transition temperatures ranging from 221 to 269 °C and 10% weight loss temperatures ranging from 437 to 458 °C in nitrogen. These polymers could afford transparent and tough films by solution-casting with tensile strengths of 59.6–82.8 MPa, tensile moduli of 1.78–2.12 GPa, and elongations at break of 7.5–12.5%. The Fe3O4@SiO2-2P-Pd(OAc)2 catalyst can be conveniently separated from the polymer and recovered by simply using an external magnetic field, and recycled at least eight times without apparent decrease in catalytic efficiency. [ABSTRACT FROM AUTHOR]

Carbon-carbon cross-coupling reactions are among the most important synthetic tools for the preparation of pharmaceuticals and bioactive compounds. However, these reactions are normally carried out using copper, phosphines, and/or amines, which are poisonous for pharmaceuticals. The use of nanocomposite catalysts holds promise for facilitating these reactions and making them more environmentally friendly. In the present work, the PEGylated (PEG stands for poly(ethylene glycol) pyridylphenylene dendrons immobilized on silica loaded with magnetic nanoparticles have been successfully employed for the stabilization of Pd2+ complexes and Pd nanoparticles. The catalyst developed showed excellent catalytic activity in copper-free Sonogashira and Heck cross-coupling reactions. The reactions proceeded smoothly in green solvents at low palladium loading, resulting in high yields of cross-coupling products (from 80% to 97%) within short reaction times. The presence of magnetic nanoparticles allows easy magnetic separation for repeated use without a noticeable decrease of catalytic activity due to the strong stabilization of Pd species by rigid and bulky dendritic ligands. The PEG dendron periphery makes the catalyst hydrophilic and better suited for green solvents. The minor drop in activity upon the catalyst reuse is explained by the formation of Pd nanoparticles from the Pd2+ species during the catalytic reaction. The magnetic separation and reuse of the nanocomposite catalyst reduces the cost of target products as well as energy and material consumption and diminishes residual contamination by the catalyst. These factors as well as the absence of copper in the catalyst makeup pave the way for future applications of such catalysts in cross-coupling reactions.

The aim of the present work is the synthesis and characterization of new perfluorinated monomers bearing, similarly to Nafion®, acidic groups for proton transport for potential and future applications in proton exchange membrane (PEM) fuel cells. To this end, we focused our attention on the synthesis of various molecules with (i) sufficient volatility to be used in vacuum polymerization techniques (e.g., PECVD)), (ii) sulfonic, phosphonic, or carboxylic acid functionalities for proton transport capacity of the resulting membrane, (iii) both aliphatic and aromatic perfluorinated tags to diversify the membrane polarity with respect to Nafion®, and (iv) a double bond to facilitate the polymerization under vacuum giving a preferential way for the chain growth of the polymer. A retrosynthetic approach persuaded us to attempt three main synthetic strategies: (a) organometallic Heck-type cross-coupling, (b) nucleophilic displacement, and (c) Wittig–Horner reaction (carbanion approach). Preliminary results on the plasma deposition of a polymeric film are also presented. The variation of plasma conditions allowed us to point out that the film prepared in the mildest settings (20 W) shows the maximum monomer retention in its structure. In this condition, plasma polymerization likely occurs mainly by rupture of the π bond in the monomer molecule.

Sclareol, a bioactive diterpene alcohol isolated from Salvia sclarea , was subjected to structural modification and cytotoxic evaluation. Boron-Heck-coupled analogs of manoyl oxide were prepared from sclareol in a two-step reaction scheme. In the first step manoyl oxide was prepared from sclareol using cerium (IV) ammonium nitrate. Further the structural modification of manoyl oxide via Palladium (II) catalysed Boron-Heck coupling reaction produced a new series of compounds. All the synthesised compounds were screened for in vitro cytotoxic evaluation against four cancer cell lines HCT-116, MCF-7, MDA-MB231and MDA-MB468. The results showed that manoyl oxide is less active than sclareol. Sclareol shows an IC 50 of 2.0 µM compared to manoyl oxide with an IC 50 of 50 µM against the MCF-7 cell line. From the results it was inferred that the presence of two tertiary hydroxyls in sclareol are necessary for its cytotoxic activity and Heck coupled analogs are more active than sclareol and manoyl oxide.

This work reports an efficient approach for the fabrication of novel nitrogen‐doped hierarchical porous carbon (NHPC) and its application as support for Ni−Pd NPs immobilization and then its catalytic performance toward Heck reaction and sequential one‐pot cross coupling‐nitro reduction. Herein, NHPC has been synthesized via the in situ polymerization of pyrrole onto the Luffa sponge surface as a cost‐effective, green and biological template and a carbonization process. The high nitrogen content (7.24 wt%) and hierarchical porous structure of NHPC resulted in well dispersion of Ni−Pd NPs onto the surface and remarkable stability of them during the reactions. Also, the combination of Ni and Pd NPs with the Ni: Pd ratio of 70:30 exhibited high catalytic activity in the Heck coupling and one‐pot sequential coupling‐nitro reduction. Furthermore, the prepared support and catalyst were studied by FT‐IR, composition and elemental analysis, X‐ray diffraction (XRD), Raman, Field emission scanning electron microscopy and elemental (FESEM), mapping, High‐resolution transmission electron microscopy (HRTEM), ICP‐AES, N2 adsorption‐desorption, Diffuse reflectance spectra (DRS/UV), zeta potential and X‐ray photoelectron spectroscopy (XPS) techniques. [ABSTRACT FROM AUTHOR]

A smart strategy for the synthesis of hierarchical CoAl-LDH hollow spheres assembled with nitrogen and sulfur co-doped graphene for high holding of palladium nanoparticles (CoAl-LDH@N,S-G@Pd) is reported. This architecture exhibited excellent activity in Heck reactions with TOF as high as 1633 h−1 due to a strong metal–support interaction, good electron transfers and high surface area. [ABSTRACT FROM AUTHOR]

We have synthesized palladium nanoparticles supported iron oxide catalyst by controlled deposition of palladium in presence of triethanolamine and polyvinylpyrrolidone (PVP), where triethanolamine act as mild reducing agent and PVP act as capping agent. Prepared (0.9% Pd‐Fe2O3CD) catalyst showed high activity towards Heck coupling reaction, under mild reaction conditions. Different analytical techniques were systematically employed to characterize the prepared material in order to find the specific surface area, Pd loading, crystal structure, surface morphology, particle size, reducibility behavior, surface chemical state, phase purity and crystallinity, optical property and local environment of active species etc. 0.9% Pd‐Fe2O3CD catalyst showed high activity toward Heck coupling with iodo‐derivatives at room temperature in solvent‐free reaction conditions and prevented the leaching of active species, during catalysis. The catalyst possessed strong metal‐support interaction due to smaller Pd nanoparticles (2‐12 nm) and maintained its heterogeneous nature during recycling experiments. [ABSTRACT FROM AUTHOR]

A novel synthetic route to CSF1R inhibitor pexidartinib was designed and demonstrated. Crucial to the successful synthesis is a tandem Tsuji–Trost reaction and Heck coupling in combination with palladium and silver catalysis. The final product was obtained via five steps in 49% yield with purity as high as 99.2%. The cheap and available materials and reagents and easy operations for workup and purification make this route more practical. [ABSTRACT FROM AUTHOR]

In this study, novel 4-phenoxybutyl-substituted benzimidazolium salts as Nheterocyclic carbene (NHC) ligands were successfully synthesized and their structures characterized by ¹H NMR, 13C NMR, FT-IR, and elemental analysis techniques. The in situ formed catalytic system using the NHC ligands and Pd(OAc)2 was used in the Heck coupling reactions between aryl bromides and strene with potassium carbonate in water/DMF mixture. The corresponding coupling products were obtained in high yields. [ABSTRACT FROM AUTHOR]

Glucose stabilized palladium nanoparticles (PdNPs) have been prepared and the application of NPs in catalyzing both Suzuki and Heck reactions has been explored in aqueous media under microwave conditions. Both electron-rich and electron-deficient aryl halides can be coupled with a variety of boronic acids and styrene to access a wide variety of biaryl compounds and substituted alkenes in good to excellent yields. The catalyst can be recycled and reused four times with minimally affecting the morphology and efficiency of the nanoparticles. A plausible reaction mechanism has been proposed. [ABSTRACT FROM AUTHOR]

A palladium‐catalyzed coupling between aryl halides and monocyclopropanated pyrroles or furans has been developed, leading to valuable six‐membered N‐ and O‐heterocycles. As the key step, a selective cleavage of the non‐activated endocyclic C−C bond of the 2‐heterobicyclo‐[3.1.0]hexane framework is achieved. The developed method offers access to highly functionalized piperidines, pyridines, and pyrans that are challenging to access by traditional methods. Heck‐type arylation of cyclopropanated furans and pyrroles proceeds with ring expansion via the unactivated cyclopropyl bond, giving rise to arylated diyhdropyridines, pyridines, and 2H‐pyrans. [ABSTRACT FROM AUTHOR]

[Display omitted] • Designer surfactants with C8 to C18 chain length designed, synthesized & studied. • Relationship between product yield, surfactant hydrophobicity and CMC identified • Key Intra/Inter C C & C N bond forming reactions performed. Designer micellar medium was explored for the transformation of diverse anilines to the corresponding densely substituted biologically relevant skatole derivatives in an aqueous medium via 5-exo-trig cyclization reaction. The scope of the reaction was extended to intermolecular Csp2-Csp2 and Csp2-N bond forming reactions in water. Systematic investigations revealed that altering hydrophobicity of surfactant influences the yield of both C C and C N bond forming reactions in water. [ABSTRACT FROM AUTHOR]

The synthesis and evaluation of ten new dihydrophthalazine-appended 2,4-diaminopyrimidines as potential drugs to treat Bacillus anthracis is reported. An improved synthesis utilizing a new pincer catalyst, dichlorobis[1-(dicyclohexylphosphanyl)-piperidine]palladium(II), allows the final Heck coupling to be performed at 90 °C using triethylamine as the base. These milder conditions have been used to achieve improved yields for new and previously reported substrates with functional groups that degrade or react at the normal 140 °C reaction temperature. An analytical protocol for separating the S and R enantiomers of two of the most active compounds is also disclosed. Finally, the X-ray structure for the most active enantiomer of the lead compound, (S)-RAB1, is given.

The Pd‐II catalysed C−C bond formation Heck and Suzuki coupling reactions with moderate to excellent yields are reported, using curcumin as ligand, which is extracted from turmeric powder. The application of curcumin based [Pd(Curc‐H)2] catalyst in organic synthesis tested here, is the novelty of this protocol. This novel, highly efficient and simple protocol shows a broad substrate scope for aryl halides, substituted alkenes and phenyl boronic acid as coupling partners. The [Pd(Curc‐H)2] catalyst, synthesized from Pd(OAC)2 and naturally occuring curcumin (isolated from turmeric) as bidentate ligand, efficiently worked for C−C bond forming Heck and Suzuki couplings with moderate to excellent yields; where no requirement of inert atmosphere and cheaper ligand are the key feature of this protocol. [ABSTRACT FROM AUTHOR]

The development and optimization of synthetic methods leading to functionalized biologically active compounds is described. Two alternative pathways based on Heck-type reactions, employing iodobenzene or phenylboronic acid, were elaborated for the arylation of eugenol and estragole. Cinnamyl alcohol was efficiently transformed to saturated arylated aldehydes in reaction with iodobenzene using the tandem arylation/isomerization sequential process. The arylation of cinnamyl alcohol with phenylboronic acid mainly gave unsaturated alcohol, while the yield of saturated aldehyde was much lower. Catalytic reactions were carried out using simple, phosphine-free palladium precursors and water as a cosolvent, following green chemistry rules as much as possible. [ABSTRACT FROM AUTHOR]

Efficient Mizoroki-Heck couplings were obtained using a very easily synthesizable palladium(II) complex of hemilabile N-O ligand (picolinate), with high turnover frequencies up to >10,000 h−1, in just 15 min, with high selectivity of >99% to the desired products. Wide applicability of the simple-looking palladium complex catalyst was established with differently functionalized substrates. Catalyst screening studies revealed intricate details of dependence of catalyst performance on different reaction parameters and conditions and arriving at the optimized facile methodology. [ABSTRACT FROM AUTHOR]

Abstract: The Heck coupling of aryl halides and N-methoxy-N-methylacrylamide was investigated in the room-temperature ionic liquids [BMIM][PF6], [BMIM][Br], [BMIM][BF4], [BMIM][OH], [BMIM][HCOO], EAN, PAN, and ETAN. Excellent yields of the expected N-methoxy-N-methylcinnamamides (ca 90%) and purity (> 96%) were afforded on simple diethyl ether extraction from [BMIM][PF6] and [BMIM][OH]. The described procedure was highly substrate tolerant with methyl, methoxy, fluoro, trifluoromethyl, ester, cyano, hydroxy, naphthyl, and quinolone moieties well tolerated. Poor yields or no reactions were observed with -NH2 and -NO2 moieties. The use of microwave irradiation reduced reaction times from 3 h (thermal) to 5-15 min with no substantive effect on reaction outcome.Graphical abstract: [ABSTRACT FROM AUTHOR]

Heck arylation of 2,3-dihydrofuran with iodobenzene was carried out in systems consisting of different palladium precursors (Pd2(dba)3, Pd(acac)2, PdCl2(cod), [PdCl(allyl)]2, PdCl2(PhCN)2, PdCl2(PPh3)2) and ionic liquids (CILs) with L-prolinate or L-lactate anions. All the tested CILs caused remarkable increases of the conversion values and in all of the reactions 2-phenyl-2,3-dihydrofuran (3) was obtained as the main product with a yield of up to 59.2%. The highest conversions of iodobenzene were achieved for the [PdCl(allyl)]2 precursor. Formation of Pd(0) nanoparticles, representing the resting state of the catalyst, was evidenced by TEM.

[Display omitted] • High efficiency of simple palladium complexes in the Heck coupling of allylic alcohols with aryl iodides. • Promoting effect of ionic liquids as co-catalysts. • Efficient synthesis of saturated aryl ketones in the Heck coupling under 1 atm of H 2. Allylic alcohols, 1-buten-3-ol, 1-penten-3-ol and 1-octen-3-ol, reacted with aryl iodides (iodotoluene, 4-iodotoluene, 4-iodophenol and 4-iodanisole) under Heck reaction conditions to form corresponding saturated aryl ketones in one step. The same products were obtained in a two-step tandem reaction consisted of the Heck coupling of allylic alcohols with aryl iodides, followed by hydrogenation. Reactions were catalyzed by phosphorus-free palladium precursors modified with the menthol-substituted imidazolium chlorides. Formation of crystalline palladium nanoparticles, of the diameter up to 65 nm, in the reaction mixture was evidenced by TEM. [ABSTRACT FROM AUTHOR]

In situ-generated palladium nanoparticles (Pd NPs) using Triton X-100 non-ionic surfactant-catalyzed one-pot sequential Hiyama and Heck coupling reactions in water under aerobic conditions has been demonstrated. The reaction was highly efficient for the synthesis of symmetrical stillbenes utilizing arenediazonium salts and vinyl triethoxy silane. The in situ-generated Pd NPs were characterized by transmission electron microscopy analysis and had a size below 20 nm. The aqueous system containing the surfactant along with the Pd NPs was recycled five times, without significant loss of catalytic activity. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Mechanistic insights into Heck and Suzuki-Miyaura cross coupling reactions with C59M (M = Pd/Ni) catalysts were developed. Density functional theory was used for the analysis of all the intermediates and transition states possible during C-C cross coupling reactions over the catalysts under study. Oxidative addition, a step common to both Heck and Suzuki-Miyaura cross coupling reactions, was observed to proceed with smaller activation barriers over C59Pd. Heck coupling of iodobenzene with styrene was observed to proceed via oxidative addition, migratory insertion, and reductive elimination steps. The free energy barriers for oxidative addition, migratory insertion, and reductive elimination steps were 14.8, 11.6, and 4.8 kcal/mol, respectively, over C59Pd, and 17.4, 79.3, and 17.4 kcal/mol, respectively, over C59Ni, indicating oxidative addition and migratory insertion to be the rate-determining steps over C59Pd and C59Ni, respectively. Similarly for Suzuki-Miyaura coupling reaction, activation barriers for oxidative addition, transmetalation, and reductive elimination steps were 14.8, 52.4, and 7.9 kcal/mol, respectively, over C59Pd, and 17.4, 64.7, and 60.2 kcal/mol, respectively, over C59Ni, indicating transmetalation step to be the rate-determining step over both the heterofullerenes. [ABSTRACT FROM AUTHOR]

Abstract: An effective two‐step process for the synthesis of functionalized flavans is presented. The proposed route comprises one‐pot method involving Heck reaction with allylic alcohols and 2‐iodophenols followed by reduction. These diols upon treatment with the Lewis acid mediated intramolecular cyclization, under mild reaction conditions, afforded the flavans. [ABSTRACT FROM AUTHOR]

Pincer type aminomethylphosphine-Pd(II) complexes supported on multi-walled carbon nanotube (MWCNT) have been synthesized and characterized using X-Ray diffraction spectrometry, scanning electron microscopy, thermal analysis, energy dispersive X-Ray, Fourier transform infrared spectrometry, transmission electron microscopy (TEM) and ultraviolet-visible spectrometry techniques. The novel complexes were tried as catalysts in Heck C-C coupling reactions. The crystallite size and lattice strain of the MWCNT based compounds were calculated by the Scherrer's equation. The optical parameters of the MWCNT based structures were analyzed and the band gap enhanced from 4.42 to 4.98 eV. Different solvents (toluene, 1,4-diooxane, DMF and NMP) and bases (EtN, NaCO, NaOAc and KCO) were tried at different temperatures (80, 100 and 110 °C) in the cross-coupling of bromobenzene with styrene. The optimum yield was found in the presence of KCO, 110 °C in 1,4-dioxane solvent system. [ABSTRACT FROM AUTHOR]

Pd(0) nanoparticles ca. 2 nm in diameter were obtained by the reduction of PdCl 2 and Pd(OAc) 2 in water at 80 °C in the presence of a PVP-stabilizing polymer. Pd(0) NPs were successfully used in the Heck coupling of allyl alcohol with iodo- and bromobenzenes. Iodobenzenes reacted under solventless conditions or in DMF solution producing 3-arylpropanals and 2-arylpropanals as the main products. The same products were obtained in the reaction of bromobenzene in TBAB as the reaction medium. The stability of Pd(0) NPs was evidenced in recycling experiments. Similar Heck coupling results were also obtained with the palladium compounds PdCl 2 (cod) and Pd(OAc) 2 under the same conditions. [ABSTRACT FROM AUTHOR]

2-Hydroxyindan-1-ones have been efficiently synthesized and successfully applied as ligands in Pd-catalyzed Ullmann type, Suzuki-Miyaura, and Mizoroki-Heck cross-coupling reactions with aryl tosylates and aryl halides. The ligands are air-and moisture-stable and have shown high catalytic activity with Pd(OAc)2 in these cross-coupling reactions. The system tolerates a variety of functional groups in the product and can be re-used at least three times with maximum efficiency. [ABSTRACT FROM AUTHOR]

The use of 1,3-bis(N-heterocyclic)carbene ligands with different alkyl wingtip groups (alkyl = methyl, isopropyl and tert-butyl) is an effective method for the palladium-catalysed direct S-arylation of methylphenyl sulfoxide and C-C coupling of various of aryl halides with alkenes. The reactions proceed in moderate to good yields. Interestingly, it is shown experimentally that, by using bulkier bidentate N-heterocyclic carbene ligands, more selective catalytic systems towards cis products in Heck coupling reactions can be achieved. [ABSTRACT FROM AUTHOR]