Hiyama Reaction Research Articles

Frontispiece: Selective Coupling of β‐(Borylvinyl)silanes by a Gold‐Catalyzed Hiyama Reaction—An Easy Way to Diaryl‐Substituted Vinyl Boronates

Frontispiece: Selective Coupling of β‐(Borylvinyl)silanes by a Gold‐Catalyzed Hiyama Reaction—An Easy Way to Diaryl‐Substituted Vinyl Boronates

(NHC)Pd(allyl)Cl] Precatalysts in The Hiyama Reaction of Aryl Chlorides with Aryl Trimethoxysilanes: A Study in Side Reactions

(NHC)Pd(allyl)Cl] Precatalysts in The Hiyama Reaction of Aryl Chlorides with Aryl Trimethoxysilanes: A Study in Side Reactions

Aryltriazenes as Coupling Partners in the Hiyama, Hiyama‐Suzuki and Hiyama‐Heck Cross‐Coupling Reactions Using Conventional and Ionic Liquid Reagents and Solvents

AbstractApplication of conventional and ionic liquid (IL) solvents and reagents in the Hiyama cross‐coupling reactions using triazenes as coupling partners was investigated. The microwave‐assisted and Pd‐catalyzed reactions in ROH/HBF4, ROH/BF3 ⋅ Et2O and in [BMIM][X]/[BMIM(SO3H)][OTf]/[BMIM][F] proved effective and gave respectable isolated yields within minutes. The scope of the Hiyama coupling reaction with triazenes was investigated in these media. The IL reagents and solvents were successfully employed to develop stepwise and sequential/tandem Hiyama‐Suzuki (H−S) and Hiyama‐Heck (H−H) methods. Study of the scope of these transformations led to facile synthesis of libraries of biaryls, hetero‐biaryls, diphenylmethanes, styryl‐biphenyls, and a host of biphenyl‐appended heterocycles. The potential for the recycling/reuse of the IL solvents in the Hiyama reaction, and in stepwise and sequential transformations was also examined.

A Pd(II) Magnetically Retrievable Catalyst for Hiyama Reaction: Functionalization of Magnetic Mesoporous Silica via Click Reaction

A Pd(II) Magnetically Retrievable Catalyst for Hiyama Reaction: Functionalization of Magnetic Mesoporous Silica via Click Reaction

Palladium-catalyzed Hiyama cross-couplings of pyrimidin-2-yl tosylates with organosilanes

An efficient palladium-catalyzed Hiyama reaction between various pyrimidin-2-yl tosylates with organosilanes has been developed. The use of CuCl with TBAF as additive is essential for promotion of the construction of the carbon–carbon bond. This procedure shows wide functional group tolerance for electrophilic pyrimidin-2-yl tosylates and has been extended to aromatic amino-substituted pyrimidin-2-yl tosylates, affording the desired C2-aryl and alkenyl pyrimidine derivatives in good to excellent yields.

A Green Synthesis Strategy of Binuclear Catalyst for the C-C Cross-Coupling Reactions in the Aqueous Medium: Hiyama and Suzuki-Miyaura Reactions as Case Studies.

Cellulose, as a green and available phytochemical, was immobilized on the surface of magnetite nanoparticles then doped with imidazole and Co. complex (Fe3O4@CNF ∼ ImSBL ∼ Co.) and used as a water-dispersible, recyclable and efficient nano catalyst for the synthesis of C−C cross-coupling reactions including fluoride-free Hiyama and Suzuki reactions in an aqueous medium as an efficient and vital solvent, due to their high application and importance in various fields of science. Different spectroscopic and microscopic techniques were used for the catalyst characterization such XRD, FESEM, TEM, FT-IR, EDX, DLS, VSM, UV-Vis, and ICP analyses. The presence of imidazole as ionic section tags with hydrophilic character on the Co-complex supported on magnetic nanoparticles provides dispersion of the catalyst particles in water, which leads to both higher catalytic performance and also facile catalyst recovery and reuse six times by successive extraction and final magnetic separation. High catalytic activity was found for the catalyst and high to excellent efficiency was obtained for all Suzuki (80–98% yield; E factor: 1.1–1.9) and Hiyama (87–98% yield; E factor: 0.26–1.1) derivatives in short reaction times under mild reaction conditions in the absence of any hazardous or expensive materials. There is not any noticeable by-product found whether for Suzuki or Hiyama derivatives, which reflects the high selectivity and also the lower the E factor the more favorable is the process in view of green chemistry. The bi-aryls were achieved from the reaction of various aryl iodides/bromides and even chlorides as the highly challenging substrates, which are more available and cheaper, with triethoxyphenylsilane or phenylboronic acid. To prove the performance of the catalyst components (synergistic of SBL ∼ Co. and IL), its different homologs were incorporated individually and studied for a model reaction. Exclusively, this is an introductory statement on the use of Cobalt binuclear symmetric ionic liquid catalysts in Hiyama reactions.

A new Pd(II)‐supported catalyst on magnetic SBA‐15 for CC bond formation via the Heck and Hiyama cross‐coupling reactions

Magnetic mesoporous silica composite (MNP@SiO2‐SBA) was obtained via embedding magnetite nanoparticles between SBA‐15 channels. It was silylated with N‐(3‐(trimethoxysilyl)propyl)picolinamide (TMS‐PCA) and then complexed with Pd(II). The obtained supported Pd(II) catalyst (MNP@SiO2‐SBA‐PCA) was characterized by conventional methods. The prepared magnetic catalyst showed high activity in the Heck and Hiyama reactions under optimal reaction conditions, including solvent, amount of catalyst, base, and temperature. Aryl bromides and iodides showed better results than aryl chlorides, and the catalyst exhibited noticeable stability and reused several times.

New Nanomagnetic Heterogeneous Cobalt Catalyst for the Synthesis of Aryl Nitriles and Biaryls.

Cobalt nanoparticles immobilized on magnetic chitosan (Fe3O4@CS-Co) have been prepared. They were identified using various techniques such as Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, thermogravimetric analysis, vibrating sample magnetometry, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission spectroscopy analysis and applied efficiently as a cobalt catalyst in the cyanation and fluoride-/palladium-free Hiyama reactions of different types of aryl halides employing K4[Fe(CN)6]·3H2O and triethoxyphenylsilane, respectively. After each reaction, the catalyst was isolated and reused for the second run. The catalytic activity of the catalyst was not lost apparently even after five runs. No considerable changes in its chemical structure and morphology were observed. It is worth to note that in this paper, the cobalt catalyst has been used for the first time for the cyanation of aryl halides.

Silver-Mediated Decarboxylative Fluorodiiodination of Alkynoic Acids: Synthesis of Regio- and Stereoselective Fluoroalkenes.

A variety of arylalkynoic acids reacted with 1,3-diiodo-5,5-dimethylhydantoin and HF·pyridine in the presence of AgOAc to provide the corresponding 1-fluoro-2,2-diiodovinylarenes in good yields and high regioselectivity. In addition, Pd-catalyzed cross-coupling reaction of 1-fluoro-2,2-diiodovinylarenes afforded diaryl coupling products in the Suzuki reaction and monoaryl coupling products with high stereoselectivity in the Hiyama reaction. It was found that C-F-activated borylation of fluoroalkenes using Pd catalyst afforded the vinylboranes with good yields.

Magnetic Mesoporous SBA‐15 Functionalized with a NHC Pd(II) Complex: An Efficient and Recoverable Nanocatalyst for Hiyama Reaction

AbstractMagnetite nanoparticles (MNPs) were covered by a silica shell and then embedded into mesoporous silica (SBA‐15). Magnetic mesoporous silica (Fe3O4@SiO2‐SBA) was then reacted with 3‐chloropropyltriethoxysilane (CPTS), sodium salt of imidazole and 2‐bromopyridine to give Fe3O4@SiO2‐SBA functionalized with 3‐(pyridin‐2‐yl)‐1H‐imidazol‐3‐ium‐propyl (PIP) as a supported pincer ligand for Pd(II). The functionalized magnetic mesoporous silica were then treated with t‐BuOK at −80 °C in THF and then reacted with [PdCl2(SMe2)2] to give supported Pd(II)‐carbene complex containing C,N‐bidentate ligand. The chloride ions were then exchanged by bromide ions using a NaBr solution of diethylether/acetone mixture. The prepared catalyst was characterized with, FT‐IR, thermo gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), Brunauer–Emmett–Teller surface area measurement (SBET), energy dispersive X‐ray analysis (EDX) and wide angle X‐ray diffraction spectroscopy (XRD). The prepared magnetic catalyst was effectively used in the coupling reaction of triethoxyphenylsilane with aryl halides (Hiyama reaction) in the presence of a base. The reaction parameters such as solvents, amount of catalyst, base and temperature were optimized. The catalyst was then magnetically decanted, washed, and reused several times.

Fluoride-mediated rearrangement of phenylfluorosilanes

Combining Ph3SiF and fluoride ion under conditions used for the Hiyama coupling causes rapid formation of the expected [Ph3SiF2]−; however, real-time electrospray mass spectrometric analysis reveals that phenyl-fluoride exchange occurs concomitantly, also producing substantial quantities of [PhnSiF5–n]− (n = 0–2). The exchange process is verified using 19F NMR spectroscopy. This observation may have implications for Hiyama reaction protocols, which use transmetallation from triaryldifluorosilicates as a key step in cross-coupling.

NCN–Pincer–Pd Complex as Catalyst for the Hiyama Reaction in Biomass-Derived Solvents

A NCN–pincer–Pd complex has been synthesized and applied to Hiyama-type cross-coupling reactions between aryl halides and different types of organosilanes using neoteric solvents. This report constitutes a green approach to cross-coupling reactions since the reagents employed are stable and nontoxic. The solvents used (deep eutectic solvents based on choline chloride or glycerol) are also biodegradable, nontoxic, nonflammable, and biorenewable. Furthermore, the catalytic system can be recycled, allowing us to perform the reaction for at least three cycles without adding more catalyst or solvent, increasing the value of the process from an economical and environmental point of view. The effect of these solvents on the catalytic activity has been studied. Finally, a gram-scale reaction has also been tested affording biaryl products in high yields and purity by a simple liquid–liquid extraction, without the need of aqueous workup or chromatographic steps, proving the applicability of this approach in a susta...

Nickel embedded on triazole-modified magnetic nanoparticles: A novel and sustainable heterogeneous catalyst for Hiyama reaction in fluoride-free condition

An interesting MNPs -supported nano-nickel catalyst was successfully synthesized through “click” reaction of azide-functionalized magnetic nanoparticles with 2-ethynylpyridine followed by immobilization of nickel nanoparticles. In deed, the azide group was introduced into the magnetic nanoparticles surface via ring-opening of exist oxirane rings on the surface. The catalytic activity of this catalyst was then evaluated for Hiyama cross-coupling reaction under fluoride-free conditions. Besides, the as-prepared nanocatalyst can be reused easily by an external magnet for several times.

Role of Fluoride Ions in Palladium-Catalyzed Cross-Coupling Reactions­

Fluoride ions are known to promote Suzuki–Miyaura, Hiyama, and Stille reactions [cross-coupling between aryl halides ArX and nucleo­philes Ar′B(OH)2, Ar′Si(OMe)3, and Ar′SnBu3, respectively], where they exert a similar triple role: (1) They favor transmetalation by formation of trans-ArPdFL2 (L = PPh3) complexes that react with the nucleophiles in contrast to trans-ArPdXL2. (2) They catalyze the reductive elimination from trans-ArPdAr′L2 generated in the transmetalation. (3) The final role is negative, by formation of unreactive anionic species [Ar′BF(OH)2]–, [Ar′SiF(OMe)3]–, or [Ar′SnFBu3]–, respectively. Consequently the rate of the rate-determining transmetalation is controlled by the concentration ratio [F–]/[nucleophile] which must be less or close to one to ensure fast transmetalation. 1 Introduction 2 Reaction of Fluoride Ions with ArPdXL2 Complexes 3 The Triple Role of Fluoride Ions in Suzuki–Miyaura Reactions 4 The Triple Role of Fluoride Ions in Hiyama Reactions 5 The Triple Role of Fluoride Ions in Stille Reactions 6 Conclusion

ChemInform Abstract: Palladium Supported on Zinc Oxide Nanoparticles as Efficient Heterogeneous Catalyst for Suzuki—Miyaura and Hiyama Reactions under Normal Laboratory Conditions.

ChemInform Abstract: Palladium Supported on Zinc Oxide Nanoparticles as Efficient Heterogeneous Catalyst for Suzuki—Miyaura and Hiyama Reactions under Normal Laboratory Conditions.

Palladium and Bimetallic Palladium–Nickel Nanoparticles Supported on Multiwalled Carbon Nanotubes: Application to CarbonCarbon Bond‐Forming Reactions in Water

AbstractPalladium and bimetallic Pd–Ni nanoparticles (NPs) protected by polyvinylpyrrolidone were prepared by the reduction‐by‐solvent method and deposited on multiwalled carbon nanotubes (MWCNTs). The catalytic activity of these NPs to carbon–carbon bond‐forming reactions was studied by using 0.1 mol % Pd loading, at 120 °C for 1 h and water as a solvent under ligand‐free conditions. The Suzuki–Miyaura reaction took place quantitatively for the cross‐coupling of 4‐bromoanisole with phenylboronic acid, better than those obtained with potassium phenyltrifluoroborate, with Pd50Ni50/MWCNTs as a catalyst and K2CO3 as a base and TBAB as an additive, with good recyclability during 4 cycles with some Ni leaching. The Hiyama reaction of 4‐iodoanisole with trimethoxyphenylsilane, under fluoride‐free conditions using 50 % aqueous NaOH solution, was performed with Pd/MWCNTs as a catalyst in 83 % yield with low recyclability. For the Mizoroki‐Heck reaction 4‐iodoanisole and styrene gave the corresponding 4‐methoxystilbene quantitatively with Pd50Ni50/MWCNTs using K2CO3 as a base and TBAB as an additive although the recycle failed. In the case of the Sonogashira‐Hagihara reaction, Pd/MWCNTs had to be used as a catalyst and pyrrolidine as a base for the coupling of 4‐iodoanisole with phenylacetylene under copper‐free conditions. The corresponding 4‐methoxytolane was quantitatively obtained allowing the recycling of the catalyst during 3 cycles.

Homoleptic chelating N-heterocyclic carbene complexes of palladium immobilized within the pores of SBA-15/IL (NHC–Pd@SBA-15/IL) as heterogeneous catalyst for Hiyama reaction

In this work, SBA-15 was selected as a support for the homoleptic chelating N-heterocyclic carbene complexes of palladium. Here, Pd2+ ions were coordinated to N-heterocyclic carbene (NHC–Pd) which also contain ionic liquid. Then, this NHC–Pd@SBA-15/IL catalyst (NHC–Pd active part of the catalyst) was successfully applied in the catalysis of Hiyama coupling reaction with lower mol% Pd rather to previously reported literatures. The role of TBAF and Cs2CO3 in the decrease of Pd mol% was crucial. Recyclability test showed a successful reusability for 5 runs. Simultaneous application of TBAF and NaOH did destroy the silica structure of SBA-15 in the first run.

Exfoliated Pd decorated graphene oxide nanosheets (PdNP–GO/P123): Non-toxic, ligandless and recyclable in greener Hiyama cross-coupling reaction

Graphene oxide nanosheets were applied as a support for Pd nanoparticles in Hiyama reaction of various aryl halides and triethoxyphenylsilane to generate biaryl derivatives in aqueous conditions. Addition of surfactant during the catalysis caused a significant increase in yields of products through well-exfoliation of PdNP–GO. Among various studied surfactants, P123 showed superior activity rather to other surfactants, SDS and CTAB. This heterogeneous catalytic system has attained the advantages of being non-toxic, available, recyclable, ligand-free, and compatible to reaction medium.

ChemInform Abstract: 1,2‐Functionalized Imidazoles as Palladium Ligands: An Efficient and Robust Catalytic System for the Fluorine‐Free Hiyama Reaction.

AbstractAn imidazole derivative is found to be an efficient ligand for the Pd‐catalyzed coupling of aryl bromides and chlorides with aryl siloxanes using microwave irradiation under fluorine‐free and solvent‐free conditions.

γ-Valerolactone as a Renewable Dipolar Aprotic Solvent Deriving from Biomass Degradation for the Hiyama Reaction

γ-Valerolactone (GVL) can be a valid biobased replacement for toxic dipolar aprotic solvents especially in widely used cross-coupling reactions. In this contribution, we have proved that GVL can be a useful medium for the Hiyama reaction, and we developed a practical and efficient protocol for the Hiyama coupling using a nonexpensive and commercially available heterogeneous palladium catalyst without the use of any ligand or additive. Desired cross-coupling products 3a–m have been obtained in good to excellent yields (74–94%).