- Transition-Metal-Free Matsuda-Heck Type Cross-Coupling and Mechanistic Evidence for a Radical Mechanism
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The Matsuda-Heck reaction, usually performed with palladium catalysts, can be carried out under transition-metal-free conditions in the presence of a KOtBu/DMF couple. This system allows the selective and direct synthesis of stilbenes from aryldiazonium salts under mild temperature (20 °C). Mechanistic studies suggest a radical pathway in which the DMF acts as the initiator of the overall process.
- Bergès, Julien,Zaid, Yassir,Tlili, Anis,Sotiropoulos, Jean-Marc,Taillefer, Marc
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- Resolution of different conformers of methoxy-trans-stilbenes via rotational coherence spectroscopy
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The excitation spectra of 4-methoxy-t-stilbene (MoS) and 4-methoxy,4'-methyl-t-stilbene (MoMeS) both exhibit two electronic origin transitions, separated by 260-280 cm-1.This suggests the presence of two structural forms, as predicted by semi-e
- Troxler, Thomas,Topp, Michael R.,Metzger, Brian S.,Spangler, Lee H.
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- Substituent Effects on Torsional Barriers: p-Methoxy- and p-Methoxy-p'-methyl-trans-stilbene
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Jet-cooled fluorescence excitation spectra and selected single vibronic level dispersed fluorescence spectra are presented for p-methoxy-trans-stilbene and p-methoxy-p'-methyl-trans-stilbene.Two stable conformers of the methoxy group are evident in the sp
- Siewert, Sonja S.,Spangler, Lee H.
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- PVC-NHC-Pd(0): An efficient and reusable heterogeneous catalyst for highly cis-selective semihydrogenation of alkynes using formic acid as hydrogen source
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PVC-NHC-Pd(0) catalyst was prepared and exerted to highly cis-selective semihydrogenation of diarylacetylene using formic acid as hydrogen source under mild condition. The as-prepared catalyst was well characterized by various techniques such as FT-IR, 1H NMR, XRD, SEM, EDX, TEM, XPS, and TGA. The catalyst can be easily recovered and recycled without loss of its activity and selectivity owing to the metal-ligand interaction between Pd(0) with polymeric NHC ligands. This protocol is an attractive alternative of the classical Lindlar's hydrogenation.
- Li, Yiqun,Zheng, Waner,Zhou, Yuemin
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- A photocatalyst-free visible-light-mediated solvent-switchable route to stilbenes/vinyl sulfones from β-nitrostyrenes and arylazo sulfones
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Photocatalyst-free visible-light-mediated reactions, based on the presence of a visible-light-absorbing functional group in the starting material itself in order to exclude the often costly, hazardous, degradable and difficult to remove or recover photoredox catalysts, have been gaining momentum recently. We have employed this approach to develop a denitrative photocatalyst-free visible-light-mediated protocol for the arylation/sulfonylation of β-nitrostyrenes employing arylazo sulfones (bench-stable photolabile compounds) in a switchable solvent-controlled manner. Arylazo sulfones served as the aryl and sulfonyl radical precursors under blue LED irradiation for the synthesis oftrans-stilbenes and (E)-vinyl sulfones in CH3CN and dioxane/H2O 2?:?1, respectively. The absence of any metal, photocatalyst and additive; excellent selectivity (E-stereochemistry) and solvent-switchability; and the use of visible light and ambient temperature are the prime assets of the developed method. Moreover, we report the first photocatalyst-free visible light-driven route to synthesize stilbenes and vinyl sulfones from readily available β-nitrostyrenes.
- Chawla, Ruchi,Dutta, P. K.,Jaiswal, Shefali,Yadav, Lal Dhar S.
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supporting information
p. 6487 - 6492
(2021/08/03)
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- Tandem Acceptorless Dehydrogenative Coupling-Decyanation under Nickel Catalysis
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The development of new catalytic processes based on abundantly available starting materials by cheap metals is always a fascinating task and marks an important transition in the chemical industry. Herein, a nickel-catalyzed acceptorless dehydrogenative coupling of alcohols with nitriles followed by decyanation of nitriles to access diversely substituted olefins is reported. This unprecedented C=C bond-forming methodology takes place in a tandem manner with the formation of formamide as a sole byproduct. The significant advantages of this strategy are the low-cost nickel catalyst, good functional group compatibility (ether, thioether, halo, cyano, ester, amino, N/O/S heterocycles; 43 examples), synthetic convenience, and high reaction selectivity and efficiency.
- Babu, Reshma,Balaraman, Ekambaram,Midya, Siba P.,Subaramanian, Murugan,Yadav, Vinita
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p. 7552 - 7562
(2021/06/28)
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- Stereospecific Iron-Catalyzed Carbon (sp2)-Carbon (sp2) Cross-Coupling of Aryllithium with Vinyl Halides
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We present herein an efficient synthetic protocol involving iron-catalyzed cross-coupling of organolithium compounds with vinyl halides as key coupling partners. More than 30 examples were obtained with moderate to good yields and high stereoselectivities. The practicality of this method is evidenced by a gram-scale synthesis. In addition, a preliminary mechanistic investigation was also performed.
- Chen, Peng,Peng, Xiao-Shui,Wang, Zhi-Yong,Wong, Henry N. C.
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supporting information
p. 4385 - 4390
(2021/06/27)
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- N-Heterocyclic carbene palladium (II)-pyridine (NHC-Pd (II)-Py) complex catalyzed heck reactions
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A mild, efficient, and practical catalytic system for the synthesis of highly privileged stilbene pharmacophores is reported. This system uses N-heterocyclic carbene palladium (II) Pyridine (NHC-Pd (II)-Py) complex to catalyze the formation of carbon-carbon bonds between olefin derivatives and various bromide. This simple, gentle and user-friendly method can offer a variety of stilbene products in excellent yields under solvent-free condition. And its scale-up reaction has excellent yield and this system can be applied to industrial fields. The utility of this method is highlighted by its universality and modular synthesis of a series of bioactive molecules or important medical intermediates.
- Li, Dan,Tian, Qingqiang,Wang, Xuetong,Wang, Qiang,Wang, Yin,Liao, Siwei,Xu, Ping,Huang, Xin,Yuan, Jianyong
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supporting information
p. 2041 - 2052
(2021/05/25)
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- Dual ligand-promoted palladium-catalyzed nondirected C-H alkenylation of aryl ethers
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Direct C-H functionalization of aryl ethers remains challenging owing to their low reactivity and selectivity. Herein, a novel strategy for nondirected C-H alkenylation of aryl ethers promoted by a dual ligand catalyst was demonstrated. This catalytic system readily achieved the highly efficient alkenylation of alkyl aryl ethers (anisole, phenetole, n-propyl phenyl ether, n-butyl phenyl ether and benzyl phenyl ether), cyclic aryl ethers (1,4-benzodioxan, 2,3-dihydrobenzofuran, dibenzofuran), and diphenyl oxides. Moreover, the proposed methodology was successfully employed for the late-stage modification of complex drugs containing the aryl ether motif. Interestingly, the compounds developed herein displayed fluorescent properties, which would facilitate their biological applications.
- Fu, Manlin,Liu, Jiang,Wang, Lei,Yin, Biao,Zhu, Qing
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supporting information
p. 3293 - 3296
(2020/04/02)
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- Novel Carbazole-Based N-Heterocyclic Carbene Ligands to Access Synthetically Relevant Stilbenes in Pd-Catalyzed Coupling Processes
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A series of new carbazole-based N-heterocyclic carbene (NHC) ligands have been synthesized in a simple and facile synthetic route and subsequently used in a Pd/carbazole-based NHC catalytic system, which was found to be effective in catalyzing Heck reactions to provide substituted stilbene derivatives in good yields. Several bioactive stilbenes, including pterostilbene, pinosylvin, trimethoxy resveratrol, and resveratrol, were synthesized in good yields, and a 10 mmol scale-up was also performed for trimethoxy resveratrol. The synthetic application was also extended by performing a double-tandem chemoselective Heck reaction followed by Miyaura borylation in a one-pot procedure to give single-step access to synthetically useful stilbenyl boronate esters. Similarly, a unique triple-tandem protocol of a chemoselective Heck reaction/Miyaura borylation/Suzuki–Miyaura coupling reaction sequence was performed for the one-pot modification of biologically relevant molecules.
- Girase, Tejpalsingh Ramsingh,Kapdi, Anant R.
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supporting information
p. 2611 - 2619
(2019/07/05)
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- Pd/Cu-catalyzed facile approach to stilbenes: A novel diversity of TosMIC as an aryl source
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Pd/Cu-catalyzed Heck type cross-coupling reaction of p-toluenesulfonylmethyl isocyanide (TosMIC) with various styrenes to access stilbenes in DMSO solvent under mild conditions is developed. This efficient and simple approach employs TosMIC as an aryl sou
- Kadari, Lingaswamy,Palakodety, Radha Krishna
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supporting information
p. 1978 - 1981
(2019/07/03)
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- Palladium(ii) ligated with a selenated (Se, CNHC, N-)-type pincer ligand: An efficient catalyst for Mizoroki-Heck and Suzuki-Miyaura coupling in water
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A new 1-[N-benzylacetamido]-3-[1-(2-phenylselenylethyl)]benzimidazolium chloride (L), the precursor of a novel (Se, CNHC, N-)-type pincer ligand (L) was synthesised in high yield through a sequence of consecutive reactions of 1H-benzimidazole with ethylene dichloride, sodium selenophenolate, and N-benzyl-2-chloroacetamide. The palladium-promoted reaction of L with PdCl2 resulted in a moisture- and air-insensitive complex [Pd(L-H2Cl)Cl] (1), which demonstrated outstanding catalytic potential for Mizoroki-Heck coupling of aromatic bromides and chlorides (with yields up to 94% and 70%, respectively) at very low catalyst loading (0.2 mol%) and under mild reaction conditions in water. The complex (1) was also investigated for Suzuki-Miyaura coupling and found to be selectively efficient (yields up to 94%) for Suzuki-Miyaura coupling of aromatic bromides at 0.01 mol% of 1 in water. All coupling reactions were carried out in the green and economical solvent, water, which is highly desirable for bulk synthesis of complex molecules in industry. During the catalytic process, complex 1 converted into PdSe nanoparticles (NPs, size range 5-6 nm) in situ. The morphology and composition of these NPs were analysed through high-resolution transmission electron microscopy and transmission electron microscopy-energy dispersive X-ray spectroscopy, respectively. The core-level, X-ray photoelectron spectroscopy analysis confirmed the presence of stable Pd0 and Pd2+ oxidation states in these PdSe NPs. Based on further experimental investigations, these nanoparticles were found to work as a stock of true catalytic species. The hot filtration test, as well as the two-phase test, confirmed the largely homogeneous nature of the catalytic process, which probably proceeds by leaching of solution-phase Pd species from these NPs.
- Sharma, Kamal Nayan,Satrawala, Naveen,Srivastava, Avinash Kumar,Ali, Munsaf,Joshi, Raj Kumar
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p. 8969 - 8976
(2019/10/28)
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- Efficient Mizoroki–Heck coupling reactions using phosphine-modified Pd(II)–picolinate complex
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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.
- Sharma, Sonam,Sarkar, Bibhas R.
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supporting information
p. 906 - 914
(2018/03/21)
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- Nickel-Catalyzed system for the cross-coupling of alkenyl methyl ethers with grignard reagents under mild conditions
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A nickel-catalyzed cross-coupling of alkenyl methyl ethers with Grignard reagents, under mild conditions, is described. These conditions allowed access to various stilbenes and heterocyclic stilbenic derivatives as well as to a potential anticancer agent DMU-212.
- Hostier, Thomas,Neouchy, Zeina,Ferey, Vincent,Gomez Pardo, Domingo,Cossy, Janine
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supporting information
p. 1815 - 1818
(2018/04/14)
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- Palladium-Catalyzed Reductive Coupling Reaction of Terminal Alkynes with Aryl Iodides Utilizing Hafnocene Difluoride as a Hafnium Hydride Precursor Leading to trans-Alkenes
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Herein, we describe a reductive cross-coupling of alkynes and aryl iodides by using a novel catalytic system composed of a catalytic amount of palladium dichloride and a promoter precursor, hafnocene difluoride (Cp2HfF2, Cp=cyclopentadienyl anion), in the presence of a mild reducing reagent, a hydrosilane, leading to a one-pot preparation of trans-alkenes. In this process, a series of coupling reactions efficiently proceeds through the following three steps: (i) an initial formation of hafnocene hydride from hafnocene difluoride and the hydrosilane, (ii) a subsequent hydrohafnation toward alkynes, and (iii) a final transmetalation of the alkenyl hafnium species to a palladium complex. This reductive coupling could be chemoselectively applied to the preparation of trans-alkenes with various functional groups, such as an alkyl group, a halogen, an ester, a nitro group, a heterocycle, a boronic ester, and an internal alkyne.
- Takahashi, Keita,Ogiwara, Yohei,Sakai, Norio
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supporting information
p. 809 - 814
(2018/03/13)
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- Synthesis, crystal structures, and application of two new pincer type palladium(II)-Schiff base complexes in C-C cross-coupling reactions
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Two new pincer type Pd(II)-Schiff base complexes of the general formula [PdL1(PPh3)] 1 and [PdL2(PPh3)] 2, (where L1 = 2-(2,3-Dihydroxybenzylideneamino)phenolate and L2 = 2-(2,3-dihydroxybenzylidene)hydrazinecarbothioamidate) were synthesised by the reaction of the palladium acetate with the corresponding ligand in methanol as yellow crystalline solids in high yields. Both complexes were fully characterized by FT-IR, 1H NMR, 13C NMR, 31P NMR, elemental analysis and single crystal X-ray diffraction studies. The crystal structures confirmed the tridentate nature of the pincer type Schiff base ligands and the distorted square planar geometry around the metal centre in both cases. The triphenylphosphine acted as an auxiliary ligand and occupied the fourth coordination site at palladium. The complexes were found to be efficient homogenous catalysts for a series of Suzuki-Miyaura, Heck-Mizoroki and Sonogashira reactions at a low catalyst loading (0.08 mol%), and without the use of any additives. All organic products were fully characterized by 1H and 13C NMR studies.
- Agrahari, Bhumika,Layek, Samaresh,Anuradha,Ganguly, Rakesh,Pathak, Devendra D.
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p. 345 - 354
(2017/12/01)
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- Metal-free denitrative arylation of β-nitrostyrenes using benzoyl peroxide: An easy access to: Trans -stilbenes
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A simple, novel and stereoselective synthesis of trans-stilbenes has been described using denitrative arylation of β-nitrostyrenes in the presence of benzoyl peroxide under metal-free conditions. The reaction is assumed to involve homolytic cleavage of benzoyl peroxide followed by decarboxylation to generate a phenyl radical, which brings about ipso-substitution of the nitro group of nitrostyrenes to afford trans-stilbenes.
- Yadav, Arvind Kumar,Singh, Krishna Nand
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supporting information
p. 14914 - 14917
(2017/12/15)
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- Synthesis and characterization of a new Pd(II)-Schiff base complex [Pd(APD)2]: An efficient and recyclable catalyst for Heck-Mizoroki and Suzuki-Miyaura reactions
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The synthesis of a new Schiff base ligand “4-((Z)-((Z)-3-hydroxy-1,3-diphenylallylidene)amino) -1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (APD)” and its palladium complex [Pd(APD)2] is described. The ligand and complex are characterized by FTIR, FESEM, EDX, Elemental analyses and Mass spectrometry. The structure of the ligand is also confirmed by single crystal X-ray determination and 1H NMR data. The complex is insoluble in almost all common organic solvents. It has been used as an efficient catalyst in a series of Heck-Mizoroki and Suzuki-Miyaura coupling reactions giving good TON and TOF. The ease of synthesis, air-stability and recyclability are some of the important characteristics of the synthesized catalyst.
- Layek, Samaresh,Anuradha,Agrahari, Bhumika,Pathak, Devendra D.
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supporting information
p. 105 - 112
(2017/06/19)
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- Olefination of N-Sulfinylimines under Mild Conditions
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A very simple and efficient diastereoselective synthesis of 1,2-disubstituted alkenes has been achieved under mild conditions. Sulfoxide stabilised N-sulfinylimines reacted with in-situ-generated phosphonate carbanions to give 1,2-disubtituted alkenes in good to excellent yields. Different aryl phosphonates reacted with a range of electronically diverse N-sulfinylimines to give alkenes with >99:1 E selectivity. The most important feature of this protocol is that the reaction can be carried out at room temperature with inexpensive sodium hydride as the most effective base to generate the reactive phosphonate carbanions, and producing the alkenes with E selectivity in up to 85 % isolated yield.
- Dhara, Shubhendu,Diesendruck, Charles E.
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p. 1184 - 1190
(2017/03/11)
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- Palladium nanoparticles immobilized on a magnetic chitosan-anchored Schiff base: Applications in Suzuki-Miyaura and Heck-Mizoroki coupling reactions
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A palladium nanocatalyst Fe3O4@CS-SB-Pd has been synthesized and characterized by FT-IR, XRD, XPS, FESEM, EDX, TEM, TGA, and ICP-AES analysis. The nanocatalyst has been found to be an efficient and magnetically separable heterogeneous catalyst for Suzuki-Miyaura and Heck-Mizoroki coupling reactions at a low concentration (0.02 mol% of Pd). The nanocatalyst afforded arylated products with high TON (4950) and TOF (9900 h-1) in the Suzuki-Miyaura coupling reactions. However, for the Heck-Mizoroki coupling reaction, the values of TON and TOF were found to be 4900 and 7350 h-1, respectively. The nanocatalyst could be easily recovered from the reaction mixture by using an external magnet and recycled up to five times without significant decrease in its catalytic activity. All isolated products were obtained as white to off-white crystalline solids and brown oils and fully characterized by 1H and 13C NMR spectroscopy.
- Anuradha,Kumari, Shweta,Layek, Samaresh,Pathak, Devendra D.
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p. 5595 - 5604
(2017/07/11)
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- Synthesis of novel pillar[5]arene-based N-heterocyclic carbene ligands for Pd-catalysed Heck reactions
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Pillar[5]arene-based 1-benzylimidazole and 1-(9-anthracenylmethyl)imidazole salts were prepared for the first time as novel class supramolecular NHC ligands. These ligands, together with PdCl2(CH3CN)2, were used as catalysts in the Heck coupling reactions of styrene and aryl halide derivatives. The 1-(9-anthracenylmethyl)imidazole salt exhibited better catalytic activity than the 1-benzylimidazole salt, owing to the steric bulk of the ligand. The novel pillar[5]arene-based imidazolium salt is a promising supramolecular skeleton for the construction of highly active catalysts.
- Xiao, Xue-Dong,Bai, Ya-Li,Liu, Jia-Qi,Wang, Jun-Wen
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supporting information
p. 3385 - 3388
(2016/07/11)
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- Fe-Catalyzed Cross-Coupling Reaction of Vinylic Ethers with Aryl Grignard Reagents
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Iron-catalyzed cross-coupling reaction of vinylic ethers with aryl Grignard reagents is described. The reaction proceeded at room temperature with catalytic amounts of an iron salt without the aid of costly ligands and additives. In this catalytic system, vinylic C?O bonds were preferentially cleaved over aromatic C?O bonds of aryl ethers or aryl sulfonates.
- Iwasaki, Takanori,Akimoto, Ryo,Kuniyasu, Hitoshi,Kambe, Nobuaki
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supporting information
p. 2834 - 2837
(2016/10/24)
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- Mono- and multifold C-C coupling reactions catalyzed by a palladium complex encapsulated in MIL-Cr as a three dimensional nano reactor
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The organic palladium complex (trans-dichlorobis(4-iodoaniline-κN)palladium(ii)) was encapsulated into a porous metal-organic framework MIL-Cr (Pd complex@MIL-Cr) using ship-in-a-bottle strategy. The novel catalyst as a three dimensional nanoreactor was fully characterized using different techniques such as XRD, BET, XPS, SEM, EDX, TEM and ICP. The Pd complex@MIL-Cr is isostructural to the parent MIL-Cr framework, with a high surface area and pore volume of ca. 1418 m2 g-1 and 0.87 cm3 g-1, respectively. The nanoreactor was highly efficient in the catalytic conversion of aryl halides, showing extraordinarily higher activity than the homogeneous Pd counterparts. Surprisingly, high yields were achieved in Suzuki-Miyaura and Heck coupling reactions of chloroarenes bearing a wide range of substituents. Besides, this protocol could be extended to the cross-couplings of 2-bromo and 2,6-dibromopyridine with arylboronic acids in excellent yields at room temperature. The Pd complex@MIL-Cr was also used as an efficient and convenient catalyst for the preparation of a series of C3-symmetric molecules with benzene, pyridine or pyrimidine units as the central core. Moreover, the catalyst could be recovered easily and reused several times without any considerable loss of its catalytic activity. Investigation of the nature of the recovered catalyst showed that the catalyst is converted to Pd nanoparticles.
- Rezaei, Saghar,Landarani-Isfahani, Amir,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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p. 92463 - 92472
(2016/10/11)
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- Improving reactivity and selectivity of aqueous-based Heck reactions by the local hydrophobicity of phosphine ligands
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Modification of a triarylphosphine with a cholate moiety affords a new ligand, 1, which is effective in palladium-catalyzed Heck cross-couplings between acrylates and aryl iodides under mild, aqueous reaction conditions. High yields, up to 99%, were achieved in water at 40 °C. In competition studies, a more hydrophobic substrate (n-Bu acrylate) was preferred over the least hydrophobic substrate (methyl acrylate), supportive of a localized hydrophobic microenvironment near the catalytic center. The enhanced reactivity and selectivity for hydrophobic substrates disappeared when the local hydrophobicity was eliminated using a standard water-soluble phosphine or in organic solvents.
- Roberts, Gina M.,Zhang, Shiyong,Zhao, Yan,Woo, L. Keith
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p. 8263 - 8270
(2015/10/05)
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- THERAPEUTIC AGENTS FOR SKIN DISEASES AND CONDITIONS
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The present invention relates to method(s) of treating a subject afflicted with a skin disease or condition, the method comprising administering to the subject or patient in need a composition comprising a therapeutically effective amount of a substituted cis or trans- stilbene or a stilbene hybrid. A method of treating or reducing the likelihood of a skin disease or condition in a patient is an additional embodiment of the present invention. Preferred pharmaceutical compositions of the invention include nanoemulsions comprising a therapeutically effective amount of a substituted cis or trans-stilbene or stilbene hybrid and at least one antibiotic.
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Page/Page column 36; 48-49; 53
(2015/06/18)
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- Pd(II) complexes with amide-based macrocycles: Syntheses, properties and applications in cross-coupling reactions
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This work shows Pd(ii) complexes in a set of 13-membered amide-based macrocyclic ligands varied by the placement of e--donating and e--withdrawing substituents on the ligand framework. Ligands constitute a N4 square-planar cavity and optimally house the Pd(ii) ion. The solution-state structure via NMR and absorption spectra substantiates the solid-state structure obtained by crystallography. The electrochemical studies display the impact of electronic substituents on ligands that significantly influence the redox properties and also shift the locus of oxidation. These complexes were used in the Suzuki and Heck cross-coupling reactions. The moderate cross-coupling reaction results are due to limited redox accessibility that can be improved either by using substrates with a better leaving group or by placing electron-withdrawing substituents on the macrocyclic ligands.
- Kumar, Sushil,Jha, Rajeev Ranjan,Yadav, Sunil,Gupta, Rajeev
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p. 2042 - 2051
(2015/03/18)
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- An efficient trifunctional benzhydrazone ligated Pd(II) complex for Heck reaction of aryl bromides
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Synthesis of air and thermally stable trifunctional O, N, and O-terdentate benzhydrazone Pd(II) complex is reported and characterized by elemental analysis, spectral methods, and single crystal X-ray crystallographic technique. The new and reusable homogeneous catalyst has been effectively applied to the Mizoroki-Heck reaction of activated and deactivated aryl bromides with various olefins under mild reaction conditions in good to excellent yields up to 99%.
- Muthumari, Subramanian,Mohan, Nanjan,Ramesh, Rengan
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supporting information
p. 4170 - 4174
(2015/06/22)
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- Polystyrene supported thiopseudourea Pd(II) complex: Applications for Sonogashira, Suzuki-Miyaura, Heck, Hiyama and Larock heteroannulation reactions
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A new polystyrene supported thiopseudourea palladium(II) complex (3) is found to be a highly active catalyst for the copper-free Sonogashira, Suzuki, Heck, Hiyama and Larock heteroannulation reactions of aryl halides. All the reactions proceeded well affording the corresponding cross-coupling products in good to excellent yields. Further, the catalyst showed excellent recyclability without any significant loss in its activity.
- Keesara, Srinivas,Parvathaneni, Saiprathima,Dussa, Govardhan,Mandapati, Mohan Rao
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- Ultrasound-assisted C-C coupling reactions catalyzed by unique SPION-A-Pd(EDTA) as a robust nanocatalyst
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A novel and highly stable Pd(EDTA)2- salt was synthesized as a catalyst, using a counter-cation of N-methylimidazolium bonded to 1,3,5-triazine-tethered SPIONs (superparamagnetic iron oxide nanoparticles). This well-defined complex efficiently
- Ghotbinejad, Marzieh,Khosropour, Ahmad R.,Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah
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p. 8590 - 8596
(2014/03/21)
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- Palladium nanoparticles supported on triazine functionalised mesoporous covalent organic polymers as efficient catalysts for Mizoroki-Heck cross coupling reaction
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A novel class of mesoporous covalent organic polymer (MCOP) was synthesised by the nucleophilic substitution of cyanuric chloride with 4,4′- dihydroxybiphenyl. The MCOP was fully characterized using powder X-ray diffraction analysis, Fourier transform infrared spectroscopy, 13C-solid state NMR spectroscopy, field emission scanning electron microscopy and thermogravimetric analysis. These nitrogen rich materials act as good supports for palladium nanoparticles (Pd NPs) and exhibit excellent catalytic activity towards Mizoroki-Heck cross coupling between aryl bromides and alkenes. Hot filtration tests demonstrate that the presence of the triazine rings on the polymers is beneficial for enhancing the stability of Pd NPs. The polymers are also cheap, easy to synthesise and can be recycled up to five times with only a minor loss of activity. the Partner Organisations 2014.
- Puthiaraj, Pillaiyar,Pitchumani, Kasi
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p. 4223 - 4233
(2014/10/15)
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- Rhodium-Catalyzed Cross-Coupling of Vinylarenes with Arylaluminum Reagents in the Presence of Ketones
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Rhodium-catalyzed addition/elimination of arylaluminum reagents with vinylarenes was achieved to obtain stilbene derivatives. The reaction of diethyl(phenyl)aluminum with styrene in the presence of the chloro(1,5-cyclooctadiene)rhodium(I) dimer, [RhCl(cod)]2, and diisopropyl ketone (2,4-dimethyl-3-pentanone) as an additive occurred to give (E)-stilbene in quantitative yield. The use of other arylaluminum reagents afforded β-arylated products in good to excellent yields. This reaction was found to be promoted by ketones as additives, which are reduced to the corresponding alcohols, as confirmed by analysis of the crude reaction mixture by 1H NMR spectroscopy.
- Tanaka, Shota,Mori, Atsunori
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supporting information
p. 1167 - 1171
(2015/10/05)
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- Rhodium-catalyzed cross-coupling of vinylarenes with arylaluminum reagents in the presence of ketones
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Rhodium-catalyzed addition/elimination of arylaluminum reagents with vinylarenes was achieved to obtain stilbene derivatives. The reaction of diethyl(phenyl)aluminum with styrene in the presence of the chloro(1,5- cyclooctadiene)rhodium(I) dimer, [RhCl(cod)]2, and diisopropyl ketone (2,4-dimethyl-3-pentanone) as an additive occurred to give (E)-stilbene in quantitative yield. The use of other arylaluminum reagents afforded β-arylated products in good to excellent yields. This reaction was found to be promoted by ketones as additives, which are reduced to the corresponding alcohols, as confirmed by analysis of the crude reaction mixture by 1H NMR spectroscopy. Ketones play a key role in the Rh-catalyzed addition/elimination of arylaluminum reagents with vinylarenes, which leads to 1,2-diarylethenes in excellent yields; in the absence of ketones, the same products are delivered in only moderate yields. Reaction of diethyl(phenyl) aluminum and styrene with [RhCl(cod)]2 in the presence of diisopropyl ketone gives stilbene in a quantitative yield. Copyright
- Tanaka, Shota,Mori, Atsunori
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supporting information
p. 1167 - 1171
(2014/03/21)
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- Evidences of release and catch mechanism in the Heck reaction catalyzed by palladium immobilized on highly cross-linked-supported imidazolium salts
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Palladium (10 wt%) on a highly cross-linked imidazolium-based material was used as catalyst in 0.1 mol% in the Heck reaction between several alkenes and aryl iodides. Products were obtained from good to high yields. Deeper investigations showed a release of Pd species in solution and their capture by the imidazolium-based support. When a sixfold amount of support was employed the re-captured Pd species (0.5-0.6 wt%) were not anymore catalytically active. This result represents a new interesting aspect of this work since the highly cross-linked imidazolium-based material can act also as Pd scavenger avoiding the release of the metal in solution. Important differences between Heck and Suzuki reactions have been evidenced when the reactions were carried out in the presence of the scavenging support.
- Pavia, Cinzia,Giacalone, Francesco,Bivona, Lucia Anna,Salvo, Anna Maria Pia,Petrucci, Chiara,Strappaveccia, Giacomo,Vaccaro, Luigi,Aprile, Carmela,Gruttadauria, Michelangelo
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- Palladium complexes containing multidentate phenoxy-pyridyl-amidate ligands: Highly efficient catalyst for Heck coupling of deactivated aryl halides
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N,N′,N″,O-Tetrafunctional Pd(II) complexes prepared from the easily available amino acids are shown to be highly efficient catalysts for the Heck reaction of deactivated aryl bromides and iodides with high turnover numbers up to ca.104 and moderate activity for the activation of aryl chlorides under phosphine-free conditions.
- Kantam, M. Lakshmi,Annapurna, Manne,Likhar, Pravin R.,Srinivas,Mirzadeh, Nedaossadat,Bhargava, Suresh K.
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supporting information
p. 129 - 136
(2013/02/22)
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- Heck-Matsuda reaction of arenediazonium salts in water
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The palladium-catalyzed arylation of alkenes with aryldiazonium salts can be carried out through an environmentally friendly protocol using neat water low palladium loadings at room temperature under base-additive- and ligand-free conditions.
- Salabert, Jordi,Sebastián, Rosa María,Vallribera, Adelina,Cívicos, José Francisco,Nájera, Carmen
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p. 2655 - 2659
(2013/03/28)
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- Visible light-mediated oxidative quenching reaction to electron-rich epoxides: Highly regioselective synthesis of α-bromo (di)ketones and mechanism study
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A novel and simple procedure was developed for the regioselective synthesis of α-bromo (di)ketones from electron-rich epoxides via visible light photoredox catalysis. Through optimization of solvent and light source, the reaction can be rapidly achieved under mild conditions. Moreover, the possible reaction mechanism was proposed and further supported by control experiments.
- Guo, Lin,Yang, Chao,Zheng, Lewei,Xia, Wujiong
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supporting information
p. 5787 - 5792
(2013/09/12)
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- Scope and limitations of the Heck-Matsuda-coupling of phenol diazonium salts and styrenes: A protecting-group economic synthesis of phenolic stilbenes
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4-Phenol diazonium salts undergo Pd-catalyzed Heck reactions with various styrenes to 4′-hydroxy stilbenes. In almost all cases higher yields and fewer side products were observed, compared to the analogous 4-methoxy benzene diazonium salts. In contrast, the reaction fails completely with 2- and 3-phenol diazonium salts. For these substitution patterns the methoxy-substituted derivatives are superior. The Royal Society of Chemistry 2013.
- Schmidt, Bernd,Elizarov, Nelli,Berger, René,H?lter, Frank
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p. 3674 - 3691
(2013/06/27)
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- Palladium nanoparticles immobilized on nano-silica triazine dendritic polymer (Pdnp-nSTDP): An efficient and reusable catalyst for suzuki-miyaura cross-coupling and heck reactions
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A new catalyst based on palladium nanoparticles immobilized on nano-silica triazine dendritic polymer (Pdnp-nSTDP) was synthesized and characterized by FT-IR spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, energy dispersive X-ray, transmission electron microscopy and elemental analysis. The size of the palladium nanoparticles was determined to be 3.1±0.5 nm. This catalytic system showed high activity in the Suzuki-Miyaura cross-coupling of aryl iodides, bromides and chlorides with arylboronic acids and also in the Heck reaction of these aryl halides with styrenes. These reactions were best performed in a dimethylformamide (DMF)/water mixture (1:3) in the presence of only 0.006 mol% and 0.01 mol% of the catalyst, respectively, under conventional conditions and microwave irradiation to afford the desired coupling products in high yields. The Pdnp-nSTDP was also used as an efficient catalyst for the preparation of a series of star- and banana-shaped compounds with a benzene, pyridine, pyrimidine or 1,3,5-triazine unit as the central core. Moreover, the catalyst could be recovered easily and reused several times without any considerable loss of its catalytic activity. Copyright
- Isfahani, Amir Landarani,Mohammadpoor-Baltork, Iraj,Mirkhani, Valiollah,Khosropour, Ahmad R.,Moghadam, Majid,Tangestaninejad, Shahram,Kia, Reza
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supporting information
p. 957 - 972
(2013/05/08)
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- Feeding the Heck reaction with alcohol: One-pot synthesis of stilbenes from aryl alcohols and bromides
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Aryl alcohols are employed as feedstock for the Heck reaction. Keggin-type heteropolyacids catalyse the selective dehydration of the alcohols to styrenes, which, in one-pot, undergo palladium-catalysed Heck arylation with aryl bromides, affording broadly functionalised stilbenes. The choice of solvent is critical for the cascade dehydration-Heck reaction, with electron-rich aryl alcohols preferring a basic medium while electron-deficient ones demanding solvents of lower basicity. Copyright
- Colbon, Paul,Barnard, Jonathan H.,Purdie, Mark,Mulholland, Keith,Kozhevnikov, Ivan,Xiao, Jianliang
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supporting information; scheme or table
p. 1395 - 1400
(2012/07/03)
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- Sodium sulfinate-mediated trans-stilbene formation from benzylic halides
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A convenient and efficient method for the synthesis of various symmetrical and non-symmetrical trans-stilbene derivatives from benzylic halides in the absence of any transition metals is described. Sodium sulfinates played an important role in this transformation. Various functional groups were well tolerated under the optimized reaction conditions. Copyright
- Zhao, Feng,Luo, Jiaying,Tan, Qi,Liao, Yunfeng,Peng, Shengming,Deng, Guo-Jun
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supporting information; experimental part
p. 1914 - 1918
(2012/09/22)
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- Cross-coupling of aryllithiums with aryl and vinyl halides in flow microreactors
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The use of Pd catalysts that contained a carbene ligand, such as PEPPSI-SIPr, speeded up the Murahashi coupling of ArLi with ArBr, by enabling its integration with the Br/Li exchange of ArBr with BuLi in flow. Space integration realized the rapid cross-coupling of two different ArBr substrates. However, the cross-coupling reaction with vinyl halides could not be achieved under similar conditions. Pd(OAc)2 was an effective catalyst, and the space integration of the Br/Li exchange of ArBr with BuLi and the Murahashi coupling with vinyl halides was successfully achieved.
- Nagaki, Aiichiro,Moriwaki, Yuya,Haraki, Suguru,Kenmoku, Akira,Takabayashi, Naofumi,Hayashi, Atsushi,Yoshida, Jun-Ichi
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supporting information; experimental part
p. 1061 - 1068
(2012/07/31)
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- Oxidative Mizoroki-Heck-type reaction of arylsulfonyl hydrazides for a highly regio- and stereoselective synthesis of polysubstituted alkenes
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A useful source: Arylsulfonyl hydrazides have been identified as synthetically useful aryl sources for the Pd(OAc)2 catalyzed oxidative Mizoroki-Heck-type reaction under molecular oxygen to provide a convenient access to polysubstituted alkenes in a highly regio- and stereoselective manner (see scheme). The reaction well tolerates various functional groups such as alkoxy, halo, alcohol, carboxylic acid, ester, amide, sulfonamide, and sulfone. Copyright
- Yang, Fu-Lai,Ma, Xian-Tao,Tian, Shi-Kai
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supporting information; experimental part
p. 1582 - 1585
(2012/03/11)
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- Catalytic application of dinuclear palladium(II) bis(thiosemicarbazone) complex in the Mizoroki-Heck reaction
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A convenient synthesis of new square planar dinuclear palladium(II) terephthaldehyde bis(thiosemicarbazone) complex has been described. The compositions of the complex have been established by elemental analysis, spectral methods and single crystal X-ray crystallographic technique. The new complex acts as an active recyclable homogeneous catalyst for the Mizoroki-Heck reaction of electron deficient (activating) and electron rich (deactivating) aryl halides with various olefins under optimized conditions.
- Prabhu, Rupesh Narayana,Ramesh, Rengan
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supporting information
p. 5961 - 5965,5
(2020/08/20)
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- The synthesis of non-symmetrical stilbene analogs of trans-resveratrol using the same Pd catalyst in a sequential double-Heck arylation of ethylene
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We have developed a sequential and selective Pd-catalyzed double-Heck arylation of ethylene that results in non-symmetrical nitro-stilbene analogs of trans-resveratrol at excellent yields. A catalytic system consisting of Pd(OAc)2 and P(o-tolyl)3 permitted us to carry out the two consecutive Heck arylations without losing activity from the first to the second Heck reaction. After the first Heck arylation of ethylene, no isolation or additional catalyst loading is required for the second Heck arylation reaction. This protocol was applied to the synthesis of methylated trans-resveratrol, which was obtained at a 65% overall yield.
- Nobre, Sabrina M.,Muniz, Mauro N.,Seferin, Marcus,Da Silva, Wagner M.,Monteiro, Adriano L.
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experimental part
p. 289 - 293
(2012/01/04)
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- Mizoroki-heck-type reaction mediated by potassium tert-butoxide
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In the absence of transition-metal catalysts, a Mizoroki-Heck-type reaction proceeded to give stilbene derivatives in a simple manner using an aryl halide, a styrene derivative, KOtBu, EtOH, and DMF (see scheme; DMF=N,N- dimethylformamide).
- Shirakawa, Eiji,Zhang, Xuejing,Hayashi, Tamio
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supporting information; experimental part
p. 4671 - 4674
(2011/06/27)
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- Amino oxazolines as easily accessible water stable ligands for palladium catalysed aqueous Heck reaction
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A series of amino oxazolinyl ligands were screened for palladium catalysed Heck reaction. These ligands work well as phosphine free system in aqueous, micellar medium, can be effectively recovered and reused for subsequent cycles.
- Saiyed, Akeel S.,Joshi, Reshma S.,Bedekar, Ashutosh V.
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experimental part
p. 408 - 411
(2011/10/08)
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- Wittig reaction with ion-supported Ph3P
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Ion-supported Ph3P, 4-(diphenylphosphino)benzyltrimethylammonium bromide A and N-methyl-N-[4-(diphenylphosphino)benzyl]pyrrolidinium bromide B, were used for the Wittig reaction. Ion-supported phosphonium salts A1 and B1, which were prepared from the reactions of ion-supported Ph3P A and B with ethyl bromoacetate, respectively, reacted with aromatic and aliphatic aldehydes in the presence of K2CO3 to give the corresponding α,β-unsaturated ethyl esters in good yields with high purity by simple filtration of the reaction mixture and subsequent removal of the solvent from the filtrate. Similarly, ion-supported phosphonium salts A2 and B2, which were prepared from the reactions of ion-supported Ph3P A and B with p-methylbenzyl bromide, respectively, reacted with aromatic and aliphatic aldehydes in the presence of NaH to provide the corresponding p-methylstyrene derivatives in good yields with high purity by simple filtration of the reaction mixture and the subsequent removal of the solvent from the filtrate. In both reactions, the co-product, ion-supported Ph3PO, could be obtained quantitatively by simple filtration, and was converted into the corresponding ion-supported Ph3P A and B again in high yields using dimethyl sulfate, followed by the reduction with LiAlH4. Recovered and regenerated ion-supported Ph3P A and B could be reused for the same Wittig reaction while maintaining good yields of ethyl (E)-3-(4′-chlorophenyl)-2-propenoate and 1-(4′-chlorophenyl)-2- (4″-methylphenyl)ethene with high purity by simple filtration and removal of the solvent from the filtrate.
- Shimojuh, Naoya,Imura, Yumi,Moriyama, Katsuhiko,Togo, Hideo
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experimental part
p. 951 - 957
(2011/03/18)
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- Effects of substituent and solvent on the UV absorption energy of 4,4′-disubstituted stilbenes
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Twenty five samples of 4,4′-disubstituted stilbene derivatives were synthesized, and their UV absorption max wavelengths were determined in over 10 kinds of solvents including cyclohexane, ether, chloroform, acetonitrile and ethanol, in which 242 experimental data were recorded. The effects of substituents and solvents on the energy of their UV absorption max wavelengths were discussed. The research results showed: the energy of UV absorption max wavelengths of 4,4′-disubstituted stilbenes was mainly affected by their intramolecular structure (substituent effect) in a given solvent, that is, the energy is dominated by both of excited-state substituent parameter σ CC ex and polar substituent constant σ p. While their energy was dominated by the substituent effect and solvent effect in different kinds of solvents. An equation quantifying the energy of UV absorption max wavelengths of 4,4′-disubstituted stilbenes was developed. In addition, it is found that the n-octanol/water partition coefficient (logP) is more effective than the solvatochromic dye (E T(30)) in scaling the solvent effect. The equation employed the parameter logP has a better correlation and more specific physical meaning. Further, the energies of UV absorption max wavelengths of some reported compounds were predicted by the obtained equation, which are in agreement with their experimental values.
- Cao, Chenzhong,Chen, Guanfan,Wu, Yaxin
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scheme or table
p. 1735 - 1744
(2012/05/05)
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- Synthesis and biological evaluation of some stilbene derivatives
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Several trans and cis stilbenes with substitution n the olefinic bridge were synthesized and characterized by IR, NMR and mass spectroscopy in an effort to obtain ubstances that could be more readily formulated. All the synthesized compounds were screened against Molt4/C8, CEM and L1210 cell lines. None of these compounds were ndowed with pronounced cytostatic activity. However,Schiff derivatives emerged as cytostatic agents (IC50: 0.77-10 μg/ml) that deserve further investigation. Springer Science+Business Media, LLC 2010.
- Karki, Subhas Somalingappa,Bhutle, Santosh Ramarao,Sahoo, Subhas,Reddy, Ratnakar,Balzarini, Jan,De Clercq, Erik,Darji, Satyanarayana Y.
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p. 1349 - 1356
(2012/05/05)
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- Arenediazonium salts immobilized in imidazolium ionic liquids as electrophilic partners in the Pd(OAc)2-catalyzed Matsuda-Heck arylation
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The utility of arenediazonium salts immobilized in imidazolium-ILs [BMIMPF6 and BMIMBF4] for facile, high yielding, synthesis of olefins via the Pd(OAc)2-catalyzed Matsuda-Heck arylation reaction has been demonstrated. The reaction can also be performed as a two-step process in the IL starting from ArNH2, by sequential in-situ diazotization-arylation. Simple product isolation and the recycling/re-use of the IL are additional advantages of this one-pot method.
- Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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experimental part
p. 1733 - 1737
(2011/05/05)
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- H2SO4-promoted synthesis of (E)-stilbenes from substituted phenylacetones and substituted benzaldehydes through tandem aldol-Grob reaction
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Stilbene derivates (stilbenoids) are present in plants and show a wide range of biological activities and potential therapeutic value. In continuation of our natural product synthesis program, an efficient, simple, and practical method has been developed to regioselectively synthesize (E)-stilbenes using H2SO4 as a catalyst in a short time (30-60 s) at room temperature in good to excellent yields.
- Narender,Papi Reddy,Tiwari, Sriniwas
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experimental part
p. 1572 - 1583
(2011/06/27)
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- Uridate/pyridyl Pd(II) complexes: Phosphine-free high turnover catalysts for the Heck reaction of deactivated aryl bromides
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The synthesis and structure of palladium(II) complexes bearing uridato/pyridyl ligands as an anionic N-donor coordination sites are reported. The complexes have been shown to be highly active catalysts for the Heck reaction of aryl bromides (TON 4.0×10su
- Srinivas, Pottabathula,Srinivas, Keesara,Likhar, Pravin R.,Sridhar, Balsubramanian,Mohan, Kakita Veera,Bhargava, Suresh,Kantam, Mannepalli Lakshmi
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experimental part
p. 795 - 801
(2011/03/20)
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