- The photoinduced reaction of 2-iodothiophene in solutions of n-heptane, dichloromethane and methanol
-
The photoinduced reaction of 2-iodothiophene in n-heptane, dichloromethane and methanol was studied at room temperature from experiments carried out with degassed solutions. The photoproducts of the reaction were mainly thiophene and small amounts of iodine in all three solvents used. The concentration of 2-iodothiophene decreases throughout photolysis, following a first-order rate law and the pseudo-first-order rate constants were determined in the three solvents used. The photochemistry of the system was quantified determining the quantum yields of 2-iodothiophene consumption and thiophene formation in n-heptane solutions. The results show that under the experimental conditions of this research, products deriving only from the reaction of the thienyl radical were observed. To support the experimental results, calculations were performed of the ionization potential of the thienyl radical, electron affinity of the iodine atom and free energy of solvation of the corresponding iodide and carbocation in the different solvents used. Copyright
- Herrera,Nieto,Olleta,Lane
-
-
Read Online
- Surface-Induced Heterocycle Formation: Sulfur Atom Abstraction during Cyclization
-
We have studied the mechanism of a novel cyclization reaction in which acetylene abstracts sulfur from the Pd(111) surface in the form of thiophene. The proposed mechanism is one in which adsorbed acetylene first dimerizes to form a C4H4 intermediate which is then capable of abstracting atomic sulfur to form thiophene. The appearance of thiophene in the gas phase is then rate limited by thiophene desorption kinetics. This sequential mechanism has also been proposed for acetylene cyclotrimerization to benzene on the clean Pd(111) surface. Thiophene formation from acetylene is sensitive to both the surface sulfur coverage and the temperature at which the sulfur overlayer is produced. The reaction of a C4H4 species produced from cis-3,4-dichlorocyclobutene exhibits exactly the same sensitivity to surface characteristics and hence is identified as the intermediate produced by acetylene dimerization. We discuss the potential of this chemistry as a process for the regeneration of catalytic surfaces deactivated by sulfur contamination.
- Gellman, Andrew J.
-
-
Read Online
- HETEROCYCLIZING PROPERTIES OF FERRISILICATE IN THE REACTION OF n-PENTANE WITH HYDROGEN SULFIDE
-
Unlike the iron-modified pentasil, the ferrisilicate has high heterocyclizing activity in the formation of 2-methylthiophene from hydrogen sulfide and n-pentane.During the reaction and the subsequent regenerations a considerable proportion of iron ions leaves the ferrisilicate lattice.The heterocyclizing activity is probably related to the formation of a highly dispersed Fe sulfide phase in the zeolite channels.
- Ryashentseva, M. A.,Belanova, E. P.,Minachev, Kh. M.,Kucherov, A. V.
-
-
Read Online
- Heterocyclization Sites on the Sulfided Pd(111) Surface
-
We have examined the heterocyclization of acetylene (C2H2) to thiophene (C4H4S) on the sulfided Pd(111) surface.This reaction has been found to occur at defects in the sulfided surface which can be produced either by annealing the surface to temperatures >800 K or by sulfiding the surface to near-saturation.At 300 K both thiophene and CO will adsorb selecetively at these defects and can be used to titrate the surface defect concentration.The yield of thiophene from the acetylene heterocyclization reaction is correlated with the defect concentration as measured by these methods and, hence, it appears that the reaction occurs at defects in the sulfided surface.Vibrational spectra indicate that CO adsorbed at these defects is bound in a bridging configuration between Pd atoms indicating that the defects expose the metallic substrate.
- Gellman, Andrew J.
-
-
Read Online
- Competitive carbon-sulfur vs carbon-carbon bond activation of 2-cyanothiophene with [Ni(dippe)H]2
-
The processes of C-C and C-S bond cleavage have been studied with the homogeneous organometallic compound [Ni(dippe)H]2 (1). When 1 is reacted with 2-cyanothiophene at room temperature, cleavage of the nitrile-substituted C-S bond occurs, forming the Ni-metallacycle complex (dippe)Ni(κ2-S,C-SCH=CHCH=C(CN)) (2a), which has been fully characterized by NMR spectroscopy and X-ray diffraction. 2a was converted to the C-CN cleavage product (dippe)Ni(CN)(2-thiophenyl) (3) when heated in solution. On closer inspection, four other intermediates were observed by 31P NMR spectroscopy at low temperature. Structures for the intermediates were elucidated through a combination of independent synthesis, theoretical calculations, chemical characterization, and experimental precedent. A kinetic product (dippe)Ni(κ2-S,C-SC(CN)=CHCH=CH) (2b) was formed from cleavage of the nonsubstituted C-S bond, as well as a Ni(0) η2- nitrile intermediate, (dippe)Ni(η2-C,N-2-cyanothiophene) (4), and a dinuclear mixed Ni(0)-Ni(II) product (6b). A complete DFT analysis of this system has been carried out to reveal comparative details about the two bond cleavage transition states.
- Grochowski, Matthew R.,Li, Ting,Brennessel, William W.,Jones, William D.
-
-
Read Online
- Influence of the texture of chromia catalysts on their activity in synthesis of 2-methylthiophene
-
The texture of Cr2O3-K2O/Al 2O3 catalysts containing oxides of rare earth elements (REE) was studied. The catalysts are used for the synthesis of 2-methylthiophene by the reaction of H2S with n-pentane or piperilene. The heterocyclization of n-pentane is a consecutive reaction involving a step of dehydrogenation of initial hydrocarbon. At this step the texture of the catalyst affects the yield of 2-methylthiophene. The yield of 2-methylthiophene obtained from piperilene and H2S is independent of the catalyst texture.
- Ryashentseva,Brueva
-
-
Read Online
- 5-Methyl-2-thienylcalcium iodide
-
The reduction of 2-bromo- and 3-bromothiophene with calcium powder gives impure thienylcalcium complexes due to interference of various subsequent metalation and calcium-halogen exchange reactions as well as ether degradation. Therefore, calcium-iodine exchange succeeds via the reaction of trimethylsilylmethylcalcium halide with 3-iodothiophene in tetrahydrofuran at -78 °C in the presence of chloro-trimethylsilane, leading to the quantitative formation of 3-(trimethylsilyl)thiophene. The synthesis and isolation of a thienylcalcium halide, a heavy Grignard reagent with a thienyl group, is possible via the reduction of 2-iodo-5-methylthiophene with activated calcium in THF. Substitution of the thf ligands in 5-methyl-2-thienylcalcium iodide ([5-MeThien-2-Ca(thf)4I], 1) by dissolution in tetrahydropyran (THP) leads to the thp complex of 5-methyl-2-thienylcalcium iodide ([5-MeThien-2-Ca(thp)4I], 2). A low field shift of the calcium-bound carbon atom is characteristic of thienylcalcium complexes.
- Koch, Alexander,Krieck, Sven,G?rls, Helmar,Westerhausen, Matthias
-
-
Read Online
- Synthesis of tungsten thienyl complexes via C-H bond activation of thiophenes
-
The reactions of cis-Cp*W(CO)2(MeCN)Me (1) with thiophene or 3-methylthiophene resulted in selective α-C-H bond activation to give cis-Cp*W(CO)2(MeCN)R [R = 2-C4H3S (2a), 2-C4H2S-4-Me (2b)]
- Sakaba, Hiroyuki,Yumoto, Takahiro,Watanabe, Sanae,Kabuto, Chizuko,Kabuto, Kuninobu
-
-
Read Online
- Investigation of the mechanism of catalytic recyclization of furan to thiophene
-
Investigation of the formation of thiophene from furan and hydrogen sulfide at various catalysts showed that the activity of the catalysts increases with increase in the strength and concentration of Lewis acid centers. It was found by IR spectroscopy that if the degree of coverage of the aluminum oxide surface with hydrogen sulfide is higher than monolayer its dissociative chemisorption does not occur. Mechanism was postulated wich assume that the reaction takes place through stage with the formation of a surface intermediate, including coordination of the α-carbon atoms of the furan ring with the Lewis acid center and with the sulfur atom of molecular hydrogen sulfide.
- Mashkina
-
-
Read Online
- FORMATION OF THIENOTHIOPHENES IN THE HIGH TEMPERATURE REACTION OF 2-CHLOROTHIOPHENE WITH COMPOUNDS CONTAINING THE C2H5S GROUP
-
The high temperature gas-phase reaction of 2-chlorothiophene with a mixture of diethyl disulfide and diethyl trisulfide constitutes a simple one-step synthesis of a 4:1 mixture of thioeno- and thieno-thiophenes.Their total yield depends on the nature of the donor of the ethylthio group.
- Korchevin, N. A.,Sukhomoazova, E. N.,Turchaninova, L. P.,Efremova, G. G.,Kalinina, N. A.,et al
-
-
Read Online
- Radical Hydrodehalogenation of Aryl Halides with H2 Catalyzed by a Phenanthroline-Based PNNP Cobalt(I) Complex
-
Radical hydrodehalogenation of aryl halides (Ar-X; X = Cl, Br, I) is achieved in the presence of atmospheric pressure H2 as a H-atom donor using a Co(I) catalyst bearing a phenanthroline-based PNNP ligand (2,9-bis((diphenylphosphanyl)methyl)-1,10-phenanthroline). The reaction proceeds under mild conditions (1 atm H2) and is applicable to aryl bromides and aryl chlorides with various functional groups. A mechanistic study revealed that the PNNP-Co complex underwent facile H-H cleavage and facilitated a H-atom transfer. This process is mediated by a long-range metal-ligand cooperation of the PNNP-Co system, which includes the dearomatization/aromatization sequence of the phenanthroline ligand backbone. A radical clock experiment demonstrated the Ar-X bond cleavage via a radical mechanism. Further kinetic study supported that the rate-determining step includes electron transfer from the Co center to the substrate, affording a radical pair ArX?- and an odd-electron metal-halide complex [Co(II) + ArX?-]? as a transition state.
- Jheng, Nai-Yuan,Ishizaka, Yusuke,Naganawa, Yuki,Minami, Yasunori,Sekiguchi, Akira,Iizuka, Kosuke,Nakajima, Yumiko
-
p. 2320 - 2329
(2022/02/16)
-
- Exploiting a silver-bismuth hybrid material as heterogeneous noble metal catalyst for decarboxylations and decarboxylative deuterations of carboxylic acids under batch and continuous flow conditions
-
Herein, we report novel catalytic methodologies for protodecarboxylations and decarboxylative deuterations of carboxylic acids utilizing a silver-containing hybrid material as a heterogeneous noble metal catalyst. After an initial batch method development, a chemically intensified continuous flow process was established in a simple packed-bed system which enabled gram-scale protodecarboxlyations without detectable structural degradation of the catalyst. The scope and applicability of the batch and flow processes were demonstrated through decarboxylations of a diverse set of aromatic carboxylic acids. Catalytic decarboxylative deuterations were achieved on the basis of the reaction conditions developed for the protodecarboxylations using D2O as a readily available deuterium source.
- ?tv?s, Sándor B.,Fül?p, Ferenc,Kónya, Zoltán,Kukovecz, ákos,Márton, András,Mészáros, Rebeka,Pálinkó, István,Szabados, Márton,Varga, Gábor
-
p. 4685 - 4696
(2021/07/12)
-
- Cyclometalated Platinum(II) Complexes with Donor-Acceptor-Containing Bidentate Ligands and Their Application Studies as Organic Resistive Memories
-
A series of heteroleptic cyclometalated platinum(II) complexes, [Pt(C^N)(O^O)], (1–10) with various donors and acceptors has been synthesized and characterized by 1H NMR spectroscopy, elemental analyses, infrared spectroscopy and mass spectrometry. The X-ray structure of 2 has also been determined. The electrochemical and photophysical properties of the platinum(II) complexes were studied. These experimental results have been supported by computational studies. Furthermore, two of the complexes have been employed as the active material in the fabrication of resistive memory devices, exhibiting stable binary memory performance with low operating voltage, high ON/OFF ratio and long retention time.
- Poh, Wei Church,Au-Yeung, Ho-Leung,Chan, Alan Kwun-Wa,Hong, Eugene Yau-Hin,Cheng, Yat-Hin,Leung, Ming-Yi,Lai, Shiu-Lun,Low, Kam-Hung,Yam, Vivian Wing-Wah
-
supporting information
p. 3669 - 3676
(2021/09/29)
-
- A copper nitride catalyst for the efficient hydroxylation of aryl halides under ligand-free conditions
-
Copper nitride (Cu3N) was used as a heterogeneous catalyst for the hydroxylation of aryl halides under ligand-free conditions. The cubic Cu3N nanoparticles showed high catalytic activity, comparable to those of conventional Cu catalysts with nitrogen ligands, demonstrating that the nitrogen atoms in Cu3N act as functional ligands that promote hydroxylation.
- Mitsudome, Takato,Mizugaki, Tomoo,Xu, Hang,Yamaguchi, Sho
-
supporting information
p. 6593 - 6597
(2021/08/10)
-
- Nucleophilic C-H Etherification of Heteroarenes Enabled by Base-Catalyzed Halogen Transfer
-
We report a general protocol for the direct C-H etherification of N-heteroarenes. Potassium tert-butoxide catalyzes halogen transfer from 2-halothiophenes to N-heteroarenes to form N-heteroaryl halide intermediates that undergo tandem base-promoted alcohol substitution. Thus, the simple inclusion of inexpensive 2-halothiophenes enables regioselective oxidative coupling of alcohols with 1,3-azoles, pyridines, diazines, and polyazines under basic reaction conditions.
- Bandar, Jeffrey S.,Klaus, Danielle R.,Puleo, Thomas R.
-
supporting information
p. 12480 - 12486
(2021/08/24)
-
- Decarboxylative Hydroxylation of Benzoic Acids
-
Herein, we report the first decarboxylative hydroxylation to synthesize phenols from benzoic acids at 35 °C via photoinduced ligand-to-metal charge transfer (LMCT)-enabled radical decarboxylative carbometalation. The aromatic decarboxylative hydroxylation is synthetically promising due to its mild conditions, broad substrate scope, and late-stage applications.
- Ritter, Tobias,Su, Wanqi,Xu, Peng
-
supporting information
p. 24012 - 24017
(2021/10/06)
-
- Transition metal catalyzed nitro-aromatic denitration method
-
The invention provides a transition metal catalyzed nitro-aromatic denitration method, which comprises the following steps: in a nitrogen atmosphere, taking nitro-aromatic as a substrate in an organicsolvent, reacting under the action of alkali and a reducing agent under the action of a transition metal catalyst and a ligand, and carrying out column chromatography separation to obtain an aromaticcompound. The method can directly convert nitro aromatic hydrocarbon into corresponding aromatic hydrocarbon compounds, is high in catalytic efficiency, low in cost and convenient to operate, and canbe compatible with various functional groups. In addition, the directional reduction nitro group, position and number of the nitro group of the polynitro compound are regulated and controlled throughthe proportion and addition amount of the reducing agent and the catalytic system, so that the directional conversion of the polynitro group is realized.
- -
-
Paragraph 0027; 0029-0032; 0053-0056
(2020/08/18)
-
- Light-driven activation of carbon-halogen bonds by readily available amines for photocatalytic hydrodehalogenation
-
A straightforward protocol using readily available aromatic amines, N,N,N′,N′-tetramethyl- p-phenylenediamine or N,N′,N′-tetramethylbenzidine, as photocatalysts was developed for the efficient hydrodehalogenation of organic halides, such as 4′-bromoacetophenone, polyfluoroarenes, cholorobenzene, and 2,2′,4,4′-tetrabromodiphenyl ether(a resistant and persistent organic pollutant). The strongly reducing singlet excited states of the amines enabled diffusion-controlled dissociative electron transfer to effectively cleave carbon-halogen bonds, followed by radical hydrogenation. Diisopropylethylamine served as the terminal electron/proton donor and regenerated the amine sensitizers.
- Chen, Chuncheng,Duan, Ran,Meng, Di,Song, Wenjing,Wei, Yan,Zhao, Jincai,Zhen, Shengli,Zhu, Qian
-
p. 1474 - 1479
(2020/04/29)
-
- Amphiphilic Polymeric Nanoparticles for Photoredox Catalysis in Water
-
Photoredox catalysis has recently emerged as a powerful synthesis tool in organic and polymer chemistry. In contrast to the great achievements realized in organic solvents, performing photocatalytic processes efficiently in aqueous media encounters several challenges. Here, it is presented how amphiphilic single-chain polymeric nanoparticles (SCPNs) can be utilized as small reactors to conduct light-driven chemical reactions in water. By incorporating a phenothiazine (PTH) catalyst into the polymeric scaffold, metal-free reduction and C?C cross-coupling reactions can be carried out upon exposure to UV light under ambient conditions. The versatility of this approach is underlined by a large substrate scope, tolerance towards oxygen, and excellent recyclability. This approach thereby contributes to a sustainable and green way of implementing photoredox catalysis.
- Eisenreich, Fabian,Meijer,Palmans, Anja R. A.
-
supporting information
p. 10355 - 10361
(2020/07/27)
-
- Nickel-Catalyzed Electrosynthesis of Aryl and Vinyl Phosphinates
-
A mild and useful nickel-catalyzed electrochemical phosphonylation of aryl and vinyl bromides is described. We show that alkyl H-phenylphosphinates can be coupled electrochemically with functionalized aryl and vinyl bromides using very simple conditions (Fe/Ni anode, bench-stable nickel pre-catalyst, undivided cell, galvanostatic electrolysis) to furnish the corresponding aryl and vinyl phosphinates in satisfactory to good yields. Couplings can also be applied to heteroaromatic bromides with some limitations like increased propensity to hydro-dehalogenation.
- Daili, Farah,Ouarti, Abdelhakim,Pinaud, Marine,Kribii, Ibtihal,Sengmany, Stéphane,Le Gall, Erwan,Léonel, Eric
-
supporting information
p. 3452 - 3455
(2020/05/25)
-
- Synthesis of thioethers, arenes and arylated benzoxazoles by transformation of the C(aryl)-C bond of aryl alcohols
-
Transformation of aryl alcohols into high-value functionalized aromatic compounds by selective cleavage and functionalization of the C(aryl)-C(OH) bond is of crucial importance, but very challenging by far. Herein, for the first time, we report a novel and versatile strategy for activation and functionalization of C(aryl)-C(OH) bonds by the cooperation of oxygenation and decarboxylative functionalization. A diverse range of aryl alcohol substrates were employed as arylation reagents via the cleavage of C(aryl)-C(OH) bonds and effectively converted into corresponding thioether, arene, and arylated benzoxazole products in excellent yields, in a Cu based catalytic system using O2 as the oxidant. This study offers a new way for aryl alcohol conversion and potentially offers a new opportunity to produce high-value functionalized aromatics from renewable feedstocks such as lignin which features abundant C(aryl)-C(OH) bonds in its linkages.
- Chen, Bingfeng,Han, Buxing,Liu, Mingyang,Meng, Qinglei,Song, Jinliang,Zhang, Pei,Zhang, Zhanrong
-
p. 7634 - 7640
(2020/08/14)
-
- Visible-Light-Induced Ni-Catalyzed Radical Borylation of Chloroarenes
-
A highly selective and general photoinduced C-Cl borylation protocol that employs [Ni(IMes)2] (IMes = 1,3-dimesitylimidazoline-2-ylidene) for the radical borylation of chloroarenes is reported. This photoinduced system operates with visible light (400 nm) and achieves borylation of a wide range of chloroarenes with B2pin2 at room temperature in excellent yields and with high selectivity, thereby demonstrating its broad utility and functional group tolerance. Mechanistic investigations suggest that the borylation reactions proceed via a radical process. EPR studies demonstrate that [Ni(IMes)2] undergoes very fast chlorine atom abstraction from aryl chlorides to give [NiI(IMes)2Cl] and aryl radicals. Control experiments indicate that light promotes the reaction of [NiI(IMes)2Cl] with aryl chlorides generating additional aryl radicals and [NiII(IMes)2Cl2]. The aryl radicals react with an anionic sp2-sp3 diborane [B2pin2(OMe)]- formed from B2pin2 and KOMe to yield the corresponding borylation product and the [Bpin(OMe)]?- radical anion, which reduces [NiII(IMes)2Cl2] under irradiation to regenerate [NiI(IMes)2Cl] and [Ni(IMes)2] for the next catalytic cycle.
- Tian, Ya-Ming,Guo, Xiao-Ning,Krummenacher, Ivo,Wu, Zhu,Nitsch, J?rn,Braunschweig, Holger,Radius, Udo,Marder, Todd B.
-
supporting information
p. 18231 - 18242
(2020/11/02)
-
- Implementing Hydrogen Atom Transfer (HAT) Catalysis for Rapid and Selective Reductive Photoredox Transformations in Continuous Flow
-
The reductive transformation of aryl halides and carbonyl compounds is a key step in many photoredox transformations. By combining a highly reducing organic photocatalyst with a thiol hydrogen atom transfer (HAT) catalyst, we showcase rapid and highly selective reactions of these synthetically important starting materials in continuous flow. The fast reduction of aryl iodides, bromides and chlorides has been demonstrated with residence times in some cases below one minute. Selectivity between mono- and di-dehalogenation could also be achieved in some cases. Aryl ketones, aldehydes and imines were shown to undergo facile pinacol couplings, and the coupling of an aryl chloride with a styrene was also successful.
- Steiner, Alexander,Williams, Jason D.,Rincón, Juan A,de Frutos, Oscar,Mateos, Carlos,Kappe, C. Oliver
-
supporting information
p. 5807 - 5811
(2019/08/01)
-
- Involving Single-Atom Silver(0) in Selective Dehalogenation by AgF under Visible-Light Irradiation
-
The dehalogenation-arylation and the hydrodehalogenation of various types of organic halides are selectively realized using AgF and visible light without any organic additives under mild conditions. Single-atom silver(0) (denoted as SAAg) serves as the catalytically active center, and the TOF of SAAg reaches 6000 h-1. This elusive activity of Ag is beyond that expected from its ionic, nano, or bulk forms.
- Wu, Wenli,Cui, Enxin,Zhang, Yun,Zhang, Chen,Zhu, Feng,Tung, Chen-Ho,Wang, Yifeng
-
p. 6335 - 6341
(2019/07/04)
-
- Photocatalytic degradation of benzothiophene by a novel photocatalyst, removal of decomposition fragments by MCM-41 sorbent
-
In this study, a catalyst was synthesized by introduction of ZnO onto the surface of FSM-16 catalyst support (ZnO/FSM-16). Impregnation of catalyst support by ZnO proceeded through reacting of FSM-16 nanoparticles with Zn(CH3COO)2 solution followed by calcination of the product. The synthesized photocatalyst was then identified by different methods, and the optical property of the photocatalyst was studied by the DRS method. The results showed that after deposition of photocatalyst on FSM-16 support, the photocatalyst band gap was shifted to the visible region. The photoluminescence studies revealed lower recombination of electron–holes of the photocatalyst after immobilization on FSM-16. The influence of different variables on the photocatalytic performance of the samples was studied. Under optimized conditions, the high degradation efficiency of 97% was obtained by ZnO/FSM-16. The compounds produced from degradation of benzothiophene were recognized by the GC–MS method, and the products containing sulfur were properly adsorbed by MCM-41 sorbent. The photocatalyst showed high regeneration capability, and its activity was mostly preserved after six regeneration cycles.
- Hosseini, Asma,Faghihian, Hossein
-
p. 2383 - 2401
(2019/01/29)
-
- Self-assembly of catalytically active supramolecular coordination compounds within metal?organic frameworks
-
Supramolecular coordination compounds (SCCs) represent the power of coordination chemistry methodologies to self-assemble discrete architectures with targeted properties. SCCs are generally synthesized in solution, with isolated fully coordinated metal atoms as structural nodes, thus severely limited as metal-based catalysts. Metal?organic frameworks (MOFs) show unique features to act as chemical nanoreactors for the in situ synthesis and stabilization of otherwise not accessible functional species. Here, we present the self-assembly of PdII SCCs within the confined space of a pre-formed MOF (SCCs@MOF) and its post-assembly metalation to give a PdII?AuIII supramolecular assembly, crystallography underpinned. These SCCs@MOFs catalyze the coupling of boronic acids and/or alkynes, representative multi-site metal-catalyzed reactions in which traditional SCCs tend to decompose, and retain their structural integrity as a consequence of the synergetic hybridization between SCCs and MOFs. These results open new avenues in both the synthesis of novel SCCs and their use in heterogeneous metal-based supramolecular catalysis.
- Adam, Rosa,Mon, Marta,Greco, Rossella,Kalinke, Lucas H.G.,Vidal-Moya, Alejandro,Fernandez, Antonio,Winpenny, Richard E.P.,Domenech-Carbo, Antonio,Leyva-Perez, Antonio,Armentano, Donatella,Pardo, Emilio,Ferrando-Soria, Jesus
-
supporting information
p. 10350 - 10360
(2019/08/20)
-
- Self-Assembly of Catalytically Active Supramolecular Coordination Compounds within Metal-Organic Frameworks
-
Supramolecular coordination compounds (SCCs) represent the power of coordination chemistry methodologies to self-assemble discrete architectures with targeted properties. SCCs are generally synthesized in solution, with isolated fully coordinated metal atoms as structural nodes, thus severely limited as metal-based catalysts. Metal-organic frameworks (MOFs) show unique features to act as chemical nanoreactors for the in situ synthesis and stabilization of otherwise not accessible functional species. Here, we present the self-assembly of PdII SCCs within the confined space of a pre-formed MOF (SCCs?MOF) and its post-assembly metalation to give a PdII-AuIII supramolecular assembly, crystallography underpinned. These SCCs?MOFs catalyze the coupling of boronic acids and/or alkynes, representative multi-site metal-catalyzed reactions in which traditional SCCs tend to decompose, and retain their structural integrity as a consequence of the synergetic hybridization between SCCs and MOFs. These results open new avenues in both the synthesis of novel SCCs and their use in heterogeneous metal-based supramolecular catalysis.
- Adam, Rosa,Mon, Marta,Greco, Rossella,Kalinke, Lucas H. G.,Vidal-Moya, Alejandro,Fernandez, Antonio,Winpenny, Richard E. P.,Doménech-Carbó, Antonio,Leyva-Pérez, Antonio,Armentano, Donatella,Pardo, Emilio,Ferrando-Soria, Jesús
-
supporting information
p. 10350 - 10360
(2019/08/27)
-
- Synthesis, crystal structure and reactivity of η2-thiophyne Ni complexes
-
The first synthesis and crystal structures of five-membered ring aryne complexes, Ni(dcpe)(η2-thiophyne) and Ni(dcpe)(η2-benzo[b]thiophyne), are described. The aryne fragments retain considerable aromatic character and the two coordi
- Terada, Misaki,Nishii, Yuji,Miura, Masahiro
-
p. 2918 - 2921
(2018/03/23)
-
- Reductive Cleavage of Aromatic and Heteroaromatic Ester Functions via Copper-Catalyzed Proto-Decarbomethoxylation
-
An unprecedented catalytic reductive cleavage of aromatic and heteroaromatic methyl ester functions was successfully achieved with a cheap, nontoxic, and air-stable Cu(OAc)2 catalyst. This reaction is fast, features good functional group tolerance, does not require inert atmosphere or anhydrous solvent, and can be scaled up to 1 g. Moreover, carboxylic acids and t-butyl esters also reacted smoothly under these conditions.
- Fichez, Jeanne,Prestat, Guillaume,Busca, Patricia
-
supporting information
p. 2724 - 2727
(2018/05/22)
-
- Mechanochemical Activation of Zinc and Application to Negishi Cross-Coupling
-
A form independent activation of zinc, concomitant generation of organozinc species and engagement in a Negishi cross-coupling reaction via mechanochemical methods is reported. The reported method exhibits a broad substrate scope for both C(sp3)–C(sp2) and C(sp2)–C(sp2) couplings and is tolerant to many important functional groups. The method may offer broad reaching opportunities for the in situ generation organometallic compounds from base metals and their concomitant engagement in synthetic reactions via mechanochemical methods.
- Cao, Qun,Howard, Joseph L.,Wheatley, Emilie,Browne, Duncan L.
-
supporting information
p. 11339 - 11343
(2018/08/28)
-
- A practical non-metal catalytic silicon of the amino protection of the new method (by machine translation)
-
The invention relates to a high efficiency, mild organic silicon reagent carbon silicon key fracture of the new method. The method of this reaction to the alkali is cheap and easy to obtain metal catalyst, in order to common commercial solvent as a reaction solvent and a hydrogen source, in the air and in the under mild conditions can be successfully catalytic trimethyl aryl silicon reagent or aryl alkyne base silicon reagent selectively generating carbon silicon key cracking hydrogenation reaction, the substrate universality is wide, functional group compatibility outstanding. The first innovative to realize the non-transition metal catalyzed carbon silicon key breaking reaction, also overcome the traditional method requires the use of greatly excessive inorganic alkali or an expensive metal catalyst to the limitation of the silicon of the amino protection, for the laboratory preparation and industry in the production of the organosilicon group deprotection provides a completely new strategy. (by machine translation)
- -
-
Paragraph 0044; 0045
(2018/04/01)
-
- Palladium-Catalyzed Deformylation Reactions with Detailed Experimental and in Silico Mechanistic Studies
-
A facile, efficient, and general deformylation reaction with a wide-ranging functional group compatibility has been developed with palladium acetate as a precatalyst under exogenous ligand-free conditions. The mechanistic details of the palladium-catalyzed deformylation reaction have been outlined on the basis of a combination of experimental and computational studies. The heterogeneous pathway is predominant for the deformylation, and homogeneous catalysis occurs to a lesser extent. This ligand-free catalytic cycle is proposed to undergo oxidative addition, migratory extrusion, and reductive elimination as the key steps. Kinetic studies reveal a first-order rate dependency with respect to the aldehyde. Furthermore, kinetic isotope effects, competition experiments, and Hammett studies suggest that the migratory extrusion step is the rate-determining step. For the homogeneous pathway, the experimental findings are also supported by DFT studies.
- Modak, Atanu,Rana, Sujoy,Phukan, Ashwini K.,Maiti, Debabrata
-
supporting information
p. 4168 - 4174
(2017/08/07)
-
- Functionalised [(NHC)Pd(allyl)Cl] complexes: Synthesis, immobilisation and application in cross-coupling and dehalogenation reactions
-
A novel NHC–palladium(II) (NHC?=?N-heterocyclic carbene) complex and its immobilised version have been prepared and fully characterised. Optimisation studies led to good catalytic activities in Suzuki-Miyaura cross coupling and chloroarene dehalogenation reactions. Furthermore, the unexpected palladium-mediated transfer hydrogenation of a carbonyl compound is reported.
- Collinson, John-Michael,Wilton-Ely, James D.E.T.,Díez-González, Silvia
-
-
- A practical and highly efficient reductive dehalogenation of aryl halides using heterogeneous Pd/AlO(OH) nanoparticles and sodium borohydride
-
The reductive dehalogenation of aryl halides was performed by using commercially available aluminium oxy-hydroxide-supported palladium (Pd/AlO(OH)) nanoparticles of about 3?nm size (0.5?wt.?% Pd) with sodium borohydride. The dehalogenated products were obtained with absolute conversion in a mixture of H2O/MeOH (v/v=1/1) under ultrasonic conditions at room temperature. All aryl halides were successfully converted to halogen-free compounds within 1.5–4?h with yields of over 95%. The one-pot catalytic method is presented as a new process for the reductive dehalogenation of halogenated compounds. This method is quite simple, highly efficient and eco-friendly, and has an exceptional recovery rate.
- Kara, Belguzar Yasemin,Yazici, Melike,Kilbas, Benan,Goksu, Haydar
-
p. 5898 - 5902
(2016/09/07)
-
- On the Route to the Photogeneration of Heteroaryl Cations. the Case of Halothiophenes
-
2-Chloro-, 2-bromo-, and 2-iodothiophenes undergo photochemical dehalogenation via the triplet state. In the presence of suitable π-bond nucleophiles, thienylation occurs with modest yield from chloro and bromo derivatives (via photogenerated triplet 2-thienyl cation). Specific trapping by using oxygen along with computational analysis carried out by means of a density functional method support that, in the case of iodo derivatives, homolytic thienyl-I bond fragmentation occurs first and heteroaryl cations are formed by electron transfer within the triplet radical pair, thus opening an indirect access to such cations.
- Raviola, Carlotta,Chiesa, Francesco,Protti, Stefano,Albini, Angelo,Fagnoni, Maurizio
-
p. 6336 - 6342
(2016/08/16)
-
- A highly reducing metal-free photoredox catalyst: Design and application in radical dehalogenations
-
Here we report the use of 10-phenylphenothiazine (PTH) as an inexpensive, highly reducing metal-free photocatalyst for the reduction of carbon-halogen bonds via the trapping of carbon-centered radical intermediates with a mild hydrogen atom donor. Dehalogenations were carried out on various substrates with excellent yields at room temperature in the presence of air.
- Discekici, Emre H.,Treat, Nicolas J.,Poelma, Saemi O.,Mattson, Kaila M.,Hudson, Zachary M.,Luo, Yingdong,Hawker, Craig J.,De Alaniz, Javier Read
-
supporting information
p. 11705 - 11708
(2015/07/15)
-
- Base-promoted silver-catalyzed protodeboronation of arylboronic acids and esters
-
The silver-catalyzed protodeboronation of arylboronic acids and esters in the presence of a base was developed. This method was highly efficient for the protodeboronation of various arylboronic acids and was applied to an efficient deprotection of bifunctional amine under mild conditions. A base-promoted mechanism was proposed. This journal is
- Liu, Chun,Li, Xinmin,Wu, Yonghua
-
p. 15354 - 15358
(2015/02/19)
-
- Room-temperature carbon-sulfur bond activation by a reactive (dippe)Pd fragment
-
The reactivity of [Pd(dippe)(μ-H)]2 (1) and [(μ-dippe)Pd]2 (2) (dippe = 1,2-bis(diisopropylphosphino)ethane) toward C-S bonds in thiophene derivatives and thioethers was investigated, which led to C-S bond activation products. The thiapalladacycles derived from thiophenic substrates were fully characterized by 1H, 31P, and 13C NMR spectroscopy, elemental analysis, and X-ray diffraction. The stability of the C-S insertion products was probed by performing competition experiments which follow the thermodynamic stability order (dippe)Pd(κ2C,S-benzothiophene) (6) > (dippe)Pd(κ2C,S-dibenzothiophene) (8) > (dippe)Pd(κ2C,S-thiophene) (3). The reactivity of the thiapalladacycles with small molecules such as H2, CO, and alkynes was investigated.
- Munjanja, Lloyd,Brennessel, William W.,Jones, William D.
-
p. 1716 - 1724
(2015/05/20)
-
- Protodecarboxylation of carboxylic acids over heterogeneous silver catalysts
-
A heterogeneous supported Ag catalyst for the protodecarboxylation of aromatic carboxylic acids has been developed. Control of the metal particle size proved extremely important. The highest activity was achieved with a silver loading of 10 wt%, which had relatively big metal crystallites of 40 nm. It is inferred that the adsorption of the aromatic moiety requires terrace sites rather than edges or corners at the metal nanoparticle. The amphoteric support, γ-Al2O3, gave the most active catalysts. Oxygen coverage of the surface is essential for catalytic activity. A mechanism has been proposed with the critical steps (1) formation of a benzoyl anion by reaction with a base in the reaction medium, (2) binding of the anionic species at the Ag+ surface sites with (3) extrusion of CO2 and (4) proton transfer from another molecule of carboxylic acid, followed by desorption of the decarboxylated species and binding of the benzoate to the active site to complete the catalytic cycle. With 2-nitrobenzoic acid as substrate, the catalyst had a turnover frequency (TOF) of 216 h-1. The catalyst showed good activity for benzoic acid with nitro, methoxy and halogen substituents at the ortho-position as well as for heteroaromatic carboxylic acids. The Royal Society of Chemistry.
- Toy, Xiu Yi,Roslan, Irwan Iskandar Bin,Chuah, Gaik Khuan,Jaenicke, Stephan
-
p. 516 - 523
(2014/02/14)
-
- Copper-catalyzed protodeboronation of arylboronic acids in aqueous media
-
A general and efficient protocol for the CuSO4·5H2O-catalyzed protodeboronation of arylboronic acids in aqueous ethanol is described. This catalytic system exhibits high activity towards a wide range of arylboronic acids. The results
- Liu, Chun,Li, Xinmin,Wu, Yonghua,Qiu, Jieshan
-
p. 54307 - 54311
(2015/01/16)
-
- Pd/C-catalyzed direct formylation of aromatic iodides to aryl aldehydes using carbon dioxide as a C1 resource
-
Pd/C-catalyzed direct formylation of aromatic iodides to aryl aldehydes using CO2 as a C1 resource was realized for the first time in the presence of hydrosilanes and base DBU under mild conditions, giving a series of aldehydes in good yields. The Royal Society of Chemistry 2014.
- Yu, Bo,Zhao, Yanfei,Zhang, Hongye,Xu, Jilei,Hao, Leiduan,Gao, Xiang,Liu, Zhimin
-
supporting information
p. 2330 - 2333
(2014/03/21)
-
- Application of cooperative iron/copper catalysis to a palladium-free borylation of aryl bromides with pinacolborane
-
A new cooperative copper/iron catalysis for the borylation of various aryl bromides with pinacolborane, at -10 °C, is reported. Use of the toxic, precious metal Pd is avoided. The mechanism of the protodebromination side reaction is discussed.
- Labre, Flavien,Gimbert, Yves,Bannwarth, Pierre,Olivero, Sandra,Dunach, Elisabet,Chavant, Pierre Y.
-
supporting information
p. 2366 - 2369
(2014/05/20)
-
- Copper-catalyzed decarboxylation of aromatic carboxylic acids: En route to milder reaction conditions
-
The copper-catalyzed decarboxylation of carboxylic aromatic acids has been advantageously achieved by using aliphatic amines like tetramethylethylenediamine (TMEDA) or hexamethylenetetraamine (HMTA) as ligands instead of the aromatic heterocyclic amines (quinoline, phenanthroline) used until now. The improvement is significant since the reaction can be performed at a lower temperature (ca. 50 °C less) and the reaction time is clearly shorter (15 min instead of 12 to 24 h). Copyright
- Cahiez, Gerard,Moyeux, Alban,Gager, Olivier,Poizat, Mael
-
supporting information
p. 790 - 796
(2013/04/10)
-
- Gold(I)-catalyzed protodecarboxylation of (Hetero)aromatic carboxylic acids
-
Readily available, inexpensive and easy to handle, carboxylic acids have been shown to be very effective, greener coupling partners compared to costly organometallic reagents for the formation of C-C bonds. The use of well-defined gold complexes furnished 3 in slightly better yield with butyric acid, and in quantitative yield with adamantane-1-carboxylic acid. All reactions reached completion within 16 h. As with silver systems, this reactivity trend highlights, as previously observed, the benefits of potential coordinating groups in the ortho position to the gold binding site, which possibly facilitate the decarboxylation step. Additional reaction time and increased temperatures were necessary to afford the gold aryl products in satisfactory yields. Yet, some substrates such as 2-nitrobenzoic acids reacted poorly and could only be transformed in 50% yield.
- Dupuy, Stéphanie,Nolan, Steven P.
-
supporting information
p. 14034 - 14038
(2013/11/19)
-
- Palladium-catalyzed hydrodehalogenation of aryl halides using paraformaldehyde as the hydride source: High-throughput screening by paper-based colorimetric iodide sensor
-
Paraformaldehyde was employed as a hydride source in the palladium-catalyzed hydrodehalogenation of aryl iodides and bromides. High throughput screening using a paper-based colorimetric iodide sensor (PBCIS) showed that Pd(OAc)2 and Cs2CO3 were the best catalyst and base, respectively. Aryl iodides and bromides were hydrodehalogenated to produce the reduced arenes using Pd(OAc)2 and Pd(PPh3)4 catalyst. This catalytic system showed good functional group tolerance. In addition, it was found that paraformaldehyde is the hydride source and the reducing agent for the formation of palladium nanoparticles.
- Pyo, Ayoung,Kim, Sudeok,Kumar, Manian Rajesh,Byeun, Aleum,Eom, Min Sik,Han, Min Su,Lee, Sunwoo
-
supporting information
p. 5207 - 5210
(2013/09/02)
-
- Acetone condensation over sulfated zirconia catalysts
-
The aldol condensation reaction over sulfated zirconia led to the production of diacetone alcohol, which was further dehydrated forming mesityl oxide. The sulfated zirconia was obtained from zirconium acetate ethane sulfonate as a single source precursor. Oxides were obtained by calcinations of the precursors at 550-650 C, while the self-condensation reaction of acetone was carried out at 150 C. The precursor and the produced oxides were characterized using various characterization techniques. The precursors were synthesized with different acetate to ethane sulfonate ratio, ranging from 1 to 3. The major products obtained from the condensation reaction over the resulted oxide were mesityl oxide, mesitylene isophorone, naphthalene, and pentamers. The selectivity of mesityl oxide was approximately 100 % at the initial time-on-stream.
- Al-Hazmi, Mohammed H.,Choi, Yongman,Apblett, Allen W.
-
p. 705 - 716
(2013/07/26)
-
- Exploring the reactivity of nickel complexes in hydrodecyanation reactions
-
In the present study, the nickel-catalyzed hydrodecyanation of organic cyanides with lithium borohydride as a cheap hydride source has been examined in detail. As precatalysts straightforward nickel complexes modified by tridentate O,N,O′-ligands and triphenylphosphane as co-ligand have been applied. Noteworthy, excellent yields and chemoselectivities were feasible for a variety of organic cyanides at low catalyst loadings and low temperature (70 C) within short reaction time (3 h).
- Enthaler, Stephan,Weidauer, Maik,Irran, Elisabeth,Epping, Jan Dirk,Kretschmer, Robert,Someya, Chika I.
-
p. 262 - 274
(2013/10/01)
-
- Trifluoromethylation of aryl and heteroaryl halides with fluoroform-derived CuCF3: Scope, limitations, and mechanistic features
-
Fluoroform-derived CuCF3 recently discovered in our group exhibits remarkably high reactivity toward aryl and heteroaryl halides, performing best in the absence of extra ligands. A broad variety of iodoarenes undergo smooth trifluoromethylation with the ligandless CuCF3 at 23-50 C to give the corresponding benzotrifluorides in nearly quantitative yield. A number of much less reactive aromatic bromides also have been trifluoromethylated, including pyridine, pyrimidine, pyrazine, and thiazole derivatives as well as aryl bromides bearing electron-withdrawing groups and/or ortho substituents. Only the most electrophilic chloroarenes can be trifluoromethylated, e.g., 2-chloronicotinic acid. Exceptionally high chemoselectivity of the reactions (no side-formation of arenes, biaryls, and C2F5 derivatives) has allowed for the isolation of a large number of trifluoromethylated products in high yield on a gram scale (up to 20 mmol). The CuCF3 reagent is destabilized by CuX coproduced in the reaction, the magnitude of the effect paralleling the Lewis acidity of CuX: CuCl > CuBr > CuI. While SNAr and SRN1 mechanisms are not operational, there is a well-pronounced ortho effect, i.e., the enhanced reactivity of ortho-substituted aryl halides 2-RC6H4X toward CuCF3. Intriguingly, this ortho-effect is observed for R = NO2, COOH, CHO, COOEt, COCH3, OCH3, and even CH3, but not for R = CN. The fluoroform-derived CuCF3 reagent and its reactions with haloarenes provide an unmatched combination of reactivity, selectivity, and low cost.
- Lishchynskyi, Anton,Novikov, Maxim A.,Martin, Eddy,Escudero-Adan, Eduardo C.,Novak, Petr,Grushin, Vladimir V.
-
p. 11126 - 11146
(2013/12/04)
-
- A continuous protodecarboxylation of heteroaromatic carboxylic acids in sulfolane
-
A versatile, scalable method for the decarboxylation of indole-2-carboxylic acids has been found. With one equivalent of DBU in sulfolane, indole-2-carboxylic acid derivatives were cleanly decarboxylated in a 316 stainless steel tube reactor at 300 °C within 20 min. The corresponding indole derivatives were obtained in good yields. It was also found that indole-2-carboxylic acid (1) can be decarboxylated in either pure sulfolane or sulfolane with 3% water at 300 °C within 20 min. (1) The decarboxylation with one equivalent of DBU could successfully be transferred to benzo[b]thiophene-2-carboxylic acid derivatives if a prolonged reaction time was used. (2) Picolinic acid could also be decarboxylated in sulfolane with 3% water, and thiophene-2-carboxylic acid was smoothly decarboxylated with DABCO instead of DBU. (3) Benzoic acid derivatives were either inert or decomposed under the reaction conditions.
- Tilstam, Ulf
-
p. 1449 - 1454
(2012/10/30)
-
- Polymer-supported syntheses of thiophene-containing compounds using a new type of traceless linker
-
A new type of traceless linker is described for use in polymer-supported (PS) syntheses of thiophene-containing compounds. It is based on the cleavage of PS aryl 2-thienyl ketones by a mixture of potassium t-butoxide and water (typical mol ratio 10:3) in an ethereal solvent. Cleavage occurs to give the soluble thiophene-containing product. The method is used to prepare a range of eight thiophene-containing compounds including a terthiophene and a dialkylquaterthiophene. PS unsymmetrical diaryl ketones incorporating, for example, ortho-methoxyphenyl or pyrrole moieties could also serve as traceless linkers.
- Ben-Haida, Abderrazak,Hodge, Philip
-
experimental part
p. 1754 - 1763
(2012/04/23)
-
- A general and efficient aldehyde decarbonylation reaction by using a palladium catalyst
-
A facile decarbonylation reaction of aldehydes has been developed by employing Pd(OAc)2. A wide variety of substrates are decarbonylated, without using any exogenous ligand for palladium as well as CO-scavenger.
- Modak, Atanu,Deb, Arghya,Patra, Tuhin,Rana, Sujoy,Maity, Soham,Maiti, Debabrata
-
supporting information; experimental part
p. 4253 - 4255
(2012/05/04)
-
- Mechanism of formation of sulphur aroma compounds from l-ascorbic acid and l-cysteine during the Maillard reaction
-
The sulphur aroma compounds produced from a phosphate-buffered solution (pH 8) of l-cysteine and l-, l-[1-13C] or l-[4-13C] ascorbic acid, heated at 140 ± 2 °C for 2 h, were examined by headspace SPME in combination with GC-MS. MS data indicated that C-1 of l-ascorbic acid was not involved in the formation of sulphur aroma compounds. The sulphur aroma compounds formed by reaction of l-ascorbic acid with l-cysteine mainly contained thiophenes, thiazoles and sulphur-containing alicyclic compounds. Among these compounds, 1-butanethiol, diethyl disulphide, 5-ethyl-2-methylthiazole, cis and trans-3,5-dimethyl-1,2,4-trithiolane, thieno[2,3-b]thiophene, thieno[3,2-b]thiophene, cis and trans-3,5-diethyl-1,2,4-trithiolane, 1,2,5,6-tetrathiocane, 2-ethylthieno[2,3-b]thiophene, 2,4,6-trimethyl-1,3,5- trithiane and cyclic octaatomic sulphur (S8) were formed solely by l-cysteine degradation, and the rest by reaction of l-ascorbic acid degradation products, such as hydroxybutanedione, butanedione, acetaldehyde, acetol, pyruvaldehyde and formaldehyde with l-cysteine or its degradation products, such as H2S and NH3. A new reaction pathway from l-ascorbic acid via its degradation products was proposed.
- Yu, Ai-Nong,Tan, Zhi-Wei,Wang, Fa-Song
-
experimental part
p. 1316 - 1323
(2012/06/30)
-
- Leaving group dependence of the rates of halogen-magnesium exchange reactions
-
Relative reactivities and absolute rate constants of the reactions of haloarenes with i-PrMgCl?LiCl were investigated in THF at 0 °C. The rate of the halogen-magnesium exchange decreases in the series ArI > ArBr > ArCl (relative reactivities: 1011:106:1). Preliminary experiments show that the p-tolylsulfinyl group is exchanged slightly faster than iodide, while a tosyl group is exchanged at least 104 times more slowly than a bromide.
- Shi, Lei,Chu, Yuanyuan,Knochel, Paul,Mayr, Herbert
-
supporting information; experimental part
p. 2602 - 2605
(2012/08/08)
-
- DEHYDROGENATION OF CYCLIC THIOETHERS
-
There is disclosed a surprising reaction of an alkane thiol with a catalyst and heat to become dehydrogenated and form a thiophene rather than an expected desulfurization reaction to form the corresponding alkane or alkene. Moreover, there are disclosed surprising results regarding the form of a catalyst to allow a reaction of an alkane thiol to form the dehydrogenated thiophene at lower temperatures and at higher conversion percentages to allow for more efficient recovery of thiophenes to allow for recycling and reuse of thiophenes to hydrogenate to form alkane thiols. Further still, there is disclosed a set of reaction conditions and catalyst presentation that allows for recovery of usable diatomic hydrogen gas from a dehydrogenation reaction of substituted or unsubstituted cyclic thioethers to substituted or unsubstituted thiophene.
- -
-
Page/Page column 24
(2011/05/11)
-
- Cobalt-xantphos-catalyzed, LiCl-mediated preparation of arylzinc reagents from aryl iodides, bromides, and chlorides
-
A cobalt-Xantphos-catalyzed, LiCl-mediated system has been developed for the direct and expedient preparation of arylzinc reagents in THF from the corresponding aryl iodides, bromides, and chlorides. Owing to the use of THF as a versatile solvent, the thus-formed arylzinc reagents displayed a high degree of compatibility with a variety of conventional as well as newly emerging metal-catalyzed cross-coupling reactions.
- Jin, Meng-Yi,Yoshikai, Naohiko
-
experimental part
p. 1972 - 1978
(2011/05/19)
-
- Palladium catalyzed-dehalogenation of aryl chlorides and bromides using phosphite ligands
-
The catalytic system based on Pd-phosphite for the dehalogenation reactions of aryl chlorides and bromides is described. The Pd-phosphite catalyst effectively promoted the dehalogenation of aryl halides to give dehalogenated products in moderate to excellent yields. The aryl chlorides required strong bases such as NaOtBu for this transformation, whereas the aryl bromides were dehalogenated in the presence of weak bases such as Cs2CO3. This catalytic system exhibited tolerance to functional groups such as methoxy, amine, hydroxyl, ether, amide, benzyl and ketone groups. It also demonstrated chemoselectivity in that bromochlorobenzene was converted only to chlorobenzene.
- Moon, Jeongju,Lee, Sunwoo
-
scheme or table
p. 473 - 477
(2009/04/14)
-