- Wittig Olefination Using Phosphonium Ion-Pair Reagents Incorporating an Endogenous Base
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Despite common perception, the use of strong bases in Wittig chemistry is utterly unnecessary: we report a series of novel ion-pair phosphonium carboxylate reagents which are essentially "storable ylides". These reagents are straightforwardly prepared in excellent yields, and their fluxional nature permits clean olefination of a broad range of aldehydes and even hemiacetals.
- Vetter, Anna C.,Gilheany, Declan G.,Nikitin, Kirill
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p. 1457 - 1462
(2021/03/08)
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- Palladium Loaded Dendronized Polymer as Efficient Polymeric Sustainable Catalyst for Heck Coupling Reaction
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The palladium incorporated amine-functionalized dendronized polymer was synthesized by the addition of palladium acetate to dendronized polymer in methanol at room temperature. Palladium species are immobilized onto the dendritic structure by their coordination with amino functional groups. The newly developed dendritic system showed high palladium content in the low generation level itself, which was found to be 4.19?mmol/g. This was fairly higher than, the other palladium-based catalysts. Energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, UV–Visible spectroscopy, and X-ray photoelectron spectroscopy were used to confirm the successful synthesis of the new catalyst. It was used as a homogeneous palladium catalyst for Heck coupling reaction between olefins and differently substituted aryl halides and the products were isolated in high yield. The products isolated were in trans configuration, which indicated the selectivity of the newly developed catalytic system. Also, this catalyst system was reused up to nine times without a significant decrease in its catalytic activity. The easy accessibility of catalytic sites, stability, resistance to metal leaching, high catalytic activity and remarkable stereoselectivity with a low amount of catalyst are all due to the dendritic support. The docking study was carried out for all the stilbene derivatives obtained by the Heck coupling reaction against DprE1 protein to study its potential antitubercular activity. All the compounds displayed superior docking score values over the range ??6.5 to ??8.2?kcal/mol, compared to the standard drug isoniazid with docking score of ??6.1?kcal/mol against DprE1. Graphic Abstract: [Figure not available: see fulltext.]
- Hiba, K.,Krishna, G. Anjali,Prathapan, S.,Sreekumar, K.
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- Ruthenium-Catalyzed E-Selective Alkyne Semihydrogenation with Alcohols as Hydrogen Donors
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Selective direct ruthenium-catalyzed semihydrogenation of diaryl alkynes to the corresponding E-alkenes has been achieved using alcohols as the hydrogen source. The method employs a simple ruthenium catalyst, does not require external ligands, and affords the desired products in > 99% NMR yield in most cases (up to 93% isolated yield). Best results were obtained using benzyl alcohol as the hydrogen donor, although biorenewable alcohols such as furfuryl alcohol could also be applied. In addition, tandem semihydrogenation-alkylation reactions were demonstrated, with potential applications in the synthesis of resveratrol derivatives.
- Ekebergh, Andreas,Begon, Romain,Kann, Nina
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p. 2966 - 2975
(2020/03/04)
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- Syntheses of diarylethenes by perylene-catalyzed photodesulfonylation from ethenyl sulfones
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Diarylethenes were obtained from the corresponding ethenyl sulfones by photocatalyzed desulfonylation using UV or blue LEDs. When perylene and i-Pr2NEt were used as a photocatalyst and a sacrificing reagent, respectively, this desulfonylation proceeded smoothly to afford the desired ethenes with the functional groups such as chloro, alkoxy and heteroaromatic rings remaining untouched. The use of a flow photoreactor enabled this desulfonylation to proceed more rapidly to finish in an hour of residence time.
- Adachi, Kazumasa,Dakegata, Aki,Fukuyama, Takahide,Okuda, Yasuhiro,Orita, Akihiro,Ryu, Ilhyong,Takemoto, Mai,Wakamatsu, Kan,Watanabe, Hikaru
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p. 409 - 412
(2020/04/27)
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- Method for synthesizing trans-olefin compound
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The invention discloses a trans-olefin compound synthesis method, which comprises: carrying out a heating reaction on an alkyne compound represented by a general formula (I), a reducing agent and a solvent to obtain a trans-olefin compound represented by a general formula (II), wherein the synthesis route is as follows: R1 and R2 are independently selected from hydrogen, alkyl, cycloalkyl or aryl;wherein the reducing agent is a sulfur-containing compound and is selected from at least one of thioacetamide, N,N-dimethyl dithiocarbamate dimethyl ammonium salt, dimethyl amino sodium dithioformatedihydrate, potassium ethyl xanthate and potassium isopropyl xanthate. According to the method, a cheap, efficient and safe reducing agent is utilized to realize high-selectivity reduction of alkyne to prepare trans-olefin under the condition of no transition metal catalysis, so that the method is simple and easy to implement, wide in substrate application range and easy to realize industrialization.
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Paragraph 0095-0098
(2020/06/20)
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- New 1,2,3-triazole based bis- And trisphosphine ligands: Synthesis, transition metal chemistry and catalytic studies
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The syntheses and transition metal chemistry of triazole-based bis- and tris-phosphines, 5-(diphenylphosphanyl)-1-(2-(diphenylphosphanyl)phenyl)-4-phenyl-1H-1,2,3-triazole (2), 5-(diphenylphosphanyl)-4-(2-(diphenylphosphanyl)phenyl)-1-phenyl-1H-1,2,3-tria
- Balakrishna, Maravanji S.,Butcher, Ray J.,Kunchur, Harish S.,Namdeo, Pavan K.,Radhakrishna, Latchupatula
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p. 3434 - 3449
(2020/03/27)
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- Xanthate-mediated synthesis of (E)-alkenes by semi-hydrogenation of alkynes using water as the hydrogen donor
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Semi-hydrogenation of alkynes is one of the most widely used methods for obtaining alkenes in laboratory preparation and in industry. Transition metal catalysts have been extensively studied for this transformation, but the tolerance of functional groups, such as pyridine,-OH,-NH2,-Bpin, and halides, and the toxicity of the trace amount of transition metal catalysts are still highly challenging. In this study, we report a general and robust strategy to achieve the semi-hydrogenation of alkynes using inexpensive and commercially available xanthate as the mediator. Mechanism studies support a non-radical process and H2O acts as the hydrogen donor.
- Luo, Xianglin,Chen, Xiuwen,Chen, Lu,Zhang, Kun,Li, Yibiao
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supporting information
p. 2170 - 2173
(2019/02/24)
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- Catalytic Chemoselective and Stereoselective Semihydrogenation of Alkynes to E-Alkenes Using the Combination of Pd Catalyst and ZnI2
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An efficient E-selective semihydrogenation of internal alkynes was developed under low dihydrogen pressure and low reaction temperature from commercially available reagents: Cl2Pd(PPh3)2, Zn0, and ZnI2. Kinetic studies and control experiments underline the significant role of ZnI2 in this process under H2 atmosphere, establishing that the transformation involves syn-hydrogenation followed by isomerization. This simple and easy-to-handle system provides a route to E-alkenes under mild conditions.
- Maazaoui, Radhouan,Abderrahim, Raoudha,Chemla, Fabrice,Ferreira, Franck,Perez-Luna, Alejandro,Jackowski, Olivier
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supporting information
p. 7544 - 7549
(2019/01/03)
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- Synthesis of 1,2-diarylethylenes by Pd-catalyzed one-pot reaction of benzyl halides, tosylhydrazide, and aryl aldehydes
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Background: Substituted olefins are versatile functional groups and intermediates in chemistry, medicine, electronics, and optics and materials science fields because of their unique properties. One important class of substituted olefins 1,2-diarylethylenes have attracted considerable attention due to their presence in both natural products and pharmacologically active substances. Methods: In this paper, we developed a one-pot two-step coupling reaction of aryl aldehydes, tosylhydrazide with benzyl halides by using inexpensive Pd(PPh3)4 as catalyst, leading to a variety of 1,2- diphenylethenes derivatives with moderate to good yields. Results: The desired 1,2-diarylethylenes were obtained in 46-96% yields via Pd(0)-catalyzed one-pot reaction of benzyl halides, tosylhydrazide, and aryl aldehydes. Conclusion: The catalytic system presented here enables the use of easily accessible starting materials and good functional group tolerance.
- Shen, Xu,Liu, Ping,Liu, Yan,Dai, Bin
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p. 709 - 715
(2018/07/14)
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- Determining the excited-state substituent constants of furyl and thienyl groups
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Six series of styrene derivatives XCH═CHArY (total of 65) containing the styrene parent molecular skeleton were synthesized (here, Y is OMe, Me, H, F, Cl, CF3, CN, and NO2, and X is 2-furyl, 3-furyl, 2′-methyl-2-furyl, 2-thienyl, 3-thienyl, and 2′-methyl-2-theniyl). Their ultraviolet absorption spectra were measured in anhydrous ethanol, and their wavelength of absorption maximum λmax was recorded. For the wavenumber νmax (cm?1, νmax?=?1/λmax) of the obtained λmax, a quantitative correlation analysis was performed, and 6 excited-state substituent constants σexcc(p) of groups X were obtained by means of curve-fitting method. Taking the νmax values of total 90 compounds of styrene derivatives as a data set (including 25 compounds from reference and 65 compounds of this work), a quantitative correlation analysis was performed, and the reliability of the obtained σexcc(p) was verified. In addition, 12 samples of disubstituted Schiff bases (XCH═NArY) involving the above groups X were synthesized, and their νmax values were recorded. Using these 12 νmax together with the 14 νmax values of Schiff bases taken from reference (total of 26 compounds), it was further verified that the σexcc(p) values are reliable by means of quantitative correlation method.
- Qu, Junyan,Cao, Chao-Tun,Cao, Chenzhong
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supporting information
(2018/04/24)
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- Regioselectivity observed in manganese(III) acetate mediated addition of acetylacetone to various alkenes: mechanistic and theoretical studies
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Various alkenes substituted at the 1,2-positions by 2-thiophenyl, 3-thiophenyl, and phenyl substituted by electron-withdrawing and electron-donating groups were treated with acetylacetone in the presence of Mn(OAc)3in acetic acid. In cases wher
- Ceyhan, Selin,Cetinkaya, Yasin,Akdag, Akin,Balci, Metin
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supporting information
p. 6815 - 6824
(2016/10/04)
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- General Olefin Synthesis by the Palladium-Catalyzed Heck Reaction of Amides: Sterically Controlled Chemoselective N-C Activation
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Metal-catalyzed reactions of amides proceeding via metal insertion into the N-CO bond are severely underdeveloped due to resonance stabilization of the amide bond. Herein we report the first Heck reaction of amides proceeding via highly chemoselective N-CO cleavage catalyzed by Pd0 utilizing amide bond ground-state destabilization. Conceptually, this transformation provides access to a myriad of metal-catalyzed transformations of amides via metal insertion/decarbonylation.
- Meng, Guangrong,Szostak, Michal
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supporting information
p. 14518 - 14522
(2016/01/25)
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- 1,1′-methylene-3,3′-bis[(N -(tert -butyl)imidazol-2-ylidene] and Its effect in palladium-catalyzed C-C coupling
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A catalytic system utilizing a chelate carbene ligand containing bulk tert-butyl groups is described for palladium-catalyzed Heck and Suzuki coupling reactions. The Heck reaction focused on the coupling of different aryl bromides with mono- and 1,1-disubstituted olefins while the Suzuki reaction involved the coupling of aryl bromides and phenylboronic acid to afford the corresponding biphenyls. The catalyst system performs well with low Pd(OAc)2 levels (0.025 mol% Pd). In all cases with monosubstituted olefins, the trans-configured products were obtained, while the results of Heck reaction of 1,1-disubstituted olefins exhibited a high selectivity favoring the terminal product.
- Nadri, Shirin,Rafiee, Ezzat,Jamali, Sirous,Joshaghani, Mohammad
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supporting information
p. 619 - 624
(2015/03/14)
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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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- Palladium/copper-catalyzed oxidative arylation of terminal alkenes with aroyl hydrazides
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An unprecedented oxidative arylation reaction of terminal alkenes with simple aroyl hydrazides has been developed under aerobic conditions for the stereoselective synthesis of 1,2-disubstituted alkenes. A range of aroyl hydrazides underwent palladium/copper-catalyzed oxidative Mizoroki-Heck reaction with terminal alkenes open to air in a 1:1 mixture of dimethyl sulfoxide and acetonitrile to give structurally diverse 1,2-disubstituted alkenes in moderate to excellent yields with excellent regio- and E-selectivity. The reaction tolerated a wide variety of functional groups, such as alkoxy, hydroxy, amino, fluoro, chloro, bromo, cyano, nitro, ester, amide, imide, phosphine oxide, and sulfone groups, and, moreover, molecular oxygen and dimethyl sulfoxide were demonstrated to serve as terminal oxidants. This study provides a useful method for the stereoselective synthesis of 1,2-disubstituted alkenes through direct transformation of the vinylic Ci-H bonds in terminal alkenes. Cross-coupling: An oxidative arylation reaction of terminal alkenes with simple aroyl hydrazides has been developed in the presence of a PdCl2/CuI catalyst under aerobic conditions to give a range of structurally diverse 1,2-disubstituted alkenes in moderate to excellent yields with excellent regio- and E-selectivity (see scheme; r.s.=regioselectivity).
- Zhang, Yong-Gang,Liu, Xiang-Lei,He, Zeng-Yang,Li, Xi-Ming,Kang, Hong-Jian,Tian, Shi-Kai
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supporting information
p. 2765 - 2769
(2014/03/21)
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- DABO boronates: Stable heterocyclic boronic acid complexes for use in suzuki-miyaura cross-coupling reactions
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Diethanolamine-complexed heterocyclic boronic acids (DABO boronates) are air-stable reagents that can be used directly in Suzuki-Miyaura reactions in the presence of water or a protic co-solvent. Interestingly, heterocyclic DABO boronates can be stored for extended periods of time at room temperature with no noticeable degradation, unlike their boronic acid counterparts. Heterocyclic DABO boronates constitute an operationally simple and efficient alternative to other boronic acid derivatives as coupling partners in palladium-catalyzed cross-coupling reactions under standard Suzuki-Miyaura conditions. Georg Thieme Verlag Stuttgart - New York.
- Reilly, Maureen K.,Rychnovsky, Scott D.
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supporting information; experimental part
p. 2392 - 2396
(2011/11/05)
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- Rhodium-catalyzed regioselective olefination directed by a carboxylic group
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The ortho-olefination of benzoic acids can be achieved effectively through rhodium-catalyzed oxidative coupling with alkenes. The carboxylic group is readily removable to allow ortho-olefination/decarboxylation in one pot. α,β-Unsaturated carboxylic acids
- Mochida, Satoshi,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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body text
p. 3024 - 3033
(2011/06/24)
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- 1,3,2,4-Diazadiphosphetidines as new P-N ligands for palladium-catalyzed Heck reaction in water
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1,3,2,4-Diazadiphosphetidine-based phosphazane class have been used as a new generation of heterogeneous bidentate P(III) ligands containing nitrogen for base-free Pd(II) catalyzed C-C bond formation through Heck coupling reaction of aryl iodides, bromides and chlorides in water with styrene, n-butyl acrylate, 1-octene, and cyclohexene. The reactions occur heterogeneously in water and homogenously or partially heterogeneously in appropriate organic solvents. The ligand together with its Pd(0) complex is easily separated by filtration and reused for several runs.
- Iranpoor, Nasser,Firouzabadi, Habib,Tarassoli, Abbas,Fereidoonnezhad, Masood
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supporting information; experimental part
p. 2415 - 2421
(2010/05/18)
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- 2-Aminophenyl diphenylphosphinite as a new ligand for heterogeneous palladium-catalyzed Heck-Mizoroki reactions in water in the absence of any organic co-solvent
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In this article, 2-aminophenyl diphenylphosphinite has been introduced as a new ligand for the Heck-Mizoroki reactions of aryl halides with styrene and n-butylacrylate in water in the presence of palladium acetate. This ligand is easily prepared from the reaction of chlorodiphenyl phosphine with 2-aminophenol in high yield. Pre-catalyst [Pd(OAc)2] in the presence of the ligand produces a black solid mass. The solid catalyst has been recycled for the reaction of bromobenzene with styrene for six runs without appreciable loss of its catalytic activity.
- Firouzabadi, Habib,Iranpoor, Nasser,Gholinejad, Mohammad
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experimental part
p. 7079 - 7084
(2009/12/06)
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- An efficient palladium-catalyzed Negishi cross-coupling reaction with arylvinyl iodides: facile regioselective synthesis of E-stilbenes and their analogues
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A general synthetic route for the Pd-catalyzed cross-coupling of an arylzinc reagent with arylvinyl iodides (Negishi cross-coupling) has been developed. The system permits efficient and selective preparation of E-stilbenes and their analogues. It also functions effectively at low levels of catalyst loading without the need for an additional ligand and tolerates a wide range of functional groups including heteroaromatic substrates. A systematic study of various parameters was performed and correlated with catalyst-substrate activity.
- Kabir, M. Shahjahan,Monte, Aaron,Cook, James M.
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p. 7269 - 7273
(2008/03/13)
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- Synthesis, characterization, and applications in Heck and Suzuki coupling reactions of amphiphilic cyclopalladated ferrocenylimines
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A series of novel amphiphilic ferrocenylimines and their cyclopalladated complexes of general formula [Fe(η5-C5H5)(η5-C5H4CR1{double bond, long}NR2)] (R1=H, R2=C12H25-n 4a, R1=H, R2=C16H33-n 4b, R1=CH3, R2=C12H25-n 4c, R1=CH3, R2=C16H33-n 4d), [PdCl{[(η5-C5H5)]Fe[(η5-C5H3)CR1{double bond, long}NR2]}]2 (5a-d), [PdCl{[(η5-C5H5)]Fe[(η5-C5H3)-CR1{double bond, long}NR2]}(PPh3)] (6a-d), were prepared and characterized by 1H NMR, 13C NMR, 31P NMR, IR, HRMS, and elemental analysis. The crystal structures of 5c,d were determined by X-ray crystallography. These amphiphilic cyclopalladated complexes are thermally stable and insensitive to oxygen and moisture. The redox properties of 4a-d, 5a-d, 6a-d were also investigated using cyclic voltammetric technique. Compounds 5a-d, 6a-d displayed good activity in the Heck reaction of a variety of aryl halides with ethyl acrylate or styrene and the Suzuki-Miyaura cross-coupling reaction of aryl bromides with phenylboronic acid in bulk solution. They are also suitable for formation of Langmuir-Blodgett (LB) films.
- Mu, Bing,Li, Tiesheng,Xu, Wenjian,Zeng, Guoliang,Liu, Pingping,Wu, Yangjie
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p. 11475 - 11488
(2008/03/12)
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- Decarbonylative Heck olefination of enol esters: Salt-free and environmentally friendly access to vinyl arenes
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Thank you, no salt on the side. In this variant of the Heck olefination, enol esters serve as environmentally friendly synthetic equivalents of aryl halides. These reactants, in turn, are available from a waste-free synthesis from carboxylic acids and propyne. Thus, a salt-free overall process has been devised for preparing vinyl arenes from a variety of aromatic carboxylic acids.
- Goossen, Lukas J.,Paetzold, Jens
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p. 1095 - 1098
(2007/10/03)
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- Pd-catalyzed decarbonylative olefination of aryl esters: Towards a waste-free Heck reaction
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Easy and clean: A palladium (0)-catalyzed decarbonylative Heck olefination of activated esters of aryl, heteroaryl, and vinyl carboxylic acids opens up an opportunity for a novel waste-free Heck olefination process (see scheme).
- Goossen, Lukas J.,Paetzold
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p. 1237 - 1241
(2007/10/03)
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- Suzuki-Miyaura cross-coupling reactions of potassium alkenyltrifluoroborates
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We have previously reported that the palladium-catalyzed cross-coupling reaction of air-stable potassium alkenyltrifluoroborates with aryl halides and triflates proceeds readily with good yields. Recent progress in outlining the scope and limitations of s
- Molander, Gary A.,Bernardi, Carmem R.
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p. 8424 - 8429
(2007/10/03)
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- Heck reaction with heteroaryl halides in the presence of a palladium-tetraphosphine catalyst
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cis,cis,cis-1,2,3,4-Tetrakis(diphenylphosphinomethyl)cyclopentane/1/2[PdCl (C3H5)]2 system catalyses efficiently the Heck reaction of heteroaryl halides with n-butyl acrylate, styrene, vinylpyridine and vinyl ether derivatives. High turnover numbers can be obtained for the reactions with halo pyridines, quinolines, furans or thiophenes.
- Berthiol, Florian,Feuerstein, Marie,Doucet, Henri,Santelli, Maurice
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p. 5625 - 5628
(2007/10/03)
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- Pd-catalyzed decarbonylative heck olefination of aromatic carboxylic acids activated in situ with di-tert-butyl dicarbonate
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The first protocol for a direct Heck olefination of aromatic carboxylic acids has been developed. By treatment with commercially available di-tert-butyl dicarbonate, the carboxylic acids are converted in situ into the mixed anhydrides, which in the presen
- Goo?en, Lukas J.,Paetzold, Jens,Winkel, Lars
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p. 1721 - 1723
(2007/10/03)
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- Nickel-catalyzed electrochemical couplings of vinyl halides: Synthetic and stereochemical aspects
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Homo- and cross-coupling involving alkenyl halides have been performed efficiently using an electroassisted nickel-complex catalysis. Valuable product such as conjugated dienes, β,γ- or γ,δunsaturated esters, ketones, or nitriles, as well as alkenylated aryl compounds are thus prepared with high yields and high stereoselectivity. Partial isomerization is only observed in a few cases, when the alkenyl halide is involved in a late step of the catalytic cycle. This is the case in the preparation of (Z,Z)-1,3-diene.
- Cannes,Condon,Durandetti,Perichon,Nedelec
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p. 4575 - 4583
(2007/10/03)
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- LITHIATION OF SOME 3THIOPHENES AND INTRAMOLECULAR TRANSMETALATION
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The reaction of some halo-1-(thienyl)-2-phenylethanes such as 3-(2-phenylethyl)thiophene (1), 3-thiophene (2), 4--2-methylthiophene (3) and 4--2-chlorothiophene (4) with butyllithium and lithium diisopropylamide (LDA) under various conditions has been investigated.Competition between halogen-metal exchange in the benzene ring and metalation of thiophene ring was observed and an intramolecular transmetalation reaction was found.
- Gronowitz, Salo,Stenhammar, Karin,Svensson, Leif
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p. 947 - 959
(2007/10/02)
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- The Synthesis of 1H- and 5H-Thienodiazepines by the Electrocyclisation of α-(2-Alkenylthienyl)diazoalkanes, and Some Observations on their Photochemical Reactivity and Ring Inverison
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The cyclisation of the α-(2-alkenylthienyl)diazoalkanes (4) and (5) provides the first route to thieno- and thieno-diazepines, (10) and (11) respectively.In contrast, 3-diazomethyl-4-(trans-2-phenylethenyl)thiophen (6) did not cyclise but gave carbene-derived products.The thienodiazepines (10) and (11) were converted by base into the isomeric thieno-diazepines (15) and (16) respectively and by u.v. irradiation into the diazetothienopyrroles (21) and (22).Variable-temperature proton n.m.r. studies have shown that the energy barrier to ring inversion is lower for the thienodiazepines than for analogous benzodiazepines.
- Munro, David P.,Sharp, John T.
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p. 1718 - 1723
(2007/10/02)
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