- X-ray crystal structure of 2-styrylpyridine
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We have crystallized the 2-styrylpyridine from the condensation reaction between the 2-methylpyridine with benzaldehyde in the formation of the model compound 2-styrylpyridine. The X-ray structure and NMR are currently reported. The main features of the structure is that it shows a localization of the double bonds rather than a delocalization of π electrons in an aromatic fashion.
- Percino, M. Judith,Chapela, Víctor M.,Salmón, Manuel,Espinosa-Pérez, Georgina,Herrera, Ana M.,Flores, Américo
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- Heterobimetallic Pd/Mn and Pd/Co complexes as efficient and stereoselective catalysts for sequential Cu-free Sonogashira coupling–alkyne semi-hydrogenation reactions
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A series of heterobimetallic PdII/MII complexes (MII = Mn, Co) were synthesised and tested as precatalysts for sequential Sonogashira coupling–alkyne semi-hydrogenation reactions to form Z-aryl alkenes. The carbometalated heterobimetallic PdII/CoII complex CoPdL3′ demonstrated an apparent cooperative effect compared to the corresponding monometallic counterparts. This compound was identified as a potent single-molecule catalyst for the one-pot Cu-free Sonogashira coupling of aryl bromides with terminal alkynes followed by chemo- and stereoselective semi-hydrogenation of the alkyne intermediate using NH3·BH3 as a hydrogen source. Furthermore, different aromatic substrates have been tested to show the generality of the reaction for the synthesis of Z-alkenes, including biologically active combretastatin A-4. In addition, the homogeneous nature of the catalytically active species was demonstrated.
- Baweja, Saral,Clauss, Reike,Gelman, Dmitri,Hey-Hawkins, Evamarie
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supporting information
p. 1344 - 1356
(2022/02/03)
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- A new insight into the push-pull effect of substituents via the stilbene-like model compounds
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In this paper, authors report on 1-pyridyl-2-arylethenes, 1-furyl-2-arylethylenes, 1,2-diphenylpropylenes and substituted cinnamyl anilines as stilbene-like model compounds to investigate the factors dominating the push-pull effect of substituents via usi
- Cao, Chaotun,Cao, Chenzhong,Zeng, Zhao
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- Preparation method of alkyl/alkenyl substituted nitrogen-containing heterocyclic compound
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The invention belongs to the technical field of organic synthesis, and particularly discloses a preparation method of an alkyl/alkenyl substituted nitrogen-containing heterocyclic compound, which comprises the following steps: (1) adding a 2-methyl nitrogen-containing heterocyclic compound, primary alcohol, alkali and an additive into an organic solvent, performing stirring reaction for 24 hours, and then cooling the product to room temperature; and (2) concentrating, separating and purifying the reaction liquid obtained in the step (1). The simple and effective method for preparing the alkyl/alkenyl substituted nitrogen-containing heterocyclic compound under the metal-free and ligand-free conditions is realized, the 2-methyl nitrogen-containing heterocyclic compound and the primary alcohol which are economical and easy to obtain are used as raw materials, and the alkyl/alkenyl substituted nitrogen-containing heterocyclic compound is prepared under the synergistic promotion of alkali and additives; and methyl alkylation and alkenylation reaction are carried out to generate the corresponding alkyl/alkenyl substituted nitrogen-containing heterocyclic compound. The product has high application value and can be used in the fields of spices, medicines, materials, organic synthesis and the like. The method is wide in application range, simple in process, green, simple, high in yield and suitable for popularization and application.
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Paragraph 0066-0074; 0082-0088
(2021/07/10)
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- Role of Benzylic Deprotonation in Nickel-Catalyzed Benzylic Dehydrogenation
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Alkylarenes are readily functionalized via the corresponding benzylic anions. Benzylic anions have been used for a range of catalytic reactions, including Ni-catalyzed dehydrogenation. Interestingly, the employment of Zn(TMP) 2for slow and incomplete deprotonation of the benzylic position was observed. This manuscript describes a preliminary investigation into the deprotonation of heteroarenes and its relationship to Ni-catalyzed benzylic dehydrogenation.
- Zhang, Pengpeng,Cantrell, Rachel L.,Newhouse, Timothy R.
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supporting information
p. 1652 - 1656
(2021/07/31)
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- Immobilized Pd on a NHC-functionalized metal-organic FrameworkMIL-101(Cr): An efficient heterogeneous catalyst in the heck and copper-free Sonogashira coupling reactions
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A heterogeneous palladium catalyst system based on immobilization of palladium moieties on a N-heterocyclic carbene (NHC) modified metal organic framework (MOF) was developed for the Heck and copper-free Sonogashira coupling reactions. In order to prepare this catalyst system, first, MIL-101(Cr) was functionalized with NHC moieties through a post synthetic modification (PSM) approach, and then Pd metal was stabilized on the prepered MIL-101(Cr)-NHC substrate. This material was characterized using various microscopic and spectroscopic techniques and then was used as an efficient heterogeneous Pd catalyst system in the Heck and copper-free Sonogashira reactions. Results of the heterogeneity tests showed that the Pd-NHC-MIL-101(Cr) catalyst can efficiently catalyzed these coupling reactions heterogeneously and no remarkable changes observed in the morphology and structure of MIL-101(Cr) template during the reaction progress. Also, existence of palladium nanoparticles immobilized on the MOF structure affirmed by the TEM and XPS analysis confirmed the oxidation state of Pd. A variety of alkene and alkyne derivatives were synthesized in good to excellent yields using this heterogeneous Pd catalyst system under normal conditions. More importantly Pd-NHC-MIL-101(Cr) catalyst was simply recovered from the reaction medium without remarkable decreasing in its catalytic activities after five times of reusability. The ICP analysis showed the very low Pd and Cr metals leaching, representing high stability and applicability of this catalyst in Pd coupling reactions.
- Niknam, Esmaeil,Panahi, Farhad,Khalafi-Nezhad, Ali
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supporting information
(2021/01/12)
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- Structural Effect of Pincer Pd(II)–ONO Complexes Modified with Acylthiourea on Sizes of the In Situ Generated Pd Nanoparticles During Heck Coupling Reaction
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Abstract: The Pd nanoparticles generated in situ from Pd–pincer complexes catalyzed Heck coupling reaction. For this purpose, new Pd(II)–ONO pincer complexes (1–4) containing acylthiourea ancillary ligand were obtained by treating [Pd(ONO)(CH3CN)] with the respective N-substituted carbamothioyl benzamide ligand (L1–L4). Formation of these complexes was confirmed by UV–Visible, FT-IR, NMR and mass spectroscopic techniques. The sizes of in situ formed Pd nanoparticles were greatly affected by the substituent in ancillary ligand, which in turn influenced their catalytic activity towards Heck coupling reaction. The in situ formed Pd nanoparticles during Heck reaction were removed from the reaction medium and analyzed using HR-TEM to estimate the sizes of the Pd nanoparticles. Complex [Pd(ONO)((N-benzylcarbamothioyl)benzamide)] (1) which does not possess any substituent on the benzyl moiety of acylthiourea produced the smallest Pd nanoparticles with the average particle size of 3.7?nm. Hence, complex 1 showed the utmost catalytic activity. With complex 1, 51–99% of conversion was observed during Heck coupling reaction of styrene with various aryl halides. XPS results confirmed that the recovered black particles were Pd(0). A reasonable recyclability results were achieved by these in situ generated Pd nanoparticles. Graphic Abstract: [Figure not available: see fulltext.]
- Jerome,Babu, S. Ganesh,Karvembu
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p. 1633 - 1645
(2020/10/15)
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- Copper(0) nanoparticle catalyzed Z-Selective Transfer Semihydrogenation of Internal Alkynes
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The use of copper(0) nanoparticles in the transfer semihydrogenation of alkynes has been investigated as a lead-free alternative to Lindlar catalysts. A stereo-selective methodology for the hydrogenation of internal alkynes to the corresponding (Z)-alkenes in high isolated yields (86% average) has been developed. This green and sustainable transfer hydrogenation protocol relies on non-noble copper nanoparticles for reduction of both electron-rich and electron-deficient, aliphatic-substituted and aromatic- substituted internal alkynes. Polyols, such as ethylene glycol and glycerol, have been proven to act as hydrogen sources, and excellent stereo- and chemoselectivity have been observed. Enabling technologies, such as microwave and ultrasound irradiation are shown to enhance heat and mass transfer, whether used alone or in combination, resulting in a decrease in reaction time from hours to minutes. (Figure presented.).
- Moran, Maria Jesus,Martina, Katia,Bieliunas, Vidmantas,Baricco, Francesca,Tagliapietra, Silvia,Berlier, Gloria,De Borggraeve, Wim M.,Cravotto, Giancarlo
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p. 2850 - 2860
(2021/05/06)
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- 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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supporting information
p. 1457 - 1462
(2021/03/08)
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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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- Determination and application of the excited-state substituent constants of pyridyl and substituted phenyl groups
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Thirty six 1-pyridyl-2-arylethenes XCH=CHArY (abbreviated XAEY) were synthesized, in which, X is 2-pyridyl, 3-pyridyl and 4-pyridyl and Y is OMe, Me, H, Br, Cl, F, CF3, and CN. Their ultraviolet absorption spectra were measured in anhydrous ethanol, and their wavelengths of absorption maximum λmax were recorded. Also, the 234 λmax values of 1-substituted phenyl-2-arylethylene compounds (XAEY, where X is substituted phenyl) were collected. The excited-state substituent constants (Formula presented.) of three pyridyl groups and 23 substituted phenyl groups (total of 26) were obtained by means of curve-fitting method. Taking the λmax values of 358 samples of bi-arylethene derivatives as a data set and 126 samples of bi-aryl Schiff bases (including nine compounds synthesized by this work) as another data set, quantitative correlation analyses were performed by employing the obtained (Formula presented.) as a parameter, and good results were obtained for the two data sets. The reliability of the obtained (Formula presented.) values was verified. The results of this paper can provide excited-state substituent constants for the study and application of optical properties of conjugated organic compounds containing aryl groups.
- Cao, Chao-Tun,Yan, Lu,Cao, Chenzhong
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- First cycloruthenation of 2-alkenylpyridines: synthesis, characterization and properties
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Several cyclometalated ruthenium complexes 1-5 with 2-alkenylpyridines as C,N-chelating ligands were synthesized and then characterized by NMR, MS, IR and UV-Vis spectra. According to the single crystal of complex 2, it is evident that carbon from vinyl group is successfully bonded to Ru(ii) center. Moreover, the Ru-N bond trans to the Ru-C bond is elongated (2.127(5) ?), which is consistent with the strong trans effect of the carbon atom compared to that of the nitrogen atom. With different electron-donating groups linked to vinyl, these complexes exhibited regular changes in MLCT absorption bands, which were identified by UV-Vis and CV spectra in combination with DFT and TD-DFT. Interestingly, protonated intermediate species of these complexes in acidic solutions were tracked by the absorption changes and MS spectra, which displayed a possible protonation process of these complexes with the cleavage of Ru-C σ bonds.
- Wu, Yuhao,Su, Xianlong,Xie, Chaoyi,Hu, Rongrong,Li, Xianghong,Zhao, Qiang,Zheng, Guoli,Yan, Junkun
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p. 4138 - 4146
(2021/02/02)
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- Deaminative Olefination of Methyl N-Heteroarenes by an Amine Oxidase Inspired Catalyst
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We explored the bioinspired o-quinone cofactor catalyzed aerobic primary amine dehydrogenation for a cascade olefination reaction with nine different methyl N-heteroarenes, including pyrimidines, pyrazines, pyridines, quinolines, quinoxolines, benzimidazoles, benzoxazoles, benzthiazoles, and triazines. An o-quinone catalyst phd (1,10-phenanthroline-5,6-dione) combined with a Br?nsted acid catalyzed the reaction. N-Heteroaryl stilbenoids were synthesized in high yields and (E)-selectivities under mild conditions using oxygen (1 atm) as the sole oxidant without needing transition-metal salt, ligand, stoichiometric base, or oxidant.
- Thorve, Pradip Ramdas,Maji, Biplab
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supporting information
p. 542 - 547
(2021/01/26)
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- Desulfonative Suzuki–Miyaura Coupling of Sulfonyl Fluorides
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Sulfonyl fluorides have emerged as powerful “click” electrophiles to access sulfonylated derivatives. Yet, they are relatively inert towards C?C bond forming transformations, notably under transition-metal catalysis. Here, we describe conditions under which aryl sulfonyl fluorides act as electrophiles for the Pd-catalyzed Suzuki–Miyaura cross-coupling. This desulfonative cross-coupling occurs selectively in the absence of base and, unusually, even in the presence of strong acids. Divergent one-step syntheses of two analogues of bioactive compounds showcase the expanded reactivity of sulfonyl fluorides to encompass both S?Nu and C?C bond formation. Mechanistic experiments and DFT calculations suggest oxidative addition occurs at the C?S bond followed by desulfonation to form a Pd-F intermediate that facilitates transmetalation.
- Bahadori, Maryam,Brykczyńska, Daria,Chatelain, Paul,Moran, Joseph,Muller, Cyprien,Rowley, Christopher N.,Sau, Abhijit
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supporting information
p. 25307 - 25312
(2021/10/25)
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- Iron complex containing diphosphine meta-position carborane ligand as well as preparation method and application of same
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The invention relates to an iron complex containing a diphosphine meta-position carborane ligand as well as a preparation method and application of the same. The iron complex is prepared by the following method: reacting n-BuLi with m-carborane m-C2B10H12, then adding halogenated phosphine for continuous reaction, then adding FeCl2 into a reaction system for continuous reaction, after the reactionis finished, separating the reaction product to obtain an iron complex containing a diphosphine m-carborane ligand, and applying the iron complex to catalytic synthesis of a trans-2-alkenyl azaarenecompound. Compared with the prior art, the method shows efficient catalytic activity in synthesis of the trans-2-alkenyl aza-aromatic hydrocarbon compound through direct condensation reaction of 2-methyl aza-aromatic hydrocarbon and aromatic aldehyde, is low in catalyst dosage, mild in reaction condition, high in reaction rate and relatively high in yield, and has a wide application prospect in industry.
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Paragraph 0032; 0036-0037; 0040
(2020/10/14)
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- Palladium anchored on guanidine-terminated magnetic dendrimer (G3-Gu-Pd): An efficient nano-sized catalyst for phosphorous-free Mizoroki-Heck and copper-free Sonogashira couplings in water
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In this research, a novel type of Fe3O4&at;silica-supported dendrimer capped by guanidine groups for immobilization of palladium was reported. This novel nano-sized catalyst was characterized by FTIR, TGA, XRD, FESEM, EDX, VSM, XPS and HRTEM methods. Enhanced catalytic activity of the prepared catalyst in Mizoroki-Heck and copper-free Sonogashira coupling reactions were evaluated in water as a green solvent. The influence of the various reaction parameters such as catalyst dosage, time and temperature on two mentioned C–C coupling reactions were studied. Results showed that the catalyst could be easily recovered by simple separation by an external magnet and reused for five cycles of recovery without considerable losing of its activity.
- Khalafi-Nezhad, Ali,Moaddeli, Ali,Niknam, Esmaeil
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- Fe3O4-Lignin@Pd-NPs: A highly efficient, magnetically recoverable and recyclable catalyst for Mizoroki-Heck reaction under solvent-free conditions
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Palladium nanoparticles (Pd-NPs) were synthesized under green conditions in water by chemical reduction of PdCl2 with NaOH and supported by Fe3O4-Lignin. Fe3O4-Lignin is an organic–inorganic hybrid core-shell was synthesized by sonication of a mixture of Fe3O4-NPs (20 nm) and alkali lignin. The new materials Fe3O4-Lignin and Fe3O4-Lignin@Pd-NPs were characterized by PXRD, SEM and FT-IR spectroscopy. The Fe3O4-Lignin@Pd-NPs was further confirmed by UV–Visible spectroscopy, TEM, EDX, HRICP-AES and TGA/DTA. The average size of Pd-NPs determined from PXRD was 5–10 nm. The amount of palladium loaded on Fe3O4-Lignin obtained from EDX analysis was 26.63percent by mass. The amount of Fe and Pd present in the catalyst obtained from HRICP-AES was 11.88 (wt. percent) and 10.90 (wt. percent) respectively per gram of lignin. The catalytic potential of Fe3O4-Lignin@Pd-NPs was evaluated in Mizoroki-Heck C-C coupling reaction. During the optimization studies of reaction between iodobenzene and n-butyl acrylate in various solvents and under solvent-free but aerobic conditions using various inorganic and organic bases, the product n-butyl 3-phenylprop-2-enoate (1a) obtained was as high as 95percent in highly polar solvents as short as in 10 min and 99percent under solvent-free conditions in 3 min at 140 °C using n-Pr3N as base. The scope of the above catalyst was investigated in the Mizoroki-Heck reaction of various aryl/heterocyclic halides and n-butyl acrylate/styrene under optimized solvent-less conditions. The corresponding products were obtained in high yields (73–99percent). The catalyst recovered by magnetic decantation was reused for five times in the C-C coupling reaction between iodobenzene and n-butyl acrylate which yielded 90–95percent of the desired product, 1a.
- Madrahalli Bharamanagowda, Marulasiddeshwara,Panchangam, Raghavendra Kumar
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- [2+2] Photodimerization of Stilbazoles Promoted by Oxalic Acid in Suspension
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In this study, a very simple technique to perform efficiently photodimerization of some vinylpyridines is reported. By irradiating a stirred mixture of several stilbazoles with solid oxalic acid dihydrate dispersed in a nonpolar (i.e., cyclohexane) or moderately polar (benzene, dichloromethane, dioxane) solvent, the corresponding dimeric cyclobutane adducts were obtained in high yields and excellent regio- and stereoselectivities. The strategy could also be applied successfully to oily, waxy, or even insoluble stilbazoles. Moreover, the oxalic acid loading could be lowered to substoichiometric amounts. When further optimizations were needed, our strategy was found to be highly flexible to identify other oligocarboxylic acids as alternative additives to improve, or even overturn, the regioselectivity. Oxalic acid and other oligocarboxylic acids were found to be capable of orienting more than 50 stilbazoles toward photodimerization under these conditions.
- Nguyen, Thanh Binh,Nguyen, Tuan Minh,Retailleau, Pascal
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supporting information
p. 4682 - 4689
(2020/04/15)
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- Aqueous phase semihydrogenation of alkynes over Ni-Fe bimetallic catalysts
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Bimetallic Ni-Fe catalysts (Ni/Fe, 1?:?1, 1?:?3, and 3?:?1) are synthesized and explored for their catalytic activity in semihydrogenation of internal alkynes using H2 gas in water-ethanol solution. Our findings revealed that over the Ni1Fe3 catalyst a high diastereoselectivity for Z-alkenes with a high conversion for a wide range of internal alkynes can be achieved at moderate reaction temperature (40 °C). Notably, the selectivity for the Z-alkenes is enhanced in the presence of n-butyl amine as an additive. Deuterium labeling experiments evidenced that H2 gas becomes dissociated homolytically over the catalyst surface to hydrogenate alkynes to alkenes. Synthesized catalysts were successfully characterized by HR-TEM, SEM, XPS, EDS, P-XRD and H2-TPD.
- Awasthi, Mahendra K.,Barman, Sudipta Roy,Behrens, Silke,Rai, Rohit K.,Singh, Sanjay K.,Singh, Vipin K.
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p. 4968 - 4980
(2020/08/19)
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- Aryl-Nickel-Catalyzed Benzylic Dehydrogenation of Electron-Deficient Heteroarenes
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This manuscript describes the first practical benzylic dehydrogenation of electron-deficient heteroarenes, including pyridines, pyrazines, pyrimidines, pyridazines, and triazines. This transformation allows for the efficient benzylic oxidation of heteroarenes to afford heterocyclic styrenes by the action of nickel catalysis paired with an unconventional bromothiophene oxidant.
- Zhang, Pengpeng,Huang, David,Newhouse, Timothy R.
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supporting information
p. 1757 - 1762
(2020/02/04)
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- An Annelated Mesoionic Carbene (MIC) Based Ru(II) Catalyst for Chemo- And Stereoselective Semihydrogenation of Internal and Terminal Alkynes
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The catalytic utility of [RuL1(CO)2I2] (1), containing an annelated π-conjugated imidazo-naphthyridine-based mesoionic carbene (MIC) ligand (L1), is evaluated for E-selective alkyne semihydrogenation. The precatalyst 1, in combination with 2 equiv of AgBArF, semihydrogenates a broad range of internal alkynes with molecular hydrogen (5 bar) in water. (E)-Alkenes are accessed in high yields, and a number of reducible functional groups are tolerated. A chelate MIC ligand and two cis carbonyls provide a well-defined platform at the Ru center for hydrogenation and isomerization. The loss of two iodides and the presence of two carbonyls render the Ru center electron deficient and thus the formation of metal vinylidenes with terminal alkynes is avoided. This is leveraged for the semihydrogenation of terminal alkynes by the same catalytic system in isopropyl alcohol. Reaction profile, isomerization, kinetic, and DFT studies reveal initial alkyne hydrogenation to a (Z)-alkene, which further isomerizes to an (E)-alkene via metal-catalyzed Z → E isomerization.
- Bera, Jitendra K.,Choudhury, Joyanta,Das, Shubhajit,Dutta, Indranil,Pati, Swapan K.,Saha, Sayantani,Yadav, Suman
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p. 3212 - 3223
(2020/10/02)
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- Borane-Catalyzed Chemoselective and Enantioselective Reduction of 2-Vinyl-Substituted Pyridines
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Herein, we report that highly chemoselective and enantioselective reduction of 2-vinyl-substituted pyridines has been achieved for the first time. The reaction, which uses chiral spiro-bicyclic bisboranes as catalysts and HBpin and an acidic amide as reducing reagents, proceeds through a cascade process involving 1,4-hydroboration followed by transfer hydrogenation of a dihydropyridine intermediate. The retained double bond in the reduction products permits their conversion to natural products and other useful heterocyclic compounds by simple transformations.
- Hu, Chen-Yu,Li, Xiang,Liang, Xin-Shen,Liu, Ning,Tian, Jun-Jie,Tu, Xian-Shuang,Wang, Xiao-Chen,Yang, Zhao-Ying
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supporting information
p. 18452 - 18456
(2020/08/21)
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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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- Iron-Catalyzed Coupling of Methyl N-Heteroarenes with Primary Alcohols: Direct Access to E-Selective Olefins
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An efficient Fe-catalyzed system is reported for direct α-olefination of methyl-substituted N-heteroarenes with primary alcohols. The catalytic dehydrogenative coupling enables a series of functionalized E-olefinated N-heteroaromatics with excellent selectivity (>99%). Initial mechanistic studies including deuterium-labeling experiments provide evidence for the participation of the benzylic C-H/D bond of alcohols.
- Das, Jagadish,Vellakkaran, Mari,Sk, Motahar,Banerjee, Debasis
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supporting information
p. 7514 - 7518
(2019/10/02)
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- Nickel-catalysed direct α-olefination of alkyl substituted N-heteroarenes with alcohols
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Catalytic α-olefination of alkylheteroarenes with primary alcohols via dehydrogenative coupling is presented. A simple nickel catalyst system stabilised by readily available nitrogen ligands enables a series of interesting E-configured vinylarenes (confirmed by X-ray crystal-structure analysis) to be synthesised in good to excellent yields with olefin/alkane selectivity of >20:1. Hydrogen and water are generated as byproducts and quantitative determination of H2 was performed.
- Das, Jagadish,Vellakkaran, Mari,Banerjee, Debasis
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supporting information
p. 7530 - 7533
(2019/07/04)
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- Nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones with the liberation of H2
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A nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones to access various terminal and internal olefins with the liberation of hydrogen gas is reported.
- Landge, Vinod G.,Yadav, Vinita,Subaramanian, Murugan,Dangarh, Pragya,Balaraman, Ekambaram
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supporting information
p. 6130 - 6133
(2019/06/03)
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- Direct Wittig Olefination of Alcohols
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A base-promoted transition metal-free approach to substituted alkenes using alcohols under aerobic conditions using air as the inexpensive and clean oxidant is described. Aldehydes are relatively difficult to handle compared to corresponding alcohols due to their volatility and penchant to polymerize and autoxidize. Wittig ylides are easily oxidized to aldehydes and consequently form homo-olefination products. By the strategy of simultaneously in situ generation of ylides and aldehydes, for the first time, alcohols are directly transferred to olefins with no need of prepreparation of either aldehydes or ylides. Thus, the di/monocontrollable olefination of diols is accomplished. This synthetically practical method has been applied in the gram-scale synthesis of pharmaceuticals, such as DMU-212 and resveratrol from alcohols.
- Li, Qiang-Qiang,Shah, Zaher,Qu, Jian-Ping,Kang, Yan-Biao
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p. 296 - 302
(2018/02/19)
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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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- Method for synthesizing olefin compound by photo-induced one-pot process
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The invention discloses a method for synthesizing an olefin compound by a photo-induced one-pot process. The method comprises the following step of subjecting a halohydrocarbon and an aldehyde compound to a reaction under the condition of irradiation in an inert atmosphere by taking alkali metal carbonate as a base, taking an organic phosphine compound as an adjuvant and taking a photosensitizer as a catalyst, thereby obtaining the olefin compound. According to the method disclosed by the invention, the olefin compound is produced from the halohydrocarbon and the aldehyde compound in a high-yield manner under the condition of irradiation in the inert atmosphere under normal-temperature reaction conditions by taking acetonitrile, DMF (N,N-dimethylformamide) or DMA (N,N-dimethylacetamide) asa solvent, taking an organic phosphine reagent as a reaction adjuvant, taking the alkali metal carbonate as the base and taking the photosensitizer as the catalyst. Compared with the conventional olefin synthesis methods, the method disclosed by the invention has the obvious advantages that the reaction raw materials are readily available, the tolerance to a variety of functional groups on halohydrocarbons and aldehydes is high, the yield is high, the separation and purification of a product are simple and convenient, and the like.
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Paragraph 0129-0131
(2018/11/03)
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- Manganese-Catalyzed Direct Olefination of Methyl-Substituted Heteroarenes with Primary Alcohols
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Herein, we present the first catalytic direct olefination of methyl-substituted heteroarenes with primary alcohols through an acceptorless dehydrogenative coupling. The reaction is catalyzed by a complex of the earth-abundant transition metal manganese that is stabilized by a bench-stable NNN pincer ligand derived from 2-hydrazinylpyridine. The reaction is environmentally benign, producing only hydrogen and water as byproducts. A large number of E-disubstituted olefins were selectively obtained with high efficiency.
- Barman, Milan K.,Waiba, Satyadeep,Maji, Biplab
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supporting information
p. 9126 - 9130
(2018/07/25)
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- Semireduction of Alkynes Using Formic Acid with Reusable Pd-Catalysts
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The treatment of PdCl2 with K2CO3 and HCO2H in dioxane gives black precipitates, which are an effective catalyst for the semireduction of alkynes to alkenes using formic acid as a reductant. Even 0.05 mol % Pd promoted the reduction reaction of tolane in high yield with high selectivity.
- Iwasaki, Riku,Tanaka, Eikichi,Ichihashi, Toshinari,Idemoto, Yasushi,Endo, Kohei
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p. 13574 - 13579
(2018/11/02)
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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 of bench-stable solid triorganoindium reagents and reactivity in palladium-catalyzed cross-coupling reactions
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Bench-stable solid triorganoindium compounds have been prepared by coordination with 4-(dimethylamino)pyridine (DMAP). The solid R3In(DMAP) complexes are obtained from the corresponding solution of R3In in quantitative yield and can
- Gil-Negrete, José M.,Pérez Sestelo, José,Sarandeses, Luis A.
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supporting information
p. 1453 - 1456
(2018/02/19)
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- Piperidine-appended imidazolium ionic liquid as task-specific basic-IL for Suzuki and Heck reactions and for tandem Wittig-Suzuki, Wittig-Heck, Horner-Emmons-Suzuki, and Horner-Emmons-Heck protocols
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Facile, high yielding, one-pot methods for the synthesis of a library of diversely substituted bi-aryls, diarylethenes, and aryl-enoates, via Suzuki and Heck reactions, and by sequential Wittig-Suzuki, Wittig-Heck, Horner-Emmons-Suzuki, and Horner-Emmons-Heck reactions are reported. The reactions employ piperidine-appended imidazolium ionic liquid [PAIM][NTf2] as a task-specific basic-IL, butyl-methyl-imidazolium ionic liquid [BMIM][X] (X?=?PF6, BF4) as solvent, and catalytic amounts of Pd(OAc)2 with no other additives. Wittig and Horner-Emmons reactions are effected by reacting substituted benzaldehydes with 4-bromobenzyl-PPh3 (or bromomethyl-PPh3) phosphonium salts, or diethylphosphonate with bromobenzaldehydes respectively, to form the corresponding ethenes. Subsequent cross-coupling reactions are accomplished by addition of aryl-boronic acid or phenyl-ethenes along with Pd(OAc)2 to bring about the aforementioned hyphenated transformations. The feasibility to perform double-olefination via Wittig and Horner-Emmons reactions with dialdehydes to form highly conjugated bis-styryl and bis-enoate compounds is also shown. The [BMIM][X] solvent is recycled and reused.
- Savanur, Hemantkumar M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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p. 150 - 161
(2017/06/30)
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- Synthetic method of toluylene compound
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The invention relates to a synthetic method of a toluylene compound. According to the reaction, aryl halide or mixed halides and alkene bromine are used as a substrate. Under the action of a catalyst, a ligand, a reducing agent and an additive, the substrate in ice-water bath is slowly heated to room temperature and a mild reaction is carried out for 8-12 h so as to obtain the toluylene compound. The method has advantages of cheap catalyst metal, mild reaction, one-step reaction, simple step, short reaction time, safe operation, high yield, etc.
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Paragraph 0086; 0087; 0088; 0089; 0090
(2017/08/28)
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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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p. 105 - 112
(2017/06/19)
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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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- Orthopalladated complexes of phosphorus ylide: Poly(N-vinyl-2-pyrrolidone)-stabilized palladium nanoparticles as reusable heterogeneous catalyst for Suzuki and Heck cross-coupling reactions
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The phosphorus ylide [Ph3PCHC(O)C6H4-NO2–4] reacted with Pd(OAc)2 to give the C,C-orthometallated complex [Pd{κ2(C,C)-C6H4PPh2C(H)CO(C6H4-NO2–4)}(μ-OAc)]2, which underwent bridge exchange reaction with NaN3, NaCl, KBr and KI, respectively, to afford the binuclear C,C-orthopalladated complexes [Pd{κ2(C,C)-C6H4PPh2C(H)CO(C6H4-NO2–4)}(μ-X)]2 (X?=?N3 (1), Cl (2), Br (3) and I (4)). The complexes were identified using spectroscopy (infrared and NMR), CHNS technique and single-crystal X-ray structure analysis. Thereafter, palladium nanoparticles with narrow size distribution were easily prepared using the refluxing reaction of iodo-bridged orthopalladated complex 4 with poly(N-vinyl-2-pyrrolidone) (PVP) as the protecting group. The PVP-stabilized palladium nanoparticles were characterized using a variety of techniques including X-ray diffraction, transmission and scanning electron microscopies, energy-dispersive X-ray spectroscopy, inductively coupled plasma analysis and Fourier transform infrared spectroscopy. The catalytic activity of the PVP-stabilized palladium nanoparticles was evaluated in the Suzuki reaction of phenylboronic acid and the Heck reaction of styrene with aryl halides of varying electron densities. This catalyst exhibited excellent catalytic activity for Suzuki cross-coupling reactions in ethanol–water. Notably, aryl chlorides which are cheaper and more accessible than their bromide and iodide counterparts also reacted satisfactorily using this catalyst. After completion of reactions, the catalyst could be separated using a simple method and used many times in repeat cycles without considerable loss in its activity.
- Karami, Kazem,Abedanzadeh, Sedigheh,Vahidnia, Omolbanin,Herves, Pablo,Lipkowski, Janusz,Lyczko, Krzysztof
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- Palladium-Catalysed Cross-Coupling Reactions Controlled by Noncovalent Zn???N Interactions
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Non-covalent interactions between halopyridine substrates and catalytically inert building blocks, namely zinc(II)–porphyrins and zinc(II)–salphens, influence the catalytic outcome of Suzuki–Miyaura and Mizoroki–Heck palladium-catalysed cross-coupling reactions. The weak Zn???N interactions between halopyridine substrates and zinc(II)-containing porphyrins and salphens, respectively, were studied by a combination of 1H NMR spectroscopy, UV/Vis studies, Job-Plot analysis and, in some cases, X-ray diffraction studies. Additionally, the former studies revealed unique supramolecular polymeric and dimeric rearrangements in the solid state featuring weak Br???N (halogen bonding), C?H???π, Br???π and π???π interactions. The reactivity of halopyridine substrates in homogeneous palladium-catalysed cross-coupling reactions was found to correlate with the binding strength between the zinc(II)-containing scaffolds and the corresponding halopyridine. Such observation is explained by the unfavourable formation of inactive over-coordinated halopyridine???palladium species. The presented approach is particularly appealing for those cases in which substrates and/or products deactivate (or partially poison) a transition-metal catalyst.
- Kadri, Mohamed,Hou, Jingran,Dorcet, Vincent,Roisnel, Thierry,Bechki, Lazhar,Miloudi, Abdellah,Bruneau, Christian,Gramage-Doria, Rafael
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p. 5033 - 5043
(2017/04/18)
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- Oxidant-Controlled C-sp2/sp3-H Cross-Dehydrogenative Coupling of N-Heterocycles with Benzylamines
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Oxidant controlled ionic liquid mediated cross-dehydrogenative coupling (CDC) of benzylamines with N-heterocycles having sp2 or sp3 carbon resulted in the formation of C-benzoylated or alkenylated products. Benzoylation of N-heterocycles occurs via (NH4)2S2O8 catalyzed benzoyl radical formation. An oxidative alkenylation of N-heterocycles having C-sp3 carbon (2-methylaza-arenes) occurs via deamination of benzylamine followed by C-sp3-H bond activation in high stereoselectivity. Both benzoylation and alkenylation protocols are metal-free, green, simple, efficient, and tolerate a wide variety of functional groups.
- Sharma, Rohit,Abdullaha, Mohd,Bharate, Sandip B.
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p. 9786 - 9793
(2017/09/23)
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- A nitrogen and sulphur functionalized graphene oxide-palladium nanoparticle hybrid catalyst for an efficient Heck coupling
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A nanocomposite comprised of Pd nanoparticles supported on chemically modified graphene (CMG) has been fabricated. Morphological and chemical characterization of the CMG-PdNP heterostructure has been carried out using PXRD, FTIR, Raman, XPS, TEM, SEM, EDX, and ICP-MS studies. The material contains 25.93 wt% of Pd(0) nanoparticles, with a diameter of 10-20 nm, well-dispersed on highly reduced graphene oxide containing a C/O ratio of 5.48. The efficacy of the CMG-PdNP system as a catalyst towards Heck cross-coupling with a variety of functionalized substrates has been demonstrated. Functionalization of reduced graphene oxide with heteroatoms like sulfur and nitrogen enhanced its dispersibility in organic solvents, and helped in stabilizing the active palladium species by acting as a ligand. The CMG-Pd composite exhibited an excellent catalytic activity with a substantially low catalytic loading (0.02 mol%), and the activity sustainable up to three reaction cycles. The remarkable effect might be a manifestation of N and S coordination to Pd, facilitating a high degree of dispersion and stabilization of Pd NPs onto the graphene surface.
- Premi, Chanchal,Jain, Nidhi
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p. 74961 - 74967
(2016/08/24)
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- A pyridinium modified β-cyclodextrin: An ionic supramolecular ligand for palladium acetate in C-C coupling reactions in water
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An ionic Pd(ii) complex stabilized by a water soluble pyridinium modified β-cyclodextrin was prepared and characterized by NMR, mass spectrometry, FT-IR spectroscopy, UV-visible spectroscopy and DLS (dynamic light scattering). The resulting Pd(ii)@Pyr:β-CD complex showed very good catalytic activity in Suzuki-Miyaura and Heck C-C coupling reactions in an environmentally benign water medium. Good to excellent yields were obtained for the coupling of various aryl halides including chlorides with phenylboronic acid/styrene using a catalytic amount of Pd(ii)@Pyr:β-CD. This homogeneous catalyst can be reused and recycled more than six times with only marginal loss of its catalytic activity.
- Khan, Raihana Imran,Pitchumani, Kasi
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p. 5518 - 5528
(2016/10/21)
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- Geometry constrained N-(5,6,7-trihydroquinolin-8-ylidene)arylaminopalladium dichloride complexes: Catalytic behavior toward methyl acrylate (MA), methyl acrylate-co-norbornene (MA-co-NB) polymerization and heck coupling
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A new pair of plladium complexes (Pd4 and Pd5) ligated with constrained N-(5,6,7-trihydroquinolin-8-ylidene)arylamine ligands have been prepared and well characterized by 1H-, 13C-NMR and FTIR spectroscopies as well as elemental analysis. The molecular structure of Pd4 and Pd5 in solid state have also been determined by X-ray diffraction, showing slightly distorted square planar geometry around the palladium metal center. All complexes Pd1-Pd5 are revealed highly efficient catalyst in methyl acrylate (MA) polymerization as well as methyl acrylate/norbornene (MA/NB) copolymerization. In the case of MA polymerization, as high as 98.4% conversion with high molecular weight up to 6282 kg·mol-1 was achieved. Likewise, Pd3 complex has good capability to incorporate about 18% NB content into MA polymer chains. Furthermore, low catalyst loadings (0.002 mol %) of Pd4 or Pd5 are able to efficiently mediate the coupling of haloarenes with styrene affording up to 98% conversion.
- Zeng, Yanning,Mahmood, Qaiser,Liang, Tongling,Sun, Wen-Hua
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- Z-Stereoselective Aza-Peterson Olefinations with Bis(trimethylsilane) Reagents and Sulfinyl Imines
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Highly stereoselective aza-Peterson olefinations from bench-stable α,α-bis(trimethylsilyl)toluene reagents and N-substituted imines have been achieved using TMSO-/Bu4N+ as Lewis base activator in THF. Remarkably, and for the first time, N-t-butanesulfinyl imines were utilized for the synthesis of Z-stilbenes with excellent selectivities, while N-aryl imines generated E-stilbenes under identical reaction conditions. The protocol proved general for numerous examples with low molecular weight byproducts formed. The origin of the Z-selectivity is proposed to be a result of diastereoselective addition to N-t-butanesulfinyl imines followed by syn-elimination of an in situ formed hypervalent silicate.
- Das, Manas,OShea, Donal F.
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supporting information
p. 336 - 339
(2016/02/03)
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- Preparation of Vinyl Arenes by Nickel-Catalyzed Reductive Coupling of Aryl Halides with Vinyl Bromides
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This work emphasizes the synthesis of substituted vinyl arenes by reductive coupling of aryl halides with vinyl bromides under mild and easy-to-operate nickel-catalyzed reaction conditions. A broad range of aryl halides, including heteroaromatics, and vinyl bromides were employed to yielding products in moderate to excellent yields with high functional-group tolerance. The nickel-catalytic system displays good chemoselectivity between the two C(sp2)-halide coupling partners, thus demonstrating a mechanistic pathway distinct from other stepwise protocols.
- Liu, Jiandong,Ren, Qinghua,Zhang, Xinghua,Gong, Hegui
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supporting information
p. 15544 - 15548
(2016/12/09)
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- Br?nsted acid-catalysed conjugate addition of photochemically generated α-amino radicals to alkenylpyridines
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The conjugate addition of α-amino radicals to alkenylpyridines has been accomplished by the synergistic merger of Br?nsted acid and visible light photoredox catalysis. Key to reaction development was the protonation of the alkenylpyridines that transientl
- Hepburn, Hamish B.,Melchiorre, Paolo
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supporting information
p. 3520 - 3523
(2016/03/04)
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- Chemoselective Synthesis of Polysubstituted Pyridines from Heteroaryl Fluorosulfates
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A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib. A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib.
- Zhang, Enxuan,Tang, Jiaze,Li, Suhua,Wu, Peng,Moses, John E.,Sharpless, K. Barry
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supporting information
p. 5692 - 5697
(2016/04/20)
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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 37; 48-49; 54
(2015/06/18)
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- Manganese-Catalyzed Direct Nucleophilic C(sp2)-H Addition to Aldehydes and Nitriles
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Herein, a manganese-catalyzed nucleophilic addition of inert C(sp2)-H bonds to aldehydes and nitriles is disclosed by virtue of a dual activation strategy. The reactions feature mild reaction conditions, excellent regio- and stereoselectivity, and a wide substrate scope, which includes both aromatic and olefinic C-H bonds, as well as a large variety of aldehydes and nitriles. Moreover, mechanistic studies shed light on possible catalytic cycles.
- Zhou, Bingwei,Hu, Yuanyuan,Wang, Congyang
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p. 13659 - 13663
(2015/11/16)
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- Efficient E-Selective Transfer Semihydrogenation of Alkynes by Means of Ligand-Metal Cooperating Ruthenium Catalyst
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The manuscript describes an efficient protocol for the E-selective transfer semihydrogenation of internal alkynes employing a previously described bifunctional ruthenium-based PC(sp3)P complex, 20'mol% of sodium formate and nearly stoichiometric formic acid. Semihydrogenation of the terminal alkynes results in the formation of the corresponding styrenes. The mechanism of the reaction includes stepwise transfer of both the hydride and the proton of the formic acid to the substrate. This fact allowed for the development of a facile protocol for the synthesis of monodeuterated alkenes by simply applying formic acid/sodium formate/D2O mixture as a hydrogen source. High yields, selectivity and functional group compatibility have been generally achieved.
- Musa, Sanaa,Ghosh, Amrita,Vaccaro, Luigi,Ackermann, Lutz,Gelman, Dmitri
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supporting information
p. 2351 - 2357
(2015/07/27)
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- C(sp3)-H functionalization of methyl azaarenes: a calcium-catalyzed facile synthesis of (E)-2-styryl azaarenes and 2-aryl-1,3-bisazaarenes
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Alkaline earth (Ca2+) catalyzed sp3 C-H functionalization of methyl azaarenes for the synthesis of biologically important (E)-2-styryl azaarenes, 2-aryl-1,3-bisazaarenes and 3,3-bisazaarenyl indolinones has been described. Initially methyl azaarenes react with aryl aldehydes to give β-hydroxy derivatives, which undergo Ca(II) catalyzed thermodynamic elimination to give the styryl azaarenes in a single step. Similarly it may undergo SN1 reaction to give 2-aryl-1,3-bisazaarenes and 3,3-bisazaarenyl indolinones (if isatin used as the electrophile). This green synthetic methodology enjoys the simple reaction procedures, solvent free conditions, step economy, substrate diversity and high yields of the products in short time.
- Yaragorla, Srinivasarao,Singh, Garima,Dada, Ravikrishna
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supporting information
p. 5924 - 5929
(2015/11/02)
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