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Journal articles on the topic 'Nucleophilic'

Author: Grafiati

Published: 4 June 2021

Last updated: 6 September 2023

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1

Tsuji, Yutaka, and John P. Richard. "Swain–Scott relationships for nucleophile addition to ring-substituted phenonium ions." Canadian Journal of Chemistry 93, no. 4 (April 2015): 428–34. http://dx.doi.org/10.1139/cjc-2014-0337.

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The products of the reactions of 2-(4-methoxyphenyl)ethyl tosylate (MeO-1-OTs) and 2-(4-methyphenyl)ethyl tosylate (Me-1-OTs) with nucleophilic anions were determined for reactions in 50:50 (v/v) trifluoroethanol (TFE) / water at 25 °C. In many cases, the nucleophile selectivity kNu/ks ((mol/L)−1) for reactions of nucleophile and solvent, calculated from the ratio of product yields, depends upon [Nu−]. This demonstrates the existence of competing reaction pathways, which show different selectivities for reactions with nucleophiles. A 13C NMR analysis of the products of the reactions of substrate enriched with 13C at the α-carbon, X-1-[α-13C]OTs (X = −OCH3 or −Me), with nucleophilic anions in 50:50 (v/v) TFE/water at 25 °C shows the formation of X-1-[β-13C]OH, X-1-[β-13C]OCH2CF3, and X-1-[β-13C]Nu (Nu = Br, Cl, CH3CO2, or Cl2CHCO2) from the trapping of symmetrical phenonium ion reaction intermediates X-2+. The observation of excess label in the α-position, [α-13C]/[β-13C] > 1.0, for both the water and nucleophile adducts, shows that these nucleophiles also react by direct substitution at X-1-[α-13C]OTs. The ratios of product yields, [α-13C]/[β-13C], and observed nucleophile selectivity (kNu/ks)obs were used to dissect the contribution of nucleophile addition at Me-1-OTs and trapping of X-2+ to the product yields. The product yields from partitioning of the intermediate gave the nucleophile selectivity kNu/ks for X-2+. Swain–Scott plots of log(kNu/ks) are correlated by slopes of s = 0.78 and s = 0.73 for reactions of MeO-2+ and Me-2+, respectively. This shows that the sensitivity of bimolecular substitution at X-2+ to changes in nucleophile reactivity is smaller than for nucleophilic substitution at the methyl iodide.

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2

Barham, Joshua P., Matthew P. John, and John A. Murphy. "One-pot functionalisation of N-substituted tetrahydroisoquinolines by photooxidation and tunable organometallic trapping of iminium intermediates." Beilstein Journal of Organic Chemistry 10 (December 12, 2014): 2981–88. http://dx.doi.org/10.3762/bjoc.10.316.

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Nucleophilic trapping of iminium salts generated via oxidative functionalisation of tertiary amines is well established with stabilised carbon nucleophiles. The few reports of organometallic additions have limited scope of substrate and organometallic nucleophile. We report a novel, one-pot methodology that functionalises N-substituted tetrahydroisoquinolines by visible light-assisted photooxidation, followed by trapping of the resultant iminium ions with organometallic nucleophiles. This affords 1,2-disubstituted tetrahydroisoquinolines in moderate to excellent yields.

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3

Zhang, Yanbin, Ruiwen Jin, Guangxing Pan, and Hao Guo. "Light-enabled, AlCl3-catalyzed regioselective intramolecular nucleophilic addition of non-nucleophilic alkyls to alkynes." Chemical Communications 56, no. 78 (2020): 11621–24. http://dx.doi.org/10.1039/d0cc04636a.

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4

Eom, Ga-eul, and Seokhee Kim. "Identification of Nucleophilic Probes for Protease-Mediated Transpeptidation." Molecules 23, no. 9 (August 22, 2018): 2109. http://dx.doi.org/10.3390/molecules23092109.

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Proteases have evolved to mediate the hydrolysis of peptide bonds but may perform transpeptidation in the presence of a proper nucleophilic molecule that can effectively compete with water to react with the acyl-enzyme intermediate. There have been several examples of protease-mediated transpeptidation, but they are generally inefficient, and little effort has been made to systematically control the transpeptidation activity of other proteases with good nucleophiles. Here, we developed an on-bead screening approach to find a probe that functions efficiently as a nucleophile in the protease-mediated transpeptidation reaction, and we identified good probes for a model protease DegP. These probes were covalently linked to the C-termini of the cleaved peptides in a mild condition and made the selective enrichment of ligated peptides possible. We suggest that good nucleophilic probes can be found for many other proteases that act via acyl-enzyme intermediates, and these probes will help characterize their substrates.

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5

Selimović, Enisa, and Tanja Soldatović. "Study on the reactions between dichlorido[2,2′:6′,2″-terpyridine] zinc(II) and biologically relevant nucleophiles in aqueous solution." Progress in Reaction Kinetics and Mechanism 44, no. 2 (April 22, 2019): 105–13. http://dx.doi.org/10.1177/1468678319825724.

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Substitution reactions of square-pyramidal [ZnCl2(terpy)] complex (terpy = 2,2′:6′,2″-terpyridine) with biologically relevant nucleophiles such as imidazole, glutathione, 1,2,4-triazole, and pyrazine were investigated at pH 7.0 as a function of nucleophile concentration. The reactions were followed under pseudo first-order conditions by UV-Vis spectrophotometry. The substitution reactions comprised two steps of consecutive displacement of chlorido ligands. Different reaction pathways for the first reaction step of nucleophilic substitution were defined. The order of reactivity of the investigated nucleophiles for the first reaction was imidazole > glutathione > pyrazine > 1,2,4-triazole, while for the second reaction step it was pyrazine > 1,2,4-triazole > imidazole > glutathione.

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6

Kimura, Tsutomu. "Recent Advances in Magnesium Carbenoid Chemistry." Synthesis 49, no. 23 (September 12, 2017): 5105–19. http://dx.doi.org/10.1055/s-0036-1590894.

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Magnesium carbenoids are a class of organomagnesium species possessing a halo group at the α-position. The reactions of magnesium carbenoids can be classified into the following three categories: nucleophilic reactions resembling Grignard reagents, electrophilic reactions resembling organic halides, and rearrangements resembling carbenes. This short review summarizes recent studies on magnesium carbenoids reported between 2010 and 2016, and milestone studies reported before 2010 according to the classification of the reactions into the aforementioned three categories.1 Introduction2 Structures of Magnesium Carbenoids3 Reactions of Magnesium Carbenoids as Nucleophiles3.1 Nucleophilic Reactions of Magnesium Carbenoids3.2 Nucleophilic Reactions of Magnesium Alkylidene Carbenoids3.3 Nucleophilic Reactions of Cyclopropylmagnesium Carbenoids4 Electrophilic Reactions of Magnesium Carbenoids4.1 Reactions with Nucleophiles Followed by Electrophiles4.2 Reactions with Nucleophiles Possessing Electrophilic Functional Groups4.3 Nucleophilic Substitution Followed by β-Elimination5 Rearrangements of Magnesium Carbenoids5.1 1,2-Shifts of Magnesium Carbenoids5.2 1,3-C–H Insertions of Magnesium Carbenoids5.3 1,5-C–H Insertions of Magnesium Carbenoids5.4 [2+1] Cycloaddition of a Magnesium Carbenoid6 Conclusion and Outlook

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7

Dust, Julian M., and Richard A. Manderville. "Carbon versus oxygen nucleophilic selectivity in the reaction of the aryloxide ions, 2,6- and 3,5-di-tert-butylphenoxide, with the 2-[(nitro)\dn6 xaryl]-4,6-dinitrobenzotriazole 1-oxide series of super-electrophiles. Stereoelectronic factors on C-7 Meisenheimer complex formation versus C-1' SNAr displacement." Canadian Journal of Chemistry 76, no. 6 (June 1, 1998): 662–71. http://dx.doi.org/10.1139/v98-028.

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The 2-[(nitro)xaryl]-4,6-dinitrobenzotriazole 1-oxides (1, Pi-DNBT (x = 3); 2, DNP-DNBT (x = 2); 3, NP-DNBT (x = 1)) are electron-deficient nitro-substituted heteroaromatic substrates that possess two sites for nucleophilic attachment: C-7 and C-1'. Generally, attack at the super-electrophilic C-7 site yields spectroscopically observable anionic sigma -bonded adducts, whereas attack at C-1' leads to displacement products in an overall process of nucleophilic aromatic substitution (SNAr). To gain an understanding of the factors affecting C-1' versus C-7 attack by potentially ambident aryloxide (C- and O-)nucleophiles, we have monitored the reactions of 1-3 with 2,6-di-tert-butylphenoxide (2,6-ArO-) and 3,5-di-tert-butylphenoxide (3,5-ArO-) using 400 MHz 1H NMR spectroscopy (deuterated dimethyl sulfoxide solvent at ambient temperature). The results indicate that 2,6-ArO- acts only as a C-nucleophile with O-attack precluded, presumably by the sterically demanding tert-butyl groups flanking the O-nucleophilic centre. Although 2,6-ArO- reacts preferentially at C-7 of 1-3, the biphenyl derivative that arises from C-1' attack is also observed with 1, the first time that C-nucleophilic attack has been seen at this electrophilic site. In contrast, 3,5-ArO- acts only as an O-nucleophile, also as a consequence of the steric hindrance to the C-4 position; this aryloxide reacts entirely at C-1' of Pi-DNBT but also exclusively at C-7 of 3. However, with DNP-DNBT, 2, both the C-7 O-adduct and C-1' displacement products are noted; attack at C-1' is dominant. The selectivity (C-7 versus C-1') found in these reactions is discussed with emphasis given to stereoelectronic factors that may stabilize the putative C-1' O-adducts.Key words: aryloxides, super-electrophiles, Meisenheimer complexes, 2-[(nitro)xaryl]-4,6-dinitrobenzotriazole 1-oxides.

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8

Um, Ik-Hwan, Ji-Youn Lee, Sun-Young Bae, and Erwin Buncel. "Effect of modification of the electrophilic center on the α effect." Canadian Journal of Chemistry 83, no. 9 (September 1, 2005): 1365–71. http://dx.doi.org/10.1139/v05-157.

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We report on a nucleophilic study of esters R-C(=X)-Y-Ar in which the electrophilic center has been modified by replacing O by S in the leaving group or carbonyl center: 4-nitrophenyl acetate (1), S-4-nitrophenyl thioacetate (2), 4-nitrophenyl benzoate (3), and O-4-nitrophenyl thionobenzoate (4). The studies include O and S nucleophiles as well as α nucleophiles in H2O at 25.0 ± 0.1 °C. The sulfur nucleophile (4-chlorothiophenoxide, 4-ClPhS) exhibits significant enhanced reactivity for the reactions with thiol and thione esters 2 and 4 compared with their oxygen analogues 1 and 3. On the contrary, the common nucleophile OH is much less reactive towards 2 and 4 compared with 1 and 3. The effect of changing both the electrophilic center and the nucleofugic center on the reactivity of the other oxygen nucleophiles is not so significant: 4-chlorophenoxide (4-ClPhO) is four to six times more reactive in the reactions with thiol and thione esters 2 and 4 compared with their oxygen analogues 1 and 3. The α effects exhibited by butan-2,3-dione monoximate (Ox) and HOO are strongly dependent on the nature of the electrophilic center of the substrates, indicating that the difference in the ground-state solvation energy cannot be fully responsible for the α effect. Our results clearly emphasize the strong dependence of the α effect on the substrate structure, notably, the nature of the electrophilic center. The impact of change in the nucleofuge (1→2) and the electrophilic center (3→4) on reactivity indicates that α nucleophiles will need to be “purpose built” for decontamination and nucleophilic degradation of specific biocides.Key words: α effect, nucleophilicity, nucleofuge effect, electrophilicity, polarizability.

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9

Sheyi, Rotimi, Anamika Sharma, Ayman El-Faham, Beatriz G. de la Torre, and Fernando Albericio. "Phenol as a Modulator in the Chemical Reactivity of 2,4,6-Trichloro-1,3,5-triazine: Rules of the Game II." Australian Journal of Chemistry 73, no. 4 (2020): 352. http://dx.doi.org/10.1071/ch19524.

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2,4,6-Trichloro-1,3,5-triazine (TCT) is a privileged core that has the capacity to undergo sequential nucleophilic substitution reactions. Three nucleophiles, namely phenol, thiol and amine, were studied and the preferential order of incorporation on TCT was found to be first phenol, second thiol and third amine. The introduction of phenol was achieved at −20°C. The incorporation of this nucleophile in TCT helped to replace the third ‘Cl’ at 35°C, which is compatible with a biological context. The atomic charges on ‘Cl’ calculated by theoretical approaches were consistent with the experimental findings.

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10

Kolodiazhnyi, Oleg I. "Stereochemistry of electrophilic and nucleophilic substitutions at phosphorus." Pure and Applied Chemistry 91, no. 1 (January 28, 2019): 43–57. http://dx.doi.org/10.1515/pac-2018-0807.

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Abstract Nucleophilic and electrophilic substitutions are the most often applied reactions in organophosphorus chemistry. They are closely interrelated, because in a reacting pair always one reagent is an electrophile, and another nucleophile. The reactions of electrophilic and nucleophilic substitutions at the phosphorus center proceed via the formation of a pentacoordinated intermediate. The mechanism of nucleophilic substitution involves the exchange of ligands in the pentacoordinate phosphorane intermediate, leading to the more stable stereomer under the thermodynamic control. Electrophilic substitution proceeds with retention of absolute configuration, whereas nucleophilic substitution with inversion of configuration at the phosphorus center.

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11

Purwono, Bambang, and Estiana E. P. Daruningsih. "NUCHLEOPHILIC SUBSTITUTION REACTION OF CYANIDE AND METHOXYDE IONS TO QUATERNARY MANNICH BASE FROM VANILLIN." Indonesian Journal of Chemistry 7, no. 1 (June 15, 2010): 58–60. http://dx.doi.org/10.22146/ijc.21713.

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The nucleophilic substitution reaction to quaternary Mannich base from vanillin has been investigated. Mannich reaction to vanillin was carried out by refluxing mixture of vanillin, formaldehyde and dimethyl amine. Quaternary ammonium halide salt was obtained from reaction of Mannich vanillin base with methyl iodide in THF solvents and yielded 93.28%. Nucleophilic substituion to the halide salts with cyanide nucleophile produced 4-hidroxy-3-methoxy-5-(cyano)methylbenzaldehyde in 54.39% yield, with methoxyde ion obtained 4-hidroxy- 3-methoxy-5-(methoxy)-methyl-benzaldehide in 67.80% yield. The nucleophilic substitution reaction showed that substituen of trimethylamino quaternary Mannich base can act as a good leaving on nucleophilic reaction substitutions. Keywords: Mannich Reaction, Vanillin, nucleophilic substitution.

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12

Purwono, Bambang, and Estiana R. P. Daruningsih. "NUCLEOPHILIC SUBSTITUTION REACTION OF CYANIDE AND METHOXYDE IONS TO QUATERNARY MANNICH BASE FROM VANILLIN." Indonesian Journal of Chemistry 5, no. 3 (June 15, 2010): 203–6. http://dx.doi.org/10.22146/ijc.21789.

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The nucleophilic substitution reaction to quaternary Mannich base from vanillin has been investigated. Mannich reaction to vanillin was carried out by refluxing mixture of vanillin, formaldehyde and dimethyl amine. Quaternary ammonium halide salt was obtained from reaction of Mannich vanillin base with methyl iodide in THF solvents and yielded 93.28 %. Nucleophilic substituion to the halide salts with cyanide nucleophile produced 4-hidroxy-3-methoxy-5-(cyano)methylbenzaldehyde in 54.39% yield. Reaction with methoxyde ion yielded 4-hydroxy- 3-methoxy-5-(methoxy) -methylbenzaldehyde in 67.80% yield. The nucleophilic substitution reaction showed that trimethylamino substituent of quaternary Mannich base can act as a good leaving group on nucleophilic substitution reactions. Keywords: Mannich reaction, vanillin, nucleophilic substitution

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13

Vilotijevic, Ivan, Markus Lange, and You Zi. "Latent (Pro)Nucleophiles in Enantioselective Lewis Base Catalyzed Allylic Substitutions." Synlett 31, no. 13 (June 4, 2020): 1237–43. http://dx.doi.org/10.1055/s-0040-1707130.

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The use of latent nucleophiles, which are molecules that are not nucleophilic but can be activated to act as a nucleophile at an opportune time during the reaction, expands the scope of Lewis base catalyzed reactions. Here, we provide an overview of the concept and show examples of applications to N- and C-centered nucleophiles in allylic substitutions. N- and C-silyl compounds are superior latent (pro)nucleophiles in Lewis base catalyzed reactions with allylic fluorides in which the formation of the strong Si–F bond serves as the driving force for the reactions. The latent (pro)nucleophiles ensure high regioselectivity in these reactions and enable enantioselective transformations of Morita–Baylis–Hillman adducts by the use of common chiral Lewis base catalysts.1 Introduction2 Substitution of MBH Carbonates3 The Concept of Latent (Pro)Nucleophiles4 Enantioselective Allylation of N-Heterocycles5 Enantioselective Phosphonyldifluoromethylation of Allylic Fluorides6 Conclusion

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14

Kutschy, Peter, Pavol Kristian, Milan Dzurilla, Dušan Koščík, and Róbert Nádaskay. "Selectivity of nucleophilic addition to and substitution at isothiocyanatocarbonyl group. Reactions of 4-pentinoyl- and 2-(2-propinyl)-4-pentinoyl isothiocyanate with amines and methanol." Collection of Czechoslovak Chemical Communications 52, no. 4 (1987): 995–1005. http://dx.doi.org/10.1135/cccc19870995.

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4-Pentinoyl isothiocyanate reacts with primary and secondary amines by either nucleophilic addition to N=C=S group to yield the corresponding thioureas, or a nucleophilic substitution at the carbonyl group to give 4-pentinoic acid amides. The less nucleophilic diphenylamine reacts selectively to afford the product of nucleophilic addition only. 2-(2-Propinyl)-4-pentinoyl isothiocyanate, having a sterically hindered carbonyl group, furnished with primary amines a mixture of amides and thioureas, whereas the bulkier secondary amines react selectively to form thioureas only. Both isothiocyanates afford with methanol as a nucleophile exclusively the corresponding O-methyl monothiocarbamates.

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15

Sengee, Myagmarsuren, and Leiv K. Sydnes. "Specific conjugate addition to α,β-acetylenic ketones." Pure and Applied Chemistry 83, no. 3 (February 3, 2011): 587–96. http://dx.doi.org/10.1351/pac-con-10-10-24.

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A variety of α,β-unsaturated acetylenic ketones, prepared in good yields from 3,3,4,4-tetraethoxybut-1-yne (TEB), have been reacted with selected mono- and bis-nucleophilic reagents. The mononucleophiles react in a Michael fashion and give in most cases the corresponding α,β-unsaturated alkenones in good yield. Many of the alkenes are formed as single stereoisomers, but the configuration depends on the nature of the nucleophile. If hydrogen bonds can be formed, the Z geometry is preferred, otherwise the E geometry is completely predominant. Experiments have also uncovered that α,β-unsaturated acetylenic ketones with a gem-diethoxy moiety in the α' position decompose when reacted with sodium hydroxide in aqueous tetrahydrofuran (THF); the carbonyl group is attacked and a carboxylic acid and a terminal alkyne are formed. If the nucleophiles contain two nucleophilic centers or if the α,β-unsaturated acetylenic ketones contain an additional reactive group, such as a hydroxyl group or an acyloxy moiety, useful secondary reactions may occur. By taking advantage of such secondary transformations, two completely regioselective syntheses of furans have so far been developed.

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16

Fang, Yao-ren, Zhu-gen Lai, and Kenneth Charles Westaway. "Isotope effects in nucleophilic substitution reactions X. The effect of changing the nucleophilic atom on ion-pairing in an SN2 reaction." Canadian Journal of Chemistry 76, no. 6 (June 1, 1998): 758–64. http://dx.doi.org/10.1139/v98-056.

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The effect of ion-pairing in an SN2 reaction is very different when the nucleophilic atom is changed from sulfur to oxygen, i.e., changing the nucleophile from thiophenoxide ion to phenoxide ion. When the nucleophile is sodium thiophenoxide, ion-pairing markedly alters the secondary α -deuterium kinetic isotope effect (transition state structure) and the substituent effect found by changing the para substituent on the nucleophile. When the nucleophile is sodium phenoxide, ion-pairing does not significantly affect the secondary α -deuterium or the chlorine leaving group kinetic isotope effects (transition state structure) or the substituent effects found by changing a para substituent on the nucleophile or the substrate. The different effects of ion-pairing may occur because the electron density on the hard oxygen atom of the sodium phenoxide is not affected significantly by ion-pairing.Key words: nucleophilic substitution, SN2, kinetic isotope effect, transition state, substituent effects, ion-pair.

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17

Mahajan, Dinesh, Varun Kumar, Anil Rana, Chhuttan Lal Meena, Nidhi Sharma, and Yashwant Kumar. "Electrophilic Activation of Carboxylic Anhydrides for Nucleophilic Acylation Reactions." Synthesis 50, no. 19 (August 14, 2018): 3902–10. http://dx.doi.org/10.1055/s-0037-1609564.

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Nucleophilic acylation of symmetrical carboxylic anhydrides has inherited limitation of reaction efficiency along with relatively poor reactivity. Traditionally, one equivalent carboxylic acid is generated during nucleophilic acylation of a symmetrical anhydride, which always limits the yield of final product to 50% or less. This is a major drawback, which discourages the use of anhydrides for laboratory or industrial applications. Electrophilic activation of carboxylic anhydride using methanesulfonyl chloride is found to be an efficient method for nucleophilic acylation, which increases product yield by restricting the formation of corresponding acid as a side product. The developed protocol found to be a mild and high yielding methodology for one-pot nucleophilic acylation of carboxylic anhydrides with several type of N- and S-nucleophiles demonstrating appreciable functional group tolerance.

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18

Ajenjo, Javier, Martin Greenhall, Camillo Zarantonello, and Petr Beier. "Synthesis and nucleophilic aromatic substitution of 3-fluoro-5-nitro-1-(pentafluorosulfanyl)benzene." Beilstein Journal of Organic Chemistry 12 (February 3, 2016): 192–97. http://dx.doi.org/10.3762/bjoc.12.21.

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3-Fluoro-5-nitro-1-(pentafluorosulfanyl)benzene was prepared by three different ways: as a byproduct of direct fluorination of 1,2-bis(3-nitrophenyl)disulfane, by direct fluorination of 4-nitro-1-(pentafluorosulfanyl)benzene, and by fluorodenitration of 3,5-dinitro-1-(pentafluorosulfanyl)benzene. The title compound was subjected to a nucleophilic aromatic substitution of the fluorine atom with oxygen, sulfur and nitrogen nucleophiles affording novel (pentafluorosulfanyl)benzenes with 3,5-disubstitution pattern. Vicarious nucleophilic substitution of the title compound with carbon, oxygen, and nitrogen nucleophiles provided 3-fluoro-5-nitro-1-(pentafluorosulfanyl)benzenes substituted in position four.

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19

Zhang, Xiao, Guo-ping Lu, and Chun Cai. "Facile aromatic nucleophilic substitution (SNAr) reactions in ionic liquids: an electrophile–nucleophile dual activation by [Omim]Br for the reaction." Green Chemistry 18, no. 20 (2016): 5580–85. http://dx.doi.org/10.1039/c6gc01742h.

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20

Song, Wangze, Ming Li, Junnan He, Junhao Li, Kun Dong, and Yubin Zheng. "Copper-catalyzed tandem annulation/enol nucleophilic addition to access multisubstituted indoles." Organic & Biomolecular Chemistry 17, no. 10 (2019): 2663–69. http://dx.doi.org/10.1039/c9ob00181f.

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21

da Silva, Gabriel, Eric M. Kennedy, and Bogdan Z. Dlugogorski. "Nucleophilic Catalysis of Nitrosation: Relationship between Nitrosating Agent Equilibrium Constant and Catalyst Nucleophilicity." Journal of Chemical Research 2002, no. 12 (December 2002): 589–90. http://dx.doi.org/10.3184/030823402103171069.

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22

Gao, Yu-Qi, Yi Hou, Liming Zhu, Junhan Chen, Ruoxin Li, Sheng-Yong Zhang, Yu-Peng He, and Weiqing Xie. "Visible-light driven synthesis of polycyclic benzo[d][1,3]oxazocine from 2-aminochalcone." Chemical Communications 56, no. 49 (2020): 6739–42. http://dx.doi.org/10.1039/d0cc02416c.

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23

Arcadi, Antonio, Giancarlo Fabrizi, Andrea Fochetti, Francesca Ghirga, Antonella Goggiamani, Antonia Iazzetti, Federico Marrone, Giulia Mazzoccanti, and Andrea Serraiocco. "Palladium-catalyzed Tsuji–Trost-type reaction of benzofuran-2-ylmethyl acetates with nucleophiles." RSC Advances 11, no. 2 (2021): 909–17. http://dx.doi.org/10.1039/d0ra09601f.

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24

Aimi, Takahiro, Tomohiro Meguro, Akihiro Kobayashi, Takamitsu Hosoya, and Suguru Yoshida. "Nucleophilic transformations of azido-containing carbonyl compounds via protection of the azido group." Chemical Communications 57, no. 49 (2021): 6062–65. http://dx.doi.org/10.1039/d1cc01143j.

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25

Dust, Julian M., and Erwin Buncel. "Reactions of the super-electrophile, 2-(2′,4′-dinitrophenyl)-4,6-dinitrobenzotriazole 1-oxide, with methoxide and tert-butoxide: basicity and steric hindrance as factors in σ-complex formation versus nucleophilic displacement." Canadian Journal of Chemistry 69, no. 6 (June 1, 1991): 978–86. http://dx.doi.org/10.1139/v91-143.

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The course of the reactions of methoxide and tert-butoxide with 2-(2′,4′-dinitrophenyl)-4,6-dinitrobenzotriazole 1-oxide (4) clearly shows that the C-7 electrophilic site is significantly more reactive than the C-1′ site of the substrate. The reaction pathways of these alkoxides, which differ in basicity (as a measure of nucleophilicity) and steric bulk, were followed by 400 MHz 1H nuclear magnetic resonance spectroscopy. While both alkoxides lead to immediate formation of the respective C-7 anionic σ-adducts, a greater percentage of C-7 adduct formation occurs with methoxide as attacking nucleophile. Reaction with excess alkoxide results in attack at C-1′ being observed, as well. This leads to formation of metastable C-1′ σ-adducts, whose rapid decomposition results in formation of 2,4-dinitrophenyl ethers and the dinitrobenzotriazole 1-oxyanion in an overall nucleophilic displacement reaction. Under these excess conditions, methoxide also causes a faster rate of displacement than does tert-butoxide as nucleophile. These results are discussed on the basis of the basicity of the nucleophiles, the relative electrophilicity of the positions in the substrate (C-7 versus C-1′), the steric hindrance involved in attack and in the resultant C-7 and C-1′ complexes, and in terms of an activation energy/reaction coordinate profile comparing the pathways for attack at the two electrophilic sites. Key words: anionic σ-complexes, super-electrophiles, aromatic nucleophilic substitution (SN Ar).

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26

Rani, Poonam, and Rajendra Srivastava. "Nucleophilic addition of amines, alcohols, and thiophenol with epoxide/olefin using highly efficient zirconium metal organic framework heterogeneous catalyst." RSC Advances 5, no. 36 (2015): 28270–80. http://dx.doi.org/10.1039/c5ra00921a.

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27

Nudelman, Norma Sbarbati, Cecilia E. Silvana Alvaro, Monica Savini, Viviana Nicotra, and Jeannette Yankelevich. "Effects of the Nucleophile Structure on the Mechanisms of Reaction of 1-Chloro-2,4-dinitrobenzene with Aromatic Amines in Aprotic Solvents." Collection of Czechoslovak Chemical Communications 64, no. 10 (1999): 1583–93. http://dx.doi.org/10.1135/cccc19991583.

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The kinetics of reactions of 1-chloro-2,4-dinitrobenzene with aniline and several substituted aromatic amines, B, in toluene shows a quadratic dependence of the second-order rate constant, kA, on [B], which is preserved even in the presence of increasing amounts of dimethylaniline, while the reaction with N-methylaniline shows a linear dependence of kA vs [B]. All these results are interpreted by the "dimer nucleophile" mechanism, and confirmed by the effects of a non-nucleophilic hydrogen bond acceptor tertiary amine which show the relevance of the structure of the nucleophile and the role of mixed aggregates in defining the mechanisms of aromatic nucleophilic substitutions with amines in aprotic solvents.

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28

Schmidt, Andreas, and Thorsten Mordhorst. "Syntheses and Properties of Di- and Tricationic Hetarenium-Substituted Pyrimidines." Zeitschrift für Naturforschung B 61, no. 4 (April 1, 2006): 396–405. http://dx.doi.org/10.1515/znb-2006-0405.

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2,4-Dichloro-, 4,6-dichloro-, 2,4,6-trichloro- and tetrachloropyrimidine undergo nucleophilic displacements by 4-(dimethylamino)pyridine to give (pyrimidine-2,4-diyl)-1,1’-bis[4-(dimethylamino) pyridinium] dichloride, (pyrimidine-4,6-diyl)-1,1’-bis[4-(dimethylamino)-pyridinium] dichloride, (pyrimidine-2,4,6-triyl)-1,1’,1”-tris[4-(dimethylamino)pyridinium] trichloride, and (5- chloropyrimidine-2,4,6-triyl)-1,1’,1”-tris[4-(dimethylamino)pyridinium] trichloride, respectively. Nucleophilic substitutions of the pyridinium substituents by O- and S-nucleophiles to functionalized pyrimidines are examined

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29

McNeish, Joanne R., J. Scott Parent, and Ralph A. Whitney. "Halogenated poly(isobutylene-co-isoprene): influence of halogen leaving-group and polymer microstructure on chemical reactivity." Canadian Journal of Chemistry 91, no. 6 (June 2013): 420–27. http://dx.doi.org/10.1139/cjc-2013-0068.

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Brominated (BIIR) and chlorinated (CIIR) poly(isobutylene-co-isoprene) are commercially available materials commonly known as halobutyl rubbers. The effect of leaving-group ability on the reactivity of halogenated poly(isobutylene-co-isoprene) was studied to place iodobutyl rubber reactivity into context with these materials. The effect of microstructure on reactivity of existing commercial materials was studied through comparison to that of polymers containing rearranged halomethyl (r-CIIR, r-BIIR, and r-IIIR) microstructure (prepared from as-received BIIR). The effect of leaving group on both thermal stability and reactivity towards nucleophilic substitution with acetate, N-butylimidazole, and sulfur was examined. The material containing the iodomethyl microstructure (r-IIIR) readily underwent nucleophilic substitution at low temperatures; however, it was extremely sensitive towards dehydrohalogenation at temperatures above 65 °C. At temperatures between 100 and 135 °C, the material containing the bromomethyl microstructure (r-BIIR) demonstrated the greatest balance between reactivity toward nucleophilic substitution and elimination through dehydrohalogenation. Exceptional thermal stability at temperatures up to 190 °C was displayed by the material containing the chloromethyl microstructure (r-CIIR); however, its reactivity towards nucleophiles was variable and nucleophile dependent. Sulfur vulcanization studies showed a clear effect of microstructure on the ability to cure with sulfur. While commercial chlorobutyl rubber has no ability to cure with sulfur alone, when rearranged to its chloromethyl microstructure (r-CIIR), curing occurs readily. Both commercial (BIIR) and rearranged (r-BIIR) bromobutyl rubber readily vulcanize in the presence of sulfur; however, BIIR cures to a greater extent.

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30

Benchoam, Dayana, Jonathan A. Semelak, Ernesto Cuevasanta, Mauricio Mastrogiovanni, Juan S. Grassano, Gerardo Ferrer-Sueta, Ari Zeida, et al. "Acidity and nucleophilic reactivity of glutathione persulfide." Journal of Biological Chemistry 295, no. 46 (September 1, 2020): 15466–81. http://dx.doi.org/10.1074/jbc.ra120.014728.

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Persulfides (RSSH/RSS−) participate in sulfur trafficking and metabolic processes, and are proposed to mediate the signaling effects of hydrogen sulfide (H2S). Despite their growing relevance, their chemical properties are poorly understood. Herein, we studied experimentally and computationally the formation, acidity, and nucleophilicity of glutathione persulfide (GSSH/GSS−), the derivative of the abundant cellular thiol glutathione (GSH). We characterized the kinetics and equilibrium of GSSH formation from glutathione disulfide and H2S. A pKa of 5.45 for GSSH was determined, which is 3.49 units below that of GSH. The reactions of GSSH with the physiologically relevant electrophiles peroxynitrite and hydrogen peroxide, and with the probe monobromobimane, were studied and compared with those of thiols. These reactions occurred through SN2 mechanisms. At neutral pH, GSSH reacted faster than GSH because of increased availability of the anion and, depending on the electrophile, increased reactivity. In addition, GSS− presented higher nucleophilicity with respect to a thiolate with similar basicity. This can be interpreted in terms of the so-called α effect, i.e. the increased reactivity of a nucleophile when the atom adjacent to the nucleophilic atom has high electron density. The magnitude of the α effect correlated with the Brønsted nucleophilic factor, βnuc, for the reactions with thiolates and with the ability of the leaving group. Our study constitutes the first determination of the pKa of a biological persulfide and the first examination of the α effect in sulfur nucleophiles, and sheds light on the chemical basis of the biological properties of persulfides.

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31

Cassagne, Thierry, Henri-Jean Cristau, Gérard Delmas, Michel Desgranges, Claude Lion, Gilbert Magnaud, Έliane Torreilles, and David Virieux. "Comparative Evaluation of Oxidising and Nucleophilic Properties of Some α-Nucleophiles." Journal of Chemical Research 2002, no. 7 (July 2002): 336–38. http://dx.doi.org/10.3184/030823402103172194.

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Six α-nucleophiles were evaluated at pH = 8 in an aqueous methanolic solution for their oxidising power towards tetrahydrothiophene, and the nucleophilic properties towards paraoxon. MMPP and m-CPBA are the most versatile reagents and can act as nucleophiles as well as oxidising agents.

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32

Oh, Young-Ho, Hyoju Choi, Chanho Park, Dong Wook Kim, and Sungyul Lee. "Harnessing Ionic Interactions and Hydrogen Bonding for Nucleophilic Fluorination." Molecules 25, no. 3 (February 7, 2020): 721. http://dx.doi.org/10.3390/molecules25030721.

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We review recent works for nucleophilic fluorination of organic compounds in which the Coulombic interactions between ionic species and/or hydrogen bonding affect the outcome of the reaction. SN2 fluorination of aliphatic compounds promoted by ionic liquids is first discussed, focusing on the mechanistic features for reaction using alkali metal fluorides. The influence of the interplay of ionic liquid cation, anion, nucleophile and counter-cation is treated in detail. The role of ionic liquid as bifunctional (both electrophilic and nucleophilic) activator is envisaged. We also review the SNAr fluorination of diaryliodonium salts from the same perspective. Nucleophilic fluorination of guanidine-containing of diaryliodonium salts, which are capable of forming hydrogen bonds with the nucleophile, is exemplified as an excellent case where ionic interactions and hydrogen bonding significantly affect the efficiency of reaction. The origin of experimental observation for the strong dependence of fluorination yields on the positions of -Boc protection is understood in terms of the location of the nucleophile with respect to the reaction center, being either close to far from it. Recent advances in the synthesis of [18F]F-dopa are also cited in relation to SNAr fluorination of diaryliodonium salts. Discussions are made with a focus on tailor-making promoters and solvent engineering based on ionic interactions and hydrogen bonding.

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33

Li, Jinhua, Zhengyu Lu, Yuhui Hua, Dafa Chen, and Haiping Xia. "Carbolong chemistry: nucleophilic aromatic substitution of a triflate functionalized iridapentalene." Chemical Communications 57, no. 68 (2021): 8464–67. http://dx.doi.org/10.1039/d1cc03261e.

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34

Cheng, Huayu, Xiaofan Zhou, Anjing Hu, Shiteng Ding, Yimo Wang, Yuanjing Xiao, and Junliang Zhang. "Thioether-functionalized trifluoromethyl-alkynes, 1,3-dienes and allenes: divergent synthesis from reaction of 2-trifluoromethyl-1,3-conjugated enynes with sulfur nucleophiles." RSC Advances 8, no. 59 (2018): 34088–93. http://dx.doi.org/10.1039/c8ra07834c.

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A divergent synthesis of thioether-functionalized trifluoromethyl-alkynes, 1,3-dienes and allenes viaregioselective nucleophilic addition of sulfur nucleophiles to 2-trifluoromethyl-1,3-conjugated enynes was developed.

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35

Damas, Liliana, Rui M. B. Carrilho, Sandra C. C. Nunes, Alberto A. C. C. Pais, László Kollár, Marta Pineiro, and Mariette M. Pereira. "A novel Pd-catalysed sequential carbonylation/cyclization approach toward bis- N -heterocycles: rationalization by electronic structure calculations." Royal Society Open Science 5, no. 9 (September 2018): 181140. http://dx.doi.org/10.1098/rsos.181140.

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An unprecedented palladium-catalysed sequential aminocarbonylation/cyclization synthetic strategy, using carbon monoxide and structurally different aliphatic diamines as N -nucleophiles, gives access, in one pot, to a new family of indole-based N -heterocyclic derivatives (hydropyrazinones, benzodiazepinones and hydroquinoxalines). Optimization of the reaction conditions towards double carbonylation ( P CO = 30 bar, T = 80°C, iodoindole/diamine ratio = 1 : 1.5, toluene as solvent) allowed the target cyclic products, which are formed in situ via intramolecular cyclization of the ketocarboxamide intermediates, to be obtained through a nucleophilic addition/elimination reaction with the pendant terminal amine groups. The structure of the diamine nucleophile was revealed to affect the reaction's selectivity, with the best yields for the cyclic products being obtained in the presence of (1 S , 2S )-(+)-cyclohexane-1,2-diamine ( a ) as the nucleophile, using either 5- or 7-iodoindole as the substrate. The reaction's selectivity was rationalized based on electronic structure calculations, which explain the effect of the diamine structure on the predominant formation of the cyclic products.

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36

Vasilenko, Dmitry A., Sevastian E. Dronov, Dzianis U. Parfiryeu, Kirill S. Sadovnikov, Kseniya N. Sedenkova, Yuri K. Grishin, Victor B. Rybakov, Tamara S. Kuznetsova, and Elena B. Averina. "5-Nitroisoxazoles in SNAr reactions: access to polysubstituted isoxazole derivatives." Organic & Biomolecular Chemistry 19, no. 29 (2021): 6447–54. http://dx.doi.org/10.1039/d1ob00816a.

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An efficient protocol for the straightforward functionalization of the isoxazole ring via the reactions of aromatic nucleophilic substitution of the nitro group with various nucleophiles has been elaborated.

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37

Liljenberg, Magnus, Tore Brinck, Tobias Rein, and Mats Svensson. "Utilizing the σ-complex stability for quantifying reactivity in nucleophilic substitution of aromatic fluorides." Beilstein Journal of Organic Chemistry 9 (April 23, 2013): 791–99. http://dx.doi.org/10.3762/bjoc.9.90.

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A computational approach using density functional theory to compute the energies of the possible σ-complex reaction intermediates, the “σ-complex approach”, has been shown to be very useful in predicting regioselectivity, in electrophilic as well as nucleophilic aromatic substitution. In this article we give a short overview of the background for these investigations and the general requirements for predictive reactivity models for the pharmaceutical industry. We also present new results regarding the reaction rates and regioselectivities in nucleophilic substitution of fluorinated aromatics. They were rationalized by investigating linear correlations between experimental rate constants (k) from the literature with a theoretical quantity, which we call the sigma stability (SS). The SS is the energy change associated with formation of the intermediate σ-complex by attachment of the nucleophile to the aromatic ring. The correlations, which include both neutral (NH3) and anionic (MeO−) nucleophiles are quite satisfactory (r = 0.93 to r = 0.99), and SS is thus useful for quantifying both global (substrate) and local (positional) reactivity in SNAr reactions of fluorinated aromatic substrates. A mechanistic analysis shows that the geometric structure of the σ-complex resembles the rate-limiting transition state and that this provides a rationale for the observed correlations between the SS and the reaction rate.

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38

Hudson, R., N. P. Bizier, K. N. Esdale, and J. L. Katz. "Synthesis of indoles, benzofurans, and related heterocycles via an acetylene-activated SNAr/intramolecular cyclization cascade sequence in water or DMSO." Organic & Biomolecular Chemistry 13, no. 8 (2015): 2273–84. http://dx.doi.org/10.1039/c4ob02549k.

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The synthesis of 2-substituted indoles and benzofurans was achieved by nucleophilic aromatic substitution, followed by subsequent 5-endo-dig cyclization between the nucleophile and an ortho acetylene.

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39

Burianova, Valeria K., Dmitrii S. Bolotin, Alexander S. Mikherdov, Alexander S. Novikov, Pennie Petrus Mokolokolo, Andreas Roodt, Vadim P. Boyarskiy, et al. "Mechanism of generation of closo-decaborato amidrazones. Intramolecular non-covalent B–H⋯π(Ph) interaction determines stabilization of the configuration around the amidrazone CN bond." New Journal of Chemistry 42, no. 11 (2018): 8693–703. http://dx.doi.org/10.1039/c8nj01018h.

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40

Charushin, V. N., and O. N. Chupakhin. "SNH methodology and new approaches to condensed heterocyclic systems." Pure and Applied Chemistry 76, no. 9 (September 30, 2004): 1621–31. http://dx.doi.org/10.1351/pac200476091621.

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The review surveys the reactions of electron-deficient azaaromatic compounds with mono- and bifunctional nucleophilies in which a nucleophilic attack at the unsubstituted CH carbon of an aromatic ring is one of the key steps. Use of the SNH methodology for the synthesis of fused heterocyclic systems by means of nucleophilic addition –addition AN–AN, addition –substitution of hydrogen AN–SNH, tandem substitution of hydrogen SNH–SNH, and other strategies will be discussed. Intramolecular SNH reactions will also be considered as effective synthetic tools to obtain condensed heterocyclic systems.

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41

Imada, Yasushi, Yukihiro Arakawa, Shun Ueta, Takuma Okamoto, and Keiji Minagawa. "Nucleophilic Addition to Nitrones Using a Flow Microreactor." Synlett 31, no. 09 (February 18, 2020): 866–70. http://dx.doi.org/10.1055/s-0039-1691601.

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Nucleophilic addition reactions of soft carbon nucleophiles to nitrones in a flow microreactor are reported for the first time. Under microflow conditions at 30 to 0 °C, a range of nitrones can be efficiently transformed into the corresponding oxyiminium ions by reaction with either acyl halides or trialkylsilyl triflates. These can subsequently undergo the addition of nucleophiles including allyltributylstannane, ketene methyl tert-butyldimethylsilyl acetal, and N-silyl ketene imines to afford the corresponding adducts in high yields; such reactions at a similar temperature under batch conditions resulted in lower yields because of undesired side reactions.

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42

Cuesta, Sebastián A., F. Javier Torres, Luis Rincón, José Luis Paz, Edgar A. Márquez, and José R. Mora. "Effect of the Nucleophile’s Nature on Chloroacetanilide Herbicides Cleavage Reaction Mechanism. A DFT Study." International Journal of Molecular Sciences 22, no. 13 (June 26, 2021): 6876. http://dx.doi.org/10.3390/ijms22136876.

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In this study, the degradation mechanism of chloroacetanilide herbicides in the presence of four different nucleophiles, namely: Br−, I−, HS−, and S2O3−2, was theoretically evaluated using the dispersion-corrected hybrid functional wB97XD and the DGDZVP as a basis set. The comparison of computed activation energies with experimental data shows an excellent correlation (R2 = 0.98 for alachlor and 0.97 for propachlor). The results suggest that the best nucleophiles are those where a sulfur atom performs the nucleophilic attack, whereas the other species are less reactive. Furthermore, it was observed that the different R groups of chloroacetanilide herbicides have a negligible effect on the activation energy of the process. Further insights into the mechanism show that geometrical changes and electronic rearrangements contribute 60% and 40% of the activation energy, respectively. A deeper analysis of the reaction coordinate was conducted, employing the evolution chemical potential, hardness, and electrophilicity index, as well as the electronic flux. The charge analysis shows that the electron density of chlorine increases as the nucleophilic attack occurs. Finally, NBO analysis indicates that the nucleophilic substitution in chloroacetanilides is an asynchronous process with a late transition state for all models except for the case of the iodide attack, which occurs through an early transition state in the reaction.

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43

Lu, Ju-You, Bo Zhao, Yongmei Du, Jianxin Yang, and Jian Lu. "Transition-metal-free direct nucleophilic substitution of carboranyllithium and 2-halopyridines." Organic & Biomolecular Chemistry 17, no. 32 (2019): 7438–41. http://dx.doi.org/10.1039/c9ob00978g.

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An efficient C(cage)–heteroarylation of carborane is presented, via direct nucleophilic substitution of carboranyllithium with 2-halopyridines under transition-metal-free conditions. The process utilizes readily available carboranyllithium nucleophile, and exhibits a broad substrate scope.

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44

Crossley, Maxwell J., Lionel G. King, Simon M. Pyke, and Charles W. Tansey. "Reaction of 5-nitro-octaethylporphyrins with nucleophiles." Journal of Porphyrins and Phthalocyanines 06, no. 11 (November 2002): 685–94. http://dx.doi.org/10.1142/s1088424602000816.

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An investigation of the reactions of metallo-5-nitro-2,3,7,8,12,13,17,18-octaethylporphyrins with Grignard reagents, benzyl oxide, phenoxide and benzenethiolate nucleophiles shows that, except for benzenethiolate reactions, they are less efficient than related reactions of metallo-2-nitro-5,10,15,20-tetraarylporphyrins. Treatment of free-base and nickel(II) 5-nitro-octaethylporphyrin with the “soft” nucleophile benzenethiolate in DMF affords the corresponding 5-phenylthioporphyrins in 61 and 72% yield, respectively, by ipso-substitution of the nitro group. In contrast, with methylmagnesium iodide and benzyl oxide, “hard” nucleophiles, attack is at the diagonally opposite 15-position of the ring to give 15-substituted 5-nitroporphyrin while with phenoxide and more substituted Grignard reagents, electron-transfer reactions lead to denitration to (metallo)-octaethylporphyrin or reduction to the corresponding 5-aminoporphyrin. The lower efficiency of the latter reactions, compared to those on 2-nitro-tetraarylporphyrin analogues, is a consequence of two factors, higher energies being required for initial nucleophilic attack as macrocyclic aromaticity is lost in intermediates and the susceptibility of the resultant “non-aromatic” intermediates to further attack.

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45

Zhang, Xin, Jingyun Ren, Siu Min Tan, Davin Tan, Richmond Lee, and Choon-Hong Tan. "An enantioconvergent halogenophilic nucleophilic substitution (SN2X) reaction." Science 363, no. 6425 (January 24, 2019): 400–404. http://dx.doi.org/10.1126/science.aau7797.

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Bimolecular nucleophilic substitution (SN2) plays a central role in organic chemistry. In the conventionally accepted mechanism, the nucleophile displaces a carbon-bound leaving group X, often a halogen, by attacking the carbon face opposite the C–X bond. A less common variant, the halogenophilic SN2X reaction, involves initial nucleophilic attack of the X group from the front and as such is less sensitive to backside steric hindrance. Herein, we report an enantioconvergent substitution reaction of activated tertiary bromides by thiocarboxylates or azides that, on the basis of experimental and computational mechanistic studies, appears to proceed via the unusual SN2X pathway. The proposed electrophilic intermediates, benzoylsulfenyl bromide and bromine azide, were independently synthesized and shown to be effective.

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46

Bertuzzi, Giulio, Luca Bernardi, and Mariafrancesca Fochi. "Nucleophilic Dearomatization of Activated Pyridines." Catalysts 8, no. 12 (December 6, 2018): 632. http://dx.doi.org/10.3390/catal8120632.

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Amongst nitrogen heterocycles of different ring sizes and oxidation statuses, dihydropyridines (DHP) occupy a prominent role due to their synthetic versatility and occurrence in medicinally relevant compounds. One of the most straightforward synthetic approaches to polysubstituted DHP derivatives is provided by nucleophilic dearomatization of readily assembled pyridines. In this article, we collect and summarize nucleophilic dearomatization reactions of - pyridines reported in the literature between 2010 and mid-2018, complementing and updating previous reviews published in the early 2010s dedicated to various aspects of pyridine chemistry. Since functionalization of the pyridine nitrogen, rendering a (transient) pyridinium ion, is usually required to render the pyridine nucleus sufficiently electrophilic to suffer the attack of a nucleophile, the material is organized according to the type of N-functionalization. A variety of nucleophilic species (organometallic reagents, enolates, heteroaromatics, umpoled aldehydes) can be productively engaged in pyridine dearomatization reactions, including catalytic asymmetric implementations, providing useful and efficient synthetic platforms to (enantioenriched) DHPs. Conversely, pyridine nitrogen functionalization can also lead to pyridinium ylides. These dipolar species can undergo a variety of dipolar cycloaddition reactions with electron-poor dipolarophiles, affording polycyclic frameworks and embedding a DHP moiety in their structures.

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47

Zhang, Xiao, Guo-ping Lu, and Chun Cai. "Correction: Facile aromatic nucleophilic substitution (SNAr) reactions in ionic liquids: an electrophile–nucleophile dual activation by [Omim]Br for the reaction." Green Chemistry 18, no. 22 (2016): 6143. http://dx.doi.org/10.1039/c6gc90108e.

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Correction for ‘Facile aromatic nucleophilic substitution (S_NAr) reactions in ionic liquids: an electrophile–nucleophile dual activation by [Omim]Br for the reaction’ by Xiao Zhang, et al., Green Chem., 2016, 18, 5580–5585.

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48

Yutilova, Kseniia, Yuliia Bespal’ko, and Elena Shved. "A Computational Study of 2-(chloromethyl)oxirane Ring Opening by Bromide and Acetate Anions Considering Electrophilic Activation with Cations of Alkali Metals." Croatica chemica acta 92, no. 3 (2019): 357–67. http://dx.doi.org/10.5562/cca3505.

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Ring opening of 2-(chloromethyl)oxirane via the nucleophilic substitution with bromide and acetate anions was investigated using density functional theory (DFT) calculations. It was shown that the geometry of the transition states and the activation parameters of the reactions correspond to those of SN2-like mechanism. The nature of localized transition states was analyzed using More O’Ferrall – Jencks plots. The quantum chemical simulations of the potential energy surface for the ring-opening reaction of oxirane by nucleophiles confirmed the theoretical assumptions about the favored path of interactions, which is a backside α-attack of nucleophile. The effect of alkali metal cation (Li+, Na+, K+) on that path was estimated. It was found that the electrophilic activation with alkali metal cation is more pronounced in the reaction of 2-(chloromethyl)oxirane with dissociated ions, than with ionic pairs.

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49

Cui, Peng, and Vlad M. Iluc. "Redox-induced umpolung of transition metal carbenes." Chemical Science 6, no. 12 (2015): 7343–54. http://dx.doi.org/10.1039/c5sc02859k.

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An unprecedented umpolung of a nucleophilic palladium carbene complex was realized by successive one-electron oxidations to generate a cationic carbene complex, which shows electrophilic behavior toward nucleophiles resulting from a polarity inversion of the Pd–C_carbene bond.

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50

Schmidt, Andreas, and Thorsten Mordhorst. "Synthesis of Pyridine-Thioethers via Mono- and Tricationic Pyridinium Salts." Zeitschrift für Naturforschung B 60, no. 6 (June 1, 2005): 683–87. http://dx.doi.org/10.1515/znb-2005-0613.

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On nucleophilic substitution with S-nucleophiles at room temperature, 1-(4-dimethylamino)- [2,3,5,6-tetrachloropyridin-4-yl]pyridinium chloride (2) yielded tetrachloro-4-sulfanylpyridines and 2,3,5-trichloro-4,6-disulfanylpyridines depending on the reaction conditions. Similarly, the tricationic (3,5-dichloropyridine-2,4,6-triyl)-1,1’,1”-tris[4-(dimethylamino)pyridinium] trichloride 3 was reacted with S-nucleophiles to give the corresponding 3,5-trichloro-2,4,6-trisulfanylpyridines under mild conditions.

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