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Shee M, Singh NDP. Chemical versatility of azide radical: journey from a transient species to synthetic accessibility in organic transformations. Chem Soc Rev 2022; 51:2255-2312. [PMID: 35229836 DOI: 10.1039/d1cs00494h] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The generation of azide radical (N3˙) occurs from its precursors primarily via a single electron transfer (SET) process or homolytic cleavage by chemical methods or advanced photoredox/electrochemical methods. This in situ generated transient open-shell species has unique characteristic features that set its reactivity. In the past, the azide radical was widely used for various studies in radiation chemistry as a 1e- oxidant of biologically important molecules, but now it is being exploited for synthetic applications based on its addition and intermolecular hydrogen atom transfer (HAT) abilities. Due to the significant role of nitrogen-containing molecules in synthesis, drug discovery, biological, and material sciences, the direct addition onto unsaturated bonds for the simultaneous construction of C-N bond with other (C-X) bonds are indeed worth highlighting. Moreover, the ability to generate O- or C-centered radicals by N3˙ via electron transfer (ET) and intermolecular HAT processes is also well documented. The purpose of controlling the reactivity of this short-lived intermediate in organic transformations drives us to survey: (i) the history of azide radical and its structural properties (thermodynamic, spectroscopic, etc.), (ii) chemical reactivities and kinetics, (iii) methods to produce N3˙ from various precursors, (iv) several significant azide radical-mediated transformations in the field of functionalization with unsaturated bonds, C-H functionalization via HAT, tandem, and multicomponent reaction with a critical analysis of underlying mechanistic approaches and outcomes, (v) concept of taming the reactivity of azide radicals for potential opportunities, in this review.
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Affiliation(s)
- Maniklal Shee
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India.
| | - N D Pradeep Singh
- Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India.
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2
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Rozatian N, Hodgson DRW. Reactivities of electrophilic N-F fluorinating reagents. Chem Commun (Camb) 2021; 57:683-712. [PMID: 33367354 DOI: 10.1039/d0cc06339h] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Electrophilic fluorination represents one of the most direct and useful methods available for the selective introduction of fluorine into organic compounds. Electrophilic fluorinating reagents of the N-F class have revolutionised the incorporation of fluorine atoms into both pharmaceutically- and agrochemically-important substrates. Since the earliest N-F reagents were commercialised in the 1990s, their reactivities have been investigated using qualitative and, more recently, quantitative methods. This review discusses the different experimental approaches employed to determine reactivities of N-F reagents, focussing on the kinetics studies reported in recent years. We make critical evaluations of the experimental approaches against each other, theoretical approaches, and their applicability towards practical problems. The opportunities for achieving more efficient synthetic electrophilic fluorination processes through kinetic understanding are highlighted.
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Affiliation(s)
- Neshat Rozatian
- Chemistry Department, Durham University, South Road, Durham, UKDH1 3LE.
| | - David R W Hodgson
- Chemistry Department, Durham University, South Road, Durham, UKDH1 3LE.
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Spectral Probe for Electron Transfer and Addition Reactions of Azide Radicals with Substituted Quinoxalin-2-Ones in Aqueous Solutions. Int J Mol Sci 2021; 22:ijms22020633. [PMID: 33435233 PMCID: PMC7828026 DOI: 10.3390/ijms22020633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 01/03/2021] [Accepted: 01/07/2021] [Indexed: 12/30/2022] Open
Abstract
The azide radical (N3●) is one of the most important one-electron oxidants used extensively in radiation chemistry studies involving molecules of biological significance. Generally, it was assumed that N3● reacts in aqueous solutions only by electron transfer. However, there were several reports indicating the possibility of N3● addition in aqueous solutions to organic compounds containing double bonds. The main purpose of this study was to find an experimental approach that allows a clear assignment of the nature of obtained products either to its one-electron oxidation or its addition products. Radiolysis of water provides a convenient source of one-electron oxidizing radicals characterized by a very broad range of reduction potentials. Two inorganic radicals (SO4●-, CO3●-) and Tl2+ ions with the reduction potentials higher, and one radical (SCN)2●- with the reduction potential slightly lower than the reduction potential of N3● were selected as dominant electron-acceptors. Transient absorption spectra formed in their reactions with a series of quinoxalin-2-one derivatives were confronted with absorption spectra formed from reactions of N3● with the same series of compounds. Cases, in which the absorption spectra formed in reactions involving N3● differ from the absorption spectra formed in the reactions involving other one-electron oxidants, strongly indicate that N3● is involved in the other reaction channel such as addition to double bonds. Moreover, it was shown that high-rate constants of reactions of N3● with quinoxalin-2-ones do not ultimately prove that they are electron transfer reactions. The optimized structures of the radical cations (7-R-3-MeQ)●+, radicals (7-R-3-MeQ)● and N3● adducts at the C2 carbon atom in pyrazine moiety and their absorption spectra are reasonably well reproduced by density functional theory quantum mechanics calculations employing the ωB97XD functional combined with the Dunning's aug-cc-pVTZ correlation-consistent polarized basis sets augmented with diffuse functions.
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Zhao Y, Li W, Zhao C. Cation radical mechanisms — α, β γ - tribenzoyloxylation of 2-allyl-1,4,5-trimethoxybenzene. JOURNAL OF CHEMICAL RESEARCH 2019. [DOI: 10.3184/030823401103168361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Threo- and erythro-1-(2,4,5,-trimethoxyphenyl-1,2,3-tri(4-nitro) benzoyloxypropanes were formed in a one-electron transfer reaction between 2-allyl-1,4,5-trimethoxybenzene and 4-nitrobenzoyl peroxide and a mechanism is proposed for this very unusual, subtle reaction.
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Affiliation(s)
- Yu Zhao
- Department of Chemistry, Shanghai Jiaotong University, 800 Dongchuan Road, Minhang, Shanghai 200240, China
| | - Wei Li
- Department of Chemistry, Shanghai Jiaotong University, 800 Dongchuan Road, Minhang, Shanghai 200240, China
| | - Chengxue Zhao
- Department of Chemistry, Shanghai Jiaotong University, 800 Dongchuan Road, Minhang, Shanghai 200240, China
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Yang B, Ren X, Shen X, Li T, Lu Z. Visible Light-Promoted Three-Component Carboazidation of Unactivated Alkenes with TMSN3
and Acrylonitrile. CHINESE J CHEM 2018. [DOI: 10.1002/cjoc.201800320] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Bo Yang
- Department of Chemistry; Zhejiang University; Hangzhou 310058 China
| | - Xiang Ren
- Department of Chemistry; Zhejiang University; Hangzhou 310058 China
| | - Xuzhong Shen
- Department of Chemistry; Zhejiang University; Hangzhou 310058 China
| | - Tongtong Li
- Department of Chemistry; Zhejiang University; Hangzhou 310058 China
| | - Zhan Lu
- Department of Chemistry; Zhejiang University; Hangzhou 310058 China
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Michalski R, Sikora A, Adamus J, Marcinek A. Dihalide and Pseudohalide Radical Anions as Oxidizing Agents in Nonaqueous Solvents. J Phys Chem A 2009; 114:861-6. [DOI: 10.1021/jp9096343] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- R. Michalski
- Institute of Applied Radiation Chemistry, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz, Poland
| | - A. Sikora
- Institute of Applied Radiation Chemistry, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz, Poland
| | - J. Adamus
- Institute of Applied Radiation Chemistry, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz, Poland
| | - A. Marcinek
- Institute of Applied Radiation Chemistry, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz, Poland
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Maeda H, Nakagawa H, Mizuno K. TiO2-catalyzed photooxygenation of cinnamic acid derivatives via their radical cations. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2007.01.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Murphy RS, Bohne C. Use of Styrene Radical Cations as Probes for the Complexation Dynamics of Charged Guests with α- and β-Cyclodextrins. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2000)0710035uosrca2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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9
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Carteau D, Brunerie P, Guillemat B, Bassani DM. Photochemistry in everyday life: The effect of spontaneous emulsification on the photochemistry of trans-anethole. Photochem Photobiol Sci 2007; 6:423-30. [PMID: 17404637 DOI: 10.1039/b614244c] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photochemical behaviour of spontaneously formed microemulsions obtained upon dilution of ethanolic solutions of trans-anethole (E-1-(4-methoxyphenyl)propene, t-A) with water is compared to that of homogeneous ethanolic t-A solutions. Significant differences in reactivity reflect the confined nature of the aggregated t-A which leads to reduced yields of isomerization and dimerization products. In contrast to homogeneous solutions, where a photostationary state enriched in the Z-isomer (c-A) is rapidly reached, the proportion of c-A formed upon irradiation of t-A microemulsions remains below 15%. In the presence of oxygen the formation of trans-anethole oxide is observed which, when formed in non-homogeneous environments, undergoes polymerization.
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Affiliation(s)
- David Carteau
- ISM/CNRS UMR 5255, Université Bordeaux 1, F-33405, Talence, France
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Nájera F, García-Segura R, Pérez-Inestrosa E, Sánchez-Sánchez C, Suau R. Photoinduced Addition of Phthalimide to Unactivated Alkynes†. Photochem Photobiol 2006; 82:248-53. [PMID: 16370584 DOI: 10.1562/2005-05-30-ra-555] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Photoexcited phthalimide in equilibrium with its conjugated base produces the regioselective hydrophthalimidation of conjugated alkynes. The vinylphthalimide thus obtained is hydrolyzed to the corresponding carbonyl compound. With unconjugated alkynes, the outcome is a double addition of phthalimide to the triple bond. The reaction is assumed to take place via single electron transfer from either the alkyne or the phthalimide anion to the excited phthalimide as the primary photoprocess.
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Affiliation(s)
- Francisco Nájera
- Department of Organic Chemistry, Faculty of Sciences, University of Málaga, 29071 Málaga, Spain
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11
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DeCamp MF, DeFlores L, McCracken JM, Tokmakoff A, Kwac K, Cho M. Amide I Vibrational Dynamics ofN-Methylacetamide in Polar Solvents: The Role of Electrostatic Interactions. J Phys Chem B 2005; 109:11016-26. [PMID: 16852342 DOI: 10.1021/jp050257p] [Citation(s) in RCA: 205] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The vibrational frequency of the amide I transition of peptides is known to be sensitive to the strength of its hydrogen bonding interactions. In an effort to account for interactions with hydrogen bonding solvents in terms of electrostatics, we study the vibrational dynamics of the amide I coordinate of N-methylacetamide in prototypical polar solvents: D2O, CDCl3, and DMSO-d6. These three solvents have varying hydrogen bonding strengths, and provide three distinct solvent environments for the amide group. The frequency-frequency correlation function, the orientational correlation function, and the vibrational relaxation rate of the amide I vibration in each solvent are retrieved by using three-pulse vibrational photon echoes, two-dimensional infrared spectroscopy, and pump-probe spectroscopy. Direct comparisons are made to molecular dynamics simulations. We find good quantitative agreement between the experimentally retrieved and simulated correlation functions over all time scales when the solute-solvent interactions are determined from the electrostatic potential between the solvent and the atomic sites of the amide group.
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Affiliation(s)
- M F DeCamp
- Department of Chemistry and George R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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12
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Fernández H, Alicia Zón M. Novel studies on the electrochemical oxidation of 2-[4-(N,N-dimethylamino)phenyl]-6-methyl benzothiazole (DPMB) in acetonitrile at platinum electrodes. J Electroanal Chem (Lausanne) 2004. [DOI: 10.1016/j.jelechem.2004.05.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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13
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Stavber S, Pečan TS, Zupan M. Effect of Reaction Conditions on the Kinetic and Activation Parameters for the Mild Introduction of Fluorine into Phenyl-Substituted Alkenes with Accufluor™ NFTh. Tetrahedron 2000. [DOI: 10.1016/s0040-4020(00)00109-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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14
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Murphy RS, Bohne C. Use of styrene radical cations as probes for the complexation dynamics of charged guests with alpha- and beta-cyclodextrins. Photochem Photobiol 2000; 71:35-43. [PMID: 10649887 DOI: 10.1562/0031-8655(2000)071<0035:uosrca>2.0.co;2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The complexation dynamics of radical cations with cyclodextrins (CD) was studied using photophysical techniques. Radical cations of 4-vinylanisole and trans-anethole were formed within alpha- and beta-CD cavities by two-photon photolysis of the respective styrene precursors. Exit of the radical cations from alpha-CD complexes with 1: 1 and 1:2 (guest: CD) stoichiometries and beta-CD complexes with 1:1 stoichiometries occurred with lifetimes shorter than 100 ns. Most of the radical cations formed escape from the CD cavities, but a small portion do react with alpha-CD when this host is present in high concentrations.
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Affiliation(s)
- R S Murphy
- Department of Chemistry, University of Victoria, B.C., Canada
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15
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Fukuzumi S, Nakanishi I, Tanaka K. Multielectron Oxidation of Anthracenes with a One-Electron Oxidant via Water-Accelerated Electron-Transfer Disproportionation of the Radical Cations as the Rate-Determining Step. J Phys Chem A 1999. [DOI: 10.1021/jp990541e] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Ishii H, Shiina S, Hirano T, Niwa H, Ohashi M. Reactivity and π-facial selectivity of nucleophile addition to the radical cations of 7-benzhydrylidenenorbornene derivatives. Tetrahedron Lett 1999. [DOI: 10.1016/s0040-4039(98)02429-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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17
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Spin Trapping and Electron Transfer. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 1999. [DOI: 10.1016/s0065-3160(08)60193-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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18
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Zupan M, Škulj P, Stavber S. Evidence for Ionic Intermediates in Fluorination of Alkenes with N–F Type of Reagents. CHEM LETT 1998. [DOI: 10.1246/cl.1998.641] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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19
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Parker VD, Chao YT, Zheng G. Dynamics of Proton Transfer from Radical Cations. Addition−Elimination or Direct Proton Transfer? J Am Chem Soc 1997. [DOI: 10.1021/ja973031b] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Vernon D. Parker
- Contribution from the Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300
| | - You Tein Chao
- Contribution from the Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300
| | - Gang Zheng
- Contribution from the Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300
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20
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Burton RD, Bartberger MD, Zhang Y, Eyler JR, Schanze KS. Carbon−Carbon Bond Fragmentation in Aminoalcohol Radical Cations. Kinetics, Thermodynamic Correlations, and Mechanism. J Am Chem Soc 1996. [DOI: 10.1021/ja960378q] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Richard D. Burton
- Contribution from the Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611
| | - Michael D. Bartberger
- Contribution from the Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611
| | - Yin Zhang
- Contribution from the Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611
| | - John R. Eyler
- Contribution from the Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611
| | - Kirk S. Schanze
- Contribution from the Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611
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Johnston LJ, Schepp NP. Kinetics and mechanisms for the reactions of alkene radical cations. ADVANCES IN ELECTRON TRANSFER CHEMISTRY 1996. [DOI: 10.1016/s1061-8937(96)80004-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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22
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Arnold DR, Du X, Chen J. The effect of meta- or para-cyano substitution on the reactivity of the radical cations of arylalkenes and alkanes. Radical ions in photochemistry, Part 34. CAN J CHEM 1995. [DOI: 10.1139/v95-042] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of electron-withdrawing substituents, meta- or para-cyano, on the reactivity of the radical cation of arylalkenes and alkanes has been determined. The radical cations were generated by single electron transfer (set) to an electron-accepting photosensitizer. Three reactions were studied: (i) the addition of nucleophile to the radical cation of arylalkenes, (ii) cleavage of the benzylic carbon–carbon bond of the radical cation of arylalkanes; and (iii) the deprotonation of the benzylic carbon–hydrogen bond of the radical cation of arylalkanes. The radical cations of 4-(1-phenylethenyl)benzonitrile (1b), 3-(1-phenylethenyl)benzonitrile (1c), 4-(2-methoxy-1-phenylethyl)benzonitrile (2b), 3-(2-methoxy-1-phenylethyl)benzonitrile (2c), cis- and trans-5-cyano-2-methoxy-1-phenylindane (6b-cis and -trans), and 6-cyano-3-phenylindene (7b) were generated, by single electron transfer to the lowest excited singlet state of 1,4-dicyanobenzene (3), in acetonitrile–methanol. The radical cations of 1b, 1c, and 7b react with methanol to yield the anti-Markovnikov adducts (2b, 2c, and 6b-cis and 6b-trans). The radical cations of 2b, 2c, and 6b-trans cleave at the benzylic carbon–carbon bond to give products derived from the radical and carbocation fragments. The radical cation of 6b-cis deprotonates from the benzylic position with subsequent formation of the diastereomer, 6b-trans. This behaviour can be explained/predicted on the basis of the proposed mechanisms for these reactions. Molecular orbital calculations (AM1) support the conclusions. Keywords: photosensitized, electron transfer, radical ions, radicals, molecular orbital calculations (AM1).
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