1
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Thermodynamic and Kinetic Studies of the Activities of Aldehydic C−H Bonds toward Their H‐Atom Transfer Reactions. ChemistrySelect 2023. [DOI: 10.1002/slct.202204789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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2
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Simons RT, Nandakumar M, Kwon K, Ayer SK, Venneti NM, Roizen JL. Directed Photochemically Mediated Nickel-Catalyzed (Hetero)arylation of Aliphatic C-H Bonds. J Am Chem Soc 2023; 145:10.1021/jacs.2c13409. [PMID: 36780585 PMCID: PMC10423309 DOI: 10.1021/jacs.2c13409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Site-selective functionalization of unactivated C(sp3)-H centers is challenging because of the ubiquity and strength of alkyl C-H bonds. Herein, we disclose a position-selective C(sp3)-C(sp2) cross-coupling reaction. This process engages C(sp3)-H bonds and aryl bromides, utilizing catalytic quantities of a photoredox-capable molecule and a nickel precatalyst. Using this technology, selective C-H functionalization arises owing to a 1,6-hydrogen atom transfer (HAT) process that is guided by a pendant alcohol-anchored sulfamate ester. These transformations proceed directly from N-H bonds, in contrast to previous directed, radical-mediated, C-H arylation processes, which have relied on prior oxidation of the reactive nitrogen center in reactions with nucleophilic arenes. Moreover, these conditions promote arylation at secondary centers in good yields with excellent selectivity.
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Affiliation(s)
- R. Thomas Simons
- Duke University, Department of Chemistry, Box 90346, Durham, NC 27708, United States (before June 2021)
| | - Meganathan Nandakumar
- Duke University, Department of Chemistry, Box 90346, Durham, NC 27708, United States (before June 2021)
| | - Kitae Kwon
- Duke University, Department of Chemistry, Box 90346, Durham, NC 27708, United States (before June 2021)
| | - Suraj K. Ayer
- Duke University, Department of Chemistry, Box 90346, Durham, NC 27708, United States (before June 2021)
| | - Naresh M. Venneti
- Wayne State University, Department of Chemistry, Detroit, MI 48202, United States
| | - Jennifer L. Roizen
- Duke University, Department of Chemistry, Box 90346, Durham, NC 27708, United States (before June 2021)
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3
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Fu YH, Zhang Y, Wang F, Zhao L, Shen GB, Zhu XQ. Quantitative evaluation of the actual hydrogen atom donating activities of O-H bonds in phenols: structure-activity relationship. RSC Adv 2023; 13:3295-3305. [PMID: 36756400 PMCID: PMC9869660 DOI: 10.1039/d2ra06877j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 12/31/2022] [Indexed: 01/25/2023] Open
Abstract
The H-donating activity of phenol and the H-abstraction activity of phenol radicals have been extensively studied. In this article, the second-order rate constants of 25 hydrogen atom transfer (HAT) reactions between phenols and PINO and DPPH radicals in acetonitrile at 298 K were studied. Thermo-kinetic parameters ΔG ≠o(XH) were obtained using a kinetic equation [ΔG ≠ XH/Y = ΔG ≠o(XH) + ΔG ≠o(Y)]. Bond dissociation free energies ΔG o(XH) were calculated by the iBonD HM method, whose details are available at https://pka.luoszgroup.com/bde_prediction. Intrinsic resistance energies ΔG ≠ XH/X and ΔG ≠o(X) were determined as ΔG ≠o(XH) and ΔG o(XH) were available. ΔG o(XH), ΔG ≠ XH/X, ΔG ≠o(XH) and ΔG ≠o(X) were used to assess the H-donating abilities of the studied phenols and the H-abstraction abilities of phenol radicals in thermodynamics, kinetics and actual HAT reactions. The effect of structures on these four parameters was discussed. The reliabilities of ΔG ≠o(XH) and ΔG ≠o(X) were examined. The difference between the method of determining ΔG ≠ XH/X mentioned in this study and the dynamic nuclear magnetic method mentioned in the literature was studied. Via this study, not only ΔG o(XH), ΔG ≠ XH/X, ΔG ≠o(XH) and ΔG ≠o(X) of phenols could be quantitatively evaluated, but also the structure-activity relationship of phenols is clearly demonstrated. Moreover, it lays the foundation for designing and synthesizing more antioxidants and radicals.
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Affiliation(s)
- Yan-Hua Fu
- College of Chemistry and Environmental Engineering, Anyang Institute of Technology Anyang Henan 455000 China
| | - Yanwei Zhang
- College of Chemistry and Environmental Engineering, Anyang Institute of Technology Anyang Henan 455000 China
| | - Fang Wang
- College of Chemistry and Environmental Engineering, Anyang Institute of Technology Anyang Henan 455000 China
| | - Ling Zhao
- College of Chemistry and Environmental Engineering, Anyang Institute of Technology Anyang Henan 455000 China
| | - Guang-Bin Shen
- School of Medical Engineering, Jining Medical UniversityJiningShandong272000P. R. China
| | - Xiao-Qing Zhu
- Department of Chemistry, Nankai UniversityTianjin300071China
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4
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Zhang Y, Richards DS, Grotemeyer EN, Jackson TA, Schöneich C. Near-UV and Visible Light Degradation of Iron (III)-Containing Citrate Buffer: Formation of Carbon Dioxide Radical Anion via Fragmentation of a Sterically Hindered Alkoxyl Radical. Mol Pharm 2022; 19:4026-4042. [PMID: 36074094 DOI: 10.1021/acs.molpharmaceut.2c00501] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Citrate is a commonly used buffer in pharmaceutical formulations which forms complexes with adventitious metals such as Fe3+. Fe3+-citrate complexes can act as potent photosensitizers under near-UV and visible light exposure, and recent studies reported evidence for the photo-production of a powerful reductant, carbon dioxide radical anion (•CO2-), from Fe3+-citrate complexes (Subelzu, N.; Schöneich, N., Mol. Pharm. 2020, 17, 4163-4179). The mechanisms of •CO2- formation are currently unknown but must be established to devise strategies against •CO2- formation in pharmaceutical formulations which rely on the use of citrate buffer. In this study, we first established complementary evidence for the photolytic generation of •CO2- from Fe3+-citrate through spin trapping and electron paramagnetic resonance (EPR) spectroscopy, and subsequently used spin trapping in conjunction with tandem mass spectrometry (MS/MS) for mechanistic studies on the pathways of •CO2- formation. Experiments with stable isotope-labeled citrate suggest that the central carboxylate group of citrate is the major source of •CO2-. Competition studies with various inhibitors (alcohols and dimethyl sulfoxide) reveal two mechanisms of •CO2- formation, where one pathway involves β-cleavage of a sterically hindered alkoxyl radical generated from the hydroxyl group of citrate.
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Affiliation(s)
- Yilue Zhang
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
| | - David S Richards
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
| | - Elizabeth N Grotemeyer
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Timothy A Jackson
- Department of Chemistry and Center for Environmentally Beneficial Catalysis, University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States
| | - Christian Schöneich
- Department of Pharmaceutical Chemistry, University of Kansas, 2093 Constant Avenue, Lawrence, Kansas 66047, United States
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5
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Chang L, An Q, Duan L, Feng K, Zuo Z. Alkoxy Radicals See the Light: New Paradigms of Photochemical Synthesis. Chem Rev 2021; 122:2429-2486. [PMID: 34613698 DOI: 10.1021/acs.chemrev.1c00256] [Citation(s) in RCA: 139] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Alkoxy radicals are highly reactive species that have long been recognized as versatile intermediates in organic synthesis. However, their development has long been impeded due to a lack of convenient methods for their generation. Thanks to advances in photoredox catalysis, enabling facile access to alkoxy radicals from bench-stable precursors and free alcohols under mild conditions, research interest in this field has been renewed. This review comprehensively summarizes the recent progress in alkoxy radical-mediated transformations under visible light irradiation. Elementary steps for alkoxy radical generation from either radical precursors or free alcohols are central to reaction development; thus, each section is categorized and discussed accordingly. Throughout this review, we have focused on the different mechanisms of alkoxy radical generation as well as their impact on synthetic utilizations. Notably, the catalytic generation of alkoxy radicals from abundant alcohols is still in the early stage, providing intriguing opportunities to exploit alkoxy radicals for diverse synthetic paradigms.
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Affiliation(s)
- Liang Chang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 200032 Shanghai, China.,School of Pharmacy, Nanjing University of Chinese Medicine, 210023 Nanjing, China
| | - Qing An
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Lingfei Duan
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 200032 Shanghai, China
| | - Kaixuan Feng
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 200032 Shanghai, China
| | - Zhiwei Zuo
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 200032 Shanghai, China
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6
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Synthesis of 3-((trifluoromethyl)thio)indoles via trifluoromethylthiolation of 2-alkynyl azidoarenes with AgSCF3. J Fluor Chem 2021. [DOI: 10.1016/j.jfluchem.2021.109878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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7
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Salamone M, Galeotti M, Romero-Montalvo E, van Santen JA, Groff BD, Mayer JM, DiLabio GA, Bietti M. Bimodal Evans-Polanyi Relationships in Hydrogen Atom Transfer from C(sp 3)-H Bonds to the Cumyloxyl Radical. A Combined Time-Resolved Kinetic and Computational Study. J Am Chem Soc 2021; 143:11759-11776. [PMID: 34309387 PMCID: PMC8343544 DOI: 10.1021/jacs.1c05566] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Indexed: 12/11/2022]
Abstract
The applicability of the Evans-Polanyi (EP) relationship to HAT reactions from C(sp3)-H bonds to the cumyloxyl radical (CumO•) has been investigated. A consistent set of rate constants, kH, for HAT from the C-H bonds of 56 substrates to CumO•, spanning a range of more than 4 orders of magnitude, has been measured under identical experimental conditions. A corresponding set of consistent gas-phase C-H bond dissociation enthalpies (BDEs) spanning 27 kcal mol-1 has been calculated using the (RO)CBS-QB3 method. The log kH' vs C-H BDE plot shows two distinct EP relationships, one for substrates bearing benzylic and allylic C-H bonds (unsaturated group) and the other one, with a steeper slope, for saturated hydrocarbons, alcohols, ethers, diols, amines, and carbamates (saturated group), in line with the bimodal behavior observed previously in theoretical studies of reactions promoted by other HAT reagents. The parallel use of BDFEs instead of BDEs allows the transformation of this correlation into a linear free energy relationship, analyzed within the framework of the Marcus theory. The ΔG⧧HAT vs ΔG°HAT plot shows again distinct behaviors for the two groups. A good fit to the Marcus equation is observed only for the saturated group, with λ = 58 kcal mol-1, indicating that with the unsaturated group λ must increase with increasing driving force. Taken together these results provide a qualitative connection between Bernasconi's principle of nonperfect synchronization and Marcus theory and suggest that the observed bimodal behavior is a general feature in the reactions of oxygen-based HAT reagents with C(sp3)-H donors.
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Affiliation(s)
- Michela Salamone
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Marco Galeotti
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Eduardo Romero-Montalvo
- Department
of Chemistry, The University of British
Columbia, 3247 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - Jeffrey A. van Santen
- Department
of Chemistry, The University of British
Columbia, 3247 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - Benjamin D. Groff
- Department
of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520-8107, United States
| | - James M. Mayer
- Department
of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06520-8107, United States
| | - Gino A. DiLabio
- Department
of Chemistry, The University of British
Columbia, 3247 University Way, Kelowna, British Columbia, Canada, V1V 1V7
| | - Massimo Bietti
- Dipartimento
di Scienze e Tecnologie Chimiche, Università
“Tor Vergata”, Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
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8
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Abstract
AbstractHydrogen atom transfer (HAT) is one of the fundamental transformations of organic chemistry, allowing the interconversion of open- and closed-shell species through the concerted movement of a proton and an electron. Although the value of this transformation is well appreciated in isolation, with it being used for homolytic C–H activation via abstractive HAT and radical reduction via donative HAT, cooperative HAT (cHAT) reactions, in which two hydrogen atoms are removed or donated to vicinal reaction centers in succession through radical intermediates, are comparatively unknown outside of the mechanism of desaturase enzymes. This tandem reaction scheme has important ramifications in the thermochemistry of each HAT, with the bond dissociation energy (BDE) of the C–H bond adjacent to the radical center being significantly lowered relative to that of the parent alkane, allowing each HAT to be performed by different species. Herein, we discuss the thermodynamic basis of this bond strength differential in cHAT and demonstrate its use as a design principle in organic chemistry for both dehydrogenative (application 1) and hydrogenative (application 2) reactions. We hope that this overview will highlight the exciting reactivity that is possible with cHAT and inspire further developments with this mechanistic approach.1 Introduction and Theory2 Application: Dehydrogenative Transformations3 Application: Alkene Hydrogenation4 Future Applications of cHAT
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Sabenya G, Gamba I, Gómez L, Clémancey M, Frisch JR, Klinker EJ, Blondin G, Torelli S, Que L, Martin-Diaconescu V, Latour JM, Lloret-Fillol J, Costas M. Octahedral iron(iv)-tosylimido complexes exhibiting single electron-oxidation reactivity. Chem Sci 2019; 10:9513-9529. [PMID: 32055323 PMCID: PMC6979323 DOI: 10.1039/c9sc02526j] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 08/17/2019] [Indexed: 11/28/2022] Open
Abstract
High valent iron species are very reactive molecules involved in oxidation reactions of relevance to biology and chemical synthesis. Herein we describe iron(iv)-tosylimido complexes [FeIV(NTs)(MePy2tacn)](OTf)2 (1(IV)[double bond, length as m-dash]NTs) and [FeIV(NTs)(Me2(CHPy2)tacn)](OTf)2 (2(IV)[double bond, length as m-dash]NTs), (MePy2tacn = N-methyl-N,N-bis(2-picolyl)-1,4,7-triazacyclononane, and Me2(CHPy2)tacn = 1-(di(2-pyridyl)methyl)-4,7-dimethyl-1,4,7-triazacyclononane, Ts = Tosyl). 1(IV)[double bond, length as m-dash]NTs and 2(IV)[double bond, length as m-dash]NTs are rare examples of octahedral iron(iv)-imido complexes and are isoelectronic analogues of the recently described iron(iv)-oxo complexes [FeIV(O)(L)]2+ (L = MePy2tacn and Me2(CHPy2)tacn, respectively). 1(IV)[double bond, length as m-dash]NTs and 2(IV)[double bond, length as m-dash]NTs are metastable and have been spectroscopically characterized by HR-MS, UV-vis, 1H-NMR, resonance Raman, Mössbauer, and X-ray absorption (XAS) spectroscopy as well as by DFT computational methods. Ferric complexes [FeIII(HNTs)(L)]2+, 1(III)-NHTs (L = MePy2tacn) and 2(III)-NHTs (L = Me2(CHPy2)tacn) have been isolated after the decay of 1(IV)[double bond, length as m-dash]NTs and 2(IV)[double bond, length as m-dash]NTs in solution, spectroscopically characterized, and the molecular structure of [FeIII(HNTs)(MePy2tacn)](SbF6)2 determined by single crystal X-ray diffraction. Reaction of 1(IV)[double bond, length as m-dash]NTs and 2(IV)[double bond, length as m-dash]NTs with different p-substituted thioanisoles results in the transfer of the tosylimido moiety to the sulphur atom producing sulfilimine products. In these reactions, 1(IV)[double bond, length as m-dash]NTs and 2(IV)[double bond, length as m-dash]NTs behave as single electron oxidants and Hammett analyses of reaction rates evidence that tosylimido transfer is more sensitive than oxo transfer to charge effects. In addition, reaction of 1(IV)[double bond, length as m-dash]NTs and 2(IV)[double bond, length as m-dash]NTs with hydrocarbons containing weak C-H bonds results in the formation of 1(III)-NHTs and 2(III)-NHTs respectively, along with the oxidized substrate. Kinetic analyses indicate that reactions proceed via a mechanistically unusual HAT reaction, where an association complex precedes hydrogen abstraction.
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Affiliation(s)
- Gerard Sabenya
- Institut de Química Computacional i Catàlisi (IQCC) , Departament de Química , Universitat de Girona , Campus Montilivi , E17071 Girona , Spain .
| | - Ilaria Gamba
- Institut de Química Computacional i Catàlisi (IQCC) , Departament de Química , Universitat de Girona , Campus Montilivi , E17071 Girona , Spain .
| | - Laura Gómez
- Institut de Química Computacional i Catàlisi (IQCC) , Departament de Química , Universitat de Girona , Campus Montilivi , E17071 Girona , Spain .
| | - Martin Clémancey
- Univ. Grenoble-Alpes , CNRS , CEA , IRIG , DIESE , CBM , Grenoble 38000 , France
| | - Jonathan R Frisch
- Department of Chemistry , University of Minnesota , Pleasant Str 207 , Minneapolis , Minnesota , USA
| | - Eric J Klinker
- Department of Chemistry , University of Minnesota , Pleasant Str 207 , Minneapolis , Minnesota , USA
| | - Geneviève Blondin
- Univ. Grenoble-Alpes , CNRS , CEA , IRIG , DIESE , CBM , Grenoble 38000 , France
| | - Stéphane Torelli
- Univ. Grenoble-Alpes , CNRS , CEA , IRIG , DIESE , CBM , Grenoble 38000 , France
| | - Lawrence Que
- Department of Chemistry , University of Minnesota , Pleasant Str 207 , Minneapolis , Minnesota , USA
| | - Vlad Martin-Diaconescu
- Institut de Química Computacional i Catàlisi (IQCC) , Departament de Química , Universitat de Girona , Campus Montilivi , E17071 Girona , Spain .
- Institute of Chemical Research of Catalonia (ICIQ) , The Barcelona Institute of Science and Technology , Avinguda Països Catalans 16 , 43007 Tarragona , Spain .
| | - Jean-Marc Latour
- Univ. Grenoble-Alpes , CNRS , CEA , IRIG , DIESE , CBM , Grenoble 38000 , France
| | - Julio Lloret-Fillol
- Institut de Química Computacional i Catàlisi (IQCC) , Departament de Química , Universitat de Girona , Campus Montilivi , E17071 Girona , Spain .
- Institute of Chemical Research of Catalonia (ICIQ) , The Barcelona Institute of Science and Technology , Avinguda Països Catalans 16 , 43007 Tarragona , Spain .
- Catalan Institution for Research and Advanced Studies (ICREA) , Passeig Lluïs Companys, 23 , 08010 , Barcelona , Spain
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC) , Departament de Química , Universitat de Girona , Campus Montilivi , E17071 Girona , Spain .
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10
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Sandhiya L, Zipse H. Radical-Pair Formation in Hydrocarbon (Aut)Oxidation. Chemistry 2019; 25:8604-8611. [PMID: 31058373 DOI: 10.1002/chem.201901415] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Indexed: 11/05/2022]
Abstract
The reaction profiles for the uni- and bimolecular decomposition of benzyl hydroperoxide have been studied in the context of initiation reactions for the (aut)oxidation of hydrocarbons. The unimolecular dissociation of benzyl hydroperoxide was found to proceed through the formation of a hydrogen-bonded radical-pair minimum located +181 kJ mol-1 above the hydroperoxide substrate and around 15 kJ mol-1 below the separated radical products. The reaction of toluene with benzyl hydroperoxide proceeds such that O-O bond homolysis is coupled with a C-H bond abstraction event in a single kinetic step. The enthalpic barrier of this molecule-induced radical formation (MIRF) process is significantly lower than that of the unimolecular O-O bond cleavage. The same type of reaction is also possible in the self-reaction between two benzyl hydroperoxide molecules forming benzyloxyl and hydroxyl radical pairs along with benzaldehyde and water as co-products. In the product complexes formed in these MIRF reactions, both radicals connect to a centrally placed water molecule through hydrogen-bonding interactions.
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Affiliation(s)
- Lakshmanan Sandhiya
- Department Chemie, Ludwig-Maximilians-Universität München, 81377, München, Germany
| | - Hendrik Zipse
- Department Chemie, Ludwig-Maximilians-Universität München, 81377, München, Germany
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11
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Abdel Latif MK, Spencer JN, Paradzinsky M, Tanko JM. Does Metal Ion Complexation Make Radical Clocks Run Fast? An Experimental Perspective. J Phys Chem A 2017; 121:9682-9686. [PMID: 29016138 DOI: 10.1021/acs.jpca.7b07575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The rate constant for the β-scission of the cumyloxyl radical (kβ) was measured in the presence of various added electrolytes in acetonitrile and DMSO solvent. The results show that in CH3CN, kβ increases in the presence of added electrolyte, roughly paralleling the size of the cation: Li+ > Mg2+ ≈ Na+ > nBu4N+ > no added electrolyte. As suggested by Bietti et al. earlier, this effect is attributable to stabilizing ion-dipole interactions in the transition state of the developing carbonyl group, a conclusion further amplified by MO calculations (gas phase) reported herein. Compared to the gas phase predictions, however, this effect is seriously attenuated in solution because complexation of the cation to the electrophilic alkoxyl radical (relative to the solvent, CH3CN) is very weak. Because the interaction of Li+ and Na+ is much stronger with DMSO than with CH3CN, addition of these ions has no effect on the rate of β-scission.
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Affiliation(s)
- Marwa K Abdel Latif
- Department of Chemistry, Virginia Polytechnic Institute And State University , Blacksburg, Virginia 24061, United States
| | - Jared N Spencer
- Department of Chemistry, Virginia Polytechnic Institute And State University , Blacksburg, Virginia 24061, United States
| | - Mark Paradzinsky
- Department of Chemistry, Virginia Polytechnic Institute And State University , Blacksburg, Virginia 24061, United States
| | - James M Tanko
- Department of Chemistry, Virginia Polytechnic Institute And State University , Blacksburg, Virginia 24061, United States
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12
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van Santen JA, Rahemtulla S, Salamone M, Bietti M, DiLabio GA. A computational and experimental re-examination of the reaction of the benzyloxyl radical with DMSO. COMPUT THEOR CHEM 2016. [DOI: 10.1016/j.comptc.2015.10.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Lee R, Gryn'ova G, Ingold KU, Coote ML. Why are sec-alkylperoxyl bimolecular self-reactions orders of magnitude faster than the analogous reactions of tert-alkylperoxyls? The unanticipated role of CH hydrogen bond donation. Phys Chem Chem Phys 2016; 18:23673-9. [DOI: 10.1039/c6cp04670c] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Theory reveals that pri- and sec-alkylperoxyl bimolecular self-reactions are orders of magnitude faster than the analogous tert-alkylperoxyl reactions, because of the formation of 5-center cyclic CH⋯O hydrogen bonding.
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Affiliation(s)
- Richmond Lee
- ARC Centre of Excellence for Electromaterials Science
- Research School of Chemistry
- Australian National University
- Canberra ACT 2601
- Australia
| | - Ganna Gryn'ova
- ARC Centre of Excellence for Electromaterials Science
- Research School of Chemistry
- Australian National University
- Canberra ACT 2601
- Australia
| | | | - Michelle L. Coote
- ARC Centre of Excellence for Electromaterials Science
- Research School of Chemistry
- Australian National University
- Canberra ACT 2601
- Australia
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14
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Salamone M, Bietti M. Tuning reactivity and selectivity in hydrogen atom transfer from aliphatic C-H bonds to alkoxyl radicals: role of structural and medium effects. Acc Chem Res 2015; 48:2895-903. [PMID: 26545103 DOI: 10.1021/acs.accounts.5b00348] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hydrogen atom transfer (HAT) is a fundamental reaction that takes part in a wide variety of chemical and biological processes, with relevant examples that include the action of antioxidants, damage to biomolecules and polymers, and enzymatic and biomimetic reactions. Moreover, great attention is currently devoted to the selective functionalization of unactivated aliphatic C-H bonds, where HAT based procedures have been shown to play an important role. In this Account, we describe the results of our recent studies on the role of structural and medium effects on HAT from aliphatic C-H bonds to the cumyloxyl radical (CumO(•)). Quantitative information on the reactivity and selectivity patterns observed in these reactions has been obtained by time-resolved kinetic studies, providing a deeper understanding of the factors that govern HAT from carbon and leading to the definition of useful guidelines for the activation or deactivation of aliphatic C-H bonds toward HAT. In keeping with the electrophilic character of alkoxyl radicals, polar effects can play an important role in the reactions of CumO(•). Electron-rich C-H bonds are activated whereas those that are α to electron withdrawing groups are deactivated toward HAT, with these effects being able to override the thermodynamic preference for HAT from the weakest C-H bond. Stereoelectronic effects can also influence the reactivity of the C-H bonds of ethers, amines, and amides. HAT is most rapid when these bonds can be eclipsed with a lone pair on an adjacent heteroatom or with the π-system of an amide functionality, thus allowing for optimal orbital overlap. In HAT from cyclohexane derivatives, tertiary axial C-H bond deactivation and tertiary equatorial C-H bond activation have been observed. These effects have been explained on the basis of an increase in torsional strain or a release in 1,3-diaxial strain in the HAT transition states, with kH(eq)/kH(ax) ratios that have been shown to exceed one order of magnitude. Medium effects on HAT from aliphatic C-H bonds to CumO(•) have been also investigated. With basic substrates, from large to very large decreases in kH have been measured with increasing solvent hydrogen bond donor (HBD) ability or after addition of protic acids or alkali and alkaline earth metal ions, with kinetic effects that exceed 2 orders of magnitude in the reactions of tertiary alkylamines and alkanamides. Solvent hydrogen bonding, protonation, and metal ion binding increase the electron deficiency and the strength of the C-H bonds of these substrates deactivating these bonds toward HAT, with the extent of this deactivation being modulated by varying the nature of the substrate, solvent, protic acid, and metal ion. These results indicate that through these interactions careful control over the HAT reactivity of basic substrates toward CumO(•) and other electrophilic radicals can be achieved, suggesting moreover that these effects can be exploited in an orthogonal fashion for selective C-H bond functionalization of substrates bearing different basic functionalities.
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Affiliation(s)
- Michela Salamone
- Dipartimento
di Scienze e
Tecnologie Chimiche, Università “Tor Vergata”, Via
della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Massimo Bietti
- Dipartimento
di Scienze e
Tecnologie Chimiche, Università “Tor Vergata”, Via
della Ricerca Scientifica, 1, I-00133 Rome, Italy
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15
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Martínez-Cifuentes M, Salazar R, Escobar CA, Weiss-López BE, Santos LS, Araya-Maturana R. Correlating experimental electrochemistry and theoretical calculations in 2′-hydroxy chalcones: the role of the intramolecular hydrogen bond. RSC Adv 2015. [DOI: 10.1039/c5ra10140a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The molecular structure and electrochemical behaviour of a series of 2′-hydroxychalcones were studied. Results show the importance of the intramolecular hydrogen bond and the methoxy substituent pattern on the redox properties of these compounds.
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Affiliation(s)
| | - Ricardo Salazar
- Laboratorio de Electroquímica MedioAmbiental
- LEQMA
- Departamento de Química de los Materiales
- Facultad de Química y Biología
- Universidad de Santiago de Chile, USACh
| | - Carlos A. Escobar
- Departamento de Ciencias Químicas
- Universidad Andres Bello
- Santiago
- Chile
| | | | - Leonardo S. Santos
- Laboratorio de Síntesis Asimétrica
- Instituto de Química de los Recursos Naturales
- Universidad de Talca
- Talca
- Chile
| | - Ramiro Araya-Maturana
- Departamento de Química Orgánica y Fisicoquímica
- Facultad de Ciencias Químicas Y Farmacéuticas
- Universidad de Chile
- Santiago 1
- Chile
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16
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Milan M, Salamone M, Bietti M. Hydrogen Atom Transfer from 1,n-Alkanediamines to the Cumyloxyl Radical. Modulating C–H Deactivation Through Acid–Base Interactions and Solvent Effects. J Org Chem 2014; 79:5710-6. [DOI: 10.1021/jo5008493] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michela Milan
- Dipartimento
di Scienze e
Tecnologie Chimiche, Università “Tor Vergata″, Via
della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Michela Salamone
- Dipartimento
di Scienze e
Tecnologie Chimiche, Università “Tor Vergata″, Via
della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Massimo Bietti
- Dipartimento
di Scienze e
Tecnologie Chimiche, Università “Tor Vergata″, Via
della Ricerca Scientifica, 1 I-00133 Rome, Italy
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17
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Caicedo C, Iuga C, Castañeda-Arriaga R, Alvarez-Idaboy JR. Antioxidant activity of selected natural polyphenolic compounds from soybean via peroxyl radical scavenging. RSC Adv 2014. [DOI: 10.1039/c4ra04758c] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Excellent antioxidantsviaSPLET in aqueous solution, moderate antioxidantsviaHAT in lipid medium.
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Affiliation(s)
- Carolina Caicedo
- Departamento de Física y Química Teórica
- Facultad de Química
- Universidad Nacional Autónoma de México. Circuito Exterior SN. Ciudad Universitaria
- C.P. 04510 Coyoacán, México
| | - Cristina Iuga
- Universidad Autónoma Metropolitana-Xochimilco
- 04960 México, Mexico
| | - Romina Castañeda-Arriaga
- Departamento de Física y Química Teórica
- Facultad de Química
- Universidad Nacional Autónoma de México. Circuito Exterior SN. Ciudad Universitaria
- C.P. 04510 Coyoacán, México
| | - J. Raúl Alvarez-Idaboy
- Departamento de Física y Química Teórica
- Facultad de Química
- Universidad Nacional Autónoma de México. Circuito Exterior SN. Ciudad Universitaria
- C.P. 04510 Coyoacán, México
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18
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Li P, Zhao J, Lang R, Xia C, Li F. Copper-catalyzed methyl esterification of aromatic aldehydes and benzoic alcohols by TBHP as both oxidant and methyl source. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2013.11.040] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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19
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DiLabio GA, Koleini M, Torres E. Extension of the B3LYP–dispersion-correcting potential approach to the accurate treatment of both inter- and intra-molecular interactions. Theor Chem Acc 2013. [DOI: 10.1007/s00214-013-1389-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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20
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Salamone M, Milan M, DiLabio GA, Bietti M. Reactions of the Cumyloxyl and Benzyloxyl Radicals with Tertiary Amides. Hydrogen Abstraction Selectivity and the Role of Specific Substrate-Radical Hydrogen Bonding. J Org Chem 2013; 78:5909-17. [DOI: 10.1021/jo400535u] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via
della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Michela Milan
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via
della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Gino A. DiLabio
- National
Institute for Nanotechnology, National Research Council of Canada, 11421 Saskatchewan
Drive, Edmonton, Alberta, Canada T6G 2M9
- Department of Physics, University of Alberta, Edmonton, Alberta,
Canada T6G 2E1
| | - Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via
della Ricerca Scientifica, 1 I-00133 Rome, Italy
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21
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Johnson ER, Salamone M, Bietti M, DiLabio GA. Modeling Noncovalent Radical–Molecule Interactions Using Conventional Density-Functional Theory: Beware Erroneous Charge Transfer. J Phys Chem A 2013; 117:947-52. [DOI: 10.1021/jp3084309] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Erin R. Johnson
- Chemistry and Chemical
Biology,
School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California 95343,
United States
| | - Michela Salamone
- Dipartimento
di Scienze e Tecnologie
Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Massimo Bietti
- Dipartimento
di Scienze e Tecnologie
Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Gino A. DiLabio
- National Institute for Nanotechnology, National Research Council of Canada, 11421 Saskatchewan
Drive, Edmonton, Alberta, Canada T6G 2M9
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G
2E1
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22
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Salamone M, Giammarioli I, Bietti M. Tuning hydrogen atom abstraction from the aliphatic C–H bonds of basic substrates by protonation. Control over selectivity by C–H deactivation. Chem Sci 2013. [DOI: 10.1039/c3sc51058a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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23
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Medina ME, Iuga C, Alvarez-Idaboy JR. Antioxidant activity of propyl gallate in aqueous and lipid media: a theoretical study. Phys Chem Chem Phys 2013; 15:13137-46. [DOI: 10.1039/c3cp51644j] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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24
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Haidasz EA, Li B, Pratt DA. Reaction mechanisms: radical and radical ion reactions. ACTA ACUST UNITED AC 2013. [DOI: 10.1039/c3oc90013d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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