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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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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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3
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Fu Y, Wang Z, Zhang Y, Shen G, Zhu X. Quantitative Evaluation of the Hydrogen‐Donating Abilities ofAmines and Amides in Acetonitrile. ChemistrySelect 2022. [DOI: 10.1002/slct.202202625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yan‐Hua Fu
- College of Chemistry and Environmental Engineering Anyang Institute of Technology Anyang Henan 455000 China
| | - Zhen Wang
- 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
| | - Guang‐Bin Shen
- School of Medical Engineering Jining Medical University Jining Shandong 272000 P. R. China
| | - Xiao‐Qing Zhu
- Department of Chemistry Nankai University Tianjin 300071 China
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4
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Fu YH, Shen GB, Wang K, Zhu XQ. New Insights into the Actual H-Abstraction Activities of Important Oxygen and Nitrogen Free Radicals: Thermodynamics and Kinetics in Acetonitrile. ACS OMEGA 2022; 7:25555-25564. [PMID: 35910187 PMCID: PMC9330089 DOI: 10.1021/acsomega.2c02700] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 06/30/2022] [Indexed: 06/02/2023]
Abstract
The H-abstraction activity of a free radical is a research hotspot and has been extensively studied. In this article, the second-order rate constants of 21 HAT reactions in acetonitrile at 298 K were chosen from several published literature. A kinetic study on the H-abstraction reaction from TEMPOH by a DPPH• radical was carried out. This reaction was researched as an insertion point. By combining this reaction with the 21 HAT reactions in this paper, the thermokinetic parameters of 28 free radicals X and their corresponding antioxidants XH were obtained by the cross-HAT reaction method. The scales of the H-abstraction activities of these 28 oxygen and nitrogen free radicals were determined by using the thermokinetic parameters ΔG ≠o(X). Applications of the thermokinetic parameter ΔG ≠o(X) in assessing the actual H-abstraction activity of a free radical quantitatively and selecting a suitable free radical in scientific research and chemical production were discussed. Predictions of the rate constants by using thermokinetic parameters of reactants were researched, and the reliabilities of the predicted activation free energies of XH/Y reactions were also examined.
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Affiliation(s)
- Yan-Hua Fu
- College
of Chemistry and Environmental Engineering, Anyang Institute of Technology, Anyang, Henan 455000, China
| | - Guang-Bin Shen
- School
of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China
| | - Kai Wang
- College
of Chemistry and Environmental Engineering, Anyang Institute of Technology, Anyang, Henan 455000, China
| | - Xiao-Qing Zhu
- Department
of Chemistry, Nankai University, Tianjin 300071, China
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5
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Galeotti M, Trasatti C, Sisti S, Salamone M, Bietti M. Factors Governing Reactivity and Selectivity in Hydrogen Atom Transfer from C(sp 3)-H Bonds of Nitrogen-Containing Heterocycles to the Cumyloxyl Radical. J Org Chem 2022; 87:7456-7463. [PMID: 35609878 PMCID: PMC9171822 DOI: 10.1021/acs.joc.2c00955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
![]()
A kinetic study of
the hydrogen atom transfer (HAT) reactions from
nitrogen-containing heterocycles (secondary and tertiary lactams,
2-imidazolidinones, 2-oxazolidinones, and succinimides) to the cumyloxyl
radical has been carried out employing laser flash photolysis with
ns time resolution. HAT occurs from the C–H bonds that are
α to nitrogen, activated by hyperconjugative overlap with the
N–C=O π system. In the lactam series, the second-order
HAT rate constant (kH) was observed to
decrease by a factor of ∼4 going from the five- and six-membered
ring derivatives to the eight-membered ones, a behavior that was rationalized
on the basis of a reduced extent of hyperconjugative activation associated
to the greater flexibility of the larger rings compared to the smaller
ones. In the five-membered-ring substrate series, the kH values were observed to increase by >3 orders of
magnitude
on going from succinimide to 2-imidazolidinones, a behavior that was
explained in terms of the divergent contribution of hyperconjugative
activation and deactivating electronic effects determined by ring
functionalities. The results are discussed in the framework of the
development of HAT-based C–H bond functionalization procedures.
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Affiliation(s)
- Marco Galeotti
- Dipartimento di Scienze e Tecnologie Chimiche, Università"Tor Vergata", Via Della Ricerca Scientifica, 1, Rome I-00133, Italy
| | - Chiara Trasatti
- Dipartimento di Scienze e Tecnologie Chimiche, Università"Tor Vergata", Via Della Ricerca Scientifica, 1, Rome I-00133, Italy
| | - Sergio Sisti
- Dipartimento di Scienze e Tecnologie Chimiche, Università"Tor Vergata", Via Della Ricerca Scientifica, 1, Rome I-00133, Italy
| | - Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università"Tor Vergata", Via Della Ricerca Scientifica, 1, Rome I-00133, Italy
| | - Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università"Tor Vergata", Via Della Ricerca Scientifica, 1, Rome I-00133, Italy
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6
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Lakshmanan S, Lingappan N. Autoxidation of Formaldehyde with Oxygen-A Comparison of Reaction Channels. ACS OMEGA 2022; 7:6778-6786. [PMID: 35252672 PMCID: PMC8892663 DOI: 10.1021/acsomega.1c06375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
The autoxidation of formaldehyde through initiation by triplet oxygen is studied via two initial steps: (1) H-atom abstraction and (2) 3O2 addition reaction. The reaction energy profiles show that the reactions are thermodynamically and kinetically demanding. A comparison of the pathways of these initial reactions and the search for a less energy-demanding pathway is presented. The presence of a Brønsted acid has no effect on the energetics of the reaction, while the presence of a single water molecule catalyst enhances the initial reactions. The H-atom abstraction reaction from formaldehyde results in formyl and hydroperoxy radicals. These radicals on further reaction with the second equivalent of 3O2 lead to a CO + 2HO2 product channel. The 3O2 addition reaction to formaldehyde results in a triplet biradical intermediate which further leads to performic acid, the precursor in the synthesis of carboxylic acids from aldehydes. In the presence of water molecules, performic acid is formed in a single kinetic step, and this leads to a CO2 + OH + HO2 product channel upon subsequent reaction with 3O2 in a thermodynamically favorable reaction. The results show that the less established 3O2 addition reaction to aldehydes is a viable route for autoxidation in the absence of purpose-built initiators, in addition to the well-established H-atom abstraction route.
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Affiliation(s)
- Sandhiya Lakshmanan
- CSIR—National
Institute of Science Communication and Policy Research, New Delhi 110012, India
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7
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Najafishirtari S, Friedel Ortega K, Douthwaite M, Pattisson S, Hutchings GJ, Bondue CJ, Tschulik K, Waffel D, Peng B, Deitermann M, Busser GW, Muhler M, Behrens M. A Perspective on Heterogeneous Catalysts for the Selective Oxidation of Alcohols. Chemistry 2021; 27:16809-16833. [PMID: 34596294 PMCID: PMC9292687 DOI: 10.1002/chem.202102868] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Indexed: 01/15/2023]
Abstract
Selective oxidation of higher alcohols using heterogeneous catalysts is an important reaction in the synthesis of fine chemicals with added value. Though the process for primary alcohol oxidation is industrially established, there is still a lack of fundamental understanding considering the complexity of the catalysts and their dynamics under reaction conditions, especially when higher alcohols and liquid‐phase reaction media are involved. Additionally, new materials should be developed offering higher activity, selectivity, and stability. This can be achieved by unraveling the structure–performance correlations of these catalysts under reaction conditions. In this regard, researchers are encouraged to develop more advanced characterization techniques to address the complex interplay between the solid surface, the dissolved reactants, and the solvent. In this mini‐review, we report some of the most important approaches taken in the field and give a perspective on how to tackle the complex challenges for different approaches in alcohol oxidation while providing insight into the remaining challenges.
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Affiliation(s)
- Sharif Najafishirtari
- Faculty of Chemistry and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057, Duisburg, Germany
| | - Klaus Friedel Ortega
- Institute of Inorganic Chemistry, Kiel University, Max-Eyth-Straße 2, 24118, Kiel, Germany
| | - Mark Douthwaite
- Cardiff Catalysis Institute, Cardiff University, CF10 3AT, Cardiff, United Kingdom
| | - Samuel Pattisson
- Cardiff Catalysis Institute, Cardiff University, CF10 3AT, Cardiff, United Kingdom
| | - Graham J Hutchings
- Cardiff Catalysis Institute, Cardiff University, CF10 3AT, Cardiff, United Kingdom
| | - Christoph J Bondue
- Faculty of Chemistry and Biochemistry, Lab. of Electrochemistry & Nanoscale Materials, Ruhr-University Bochum, Universitätsstraße. 150, ZEMOS 1.41, 44780, Bochum, Germany
| | - Kristina Tschulik
- Faculty of Chemistry and Biochemistry, Lab. of Electrochemistry & Nanoscale Materials, Ruhr-University Bochum, Universitätsstraße. 150, ZEMOS 1.41, 44780, Bochum, Germany
| | - Daniel Waffel
- Faculty of Chemistry and Biochemistry, Lab. of Industrial Chemistry, Ruhr-University Bochum, Universitätsstraße 150, NBCF 04 / 690, 44780, Bochum, Germany
| | - Baoxiang Peng
- Faculty of Chemistry and Biochemistry, Lab. of Industrial Chemistry, Ruhr-University Bochum, Universitätsstraße 150, NBCF 04 / 690, 44780, Bochum, Germany
| | - Michel Deitermann
- Faculty of Chemistry and Biochemistry, Lab. of Industrial Chemistry, Ruhr-University Bochum, Universitätsstraße 150, NBCF 04 / 690, 44780, Bochum, Germany
| | - G Wilma Busser
- Faculty of Chemistry and Biochemistry, Lab. of Industrial Chemistry, Ruhr-University Bochum, Universitätsstraße 150, NBCF 04 / 690, 44780, Bochum, Germany
| | - Martin Muhler
- Faculty of Chemistry and Biochemistry, Lab. of Industrial Chemistry, Ruhr-University Bochum, Universitätsstraße 150, NBCF 04 / 690, 44780, Bochum, Germany
| | - Malte Behrens
- Faculty of Chemistry and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057, Duisburg, Germany.,Institute of Inorganic Chemistry, Kiel University, Max-Eyth-Straße 2, 24118, Kiel, Germany
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8
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Zhang J, Liu D, Liu S, Ge Y, Lan Y, Chen Y. Visible-Light-Induced Alkoxyl Radicals Enable α-C(sp 3)-H Bond Allylation. iScience 2019; 23:100755. [PMID: 31884167 PMCID: PMC6941871 DOI: 10.1016/j.isci.2019.100755] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/08/2019] [Accepted: 11/27/2019] [Indexed: 11/18/2022] Open
Abstract
The alkoxyl radical is an essential reactive intermediate in mechanistic studies and organic synthesis with hydrogen atom transfer (HAT) reactivity. However, compared with intramolecular 1,5-HAT or intermolecular HAT of alkoxyl radicals, the intramolecular 1,2-HAT reactivity has been limited to theoretical studies and rarely synthetically utilized. Here we report the first selective 1,2-HAT of alkoxyl radicals for α-C(sp3)-H bond allylation of α-carbonyl, α-cyano, α-trifluoromethyl, and benzylic N-alkoxylphthalimides. The mechanistic probing experiments, electron paramagnetic resonance (EPR) studies, and density functional theory (DFT) calculations confirmed the 1,2-HAT reactivity of alkoxyl radicals, and the use of protic solvents lowered the activation energy by up to 10.4 kcal/mol to facilitate the α-C(sp3)-H allylation reaction.
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Affiliation(s)
- Jing Zhang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Dan Liu
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Song Liu
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China
| | - Yuanyuan Ge
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Yu Lan
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China; Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China.
| | - Yiyun Chen
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
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9
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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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10
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Dutta S, Mallick RK, Prasad R, Gandon V, Sahoo AK. Alkyne Versus Ynamide Reactivity: Regioselective Radical Cyclization of Yne‐Ynamides. Angew Chem Int Ed Engl 2019; 58:2289-2294. [DOI: 10.1002/anie.201811947] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/12/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Shubham Dutta
- School of ChemistryUniversity of Hyderabad Hyderabad India
| | | | - Rangu Prasad
- School of ChemistryUniversity of Hyderabad Hyderabad India
| | - Vincent Gandon
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS UMR 8182Université Paris-Sud, Université Paris-Saclay Bâtiment 420 91405 Orsay cedex France
- Laboratoire de Chimie Moléculaire (LCM), CNRS UMR 9168Ecole PolytechniqueUniversité Paris-Saclay route de Saclay 91128 Palaiseau cedex France
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11
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Dutta S, Mallick RK, Prasad R, Gandon V, Sahoo AK. Alkyne Versus Ynamide Reactivity: Regioselective Radical Cyclization of Yne-Ynamides. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201811947] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Shubham Dutta
- School of Chemistry; University of Hyderabad; Hyderabad India
| | | | - Rangu Prasad
- School of Chemistry; University of Hyderabad; Hyderabad India
| | - Vincent Gandon
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS UMR 8182; Université Paris-Sud, Université Paris-Saclay; Bâtiment 420 91405 Orsay cedex France
- Laboratoire de Chimie Moléculaire (LCM), CNRS UMR 9168; Ecole Polytechnique; Université Paris-Saclay; route de Saclay 91128 Palaiseau cedex France
| | - Akhila K. Sahoo
- School of Chemistry; University of Hyderabad; Hyderabad India
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12
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Bosset C, Beucher H, Bretel G, Pasquier E, Queguiner L, Henry C, Vos A, Edwards JP, Meerpoel L, Berthelot D. Minisci-Photoredox-Mediated α-Heteroarylation of N-Protected Secondary Amines: Remarkable Selectivity of Azetidines. Org Lett 2018; 20:6003-6006. [DOI: 10.1021/acs.orglett.8b00991] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Cyril Bosset
- Janssen Research and Development, Division of Janssen-Cilag S.A., Chaussée du Vexin, Val de Reuil 27100 Cedex, France
| | - Hélène Beucher
- Janssen Research and Development, Division of Janssen-Cilag S.A., Chaussée du Vexin, Val de Reuil 27100 Cedex, France
| | - Guillaume Bretel
- Janssen Research and Development, Division of Janssen-Cilag S.A., Chaussée du Vexin, Val de Reuil 27100 Cedex, France
| | - Elisabeth Pasquier
- Janssen Research and Development, Division of Janssen-Cilag S.A., Chaussée du Vexin, Val de Reuil 27100 Cedex, France
| | - Laurence Queguiner
- Janssen Research and Development, Division of Janssen-Cilag S.A., Chaussée du Vexin, Val de Reuil 27100 Cedex, France
| | - Cyril Henry
- Janssen Research and Development, Division of Janssen-Cilag S.A., Chaussée du Vexin, Val de Reuil 27100 Cedex, France
| | - Ann Vos
- Janssen Research and Development, Division of Janssen Pharmaceutica N.V., Turnhoutseweg 30, 2340 Beerse, Belgium
| | - James P. Edwards
- Janssen Research and Development, LLC, 1400 McKean Road, Spring House, Pennsylvania 19002, United States
| | - Lieven Meerpoel
- Janssen Research and Development, Division of Janssen Pharmaceutica N.V., Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Didier Berthelot
- Janssen Research and Development, Division of Janssen-Cilag S.A., Chaussée du Vexin, Val de Reuil 27100 Cedex, France
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13
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Milan M, Salamone M, Costas M, Bietti M. The Quest for Selectivity in Hydrogen Atom Transfer Based Aliphatic C-H Bond Oxygenation. Acc Chem Res 2018; 51:1984-1995. [PMID: 30080039 DOI: 10.1021/acs.accounts.8b00231] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Aliphatic C-H bond functionalization is at the frontline of research because it can provide straightforward access to simplified and cost-effective synthetic procedures. A number of these methodologies are based on hydrogen atom transfer (HAT), which, as a consequence of the inert character of C-H bonds, often represents the most challenging step of the overall process. Because the majority of organic molecules contain multiple nonequivalent C-H bonds that display similar chemical properties, differentiating between these bonds with high levels of selectivity represents one of the most challenging issues. Clarification of the factors that govern the relative reactivity of C-H bonds toward HAT reagents is thus of primary importance in order to develop selective functionalization procedures. In this Account we describe, through the combination of kinetic studies employing a genuine HAT reagent such as the cumyloxyl radical, along with oxidations performed with H2O2 and iron or manganese catalysts, our contribution toward the development of selective C-H functionalization methodologies. Despite the different nature of these reagents, an oxygen-centered radical and a metal-oxo species, congruent reactivity and selectivity patterns have emerged, providing strong evidence that both reactions proceed via HAT. Consequently, selectivity in this class of metal catalyzed C-H oxidations can be reasonably predicted and synthetically exploited. Amides have been identified as preferential functional groups for governing selectivity on the basis of electronic, steric, and stereoelectronic effects. Torsional effects have proven moreover to be particularly important C-H directing factors in the oxidation of cyclohexane scaffolds where a delicate balance of these effects, in synergistic combination with catalyst design, enables highly chemoselective and enantioselective oxidations. Medium effects have been also shown to govern the relative HAT reactivity of C-H bonds in proximity to polar, hydrogen bond acceptor (HBA) functional groups. By engaging in hydrogen bonding with these groups, fluorinated alcohols strongly deactivate proximal C-H bonds toward HAT-based oxidation. As a result, alcohols, ethers, amines, and amides, which are electron rich and effective proximal C-H activating groups toward HAT reagents in conventional solvents, become oxidatively robust deactivating functionalities that direct C-H oxidation toward remote positions. These deactivating effects enable moreover the accomplishment of product chemoselective methylenic hydroxylations. Overall, clarification of the factors that govern HAT-based reactions has served to provide unique examples of catalytic methodologies for chemoselective and enantioselective oxidation of nonactivated aliphatic C-H bonds of potential utility in organic synthesis.
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Affiliation(s)
- Michela Milan
- QBIS Research Group, Institut de Química Computacional i Catàlisi (IQCC), and Departament de Química, Universitat de Girona, Campus Montilivi, Girona, E-17071 Catalonia, Spain
| | - Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
| | - Miquel Costas
- QBIS Research Group, Institut de Química Computacional i Catàlisi (IQCC), and Departament de Química, Universitat de Girona, Campus Montilivi, Girona, E-17071 Catalonia, Spain
| | - Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1, I-00133 Rome, Italy
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14
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Salamone M, Ortega VB, Martin T, Bietti M. Hydrogen Atom Transfer from Alkanols and Alkanediols to the Cumyloxyl Radical: Kinetic Evaluation of the Contribution of α-C-H Activation and β-C-H Deactivation. J Org Chem 2018; 83:5539-5545. [PMID: 29668277 DOI: 10.1021/acs.joc.8b00562] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A kinetic study on the reactions of the cumyloxyl radical (CumO•) with a series of alkanols and alkanediols has been carried out. Predominant hydrogen atom transfer (HAT) from the α-C-H bonds of these substrates, activated by the presence of the OH group, is observed. The comparable kH values measured for ethanol and 1-propanol and the increase in kH measured upon going from 1,2-diols to structurally related 1,3- and 1,4-diols is indicative of β-C-H deactivation toward HAT to the electrophilic CumO•, determined by the electron-withdrawing character of the OH group. No analogous deactivation is observed for the corresponding diamines, in agreement with the weaker electron-withdrawing character of the NH2 group. The significantly lower kH values measured for reaction of CumO• with densely oxygenated methyl pyranosides as compared to cyclohexanol derivatives highlights the role of β-C-H deactivation. The contribution of torsional effects on reactivity is evidenced by the ∼2-fold increase in kH observed upon going from the trans isomers of 4- tert-butylcyclohexanol and 1,2- and 1,4-cyclohexanediol to the corresponding cis isomers. These results provide an evaluation of the role of electronic and torsional effects on HAT reactions from alcohols and diols to CumO•, uncovering moreover β-C-H deactivation as a relevant contributor in defining site selectivity.
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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
| | - Vanesa B Ortega
- Dipartimento di Scienze e Tecnologie Chimiche , Università "Tor Vergata" , Via della Ricerca Scientifica 1 , I-00133 Rome , Italy
| | - Teo Martin
- 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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Li X. 2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-Oxide (PTIO •) Radical Scavenging: A New and Simple Antioxidant Assay In Vitro. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:6288-6297. [PMID: 28689421 DOI: 10.1021/acs.jafc.7b02247] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Current in vitro antioxidant assays have several limitations, which frequently cause inconsistent results. The study develops a new antioxidant assay using the 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO•). After the investigation of various factors, the experimental protocol was briefly recommended as follows: PTIO• and the sample solution were added to phosphate buffer (pH 7.4, 50 mM), incubated at 37 °C for 2 h, and then spectrophotometrically measured at 557 nm. The validation test based on 20 pure compounds and 30 lyophilized aqueous extracts suggested that PTIO• scavenging had a good linear relationship, stability, and reproducibility. In the ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry analysis, PTIO• was observed to give m/z 234 when encountering l-ascorbic acid. As an antioxidant assay, PTIO• scavenging possesses four advantages, i.e., oxygen-centered radical, physiological aqueous solution, simple and direct measurement, and less interference from the tested sample. It can also satisfactorily analyze the antioxidant structure-activity relationship. PTIO• scavenging has no stereospecificity and is at least involved in H+ transfer.
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Affiliation(s)
- Xican Li
- School of Chinese Herbal Medicine and Innovative Research and Development Laboratory of TCM, Guangzhou University of Chinese Medicine , 232 Waihuan East Road, Guangzhou Higher Education Mega Center, Panyu District, Guangzhou, Guangdong 510006, People's Republic of China
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16
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Okugawa N, Moriyama K, Togo H. Introduction of Quinolines and Isoquinolines onto Nonactivated α-C-H Bond of Tertiary Amides through a Radical Pathway. J Org Chem 2017; 82:170-178. [PMID: 27976909 DOI: 10.1021/acs.joc.6b02303] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Treatment of quinolines and isoquinolines with benzoyl peroxide in tertiary amides, such as N,N-dimethylacetamide, N,N-dimethylpropionamide, and N-acetylpyrrolidine, etc., under irradiation with a Hg lamp in the temperature range of 35 °C to 40 °C gave C-C-bonded quinolines and isoquinolines bearing amide groups with high regioselectivity in good to moderate yields, respectively, under transition-metal-free conditions.
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Affiliation(s)
- Naoki Okugawa
- Graduate School of Science and ‡Molecular Chirality Research Center, Chiba University , Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
| | - Katsuhiko Moriyama
- Graduate School of Science and ‡Molecular Chirality Research Center, Chiba University , Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
| | - Hideo Togo
- Graduate School of Science and ‡Molecular Chirality Research Center, Chiba University , Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
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17
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Hydrogen atom transfer from tertiary alkanamides to the cumyloxyl radical. The role of substrate structure on alkali and alkaline earth metal ion induced C–H bond deactivation. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.05.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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18
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Bietti M, Forcina V, Lanzalunga O, Lapi A, Martin T, Mazzonna M, Salamone M. Kinetic Study of the Reaction of the Phthalimide-N-oxyl Radical with Amides: Structural and Medium Effects on the Hydrogen Atom Transfer Reactivity and Selectivity. J Org Chem 2016; 81:11924-11931. [PMID: 27934460 DOI: 10.1021/acs.joc.6b02482] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A kinetic study of the hydrogen atom transfer (HAT) reactions from a series of secondary N-(4-X-benzyl)acetamides and tertiary amides to the phthalimide-N-oxyl radical (PINO) has been carried out. The results indicate that HAT is strongly influenced by structural and medium effects; in particular, the addition of Brønsted and Lewis acids determines a significant deactivation of C-H bonds α to the amide nitrogen of these substrates. Thus, by changing the reaction medium, it is possible to carefully control the regioselectivity of the aerobic oxidation of amides catalyzed by N-hydroxyphthalimide, widening the synthetic versatility of this process.
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Affiliation(s)
- Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata″ , Via della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Veronica Forcina
- Dipartimento di Chimica, Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Sapienza Università di Roma , Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Osvaldo Lanzalunga
- Dipartimento di Chimica, Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Sapienza Università di Roma , Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Andrea Lapi
- Dipartimento di Chimica, Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Sapienza Università di Roma , Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Teo Martin
- Dipartimento di Chimica, Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Sapienza Università di Roma , Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Marco Mazzonna
- Dipartimento di Chimica, Sapienza Università di Roma and Istituto CNR di Metodologie Chimiche (IMC-CNR), Sezione Meccanismi di Reazione, c/o Dipartimento di Chimica, Sapienza Università di Roma , Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata″ , Via della Ricerca Scientifica 1, I-00133 Rome, Italy
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19
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Liu X, Jiang B, Zhai G. Catalytic aerobic radical polymerization of methyl methacrylate in N,N-dimethylformamide: Stepwise in situ activation of dioxygen to peroxides and further to oxyl radicals. J Catal 2016. [DOI: 10.1016/j.jcat.2016.04.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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20
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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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21
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Panov GI, Parfenov MV, Parmon VN. The Brønsted−Evans−Polanyi Correlations in Oxidation Catalysis. CATALYSIS REVIEWS-SCIENCE AND ENGINEERING 2015. [DOI: 10.1080/01614940.2015.1074487] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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22
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Salamone M, Basili F, Bietti M. Reactivity and selectivity patterns in hydrogen atom transfer from amino acid C-H bonds to the cumyloxyl radical: polar effects as a rationale for the preferential reaction at proline residues. J Org Chem 2015; 80:3643-50. [PMID: 25774567 DOI: 10.1021/acs.joc.5b00549] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Absolute rate constants for hydrogen atom transfer (HAT) from the C-H bonds of N-Boc-protected amino acids to the cumyloxyl radical (CumO(•)) were measured by laser flash photolysis. With glycine, alanine, valine, norvaline, and tert-leucine, HAT occurs from the α-C-H bonds, and the stability of the α-carbon radical product plays a negligible role. With leucine, HAT from the α- and γ-C-H bonds was observed. The higher kH value measured for proline was explained in terms of polar effects, with HAT that predominantly occurs from the δ-C-H bonds, providing a rationale for the previous observation that proline residues represent favored HAT sites in the reactions of peptides and proteins with (•)OH. Preferential HAT from proline was also observed in the reactions of CumO(•) with the dipeptides N-BocProGlyOH and N-BocGlyGlyOH. The rate constants measured for CumO(•) were compared with the relative rates obtained previously for the corresponding reactions of different hydrogen-abstracting species. The behavior of CumO(•) falls between those observed for the highly reactive radicals Cl(•) and (•)OH and the significantly more stable Br(•). Taken together, these results provide a general framework for the description of the factors that govern reactivity and selectivity patterns in HAT reactions from amino acid C-H bonds.
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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
| | - Federica Basili
- 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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23
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Salamone M, Mangiacapra L, Bietti M. Kinetic Solvent Effects on the Reactions of the Cumyloxyl Radical with Tertiary Amides. Control over the Hydrogen Atom Transfer Reactivity and Selectivity through Solvent Polarity and Hydrogen Bonding. J Org Chem 2015; 80:1149-54. [DOI: 10.1021/jo5026767] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Michela Salamone
- Dipartimento
di Scienze e
Tecnologie Chimiche, Università “Tor Vergata”, Via
della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Livia Mangiacapra
- 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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24
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Salamone M, Basili F, Mele R, Cianfanelli M, Bietti M. Reactions of the cumyloxyl radical with secondary amides. The influence of steric and stereoelectronic effects on the hydrogen atom transfer reactivity and selectivity. Org Lett 2014; 16:6444-7. [PMID: 25474754 DOI: 10.1021/ol503277r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A time-resolved kinetic study of the hydrogen atom transfer (HAT) reactions from secondary alkanamides to the cumyloxyl radical was carried out in acetonitrile. HAT predominantly occurs from the N-alkyl α-C-H bonds, and a >60-fold decrease in kH was observed by increasing the steric hindrance of the acyl and N-alkyl groups. The role of steric and stereoelectronic effects on the reactivity and selectivity is discussed in the framework of HAT reactions from peptides.
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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
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