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Abstract
Recently, organic synthesis has seen a renaissance in radical chemistry due to the accessibility of mild methods for radical generation using visible light. While renewed interest in synthetic radical chemistry has been driven by the advent of photoredox catalysis, a resurgence of electron donor-acceptor (EDA) photochemistry has also led to many new radical transformations. Similar to photoredox catalysis, EDA photochemistry involves light-promoted single-electron transfer pathways. However, the mechanism of electron transfer in EDA systems is unique wherein the lifetimes of radical intermediates are often shorter due to competitive back-electron transfer. Distinguishing between EDA and photoredox mechanisms can be challenging since they can form identical products. In this perspective, we seek to provide insight on the mechanistic studies which can distinguish between EDA and photoredox manifolds. Additionally, we highlight some key challenges in EDA photochemistry and suggest future goals which could advance the synthetic potential of this field of research.
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Affiliation(s)
- Alan K. Wortman
- Willard Henry Dow Laboratory, Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
| | - Corey R. J. Stephenson
- Willard Henry Dow Laboratory, Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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2
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West CP, Morales AC, Ryan J, Misovich MV, Hettiyadura APS, Rivera-Adorno F, Tomlin JM, Darmody A, Linn BN, Lin P, Laskin A. Molecular investigation of the multi-phase photochemistry of Fe(III)-citrate in aqueous solution. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:190-213. [PMID: 35634912 DOI: 10.1039/d1em00503k] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Iron (Fe) is ubiquitous in nature and found as FeII or FeIII in minerals or as dissolved ions Fe2+ or Fe3+ in aqueous systems. The interactions of soluble Fe have important implications for fresh water and marine biogeochemical cycles, which have impacts on global terrestrial and atmospheric environments. Upon dissolution of FeIII into natural aquatic systems, organic carboxylic acids efficiently chelate FeIII to form [FeIII-carboxylate]2+ complexes that undergo a wide range of photochemistry-induced radical reactions. The chemical composition and photochemical transformations of these mixtures are largely unknown, making it challenging to estimate their environmental impact. To investigate the photochemical process of FeIII-carboxylates at the molecular level, we conduct a comprehensive experimental study employing UV-visible spectroscopy, liquid chromatography coupled to photodiode array and high-resolution mass spectrometry detection, and oil immersion flow microscopy. In this study, aqueous solutions of FeIII-citrate were photolyzed under 365 nm light in an experimental setup with an apparent quantum yield of (φ) ∼0.02, followed by chemical analyses of reacted mixtures withdrawn at increment time intervals of the experiment. The apparent photochemical reaction kinetics of Fe3+-citrates (aq) were expressed as two generalized consecutive reactions of with the experimental rate constants of j1 ∼ 0.12 min-1 and j2 ∼ 0.05 min-1, respectively. Molecular characterization results indicate that R and I consist of both water-soluble organic and Fe-organic species, while P compounds are a mixture of water-soluble and colloidal materials. The latter were identified as Fe-carbonaceous colloids formed at long photolysis times. The carbonaceous content of these colloids was identified as unsaturated organic species with low oxygen content and carbon with a reduced oxidation state, indicative of their plausible radical recombination mechanism under oxygen-deprived conditions typical for the extensively photolyzed mixtures. Based on the molecular characterization results, we discuss the comprehensive reaction mechanism of FeIII-citrate photochemistry and report on the formation of previously unexplored colloidal reaction products, which may contribute to atmospheric and terrestrial light-absorbing materials in aquatic environments.
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Affiliation(s)
- Christopher P West
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Ana C Morales
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Jackson Ryan
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Maria V Misovich
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | | | | | - Jay M Tomlin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Andrew Darmody
- Department of Aeronautics and Aerospace Engineering, Purdue University, West Lafayette, IN, USA
| | - Brittany N Linn
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Peng Lin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
| | - Alexander Laskin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA.
- Department of Earth, Atmospheric & Planetary Sciences, Purdue University, West Lafayette, IN, USA
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3
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Burlingham SJ, Guijarro D, Bosque I, Chinchilla R, Gonzalez-Gomez JC. Visible-light-mediated decarboxylative ( E)-alkenylation of aliphatic carboxylic acids with aryl styryl sulfones under metal-free conditions. Org Biomol Chem 2022; 20:7923-7928. [PMID: 36178275 DOI: 10.1039/d2ob01360f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The decarboxylative alkenylation of aliphatic carboxylic acids with aryl styryl sulfones is efficiently catalyzed by riboflavin tetraacetate under visible light irradiation at room temperature. This metal-free protocol is cost-efficient, environmentally friendly and provides the corresponding olefins with excellent (E)-diastereocontrol. The methodology can also be used to prepare internal alkynes regioselectively by using alkynyl sulfones as radical acceptors. The suitability as building blocks of the olefins obtained was demonstrated by performing an (E)- to (Z) photoisomerization, an iron-catalyzed allylic substitution of the phenoxy group derived from the 2-phenoxycarboxylic acid substrates, as well as syn-epoxidations, and diastereoselective intramolecular iodoarylations. Based on control experiments and DFT calculations, we proposed a reaction mechanism that accounts for the regio- and diastereo-selectivity observed.
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Affiliation(s)
- Sarah-Jayne Burlingham
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain.
| | - David Guijarro
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain.
| | - Irene Bosque
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain.
| | - Rafael Chinchilla
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain.
| | - Jose C Gonzalez-Gomez
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain.
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Tripathy AR, Yedase GS, Yatham VR. Cerium photocatalyzed radical smiles rearrangement of 2-aryloxybenzoic acids. RSC Adv 2021; 11:25207-25210. [PMID: 35478894 PMCID: PMC9037003 DOI: 10.1039/d1ra04130d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 07/15/2021] [Indexed: 01/13/2023] Open
Abstract
We report herein a cerium photocatalyzed aryl migration from an aryl ether to a carboxylic acid group through radical-Smiles rearrangement. This operationally simple protocol utilizes inexpensive CeCl3 as a photocatalyst and converted a variety of 2-aryloxybenzoic acids into aryl-2-hydroxybenzoates in good yields. Visible light-driven CeCl3-mediated aryl migration from an aryl ether to a carboxylic acid group through radical-Smiles rearrangement is reported.![]()
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Affiliation(s)
- Alisha Rani Tripathy
- School of Chemistry
- Indian Institute of Science Education and Research
- Thiruvananthapuram 695551
- India
| | - Girish Suresh Yedase
- School of Chemistry
- Indian Institute of Science Education and Research
- Thiruvananthapuram 695551
- India
| | - Veera Reddy Yatham
- School of Chemistry
- Indian Institute of Science Education and Research
- Thiruvananthapuram 695551
- India
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5
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Estruch-Blasco M, Bosque I, Guijarro D, Gonzalez-Gomez JC. Electrochemically site-selective alkoxylation of twisted 2-arylbenzoic acids via spirolactonization. Org Chem Front 2021. [DOI: 10.1039/d1qo00834j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Twisted σ-biphenyl-2-carboxyl radicals show a significant spin density in the adjacent aryl ring, facilitating the spirocyclization. Electro-cross coupling with alcohols and isomerization provide a site-selective alkoxylation of 2-arylbenzoic acids.
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Affiliation(s)
- Manel Estruch-Blasco
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
| | - Irene Bosque
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
| | - David Guijarro
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
| | - Jose C. Gonzalez-Gomez
- Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
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6
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Wegeberg C, de Aguirre A, Maseras F, McKenzie CJ. Photosynthesis of a Dihydroimidazopyridine Chelate Shines Light on the Reactions of a Photoactivated Iron(III) Complex with O 2. Inorg Chem 2020; 59:16281-16290. [PMID: 33021370 DOI: 10.1021/acs.inorgchem.0c02063] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The high-spin (S = 5/2) meridional diastereoisomer of [FeIII(tpena)]2+ (tpena = N,N,N'-tris(2-pyridylmethyl)ethylendiamine-N'-acetate), mer-[Fe(tpena)]2+, undergoes photolytic CO2 release to produce an iron(II) intermediate of a radical dihydroimidazopyridine ligand (L•). The structure of this unprecedented transient iron(II)(L•) complex is supported by UV-vis and Mössbauer spectroscopies, DFT calculations, as well as the X-ray structural characterization of an μ-oxo iron(III) complex of the oxidized derivative of L•, namely, [FeIII2O(Cl)2(L+)2](ClO4)4(MeCN)2 (L+ = 2-(2-(bis(pyridin-2-ylmethyl)amino)ethyl)-2,3-dihydro-1H-imidazo[1,5-a]pyridin-4-ium). [FeIII2O(Cl)2(L+)2]4+ is obtained only in the absence of O2. Under aerobic conditions, O2 will intercept the iron(II)(L•) complex to form a putative Fe(III)-alkylperoxide complex which cascades to an iron(II) complex of SBPy3 (SBPy3 = N,N-bis(2-pyridylmethyl)amine-N-ethyl-2-pyridine-2-aldimine). Thus, through different oxidative pathways, the unknown ligand L+ or SBPy3 forms by loss of a one-carbon-atom or a two-carbon-atom unit, respectively, from the glycyl arm of tpena. Acceleration of the photodecarboxylation step is achieved by addition of thiocyanate because of transient formation of a more photoreactive NCS- adduct of [Fe(tpena)]2+. This has allowed for kinetic observation of the reaction of [FeII(L•)]2+ with O2 which is, unexpectedly, promoted also by light. We propose that this corresponds to the energy needed for the conversion of the ring-closed radical ligand L• to a ring-opened tautomer to allow for O2 insertion between the C and Fe atoms of the iron(II) complex.
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Affiliation(s)
- Christina Wegeberg
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Adiran de Aguirre
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Avgda. Països Catalans, 16, 43007 Tarragona, Catalonia, Spain
| | - Feliu Maseras
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Avgda. Països Catalans, 16, 43007 Tarragona, Catalonia, Spain
| | - Christine J McKenzie
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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Morales‐Martínez D, Lartundo‐Rojas L, González FJ. Mechanistic Aspects on the Electrografting of Carbon Surfaces by Oxidation of Carboxylates Bearing Unsaturated Groups. ChemElectroChem 2020. [DOI: 10.1002/celc.202001096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Daniel Morales‐Martínez
- Departamento de Química Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Mexico City 07360 Mexico
| | - Luis Lartundo‐Rojas
- Centro de Nanociencias y Micro y Nanotecnologías Instituto Politécnico Nacional Mexico City 07738 Mexico
| | - Felipe J. González
- Departamento de Química Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Mexico City 07360 Mexico
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Wadekar K, Aswale S, Yatham VR. Cerium photocatalyzed dehydrogenative lactonization of 2-arylbenzoic acids. Org Biomol Chem 2020; 18:983-987. [PMID: 31939464 DOI: 10.1039/c9ob02676b] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The first cerium photocatalyzed dehydrogenative lactonization of 2-arylbenzoic acids has been developed. This operationally simple protocol allows rapid access to synthetically useful coumarins on gram scale by employing CeCl3 as a photocatalyst and O2 as a terminal oxidant. Overall, this delivers an economical and environmentally amiable entry to diversely substituted coumarins, important structural motifs in bioactive molecules.
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Affiliation(s)
- Ketan Wadekar
- CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad, India, and Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India.
| | - Suraj Aswale
- Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India.
| | - Veera Reddy Yatham
- Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007, India.
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9
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Ramirez NP, Lana-Villarreal T, Gonzalez-Gomez JC. Direct Decarboxylative Allylation and Arylation of Aliphatic Carboxylic Acids Using Flavin-Mediated Photoredox Catalysis. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900888] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Nieves P. Ramirez
- Instituto de Síntesis Orgánica y Departamento de Química Orgánica; Universidad de Alicante; Apdo 99, E -03080 Alicante Spain
| | - Teresa Lana-Villarreal
- Instituto de Electroquímica y Departamento de Química Física; Universidad de Alicante; Spain
| | - Jose C. Gonzalez-Gomez
- Instituto de Síntesis Orgánica y Departamento de Química Orgánica; Universidad de Alicante; Apdo 99, E -03080 Alicante Spain
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10
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Ramirez NP, König B, Gonzalez-Gomez JC. Decarboxylative Cyanation of Aliphatic Carboxylic Acids via Visible-Light Flavin Photocatalysis. Org Lett 2019; 21:1368-1373. [DOI: 10.1021/acs.orglett.9b00064] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Nieves P. Ramirez
- Departamento de Química Orgánica, Facultad de Ciencias and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
| | - Burkhard König
- Faculty of Chemistry and Pharmacy, University of Regensburg, D-93040 Regensburg, Germany
| | - Jose C. Gonzalez-Gomez
- Departamento de Química Orgánica, Facultad de Ciencias and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
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11
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Wegeberg C, Fernández-Alvarez VM, de Aguirre A, Frandsen C, Browne WR, Maseras F, McKenzie CJ. Photoinduced O 2-Dependent Stepwise Oxidative Deglycination of a Nonheme Iron(III) Complex. J Am Chem Soc 2018; 140:14150-14160. [PMID: 30347152 DOI: 10.1021/jacs.8b07455] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The iron(III) complex [Fe(tpena)]2+ (tpena = N, N, N'-tris(2-pyridylmethyl)ethylendiamine- N'-acetate) undergoes irreversible O2-dependent N-demethylcarboxylation to afford [FeII(SBPy3)(MeCN)]2+ (SBPy3 = N, N-bis(2-pyridylmethyl)amine- N-ethyl-2-pyridine-2-aldimine), when irradiated with near-UV light. The loss of a mass equivalent to the glycyl group in a process involving consecutive C-C and C-N cleavages is documented by the measurement of the sequential production of CO2 and formaldehyde, respectively. Time-resolved UV-vis absorption, Mössbauer, EPR, and Raman spectroscopy have allowed the spectroscopic characterization of two iron-based intermediates along the pathway. The first of these, proposed to be a low-spin iron(II)-radical ligand complex, reacts with O2 in the rate-determining step to produce a putative alkylperoxide complex. DFT calculations suggest that this evolves into an Fe(IV)-oxo species, which can abstract a hydrogen atom from a cis methylene group of the ligand to give the second spectroscopically identified intermediate, a high-spin iron(III)-hydroxide of the product oxidized ligand, [FeIII(OH)(SBPy3)]2+. Reduction and exchange of the cohydroxo/water ligand produces the crystallographically characterized products [FeII(SBPy3)(X)]2+/3+, X = MeCN, [Zn(tpena)]+.
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Affiliation(s)
- Christina Wegeberg
- Department of Physics, Chemistry and Pharmacy , University of Southern Denmark , Campusvej 55 , DK-5230 Odense M, Denmark.,Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering , University of Groningen , Nijenborgh 4 , AG Groningen 9747 , The Netherlands
| | - Víctor M Fernández-Alvarez
- Institute of Chemical Research of Catalonia (ICIQ) , The Barcelona Institute of Science and Technology , Avgda. Països Catalans, 16 , 43007 Tarragona , Catalonia , Spain
| | - Adiran de Aguirre
- Institute of Chemical Research of Catalonia (ICIQ) , The Barcelona Institute of Science and Technology , Avgda. Països Catalans, 16 , 43007 Tarragona , Catalonia , Spain
| | - Cathrine Frandsen
- Department of Physics , Technical University of Denmark , DK-2800 Kongens Lyngby , Denmark
| | - Wesley R Browne
- Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, Faculty of Science and Engineering , University of Groningen , Nijenborgh 4 , AG Groningen 9747 , The Netherlands
| | - Feliu Maseras
- Institute of Chemical Research of Catalonia (ICIQ) , The Barcelona Institute of Science and Technology , Avgda. Països Catalans, 16 , 43007 Tarragona , Catalonia , Spain.,Departament de Química , Universitat Autònoma de Barcelona , 08193 Bellaterra , Catalonia , Spain
| | - Christine J McKenzie
- Department of Physics, Chemistry and Pharmacy , University of Southern Denmark , Campusvej 55 , DK-5230 Odense M, Denmark
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12
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Abstract
The merger of open- and closed-shell elementary organometallic steps has enabled the selective intermolecular addition of nucleophilic radicals to unactivated alkynes. A range of carboxylic acids can be subjected to a CO2 extrusion, nickel capture, migratory insertion sequence with terminal and internal alkynes to generate stereodefined functionalized olefins. This platform has been further extended, via hydrogen atom transfer, to the direct vinylation of unactivated C-H bonds. Preliminary studies indicate that a Ni-alkyl migratory insertion is operative.
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Affiliation(s)
- Nicholas A Till
- Merck Center for Catalysis at Princeton University , Princeton , New Jersey 08544 , United States
| | - Russell T Smith
- Merck Center for Catalysis at Princeton University , Princeton , New Jersey 08544 , United States
| | - David W C MacMillan
- Merck Center for Catalysis at Princeton University , Princeton , New Jersey 08544 , United States
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13
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Ramirez NP, Gonzalez-Gomez JC. Decarboxylative Giese-Type Reaction of Carboxylic Acids Promoted by Visible Light: A Sustainable and Photoredox-Neutral Protocol. European J Org Chem 2017. [DOI: 10.1002/ejoc.201601478] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Nieves P. Ramirez
- Departamento de Química Orgánica; Facultad de Ciencias and Instituto de Síntesis Orgánica (ISO); Universidad de Alicante; Apdo. 99 03080 Alicante Spain
| | - Jose C. Gonzalez-Gomez
- Departamento de Química Orgánica; Facultad de Ciencias and Instituto de Síntesis Orgánica (ISO); Universidad de Alicante; Apdo. 99 03080 Alicante Spain
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14
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Le CC, MacMillan DWC. Fragment Couplings via CO2 Extrusion-Recombination: Expansion of a Classic Bond-Forming Strategy via Metallaphotoredox. J Am Chem Soc 2015; 137:11938-41. [PMID: 26333771 DOI: 10.1021/jacs.5b08304] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In this study we demonstrate that molecular fragments, which can be readily coupled via a simple, in situ RO-C═OR bond-forming reaction, can subsequently undergo metal insertion-decarboxylation-recombination to generate Csp(2)-Csp(3) bonds when subjected to metallaphotoredox catalysis. In this embodiment the conversion of a wide variety of mixed anhydrides (formed in situ from carboxylic acids and acyl chlorides) to fragment-coupled ketones is accomplished in good to high yield. A three-step synthesis of the medicinal agent edivoxetine is also described using this new decarboxylation-recombination protocol.
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Affiliation(s)
- Chi Chip Le
- Merck Center for Catalysis at Princeton University , Princeton, New Jersey 08544, United States
| | - David W C MacMillan
- Merck Center for Catalysis at Princeton University , Princeton, New Jersey 08544, United States
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15
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Ramirez NP, Bosque I, Gonzalez-Gomez JC. Photocatalytic Dehydrogenative Lactonization of 2-Arylbenzoic Acids. Org Lett 2015; 17:4550-3. [DOI: 10.1021/acs.orglett.5b02269] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Nieves P. Ramirez
- Departamento de Química
Orgánica, Facultad de Ciencias and Instituto de Síntesis
Orgánica (ISO), Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
| | - Irene Bosque
- Departamento de Química
Orgánica, Facultad de Ciencias and Instituto de Síntesis
Orgánica (ISO), Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
| | - Jose C. Gonzalez-Gomez
- Departamento de Química
Orgánica, Facultad de Ciencias and Instituto de Síntesis
Orgánica (ISO), Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain
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16
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Ventre S, Petronijevic FR, MacMillan DWC. Decarboxylative Fluorination of Aliphatic Carboxylic Acids via Photoredox Catalysis. J Am Chem Soc 2015; 137:5654-7. [PMID: 25881929 PMCID: PMC4862610 DOI: 10.1021/jacs.5b02244] [Citation(s) in RCA: 270] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The direct conversion of aliphatic carboxylic acids to the corresponding alkyl fluorides has been achieved via visible light-promoted photoredox catalysis. This operationally simple, redox-neutral fluorination method is amenable to a wide variety of carboxylic acids. Photon-induced oxidation of carboxylates leads to the formation of carboxyl radicals, which upon rapid CO2-extrusion and F(•) transfer from a fluorinating reagent yield the desired fluoroalkanes with high efficiency. Experimental evidence indicates that an oxidative quenching pathway is operable in this broadly applicable fluorination protocol.
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Affiliation(s)
| | | | - David W. C. MacMillan
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
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17
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Noble A, McCarver SJ, MacMillan DWC. Merging photoredox and nickel catalysis: decarboxylative cross-coupling of carboxylic acids with vinyl halides. J Am Chem Soc 2015; 137:624-7. [PMID: 25521443 PMCID: PMC4308738 DOI: 10.1021/ja511913h] [Citation(s) in RCA: 331] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Indexed: 12/15/2022]
Abstract
Decarboxylative cross-coupling of alkyl carboxylic acids with vinyl halides has been accomplished through the synergistic merger of photoredox and nickel catalysis. This new methodology has been successfully applied to a variety of α-oxy and α-amino acids, as well as simple hydrocarbon-substituted acids. Diverse vinyl iodides and bromides give rise to vinylation products in high efficiency under mild, operationally simple reaction conditions.
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Affiliation(s)
- Adam Noble
- Merck Center for Catalysis at Princeton
University, Princeton, New Jersey 08544, United States
| | - Stefan J. McCarver
- Merck Center for Catalysis at Princeton
University, Princeton, New Jersey 08544, United States
| | - David W. C. MacMillan
- Merck Center for Catalysis at Princeton
University, Princeton, New Jersey 08544, United States
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Noble A, McCarver SJ, MacMillan DWC. Merging Photoredox and Nickel Catalysis: Decarboxylative Cross-Coupling of Carboxylic Acids with Vinyl Halides. J Am Chem Soc 2015. [DOI: 10.1021/ja511913h pmid: 25521443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Adam Noble
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
| | - Stefan J. McCarver
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
| | - David W. C. MacMillan
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
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19
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20
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Wosinska ZM, Stump FL, Ranjan R, Lorance ED, Finley GN, Patel PP, Khawaja MA, Odom KL, Kramer WH, Gould IR. N-alkoxyheterocycles as irreversible photooxidants. Photochem Photobiol 2014; 90:313-28. [PMID: 24354634 DOI: 10.1111/php.12227] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 12/06/2013] [Indexed: 01/07/2023]
Abstract
Irreversible photooxidation based on N-O bond fragmentation is demonstrated for N-methoxyheterocycles in both the singlet and triplet excited state manifolds. The energetic requirements for bond fragmentation are studied in detail. Bond fragmentation in the excited singlet manifold is possible for ππ* singlet states with energies significantly larger than the N-O bond dissociation energy of ca 55 kcal mol(-1). For the nπ* triplet states, N-O bond fragmentation does not occur in the excited state for orbital overlap and energetic reasons. Irreversible photooxidation occurs in the singlet states by bond fragmentation followed by electron transfer. Irreversible photooxidation occurs in the triplet states via bimolecular electron transfer to the donor followed by bond fragmentation. Using these two sensitization schemes, donors can be irreversibly oxidized with oxidation potentials ranging from ca 1.6-2.2 V vs SCE. The corresponding N-ethylheterocycles are characterized as conventional reversible photooxidants in their triplet states. The utility of these sensitizers is demonstrated by irreversibly generating the guanosine radical cation in buffered aqueous solution.
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Affiliation(s)
- Zofia M Wosinska
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ
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21
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Pozdnyakov IP, Melnikov AA, Tkachenko N, Chekalin SV, Lemmetyinen H, Plyusnin VF. Ultrafast photophysical processes for Fe(iii)-carboxylates. Dalton Trans 2014; 43:17590-5. [DOI: 10.1039/c4dt01419g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent works devoted to the investigation of ultrafast processes for several environmentally important Fe(iii) carboxylates were observed and discussed.
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Affiliation(s)
- Ivan P. Pozdnyakov
- Institute of Chemical Kinetics and Combustion
- Siberian Branch of Russian Academy of Sciences
- 630090 Novosibirsk, Russian Federation
- Novosibirsk State University
- 630090 Novosibirsk, Russian Federation
| | - Alexey A. Melnikov
- Institute of Spectroscopy
- Russian Academy of Sciences
- 142190 Troitsk, Russian Federation
| | - Nikolai Tkachenko
- Department of Chemistry and Bioengineering
- Tampere University of Technology
- Tampere, Finland
| | - Sergey V. Chekalin
- Institute of Spectroscopy
- Russian Academy of Sciences
- 142190 Troitsk, Russian Federation
| | - Helge Lemmetyinen
- Department of Chemistry and Bioengineering
- Tampere University of Technology
- Tampere, Finland
| | - Victor F. Plyusnin
- Institute of Chemical Kinetics and Combustion
- Siberian Branch of Russian Academy of Sciences
- 630090 Novosibirsk, Russian Federation
- Novosibirsk State University
- 630090 Novosibirsk, Russian Federation
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22
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Chen QY, Cheng X, Wang T, Yu ZH, Zhang C, Lin SK, Li HH, Chen ZR. A Low-dimensional Viologen/Iodoargentate Hybrid [(BV)2(Ag5I9)]n: Structure, Properties, and Theoretical Study. Z Anorg Allg Chem 2013. [DOI: 10.1002/zaac.201300257] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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23
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Valencia DP, Astudillo PD, Galano A, González FJ. Self-decarboxylation of trichloroacetic acid redox catalyzed by trichloroacetate ions in acetonitrile solutions. Org Biomol Chem 2013; 11:318-25. [PMID: 23165440 DOI: 10.1039/c2ob26961a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Drochss P Valencia
- Departamento de Química del Centro de Investigación y de Estudios Avanzados del I.P.N., Av. IPN 2508, Col. San Pedro Zacatenco, 07360, Distrito Federal, Mexico
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24
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Decarboxylative radical addition of N-Boc-amino acids to acrylonitrile via photoinduced electron transfer using 1,4-dicyanonaphthalene. RESEARCH ON CHEMICAL INTERMEDIATES 2012. [DOI: 10.1007/s11164-012-0657-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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25
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26
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George C, D’Anna B, Herrmann H, Weller C, Vaida V, Donaldson DJ, Bartels-Rausch T, Ammann M. Emerging Areas in Atmospheric Photochemistry. Top Curr Chem (Cham) 2012; 339:1-53. [DOI: 10.1007/128_2012_393] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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27
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Dvorko GF. Interpretation paradoxes in unimolecular heterolysis kinetics. KINETICS AND CATALYSIS 2011. [DOI: 10.1134/s0023158411060061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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28
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Fraind A, Turncliff R, Fox T, Sodano J, Ryzhkov LR. Exceptionally high decarboxylation rate of a primary aliphatic acyloxy radical determined by radical product yield analysis and quantitative 1
H-CIDNP spectroscopy. J PHYS ORG CHEM 2011. [DOI: 10.1002/poc.1836] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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29
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Hallett-Tapley GL, Schepp NP, Cozens FL. The reactivity of diarylmethyl carbocations within non-protic zeolites. CAN J CHEM 2011. [DOI: 10.1139/v10-150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The generation of diarylmethyl carbocations within non-protic zeolites (LiY, NaY, KY, RbY, CsY, and NaX) was carried out via laser excitation (266 nm or 266 nm / 308 nm) of diarylacetic acids. Rapid loss of CO2, followed by photochemical oxidation of the diarylmethyl radicals resulted in the formation of the diarylmethyl carbocations. The reactivity of the diarylmethyl carbocations was found to be highly dependent on the alkali metal counterion and the Si/Al ratio of the zeolite framework. Furthermore, the effect of various para-electron donating substituents (4-H, 3-CH3, 4-CH3, 4,4′-CH3, and 4-OCH3) on the diarylmethyl carbocation reactivity was investigated. Comparison of the Hammett plots constructed for the reactivity of the diarylmethyl carbocations in zeolites with those in solution (CH3CN–H2O (1:2) and TFE) showed decreased sensitivity of the electrophilic species towards para-electron donating substituents in the heterogeneous media. The leveling effect observed in the zeolite Hammett plots has been attributed to the presence of an isokinetic relationship, specifically, a low isokinetic temperature for the reaction of diarylmethyl carbocations with the aluminosilicate zeolite framework.
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Affiliation(s)
| | - Norman P. Schepp
- Department of Chemistry, Dalhousie University, Halifax, NS B3H 4J3, Canada
| | - Frances L. Cozens
- Department of Chemistry, Dalhousie University, Halifax, NS B3H 4J3, Canada
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30
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Glebov EM, Pozdnyakov IP, Grivin VP, Plyusnin VF, Zhang X, Wu F, Deng N. Intermediates in photochemistry of Fe(iii) complexes with carboxylic acids in aqueous solutions. Photochem Photobiol Sci 2011; 10:425-30. [DOI: 10.1039/c0pp00151a] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Fu M, Adams RD, Cristancho D, Leon‐Plata P, Seminario JM. Spectroscopic and Photophysical Studies of Charge-Transfer in a Cd8 Thiolate Cluster Complex Containing a Coordinated N-Methyl-4,4′-bipyridinium Ligand. Eur J Inorg Chem 2010. [DOI: 10.1002/ejic.201001062] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ming‐Lai Fu
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, U.S.A
| | - Richard D. Adams
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, U.S.A
| | - Dahiyana Cristancho
- Department of Chemical Engineering, Materials Science and Engineering Program and Department of Electrical and Computer Engineering, Texas A & M University, College Station, Texas 77843, U.S.A
| | - Paola Leon‐Plata
- Department of Chemical Engineering, Materials Science and Engineering Program and Department of Electrical and Computer Engineering, Texas A & M University, College Station, Texas 77843, U.S.A
| | - Jorge M. Seminario
- Department of Chemical Engineering, Materials Science and Engineering Program and Department of Electrical and Computer Engineering, Texas A & M University, College Station, Texas 77843, U.S.A
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32
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Synthesis, Crystal Structure, Photophysical Properties, and DFT Calculations of a Bis(tetrathia-calix[4]arene) Tetracadmium Complex. J CLUST SCI 2010. [DOI: 10.1007/s10876-010-0347-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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33
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Zhang X, Gong Y, Wu F, Deng N, Pozdnyakov IP, Glebov EM, Grivin VP, Plyusnin VF, Bazhinb NM. Photochemistry of the iron(III) complex with pyruvic acid in aqueous solutions. Russ Chem Bull 2010. [DOI: 10.1007/s11172-009-0249-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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34
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Chen Y, Wang ZO, Yang Z, Ren ZG, Li HX, Lang JP. Unique assembly of low-dimensional viologen iodoplumbates and their improved semiconducting properties. Dalton Trans 2010; 39:9476-9. [DOI: 10.1039/c0dt00757a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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Pérez-Prieto J, Galian RE, Morant-Miñana MC. Aromatic ketones as photocatalysts: combined action as triplet photosensitiser and ground state electron acceptor. Chemphyschem 2007; 7:2077-80. [PMID: 16991173 DOI: 10.1002/cphc.200600328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Julia Pérez-Prieto
- Departamento de Química Orgánica/Instituto de Ciencia Molecular Universidad de Valencia 46980 Paterna, Valencia, Spain.
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36
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Guzmán MI, Hoffmann MR, Colussi AJ. Photolysis of pyruvic acid in ice: Possible relevance to CO and CO2
ice core record anomalies. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd007886] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- M. I. Guzmán
- Environmental Science & Engineering; California Institute of Technology; Pasadena California USA
| | - M. R. Hoffmann
- Environmental Science & Engineering; California Institute of Technology; Pasadena California USA
| | - A. J. Colussi
- Environmental Science & Engineering; California Institute of Technology; Pasadena California USA
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37
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Guzman MI, Colussi AJ, Hoffmann MR. Photoinduced Oligomerization of Aqueous Pyruvic Acid. J Phys Chem A 2006; 110:3619-26. [PMID: 16526643 DOI: 10.1021/jp056097z] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The 320 nm-band photodecarboxylation of aqueous pyruvic acid (PA), a representative of the alpha-oxocarboxylic acids widely found in the atmospheric aerosol, yields 2,3-dimethyltartaric (A) and 2-(3-oxobutan-2-yloxy)-2-hydroxypropanoic (B) acids, rather than 3-hydroxy-2-oxobutanone as previously reported. A and B are identified by liquid chromatography with UV and ESI-MS detection, complemented by collisionally induced dissociation and 2H and 13C isotope labeling experiments. The multifunctional ether B gives rise to characteristic delta approximately 80 ppm 13C NMR resonances. Product quantum yields are proportional to [PA](a + [PA])(-1) in the range [PA] = 5-100 mM. CO2(g) release rates are halved, while A and B are suppressed by the addition of >1.5 mM TEMPO. A and B are only partially quenched in air-saturated solutions. These observations are shown to be consistent with an oligomerization process initiated by a bimolecular reaction between 3PA and PA producing ketyl, CH3C(OH)C(O)OH, and acetyl, CH3C(O)*, radicals, rather than by the unimolecular decomposition of 3PA into 1-hydroxyethylidene, 3HO(CH3)C: (+CO2), or [CH(3)C(O)* + *C(O)OH] pairs. A arises from the dimerization of ketyl radicals, while B ensues the facile decarboxylation of the C8beta-ketoacid formed by association of acetyl radicals with the ketyl radical adduct of PA. Since the radical precursors to A and B are scavenged by O2 with a low probability per encounter (k(sc) approximately 1 x 10(6) M(-1) s(-1)), PA is able to accrete into multifunctional polar species in aerated aqueous media under solar illumination.
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Affiliation(s)
- M I Guzman
- W. M. Keck Laboratories, California Institute of Technology, Pasadena, California 91125, USA
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38
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Guzmán MI, Colussi AJ, Hoffmann MR. Photogeneration of Distant Radical Pairs in Aqueous Pyruvic Acid Glasses. J Phys Chem A 2006; 110:931-5. [PMID: 16419992 DOI: 10.1021/jp053449t] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The lambda > 300 nm photolysis of h4- or d4-pyruvic acid aqueous glasses at 77 K yields identical electron magnetic resonance (EMR) spectra arising from distant (r greater or similar 0.5 nm) triplet radical pairs. Spectra comprise: (1) well-resolved quartets, X, at g approximately ge, that closely match the powder spectra of spin pairs interacting across r approximately 1.0 nm with D approximately 3.0 mT, E approximately 0 mT zero field splittings (ZFS), and (2) broad signals, Y, centered at g approximately 2.07 that display marked g-anisotropy and g-strain, exclude D greater or similar 20.0 mT values (i.e., r less or similar 0.5 spin nm separations), and track the temperature dependence of related g approximately 4 features. These results imply that the n-pi excitation of pyruvic acid, PA, induces long-range electron transfer from the promoted carbonyl chromophore into neighboring carbonyl acceptors, rather than homolysis into contact radical pairs or concerted decarboxylation into a carbene. Since PA is associated into hydrogen-bonded dimers prior to vitrification, X signals arise from radical pairs ensuing intradimer electron transfer to a locked acceptor, while Y signals involve carbonyl groups attached to randomly arranged, disjoint monomers. The ultrafast decarboxylation of primary radical ion pairs, 3[PA+* PA-*], accounts for the release of CO2 under cryogenic conditions, the lack of thermal hysteresis displayed by magnetic signals between 10 and 160 K, and averted charge retrotransfer. All EMR signals disappear irreversibly above the onset of ice diffusivity at approximately 190 K.
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Affiliation(s)
- Marcelo I Guzmán
- W. M. Keck Laboratories, California Institute of Technology, Pasadena, California 91125, USA
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39
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Sun YQ, Zhang J, Yang GY. Molecular self-assemblies of a π-conjugated redox-active bipyridinium cation with magnetic dimetallic oxalate-bridged trimeric clusters. Dalton Trans 2006:1685-90. [PMID: 16547544 DOI: 10.1039/b512695a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of molecular assemblies constructed from a pi-conjugated redox-active bipyridinium cation, 1,4-bis(4'-pyridyl-1'-pyridinio)phthalazine (Bpyph), and magnetic dimetallic oxalate-bridged trimeric clusters, has been synthesized and characterized by elemental analysis, IR, TGA, X-ray single-crystal diffraction and magnetic susceptibility studies. The molecular assemblies formulated as (Bpyph)2{M(II)(H2O)2[M(III)(C2O4)3]2}.12.5H2O [for M(III) = Fe; M(II) = Mn (1) or Co (2); for M(III) = Cr; M(II) = Mn (3) or Co4] are isostructural, their structures feature an alternative arrangement of Bpyph2+ cations and the linear trimeric oxalate complexes {M(II)(H2O)2[M(III)(C2O4)3]2} along all three crystallographic axes, in which the dimetallic trimers form two distinct homo-chiral helices along the b axis via intermolecular hydrogen bonding interactions. Within each trimeric cluster, the two M(III) sites have opposite chirality (Delta and Lambda). Studies on the magnetic properties reveal the presence of antiferromagnetic exchange interactions within the trimeric clusters for the Fe2M and ferromagnetic for the Cr2M series.
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Affiliation(s)
- Yan-Qiong Sun
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fujian, Fuzhou, 350002, China
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40
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Aberg V, Norman F, Chorell E, Westermark A, Olofsson A, Sauer-Eriksson AE, Almqvist F. Microwave-assisted decarboxylation of bicyclic 2-pyridone scaffolds and identification of Abeta-peptide aggregation inhibitors. Org Biomol Chem 2005; 3:2817-23. [PMID: 16032359 DOI: 10.1039/b503294f] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A reagent-free microwave-assisted decarboxylation procedure for carboxylic acid functionalized bicyclic 2-pyridones has been developed. This new method, based on microwave heating at 220 degrees C for 600 seconds in N-methyl pyrrolidone (NMP), proved to be practical and very efficient, resulting in decarboxylated 2-pyridones in near-quantitative yields. The decarboxylated products and the intermediate 2-pyridones in the form of carboxylic acid methyl esters and carboxylic acids were screened for their effect on Abeta-peptide aggregation. Two out of the 21 2-pyridones described in this study inhibited amyloid formation of the Alzheimer Abeta(1-40) peptide. The effect was seen even at a 4 : 1 ratio of 2-pyridone and monomeric Abeta-peptide.
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Affiliation(s)
- Veronica Aberg
- Organic Chemistry, Department of Chemistry, Umeå University, SE-90187, Umeå, Sweden
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41
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Gould IR, Lenhard JR, Farid S. A Curve-Crossing Model for Oxidative Decarboxylation. Kinetics of Anilino Carboxylate Fragmentations. J Phys Chem A 2004. [DOI: 10.1021/jp040536x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ian R. Gould
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604
| | - Jerome R. Lenhard
- Research Laboratories, Eastman Kodak Company, Rochester, New York 14650-2109
| | - Samir Farid
- Research Laboratories, Eastman Kodak Company, Rochester, New York 14650-2109
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42
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Abel B, Assmann J, Buback M, Grimm C, Kling M, Schmatz S, Schroeder J, Witte T. Ultrafast Decarboxylation of Carbonyloxy Radicals: Influence of Molecular Structure. J Phys Chem A 2003. [DOI: 10.1021/jp0350823] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bernd Abel
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Jens Assmann
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Michael Buback
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Christian Grimm
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Matthias Kling
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Stefan Schmatz
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Jörg Schroeder
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Thomas Witte
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
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43
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Abel B, Buback M, Kling M, Schmatz S, Schroeder J. A Seemingly Well Understood Light-Induced Peroxide Decarboxylation Reaction Reinvestigated with Femtosecond Time Resolution. J Am Chem Soc 2003; 125:13274-8. [PMID: 14570504 DOI: 10.1021/ja036304d] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photoinduced (266 nm) ultrafast decarboxylation of the peroxyester tert-butyl 9-methylfluorene-9-percarboxylate (TBFC) in solution has been studied with femtosecond time resolution. While the photodissociation of TBFC occurs too fast to be resolved, the intermediate 9-methylfluorenylcarbonyloxy radical (MeFl-CO(2)) decarboxylates on a picosecond time scale. The latter process is monitored by pump-probe absorption spectroscopy at wavelengths between 400 and 883 nm. The measured transient absorbance signals reveal a dominant fast decay with a lifetime of a few picoseconds and, to a minor extent, a slow component with a lifetime of about 55 ps. Statistical modeling of MeFl-CO(2) decarboxylation employing molecular parameters calculated by density functional theory suggests that the fast component is associated with the decarboxylation of vibrationally hot radicals, whereas the 55 ps decay reflects the dissociation of thermally equilibrated MeFl-CO(2) at ambient temperature. The vast majority of MeFl-CO(2) radicals thus decarboxylate on a time scale about an order of magnitude faster than expected from the time constant of 55 ps reported by Falvey and Schuster for this reference reaction. This literature value turns out to refer to decarboxylation rate of MeFl-CO(2) at ambient temperature.
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Affiliation(s)
- Bernd Abel
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
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44
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Pincock JA, Young IS. The photochemistry of indenyl alcohols and esters: Substituent effects on the competition between ion- and radical-derived products. CAN J CHEM 2003. [DOI: 10.1139/v03-131] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The photochemistry of the indenyl acetates 1 and pivalates 2, substituted with X = H, 5-CH3O, and 6-CH3O, have been examined in both methanol and cyclohexane. The precursor alcohols 3 were also found to be photoreactive. Although only radical-derived products were obtained in cyclohexane, both ion- and radical-derived products were formed in methanol. The absence of significant fluorescence emission from any of the substrates 1, 2, and 3 indicates that the excited singlet states are highly reactive. A mechanism is proposed for the ion-derived products that proceeds through direct heterolytic cleavage to give an indenyl cation carboxylate anion pair. The indenyl cations generated are anti-aromatic in the ground state and their efficient generation by this photochemical solvolysis is in sharp contrast to the very low reactivity of related ground-state substrates. For the pivalate esters 2, an excited-state migratory decarboxylation is proposed for the formation of tert-butyl derived products.Key words: ester photochemistry, indenyl cations, indenyl radicals.
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45
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Abel B, Assmann J, Botschwina P, Buback M, Kling M, Oswald R, Schmatz S, Schroeder J, Witte T. Experimental and Theoretical Investigations of the Ultrafast Photoinduced Decomposition of Organic Peroxides in Solution: Formation and Decarboxylation of Benzoyloxy Radicals. J Phys Chem A 2003. [DOI: 10.1021/jp034858x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bernd Abel
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Jens Assmann
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Peter Botschwina
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Michael Buback
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Matthias Kling
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Rainer Oswald
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Stefan Schmatz
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Jörg Schroeder
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
| | - Thomas Witte
- Institut für Physikalische Chemie, Universität Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany
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Kling M, Schmatz S. Decarboxylation of carbonyloxy radicals: a density functional study. Phys Chem Chem Phys 2003. [DOI: 10.1039/b304544g] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lorance ED, Kramer WH, Gould IR. Kinetics of reductive N-O bond fragmentation: the role of a conical intersection. J Am Chem Soc 2002; 124:15225-38. [PMID: 12487598 DOI: 10.1021/ja020768e] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
N-alkoxyheterocycles can act as powerful one-electron acceptors in photochemical electron-transfer reactions. One-electron reduction of these species results in formation of a radical that undergoes N-O bond fragmentation to form an alkoxy radical and a neutral heterocycle. The kinetics of this N-O bond fragmentation reaction have been determined for a series of radicals with varying substituents and extents of delocalization. Rate constants varying over 7 orders of magnitude are obtained. A reaction potential energy surface is described that involves avoidance of a conical intersection. A molecular basis for the variation of the reaction rate constant with radical structure is given in terms of the relationship between the energies of the important molecular orbitals and the reaction potential energy surface. Ab initio and density functional electronic structure calculations provide support for the proposed reaction energy surface.
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Affiliation(s)
- Edward D Lorance
- Department of Chemistry and Biochemistry, Arizona State University, Box 871604, Tempe, Arizona 85287-1604, USA
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Perrin CL, Wang J, Szwarc M. Two-Electron Transfer from Potassium Anion to Peroxides: Simultaneous or Stepwise? J Am Chem Soc 2000. [DOI: 10.1021/ja9937369] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Donor/acceptor organizations and the electron-transfer paradigm for organic reactivity. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2000. [DOI: 10.1016/s0065-3160(00)35014-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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50
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Photolysis reaction mechanism of dibenzophenoneoxime hexamethylenediurethane, a new type of photobase generator. J Photochem Photobiol A Chem 1999. [DOI: 10.1016/s1010-6030(99)00129-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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