1
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Kim J, Kim M, Jeong J, Hong S. Unlocking the Potential of β-Fragmentation of Aminophosphoranyl Radicals for Sulfonyl Radical Reactions. J Am Chem Soc 2023. [PMID: 37339337 DOI: 10.1021/jacs.3c04112] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2023]
Abstract
Exploiting β-scission in aminophosphoranyl radicals for radical-mediated transformations has been a longstanding challenge. In this study, we investigated the untapped potential of β-fragmentation in aminophosphoranyl radicals by leveraging the unique properties of the P-N bond and the substituents of P(III) reagents. Our approach carefully considers factors such as cone angle and electronic properties of phosphine and employs density functional theory (DFT) calculations to probe structural and molecular orbital influence. We successfully induced β-fragmentation through N-S bond cleavage of aminophosphoranyl radicals under visible light and mild conditions, generating a range of sulfonyl radicals derived from pyridinium salts via the photochemical activity of electron donor-acceptor (EDA) complexes. This innovative synthetic strategy exhibits broad applicability, including late-stage functionalization, and paves the way for valuable sulfonyl radical-mediated reactions, such as alkene hydrosulfonylation, difunctionalization, and pyridylic C-H sulfonylation.
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Affiliation(s)
- Jieun Kim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Myojeong Kim
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Jinwook Jeong
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Sungwoo Hong
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Korea
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2
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Domzalska‐Pieczykolan A, Funes‐Ardoiz I, Furman B, Bolm C. Selective Approaches to α‐ and β‐Arylated Vinyl Ethers. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202109801] [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)
| | - Ignacio Funes‐Ardoiz
- Departamento de Química Centro de Investigación en Síntesis Química (CISQ) University of La Rioja Madre de Dios 53 26006 Logroño Spain
| | - Bartłomiej Furman
- Institute of Organic Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Carsten Bolm
- Institut für Organische Chemie RWTH Aachen University Landoltweg 1 52074 Aachen Germany
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3
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Domzalska-Pieczykolan A, Funes-Ardoiz I, Furman B, Bolm C. Selective Approaches to α- and β-Arylated Vinyl Ethers. Angew Chem Int Ed Engl 2022; 61:e202109801. [PMID: 34758166 PMCID: PMC9299197 DOI: 10.1002/anie.202109801] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/09/2021] [Indexed: 11/09/2022]
Abstract
We developed simple and efficient protocols for palladium‐catalyzed regioselective α‐ and β‐arylations of structurally diverse vinyl ethers. Both catalytic methods proceed under relatively mild reactions conditions applying to a broad substrate range including more complex compounds providing arylated glucal or isochromene. Lacking the common requirement of a large reagent excess, the transformations are highly economic and limiting the waste production. Results from computational studies (DFT) provided insight into the key factors determining the pronounced regioselectivities of the investigated reactions.
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Affiliation(s)
| | - Ignacio Funes-Ardoiz
- Departamento de Química, Centro de Investigación en Síntesis Química (CISQ), University of La Rioja, Madre de Dios 53, 26006, Logroño, Spain
| | - Bartłomiej Furman
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland
| | - Carsten Bolm
- Institut für Organische Chemie, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
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4
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Chinn AJ, Sedillo K, Doyle AG. Phosphine/Photoredox Catalyzed Anti-Markovnikov Hydroamination of Olefins with Primary Sulfonamides via α-Scission from Phosphoranyl Radicals. J Am Chem Soc 2021; 143:18331-18338. [PMID: 34672192 DOI: 10.1021/jacs.1c09484] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
New strategies to access radicals from common feedstock chemicals hold the potential to broadly impact synthetic chemistry. We report a dual phosphine and photoredox catalytic system that enables direct formation of sulfonamidyl radicals from primary sulfonamides. Mechanistic investigations support that the N-centered radical is generated via α-scission of the P-N bond of a phosphoranyl radical intermediate, formed by sulfonamide nucleophilic addition to a phosphine radical cation. As compared to the recently well-explored β-scission chemistry of phosphoranyl radicals, this strategy is applicable to activation of N-based nucleophiles and is catalytic in phosphine. We highlight application of this activation strategy to an intermolecular anti-Markovnikov hydroamination of unactivated olefins with primary sulfonamides. A range of structurally diverse secondary sulfonamides can be prepared in good to excellent yields under mild conditions.
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Affiliation(s)
- Alex J Chinn
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Kassandra Sedillo
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Abigail G Doyle
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, United States
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5
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Rossi-Ashton JA, Clarke AK, Unsworth WP, Taylor RJK. Phosphoranyl Radical Fragmentation Reactions Driven by Photoredox Catalysis. ACS Catal 2020; 10:7250-7261. [PMID: 32905246 PMCID: PMC7469205 DOI: 10.1021/acscatal.0c01923] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/04/2020] [Indexed: 12/17/2022]
Abstract
Photocatalytic generation of phosphoranyl radicals is fast emerging as an essential method for the generation of diverse and valuable radicals, typically via deoxygenation or desulfurization processes. This Perspective is a comprehensive evaluation of all studies using phosphoranyl radicals as tunable mediators in photoredox catalysis, highlighting how two distinct methods for phosphoranyl radical formation (radical addition and nucleophilic addition) can be used to generate versatile radical intermediates with diverse reactivity profiles.
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Affiliation(s)
| | - Aimee K. Clarke
- Department of Chemistry, University of York, Heslington,
York YO10 5DD, U.K.
| | - William P. Unsworth
- Department of Chemistry, University of York, Heslington,
York YO10 5DD, U.K.
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6
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Inial A, Morlet-Savary F, Lalevée J, Gaumont A, Lakhdar S. Visible-Light-Mediated Access to Phosphate Esters. Org Lett 2020; 22:4404-4407. [DOI: 10.1021/acs.orglett.0c01409] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alya Inial
- Normandie Univ., LCMT, ENSICAEN, UNICAEN, CNRS, 6, Boulevard Maréchal Juin, Caen 14000, France
| | | | - Jacques Lalevée
- Université de Haute-Alsace, CNRS, IS2M UMR 7361, F-68100 Mulhouse, France
| | - Annie−Claude Gaumont
- Normandie Univ., LCMT, ENSICAEN, UNICAEN, CNRS, 6, Boulevard Maréchal Juin, Caen 14000, France
| | - Sami Lakhdar
- Normandie Univ., LCMT, ENSICAEN, UNICAEN, CNRS, 6, Boulevard Maréchal Juin, Caen 14000, France
- Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée (LHFA, UMR 5069), 118 Route de Narbonne, 31062, Toulouse Cedex 09, France
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7
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Belh S, Walalawela N, Lekhtman S, Greer A. Dark-Binding Process Relevant to Preventing Photosensitized Oxidation: Conformation-Dependent Light and Dark Mechanisms by a Dual-Functioning Diketone. ACS OMEGA 2019; 4:22623-22631. [PMID: 31909346 PMCID: PMC6941363 DOI: 10.1021/acsomega.9b03488] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
Few photosensitizers function in both light and dark processes as they usually have no function when the lights are turned off. We hypothesized that light and dark mechanisms in an α-diketone will be decoupled by dihedral rotation in a conformation-dependent binding process. Successful decoupling of these two functions is now shown. Namely, anti- and syn-skewed conformations of 4,4'-dimethylbenzil promote photosensitized alkoxy radical production, whereas the syn conformation promotes a binding shutoff reaction with trimethyl phosphite. Less rotation of the diketone is better suited to the photosensitizing function since phosphite binding arises through the syn conformer of lower stability. The dual function seen here with the α-diketone is generally not available to sensitizers of limited conformational flexibility, such as porphyrins, phthalocyanines, and fullerenes.
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Affiliation(s)
- Sarah
J. Belh
- Department
of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States
- Ph.D.
Program in Chemistry, The Graduate Center
of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United
States
| | - Niluksha Walalawela
- Department
of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States
- Ph.D.
Program in Chemistry, The Graduate Center
of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United
States
| | - Stas Lekhtman
- Department
of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States
| | - Alexander Greer
- Department
of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States
- Ph.D.
Program in Chemistry, The Graduate Center
of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United
States
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8
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Matassini C, D'Adamio G, Vanni C, Goti A, Cardona F. Studies for the Multimerization of DAB-1-Based Iminosugars through Iteration of the Nitrone Cycloaddition/Ring-Opening/Allylation Sequence. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Camilla Matassini
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3-13 50019 Sesto Fiorentino (FI) Italy
| | - Giampiero D'Adamio
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3-13 50019 Sesto Fiorentino (FI) Italy
| | - Costanza Vanni
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3-13 50019 Sesto Fiorentino (FI) Italy
| | - Andrea Goti
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3-13 50019 Sesto Fiorentino (FI) Italy
- Associated with Consorzio Interuniversitatio Nazionale di ricerca in Metodologie e Processi Innovativi di Sintesi (CINMPIS); Università di Bari; 70125 Bari Italy
| | - Francesca Cardona
- Department of Chemistry “Ugo Schiff”; University of Florence; Via della Lastruccia 3-13 50019 Sesto Fiorentino (FI) Italy
- Associated with Consorzio Interuniversitatio Nazionale di ricerca in Metodologie e Processi Innovativi di Sintesi (CINMPIS); Università di Bari; 70125 Bari Italy
- Associated with LENS; via N. Carrara 1 50019 Sesto Fiorentino, FI Italy
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9
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Kai Y, Oku S, Tani T, Sakurai K, Tsuchimoto T. A Drastic Effect of TEMPO in Zinc‐Catalyzed Stannylation of Terminal Alkynes with Hydrostannanes via Dehydrogenation and Oxidative Dehydrogenation. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900540] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yuichi Kai
- Department of Applied Chemistry, School of Science and TechnologyMeiji University, 1-1-1 Higashimita, Tama-ku Kawasaki 214-8571 Japan
| | - Shinya Oku
- Department of Applied Chemistry, School of Science and TechnologyMeiji University, 1-1-1 Higashimita, Tama-ku Kawasaki 214-8571 Japan
| | - Tomohiro Tani
- Department of Applied Chemistry, School of Science and TechnologyMeiji University, 1-1-1 Higashimita, Tama-ku Kawasaki 214-8571 Japan
| | - Kyoko Sakurai
- Department of Applied Chemistry, School of Science and TechnologyMeiji University, 1-1-1 Higashimita, Tama-ku Kawasaki 214-8571 Japan
| | - Teruhisa Tsuchimoto
- Department of Applied Chemistry, School of Science and TechnologyMeiji University, 1-1-1 Higashimita, Tama-ku Kawasaki 214-8571 Japan
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10
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Ledovskaya MS, Voronin VV, Rodygin KS. Methods for the synthesis of O-, S- and N-vinyl derivatives. RUSSIAN CHEMICAL REVIEWS 2018. [DOI: 10.1070/rcr4782] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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11
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Kurosawa F, Nakano T, Soeta T, Endo K, Ukaji Y. (Z)-Selective Enol Triflation of α-Alkoxyacetoaldehydes: Application to Synthesis of (Z)-Allylic Alcohols via Cross-Coupling Reaction and [1,2]-Wittig Rearrangement. J Org Chem 2015; 80:5696-703. [PMID: 25970239 DOI: 10.1021/acs.joc.5b00647] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The stereoselective transformation of α-alkoxyacetoaldehydes to the corresponding (Z)-vinyl triflates was achieved by treatment with phenyl triflimide and DBU. The stereochemistry was explained by the "syn-effect," which was attributed primarily to an σ → π* interaction. The β-alkoxy vinyl triflates obtained were applied to the stereoselective synthesis of structurally diverse (Z)-allylic alcohols via transition metal-catalyzed cross-coupling reaction and [1,2]-Wittig rearrangement.
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Affiliation(s)
- Fumiya Kurosawa
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Takeo Nakano
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Takahiro Soeta
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Kohei Endo
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
| | - Yutaka Ukaji
- Division of Material Chemistry, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan
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12
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Nova A, Balcells D. Does the metal protect the ancillary ligands? C–H strengthening and deactivation in amines and phosphines upon metal-binding. Chem Commun (Camb) 2014; 50:614-6. [DOI: 10.1039/c3cc47686c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Singh GS, Mollet K, D’hooghe M, De Kimpe N. Epihalohydrins in Organic Synthesis. Chem Rev 2012; 113:1441-98. [DOI: 10.1021/cr3003455] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Girija S. Singh
- Chemistry Department, Faculty
of Science, University of Botswana, Private
Bag 0022, Gaborone, Botswana
| | - Karen Mollet
- Department of Sustainable Organic
Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent,
Belgium
| | - Matthias D’hooghe
- Department of Sustainable Organic
Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent,
Belgium
| | - Norbert De Kimpe
- Department of Sustainable Organic
Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent,
Belgium
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14
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Misaka H, Sakai R, Satoh T, Kakuchi T. Synthesis of High Molecular Weight and End-Functionalized Poly(styrene oxide) by Living Ring-Opening Polymerization of Styrene Oxide Using the Alcohol/Phosphazene Base Initiating System. Macromolecules 2011. [DOI: 10.1021/ma202115w] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hideki Misaka
- Division of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Ryosuke Sakai
- Department of Material Chemistry, Asahikawa National College of Technology, Asahikawa 071-8142, Japan
| | - Toshifumi Satoh
- Division of Biotechnology and Macromolecular Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Toyoji Kakuchi
- Division of Biotechnology and Macromolecular Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
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15
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Lamas MC, Studer A. Radical Alkylphosphanylation of Olefins with Stannylated or Silylated Phosphanes and Alkyl Iodides. Org Lett 2011; 13:2236-9. [DOI: 10.1021/ol200483p] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marie-Céline Lamas
- Organisch-Chemisches Institut, University of Münster, Corrensstrasse 40, 48149 Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, University of Münster, Corrensstrasse 40, 48149 Münster, Germany
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16
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Bietti M, Calcagni A, Cicero DO, Martella R, Salamone M. The O-neophyl rearrangement of 1,1-diarylalkoxyl radicals. Experimental evidence for the formation of an intermediate 1-oxaspiro[2,5]octadienyl radical. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2010.05.149] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Bietti M, Calcagni A, Salamone M. The Role of Structural Effects on the Reactions of Alkoxyl Radicals with Trialkyl and Triaryl Phosphites. A Time-Resolved Kinetic Study. J Org Chem 2010; 75:4514-20. [DOI: 10.1021/jo100703b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Massimo Bietti
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Alessandra Calcagni
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
| | - Michela Salamone
- Dipartimento di Scienze e Tecnologie Chimiche, Università “Tor Vergata”, Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
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18
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Synthesis of (S)-(+)-tylophorine and its seco analogues using free radical reaction. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s11426-009-0183-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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19
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Vaillard SE, Mück-Lichtenfeld C, Grimme S, Studer A. Homolytic Substitution at Phosphorus for the Synthesis of Alkyl and Aryl Phosphanes. Angew Chem Int Ed Engl 2007; 46:6533-6. [PMID: 17639520 DOI: 10.1002/anie.200701650] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Santiago E Vaillard
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
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20
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Vaillard S, Mück-Lichtenfeld C, Grimme S, Studer A. Homolytische Substitution am Phosphor zur Synthese von Alkyl- und Arylphosphanen. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200701650] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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21
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Li C, Porco JA. Synthesis of Epoxyquinol A and Related Molecules: Probing Chemical Reactivity of Epoxyquinol Dimers and 2H-Pyran Precursors. J Org Chem 2005; 70:6053-65. [PMID: 16018703 DOI: 10.1021/jo050897o] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Total syntheses of the epoxyquinoid dimers, epoxyquinols A, B, and epoxytwinol A (RKB-3564 D), have been accomplished employing [4 + 2] and [4 + 4] dimerization of 2H-pyran epoxyquinol monomers. Modifications of 2H-pyran precursors have been explored, including alteration of epoxy alcohol and diene stereochemistry. A stable 2H-pyran prepared by alteration of the epoxyquinol 2H-pyran nucleus was evaluated as a diene in Diels-Alder cycloaddition with reactive dienophiles. Extensive studies for improving the [4 + 4] dimerization of selectively protected 2H-pyran monomers to afford the novel epoxyquinoid dimer epoxytwinol A were carried out, and valuable insight regarding competitive [4 + 2] and [4 + 4] dimerization processes has been obtained. In addition, chemical reactivities and structural modifications of epoxyquinol dimers have been evaluated, including [2 + 2] photocycloaddition and [3,3] sigmatropic rearrangement, indicating the possibility for production of novel structural diversity from dimeric epoxyquinoid natural product frameworks.
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Affiliation(s)
- Chaomin Li
- Department of Chemistry and Center for Chemical Methodology and Library Development, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA
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