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Zubova E, Pokluda A, Dvořáková H, Krupička M, Cibulka R. Exploring the Reactivity of Flavins with Nucleophiles Using a Theoretical and Experimental Approach. Chempluschem 2024; 89:e202300547. [PMID: 38064649 DOI: 10.1002/cplu.202300547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/30/2023] [Indexed: 01/13/2024]
Abstract
Covalent adducts of flavin cofactors with nucleophiles play an important role in non-canonical function of flavoenzymes as well as in flavin-based catalysis. Herein, the interaction of flavin derivatives including substituted flavins (isoalloxazines), 1,10-ethylene-bridged flavinium salts, and non-substituted alloxazine and deazaflavin with selected nucleophiles was investigated using an experimental and computational approach. Triphenylphosphine or trimethylphosphine, 1-nitroethan-1-ide, and methoxide were selected as representatives of neutral soft, anionic soft, and hard nucleophiles, respectively. The interactions were investigated using UV/Vis and 1H NMR spectroscopy as well as by DFT calculations. The position of nucleophilic attack estimated using the calculated Gibbs free energy values was found to correspond with the experimental data, favouring the addition of phosphine and 1-nitroethan-1-ide into position N(5) and methoxide into position C(10a) of 1,10-ethylene-bridged flavinium salts. The calculated Gibbs free energy values were found to correlate with the experimental redox potentials of the flavin derivatives tested. These findings can be utilized as valuable tools for the design of artificial flavin-based catalytic systems or investigating the mechanism of flavoenzymes.
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Affiliation(s)
- Ekaterina Zubova
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
| | - Adam Pokluda
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
| | - Hana Dvořáková
- Central Laboratories, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
| | - Martin Krupička
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
| | - Radek Cibulka
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28, Prague, Czech Republic
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Murray J, Hodgson DRW, O’Donoghue AC. Going Full Circle with Organocatalysis and Biocatalysis: The Latent Potential of Cofactor Mimics in Asymmetric Synthesis. J Org Chem 2023; 88:7619-7629. [PMID: 37126859 PMCID: PMC10278144 DOI: 10.1021/acs.joc.2c02747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Indexed: 05/03/2023]
Abstract
Many enzymes work in tandem with small molecule cofactors, which have inspired organocatalyst designs. Chemical modification of cofactor scaffolds has increased organocatalytic reactivity and reaction scope. This synopsis presents a selection of recent advances in the use of cofactors (native and mimics) in organocatalysis and biocatalysis. We aim to highlight the benefits of combining fundamental knowledge gained in both bio- and organo-catalysis for asymmetric biocatalysis.
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Affiliation(s)
- Jacob Murray
- Department of Chemistry, Durham University, South Road, Durham DH1
3LE, United
Kingdom
| | - David R. W. Hodgson
- Department of Chemistry, Durham University, South Road, Durham DH1
3LE, United
Kingdom
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Pokluda A, Zubova E, Chudoba J, Krupička M, Cibulka R. Catalytic artificial nitroalkane oxidases - a way towards organocatalytic umpolung. Org Biomol Chem 2023; 21:2768-2774. [PMID: 36919409 DOI: 10.1039/d3ob00101f] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Nitroalkane oxidases (NAOs) are flavoenzymes that catalyse the oxidation of nitroalkanes to their corresponding carbonyl compounds while producing nitrite anions. Herein, we present an artificial catalytic system using flavins or ethylene-bridged flavinium salts that works via an NAO-like process. Under conditions optimised in terms of solvent, base, temperature and oxygen pressure, primary nitroalkanes were transformed to aldehydes. In our system, aldehydes immediately reacted with other nitroalkane molecules to form β-nitroalcohols. The reduced flavin catalyst was re-oxidised by oxygen. An alternative mechanism towards β-nitroalcohols via 5-(2-nitrobutyl)-1,5-dihydroflavin was suggested through quantum chemical calculations and by trapping and characterising this dihydroflavin intermediate. Interestingly, 5-(2-nitrobutyl)-1,5-dihydroflavin is an analogue of the flavin adenine dinucleotide adduct previously observed in an NAO X-ray structure. In both mechanistic pathways, flavin-5-iminium species is formed by nitroalkanide addition to flavin. This process represents flavin-based umpolung of an original donor to an acceptor.
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Affiliation(s)
- Adam Pokluda
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic.
| | - Ekaterina Zubova
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic.
| | - Josef Chudoba
- Central Laboratories, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic
| | - Martin Krupička
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic.
| | - Radek Cibulka
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic.
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Rehpenn A, Walter A, Storch G. Molecular Editing of Flavins for Catalysis. SYNTHESIS-STUTTGART 2021. [DOI: 10.1055/a-1458-2419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractThe diverse activity of flavoenzymes in organic transformations has fascinated researchers for a long time. However, when applied outside an enzyme environment, the isolated flavin cofactor only shows largely reduced activity. This highlights the importance of embedding the reactive isoalloxazine core of flavins in defined surroundings. The latter include crucial non-covalent interactions with amino acid side chains or backbone as well as controlled access to reactants such as molecular oxygen. Nevertheless, molecular flavins are increasingly applied in the organic laboratory as valuable organocatalysts. Chemical modification of the parent isoalloxazine structure is of particular interest in this context in order to achieve reactivity and selectivity in transformations, which are so far only known with flavoenzymes or even unprecedented. This review aims to give a systematic overview of the reported designed flavin catalysts and highlights the impact of each structural alteration. It is intended to serve as a source of information when comparing the performance of known catalysts, but also when designing new flavins. Over the last few decades, molecular flavin catalysis has emerged from proof-of-concept reactions to increasingly sophisticated transformations. This stimulates anticipating new flavin catalyst designs for solving contemporary challenges in organic synthesis.1 Introduction2 N1-Modification3 N3-Modification4 N5-Modification5 C6–C9-Modification6 N10-Modification7 Conclusion
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Thapa P, Hazoor S, Chouhan B, Vuong TT, Foss FW. Flavin Nitroalkane Oxidase Mimics Compatibility with NOx/TEMPO Catalysis: Aerobic Oxidization of Alcohols, Diols, and Ethers. J Org Chem 2020; 85:9096-9105. [PMID: 32569467 DOI: 10.1021/acs.joc.0c01013] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Biomimetic flavin organocatalysts oxidize nitromethane to formaldehyde and NOx-providing a relatively nontoxic, noncaustic, and inexpensive source for catalytic NO2 for aerobic TEMPO oxidations of alcohols, diols, and ethers. Alcohols were oxidized to aldehydes or ketones, cyclic ethers to esters, and terminal diols to lactones. In situ trapping of NOx and formaldehyde suggest an oxidative Nef process reminiscent of flavoprotein nitroalkane oxidase reactivity, which is achieved by relatively stable 1,10-bridged flavins. The metal-free flavin/NOx/TEMPO catalytic cycles are uniquely compatible, especially compared to other Nef and NOx-generating processes, and reveal selectivity over flavin-catalyzed sulfoxide formation. Aliphatic ethers were oxidized by this method, as demonstrated by the conversion of (-)-ambroxide to (+)-sclareolide.
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Affiliation(s)
- Pawan Thapa
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Shan Hazoor
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Bikash Chouhan
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Thanh Thuy Vuong
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Frank W Foss
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
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Petsi M, Zografos AL. 2,5-Diketopiperazine Catalysts as Activators of Dioxygen in Oxidative Processes. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01847] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Marina Petsi
- Department of Chemistry, Main University Campus, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Alexandros L. Zografos
- Department of Chemistry, Main University Campus, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
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Yang Z, Chen S, Yang F, Zhang C, Dou Y, Zhou Q, Yan Y, Tang L. PPh3
/Selectfluor-Mediated Transformation of Carboxylic Acids into Acid Anhydrides and Acyl Fluorides and Its Application in Amide and Ester Synthesis. European J Org Chem 2019. [DOI: 10.1002/ejoc.201901092] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zhen Yang
- College of Chemistry and Chemical Engineering; Xinyang Normal University; 464000 Xinyang P. R. China
| | - Siwei Chen
- College of Chemistry and Chemical Engineering; Xinyang Normal University; 464000 Xinyang P. R. China
| | - Fang Yang
- College of Chemistry and Chemical Engineering; Xinyang Normal University; 464000 Xinyang P. R. China
| | - Chenxi Zhang
- College of Chemistry and Chemical Engineering; Xinyang Normal University; 464000 Xinyang P. R. China
| | - You Dou
- College of Chemistry and Chemical Engineering; Xinyang Normal University; 464000 Xinyang P. R. China
| | - Qiuju Zhou
- College of Chemistry and Chemical Engineering; Xinyang Normal University; 464000 Xinyang P. R. China
| | - Yizhe Yan
- School of Food and Biological Engineering; Zhengzhou University of Light Industry; 450000 Zhengzhou P. R. China
| | - Lin Tang
- College of Chemistry and Chemical Engineering; Xinyang Normal University; 464000 Xinyang P. R. China
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