1
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Bannon R, Morrison G, Smyth M, Moody TS, Wharry S, Roth PMC, Gauron G, Baumann M. Continuous Flow Approach for Benzylic Photo-oxidations Using Compressed Air. Org Process Res Dev 2024; 28:3307-3312. [PMID: 39171129 PMCID: PMC11334174 DOI: 10.1021/acs.oprd.4c00213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 07/03/2024] [Accepted: 07/11/2024] [Indexed: 08/23/2024]
Abstract
A continuous flow approach for the aerobic photo-oxidation of benzylic substrates to ketone and aldehyde products is presented. The resulting process exploits UV-A LEDs (375 nm) in combination with a Corning AFR reactor that ensures effective gas-liquid mixing and leads to short residence times of 1 min. A variety of benzylic substrates are converted to their corresponding carbonyl products, and scalability is demonstrated to produce multigram quantities of products within a few hours. Overall, this continuous flow approach offers several improvements over alternative oxidation methods due to the combined use of air as an oxidant and SAS (sodium anthraquinone-2 sulfonate) as a water-soluble photocatalyst. The use of greener and safer conditions together with process intensification principles renders this flow approach attractive for further industrial applications.
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Affiliation(s)
- Ruairi Bannon
- School
of Chemistry, Science Centre South, University
College Dublin, Dublin D04 N2E5, Ireland
| | - Gary Morrison
- Technology
Department, Almac Sciences, Craigavon BT63 5QD, U.K.
| | - Megan Smyth
- Technology
Department, Almac Sciences, Craigavon BT63 5QD, U.K.
| | - Thomas S. Moody
- Technology
Department, Almac Sciences, Craigavon BT63 5QD, U.K.
- Arran
Chemical Company, Monksland Industrial
Estate, Roscommon N37 DN24, Ireland
| | - Scott Wharry
- Technology
Department, Almac Sciences, Craigavon BT63 5QD, U.K.
| | - Philippe M. C. Roth
- Corning
Reactor Technologies, Corning SAS, 7 bis Avenue de Valvins, CS 70156
Samois sur Seine, 77215 Avon Cedex, France
| | - Guillaume Gauron
- Corning
Reactor Technologies, Corning SAS, 7 bis Avenue de Valvins, CS 70156
Samois sur Seine, 77215 Avon Cedex, France
| | - Marcus Baumann
- School
of Chemistry, Science Centre South, University
College Dublin, Dublin D04 N2E5, Ireland
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2
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Bo C, Li M, Chen F, Liu J, Dai B, Liu N. Visible-Light-Initiated Air-Oxygenation of Alkylarenes to Carbonyls Mediated by Carbon Tetrabromide in Water. CHEMSUSCHEM 2024; 17:e202301015. [PMID: 37661194 DOI: 10.1002/cssc.202301015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/25/2023] [Accepted: 09/01/2023] [Indexed: 09/05/2023]
Abstract
Synthesizing benzyl skeleton derivatives via direct oxidation of functionalized benzylic C-H bonds has received extensive research attention. Herein, a method was developed to prepare carbonyl compounds via photoinduced aerobic oxidation of ubiquitous benzylic C-H bonds mediated by bromine radicals and tribromomethane radicals. This method employed commercially available CBr4 as a hydrogen atom transfer reagent precursor, air as an oxidant, water as a reaction solvent, and tetrabutylammonium perchlorate (TBAPC) as an additive under mild conditions. A series of substrates bearing different functional groups was converted to aromatic carbonyls in moderate to good yields. Moreover, a low environmental factor (E-factor value=0.45) showed that the proposed method is ecofriendly and environmentally sustainable.
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Affiliation(s)
- Chunbo Bo
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
| | - Min Li
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
| | - Fei Chen
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
| | - Jichang Liu
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
| | - Bin Dai
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
| | - Ning Liu
- School of Chemistry and Chemical Engineering/State Key Laboratory Incubation Base for Green Processing of Chemical Engineering, Shihezi University, North Fourth Road, Shihezi, Xinjiang, 832003, China
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3
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Bera N, Lenka BS, König B, Sarkar D. Riboflavin Photocatalyzed Dearomative Spiro-Etherification of Naphthols. J Org Chem 2023. [PMID: 37356110 DOI: 10.1021/acs.joc.2c03037] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
The dearomative spiro-etherification of naphthols is achieved using catalytic amounts of riboflavin tetracetate (RFTA) as a photosensitizer and molecular oxygen as a terminal oxidizing agent under blue light (440 nm) irradiation in the presence of acid. The presence of acid increases the photooxidation power of RFTA and facilitates the dearomatization reaction.
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Affiliation(s)
- Nabakumar Bera
- Department of Chemistry, National Institute of Technology, Rourkela, Rourkela 769008, India
| | - Bhabani Sankar Lenka
- Department of Chemistry, Indian Institute of Technology, Indore, Madhya Pradesh 453552, India
| | - Burkhard König
- Department of Chemistry and Pharmazie, University of Regensburg, 93040 Regensburg, Germany
| | - Debayan Sarkar
- Department of Chemistry, Indian Institute of Technology, Indore, Madhya Pradesh 453552, India
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4
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Rehpenn A, Walter A, Storch G. Molecular flavin catalysts for C-H functionalisation and derivatisation of dehydroamino acids. Chem Sci 2022; 13:14151-14156. [PMID: 36540823 PMCID: PMC9728571 DOI: 10.1039/d2sc04341f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 11/04/2022] [Indexed: 03/12/2024] Open
Abstract
In nature, the isoalloxazine heterocycle of flavin cofactors undergoes reversible covalent bond formation with a variety of different reaction partners. These intermediates play a crucial role inter alia as the signalling states and in selective catalysis reactions. In the organic laboratory, covalent adducts with a new carbon-carbon bond have been observed with photochemically excited flavins but have, so far, only been regarded as dead-end side products. We have identified a series of molecular flavins that form adducts resulting in a new C-C bond at the C4a-position through allylic C-H activation and dehydroamino acid oxidation. Typically, these reactions are of radical nature and a stepwise pathway is assumed. We could demonstrate that these adducts are no dead-end and that the labile C-C bond can be cleaved by adding the persistent radical TEMPO leading to flavin regeneration and alkoxyamine-functionalised substrates. Our method allows for the catalytic oxidation of dehydroamino acids (16 examples) and we show that the acylimine products serve as versatile starting points for diversification. The present results are envisioned to stimulate the design of further catalytic reactions involving intermediates at the flavin C4a-position and their reactivity towards metal complexes or other persistent organic radicals. Our method for dehydrobutyrine derivatisation is orthogonal to the currently used methods (i.e., nucleophilic attack or radical addition) and offers new perspectives for peptide natural product diversification.
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Affiliation(s)
- Andreas Rehpenn
- School of Natural Sciences and Catalysis Research Center (CRC), Technical University of Munich (TUM) Lichtenbergstr. 4 85747 Garching Germany
| | - Alexandra Walter
- School of Natural Sciences and Catalysis Research Center (CRC), Technical University of Munich (TUM) Lichtenbergstr. 4 85747 Garching Germany
| | - Golo Storch
- School of Natural Sciences and Catalysis Research Center (CRC), Technical University of Munich (TUM) Lichtenbergstr. 4 85747 Garching Germany
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5
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Yang M, Lian R, Zhang X, Wang C, Cheng J, Wang X. Photocatalytic cyclization of nitrogen-centered radicals with carbon nitride through promoting substrate/catalyst interaction. Nat Commun 2022; 13:4900. [PMID: 35987760 PMCID: PMC9392757 DOI: 10.1038/s41467-022-32623-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/09/2022] [Indexed: 11/17/2022] Open
Abstract
The use of metal-free carbon nitride and light to drive catalytic transformations constitutes a sustainable strategy for organic synthesis. At the moment, enhancing the intrinsic activity of CN catalysts by tuning the interfacial coupling between catalyst and substrate remains challenging. Herein, we demonstrate that urea-derived carbon nitride catalysts with the abundant −NH2 groups and the relative positive charged surface could effectively complex with the deprotonated anionic intermediate to improve the adsorption of organic reactants on the catalyst surface. The decreased oxidation potential and upshift in its highest occupied molecular orbital position make the electron abstraction kinetics by the catalyst more energetically favorable. The prepared catalyst is thus utilized for the photocatalytic cyclization of nitrogen-centered radicals for the synthesis of diverse pharmaceutical-related compounds (33 examples) with high activity and reusability, which shows competent performance to the homogeneous catalysts. Carbon nitride catalysts with positively charged surfaces and abundant −NH2 are found to be effective photocatalysts for dihydropyrazole synthesis. A surface-mediated mechanism where deprotonated intermediates interact with the surface is proposed.
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6
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Zhou J, Jia M, Song M, Huang Z, Steiner A, An Q, Ma J, Guo Z, Zhang Q, Sun H, Robertson C, Bacsa J, Xiao J, Li C. Chemoselective Oxyfunctionalization of Functionalized Benzylic Compounds with a Manganese Catalyst. Angew Chem Int Ed Engl 2022; 61:e202205983. [PMID: 35594169 PMCID: PMC9400980 DOI: 10.1002/anie.202205983] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Indexed: 11/06/2022]
Abstract
Whilst allowing for easy access to synthetically versatile motifs and for modification of bioactive molecules, the chemoselective benzylic oxidation reactions of functionalized alkyl arenes remain challenging. Reported in this study is a new non‐heme Mn catalyst stabilized by a bipiperidine‐based tetradentate ligand, which enables methylene oxidation of benzylic compounds by H2O2, showing high activity and excellent chemoselectivity under mild conditions. The protocol tolerates an unprecedentedly wide range of functional groups, including carboxylic acid and derivatives, ketone, cyano, azide, acetate, sulfonate, alkyne, amino acid, and amine units, thus providing a low‐cost, more sustainable and robust pathway for the facile synthesis of ketones, increase of complexity of organic molecules, and late‐stage modification of drugs.
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Affiliation(s)
- Jimei Zhou
- Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education and School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China
| | - Minxian Jia
- Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education and School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China
| | - Menghui Song
- Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education and School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China
| | - Zhiliang Huang
- Department of Chemistry University of Liverpool Liverpool L69 7ZD UK
| | - Alexander Steiner
- Department of Chemistry University of Liverpool Liverpool L69 7ZD UK
| | - Qidong An
- Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education and School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China
| | - Jianwei Ma
- Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education and School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China
| | - Zhiyin Guo
- Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education and School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China
| | - Qianqian Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education and School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China
| | - Huaming Sun
- Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education and School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China
| | - Craig Robertson
- Department of Chemistry University of Liverpool Liverpool L69 7ZD UK
| | - John Bacsa
- Department of Chemistry Emory University 1515 Dickey Dr. Atlanta GA 30322 USA
| | - Jianliang Xiao
- Department of Chemistry University of Liverpool Liverpool L69 7ZD UK
| | - Chaoqun Li
- Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education and School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an 710119 China
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7
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Ji G, Zhao L, Wang Y, Tang Y, He C, Liu S, Duan C. A Binuclear Cerium-Based Metal–Organic Framework as an Artificial Monooxygenase for the Saturated Hydrocarbon Aerobic Oxidation with High Efficiency and High Selectivity. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Guanfeng Ji
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116024, People’s Republic of China
| | - Liang Zhao
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116024, People’s Republic of China
| | - Yefei Wang
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116024, People’s Republic of China
| | - Yang Tang
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116024, People’s Republic of China
| | - Cheng He
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116024, People’s Republic of China
| | - Songtao Liu
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116024, People’s Republic of China
| | - Chunying Duan
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian 116024, People’s Republic of China
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8
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Zhou J, Jia M, Song M, Huang Z, Steiner A, An Q, Ma J, Guo Z, Zhang Q, Sun H, Robertson CM, Bacsa J, Xiao J, Li C. Chemoselective Oxyfunctionalization of Functionalized Benzylic Compounds with a Manganese Catalyst. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202205983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jimei Zhou
- Shaanxi Normal University School of Chemistry & Chemical Engineering Xi'an CHINA
| | - Minxian Jia
- Shaanxi Normal University School of Chemistry & Chemical Engineering Xi'an UNITED KINGDOM
| | - Menghui Song
- Shaanxi Normal University School of Chemistry & Chemical Engineering Xi'an UNITED KINGDOM
| | - Zhiliang Huang
- University of Liverpool Department of Chemistry UNITED KINGDOM
| | | | - Qidong An
- Shaanxi Normal University School of Chemistry & Chemical Engineering Xi'an UNITED KINGDOM
| | - Jianwei Ma
- Shaanxi Normal University School of Chemistry & Chemical Engineering Xi'an UNITED KINGDOM
| | - Zhiyin Guo
- Shaanxi Normal University School of Chemistry & Chemical Engineering Xi'an UNITED KINGDOM
| | - Qianqian Zhang
- Shaanxi Normal University School of Chemistry & Chemical Engineering Xi'an UNITED KINGDOM
| | - Huaming Sun
- Shaanxi Normal University School of Chemistry & Chemical Engineering Xi'an UNITED KINGDOM
| | | | - John Bacsa
- Emory University Department of Chemistry UNITED KINGDOM
| | - Jianliang Xiao
- University of Liverpool Department of Chemistry Oxford Street L69 7ZD Liverpool UNITED KINGDOM
| | - Chaoqun Li
- Shaanxi Normal University School of Chemistry & Chemical Engineering Xi'an CHINA
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9
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Ju ZY, Song LN, Chong MB, Cheng DG, Hou Y, Zhang XM, Zhang QH, Ren LH. Selective Aerobic Oxidation of C sp3-H Bonds Catalyzed by Yeast-Derived Nitrogen, Phosphorus, and Oxygen Codoped Carbon Materials. J Org Chem 2022; 87:3978-3988. [PMID: 35254832 DOI: 10.1021/acs.joc.1c02641] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Nitrogen, phosphorus, and oxygen codoped carbon catalysts were successfully synthesized using dried yeast powder as a pyrolysis precursor. The yeast-derived heteroatom-doped carbon (yeast@C) catalysts exhibited outstanding performance in the oxidation of Csp3-H bonds to ketones and esters, giving excellent product yields (of up to 98% yield) without organic solvents at low O2 pressure (0.1 MPa). The catalytic oxidation protocol exhibited a broad range of substrates (38 examples) with good functional group tolerance, excellent regioselectivity, and synthetic utility. The yeast-derived heteroatom-doped carbon catalysts showed good reusability and stability after recycling six times without any significant loss of activity. Experimental results and DFT calculations proved the important role of N-oxide (N+-O-) on the surface of yeast@C and a reasonable carbon radical mechanism.
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Affiliation(s)
- Zhao-Yang Ju
- College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
| | - Li-Na Song
- College of Chemical and Biological Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, P. R. China
| | - Ming-Ben Chong
- College of Chemical and Biological Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, P. R. China.,Institute of Zhejiang University-Quzhou, 78 Jiuhuabei Road, Quzhou 324000, P. R. China
| | - Dang-Guo Cheng
- College of Chemical and Biological Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, P. R. China
| | - Yang Hou
- College of Chemical and Biological Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, P. R. China
| | - Xi-Ming Zhang
- College of Biosystems Engineering and Food Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
| | - Qing-Hua Zhang
- College of Chemical and Biological Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, P. R. China
| | - Lan-Hui Ren
- College of Chemical and Biological Engineering, Zhejiang University, 38 Zheda Road, Hangzhou 310027, P. R. China.,Institute of Zhejiang University-Quzhou, 78 Jiuhuabei Road, Quzhou 324000, P. R. China
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10
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Buglioni L, Raymenants F, Slattery A, Zondag SDA, Noël T. Technological Innovations in Photochemistry for Organic Synthesis: Flow Chemistry, High-Throughput Experimentation, Scale-up, and Photoelectrochemistry. Chem Rev 2022; 122:2752-2906. [PMID: 34375082 PMCID: PMC8796205 DOI: 10.1021/acs.chemrev.1c00332] [Citation(s) in RCA: 228] [Impact Index Per Article: 114.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Indexed: 02/08/2023]
Abstract
Photoinduced chemical transformations have received in recent years a tremendous amount of attention, providing a plethora of opportunities to synthetic organic chemists. However, performing a photochemical transformation can be quite a challenge because of various issues related to the delivery of photons. These challenges have barred the widespread adoption of photochemical steps in the chemical industry. However, in the past decade, several technological innovations have led to more reproducible, selective, and scalable photoinduced reactions. Herein, we provide a comprehensive overview of these exciting technological advances, including flow chemistry, high-throughput experimentation, reactor design and scale-up, and the combination of photo- and electro-chemistry.
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Affiliation(s)
- Laura Buglioni
- Micro
Flow Chemistry and Synthetic Methodology, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, Het Kranenveld, Bldg 14—Helix, 5600 MB, Eindhoven, The Netherlands
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Fabian Raymenants
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Aidan Slattery
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Stefan D. A. Zondag
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Timothy Noël
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
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11
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Wan L, Jiang M, Cheng D, Liu M, Chen F. Continuous flow technology-a tool for safer oxidation chemistry. REACT CHEM ENG 2022. [DOI: 10.1039/d1re00520k] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The advantages and benefits of continuous flow technology for oxidation chemistry have been illustrated in tube reactors, micro-channel reactors, tube-in-tube reactors and micro-packed bed reactors in the presence of various oxidants.
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Affiliation(s)
- Li Wan
- Engineering Center of Catalysis and Synthesis for Chiral Molecules, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Meifen Jiang
- Engineering Center of Catalysis and Synthesis for Chiral Molecules, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Dang Cheng
- Engineering Center of Catalysis and Synthesis for Chiral Molecules, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Minjie Liu
- Engineering Center of Catalysis and Synthesis for Chiral Molecules, Department of Chemistry, Fudan University, Shanghai 200433, China
| | - Fener Chen
- Engineering Center of Catalysis and Synthesis for Chiral Molecules, Department of Chemistry, Fudan University, Shanghai 200433, China
- Shanghai Engineering Center of Industrial Asymmetric Catalysis for Chiral Drugs, Shanghai 200433, China
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12
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Krylov IB, Lopat’eva ER, Subbotina IR, Nikishin GI, Yu B, Terent’ev AO. Mixed hetero-/homogeneous TiO2/N-hydroxyimide photocatalysis in visible-light-induced controllable benzylic oxidation by molecular oxygen. CHINESE JOURNAL OF CATALYSIS 2021. [DOI: 10.1016/s1872-2067(21)63831-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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13
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Hassan Tolba A, Krupička M, Chudoba J, Cibulka R. Amide Bond Formation via Aerobic Photooxidative Coupling of Aldehydes with Amines Catalyzed by a Riboflavin Derivative. Org Lett 2021; 23:6825-6830. [PMID: 34424722 DOI: 10.1021/acs.orglett.1c02391] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We report an effective, operationally simple, and environmentally friendly system for the synthesis of tertiary amides by the oxidative coupling of aromatic or aliphatic aldehydes with amines mediated by riboflavin tetraacetate (RFTA), an inexpensive organic photocatalyst, and visible light using oxygen as the sole oxidant. The method is based on the oxidative power of an excited flavin catalyst and the relatively low oxidation potential of the hemiaminal formed by amine to aldehyde addition.
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14
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Pokluda A, Anwar Z, Boguschová V, Anusiewicz I, Skurski P, Sikorski M, Cibulka R. Robust Photocatalytic Method Using Ethylene‐Bridged Flavinium Salts for the Aerobic Oxidation of Unactivated Benzylic Substrates. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202100024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Adam Pokluda
- Department of Organic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
| | - Zubair Anwar
- Faculty of Chemistry Adam Mickiewicz University in Poznań Uniwersytetu Poznańskiego 8 61–614 Poznań Poland
| | - Veronika Boguschová
- Department of Organic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
| | - Iwona Anusiewicz
- Faculty of Chemistry University of Gdańsk Wita Stwosza 63 80–308 Gdańsk Poland
| | - Piotr Skurski
- Faculty of Chemistry University of Gdańsk Wita Stwosza 63 80–308 Gdańsk Poland
| | - Marek Sikorski
- Faculty of Chemistry Adam Mickiewicz University in Poznań Uniwersytetu Poznańskiego 8 61–614 Poznań Poland
| | - Radek Cibulka
- Department of Organic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
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15
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do Pim WD, Mendonça FG, Brunet G, Facey GA, Chevallier F, Bucher C, Baker RT, Murugesu M. Anion-Dependent Catalytic C-C Bond Cleavage of a Lignin Model within a Cationic Metal-Organic Framework. ACS APPLIED MATERIALS & INTERFACES 2021; 13:688-695. [PMID: 33356092 DOI: 10.1021/acsami.0c19212] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The development of heterogeneous catalysts capable of selectively converting lignin model compounds into products of added value offers an exciting avenue to explore in the production of renewable chemical feedstocks. The use of metal-organic frameworks (MOFs) in such chemical transformations relies largely on the presence of accessible open metal sites found within highly porous networks that simultaneously allow for fast transport and strong interactions with desired substrates. Here, we present the first systematic study on the modulation of catalytic performance of a cationic framework, [Cu2(L)(H2O)2](NO3)2·5.5H2O (L = 1,1'-bis(3,5-dicarboxylatophenyl)-4,4'-bipyridinium), achieved through the exchange of anionic guests. Remarkably, the catalytic activity proves to be highly anion-dependent, with a nearly 10-fold increase toward the aerobic C-C bond cleavage of a lignin model compound when different anionic species are incorporated within the MOF. Moreover, we demonstrate that the cationic nature of the MOF, imparted by the incorporation of viologen moieties within the linker, tunes the electrophilicity of the active copper(II) sites, resulting in stronger interactions with the substrate. As such, the copper-based framework exhibits enhanced catalytic performance when compared to its neutral counterpart, emphasizing the appeal of charged frameworks for use as green heterogeneous catalysts.
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Affiliation(s)
- Walace D do Pim
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Fernanda G Mendonça
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Gabriel Brunet
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Glenn A Facey
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Floris Chevallier
- Université Lyon, ENS Lyon, CNRS, Université Lyon 1, Laboratoire de Chimie, UMR 5182, 46 Allee d'Italie, 69364 Lyon, France
| | - Christophe Bucher
- Université Lyon, ENS Lyon, CNRS, Université Lyon 1, Laboratoire de Chimie, UMR 5182, 46 Allee d'Italie, 69364 Lyon, France
| | - R Tom Baker
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Muralee Murugesu
- Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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16
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Dai P, Xu L. Visible-Light-Induced Benzylic C—H Oxygenation Reaction Using Tetrabutylammonium Tribromide as the Catalyst. CHINESE J ORG CHEM 2021. [DOI: 10.6023/cjoc202106041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Srivastava V, Singh PK, Srivastava A, Singh PP. Synthetic applications of flavin photocatalysis: a review. RSC Adv 2021. [DOI: 10.1039/d1ra00925g] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Encouraging developments in the field of photocatalysis in last decades, biomolecules namely flavins have been observed to act as a catalyst in several photoredox-catalysed synthetic methodologies.
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Affiliation(s)
- Vishal Srivastava
- Department of Chemistry
- CMP Degree College
- University of Allahabad
- Prayagraj 211002
- India
| | - Pravin K. Singh
- Department of Chemistry
- CMP Degree College
- University of Allahabad
- Prayagraj 211002
- India
| | - Arjita Srivastava
- Department of Chemistry
- CMP Degree College
- University of Allahabad
- Prayagraj 211002
- India
| | - Praveen P. Singh
- Department of Chemistry
- United College of Engineering & Research
- Prayagraj 211010
- India
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18
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Lubov DP, Talsi EP, Bryliakov KP. Methods for selective benzylic C–H oxofunctionalization of organic compounds. RUSSIAN CHEMICAL REVIEWS 2020. [DOI: 10.1070/rcr4918] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Elliott Q, Dos Passos Gomes G, Evoniuk CJ, Alabugin IV. Testing the limits of radical-anionic CH-amination: a 10-million-fold decrease in basicity opens a new path to hydroxyisoindolines via a mixed C-N/C-O-forming cascade. Chem Sci 2020; 11:6539-6555. [PMID: 34094120 PMCID: PMC8159354 DOI: 10.1039/c9sc06511c] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 02/14/2020] [Indexed: 11/21/2022] Open
Abstract
An intramolecular C(sp3)-H amidation proceeds in the presence of t-BuOK, molecular oxygen, and DMF. This transformation is initiated by the deprotonation of an acidic N-H bond and selective radical activation of a benzylic C-H bond towards hydrogen atom transfer (HAT). Cyclization of this radical-anion intermediate en route to a two-centered/three-electron (2c,3e) C-N bond removes electron density from nitrogen. As this electronegative element resists such an "oxidation", making nitrogen more electron rich is key to overcoming this problem. This work dramatically expands the range of N-anions that can participate in this process by using amides instead of anilines. The resulting 107-fold decrease in the N-component basicity (and nucleophilicity) doubles the activation barrier for C-N bond formation and makes this process nearly thermoneutral. Remarkably, this reaction also converts a weak reductant into a much stronger reductant. Such "reductant upconversion" allows mild oxidants like molecular oxygen to complete the first part of the cascade. In contrast, the second stage of NH/CH activation forms a highly stabilized radical-anion intermediate incapable of undergoing electron transfer to oxygen. Because the oxidation is unfavored, an alternative reaction path opens via coupling between the radical anion intermediate and either superoxide or hydroperoxide radical. The hydroperoxide intermediate transforms into the final hydroxyisoindoline products under basic conditions. The use of TEMPO as an additive was found to activate less reactive amides. The combination of experimental and computational data outlines a conceptually new mechanism for conversion of unprotected amides into hydroxyisoindolines proceeding as a sequence of C-H amidation and C-H oxidation.
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Affiliation(s)
- Quintin Elliott
- Department of Chemistry and Biochemistry, Florida State University Tallahassee Florida 32306 USA
| | - Gabriel Dos Passos Gomes
- Department of Chemistry and Biochemistry, Florida State University Tallahassee Florida 32306 USA
| | - Christopher J Evoniuk
- Department of Chemistry and Biochemistry, Florida State University Tallahassee Florida 32306 USA
| | - Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University Tallahassee Florida 32306 USA
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20
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Peng Y, Li D, Fan J, Xu W, Xu J, Yu H, Lin X, Wu Q. Enantiocomplementary C-H Bond Hydroxylation Combining Photo-Catalysis and Whole-Cell Biocatalysis in a One-Pot Cascade Process. European J Org Chem 2020. [DOI: 10.1002/ejoc.201901682] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Yongzhen Peng
- Department of Chemistry; Zhejiang University; 310027 Hangzhou China
| | - Danyang Li
- Department of Chemistry; Zhejiang University; 310027 Hangzhou China
| | - Jiajie Fan
- Department of Chemistry; Zhejiang University; 310027 Hangzhou China
| | - Weihua Xu
- Department of Chemistry; Zhejiang University; 310027 Hangzhou China
| | - Jian Xu
- Department of Chemistry; Zhejiang University; 310027 Hangzhou China
| | - Huilei Yu
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; 200237 Shanghai China
| | - Xianfu Lin
- Department of Chemistry; Zhejiang University; 310027 Hangzhou China
| | - Qi Wu
- Department of Chemistry; Zhejiang University; 310027 Hangzhou China
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21
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Tolba AH, Vávra F, Chudoba J, Cibulka R. Tuning Flavin-Based Photocatalytic Systems for Application in the Mild Chemoselective Aerobic Oxidation of Benzylic Substrates. European J Org Chem 2019. [DOI: 10.1002/ejoc.201901628] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Amal Hassan Tolba
- Department of Organic Chemistry; University of Chemistry and Technology, Prague; Technická 5 166 28 Prague Czech Republic
| | - František Vávra
- 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
| | - Radek Cibulka
- Department of Organic Chemistry; University of Chemistry and Technology, Prague; Technická 5 166 28 Prague Czech Republic
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22
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Zelenka J, Cibulka R, Roithová J. Flavinium Catalysed Photooxidation: Detection and Characterization of Elusive Peroxyflavinium Intermediates. Angew Chem Int Ed Engl 2019; 58:15412-15420. [PMID: 31364790 PMCID: PMC6852162 DOI: 10.1002/anie.201906293] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/08/2019] [Indexed: 12/18/2022]
Abstract
Flavin-based catalysts are photoactive in the visible range which makes them useful in biology and chemistry. Herein, we present electrospray-ionization mass-spectrometry detection of short-lived intermediates in photooxidation of toluene catalysed by flavinium ions (Fl+ ). Previous studies have shown that photoexcited flavins react with aromates by proton-coupled electron transfer (PCET) on the microsecond time scale. For Fl+ , PCET leads to FlH.+ with the H-atom bound to the N5 position. We show that the reaction continues by coupling between FlH.+ and hydroperoxy or benzylperoxy radicals at the C4a position of FlH.+ . These results demonstrate that the N5-blocking effect reported for alkylated flavins is also active after PCET in these photocatalytic reactions. Structures of all intermediates were fully characterised by isotopic labelling and by photodissociation spectroscopy. These tools provide a new way to study reaction intermediates in the sub-second time range.
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Affiliation(s)
- Jan Zelenka
- Department of Spectroscopy and CatalysisInstitute for Molecules and MaterialsRadboud University NijmegenHeyendaalseweg 1356525AJNijmegenThe Netherlands
| | - Radek Cibulka
- Department of organic chemistryFaculty of Chemical TechnologyUniversity of Chemistry and Technology PragueTechnická 5166 28Prague 6Czech Republic
| | - Jana Roithová
- Department of Spectroscopy and CatalysisInstitute for Molecules and MaterialsRadboud University NijmegenHeyendaalseweg 1356525AJNijmegenThe Netherlands
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23
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Zelenka J, Cibulka R, Roithová J. Flavinium Catalysed Photooxidation: Detection and Characterization of Elusive Peroxyflavinium Intermediates. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201906293] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jan Zelenka
- Department of Spectroscopy and Catalysis Institute for Molecules and Materials Radboud University Nijmegen Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands
| | - Radek Cibulka
- Department of organic chemistry Faculty of Chemical Technology University of Chemistry and Technology Prague Technická 5 166 28 Prague 6 Czech Republic
| | - Jana Roithová
- Department of Spectroscopy and Catalysis Institute for Molecules and Materials Radboud University Nijmegen Heyendaalseweg 135 6525 AJ Nijmegen The Netherlands
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24
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Yu W, Wu W, Jiang H. Copper‐Catalyzed Benzylic C—H Functionalization, Oxidation and Cyclization of Methylarenes: Direct Access to 2‐Arylbenzothiazoles. CHINESE J CHEM 2019. [DOI: 10.1002/cjoc.201900340] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Wentao Yu
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical EngineeringSouth China University of Technology Guangzhou Guangdong 510640 China
| | - Wanqing Wu
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical EngineeringSouth China University of Technology Guangzhou Guangdong 510640 China
| | - Huanfeng Jiang
- Key Lab of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical EngineeringSouth China University of Technology Guangzhou Guangdong 510640 China
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25
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Geng S, Xiong B, Zhang Y, Zhang J, He Y, Feng Z. Thiyl radical promoted iron-catalyzed-selective oxidation of benzylic sp3 C–H bonds with molecular oxygen. Chem Commun (Camb) 2019; 55:12699-12702. [DOI: 10.1039/c9cc06584a] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A ligand-free iron-catalyzed method for the oxygenation of benzylic sp3 C–H bonds by molecular oxygen (1 atm) using a thiyl radical as a cocatalyst has been developed.
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Affiliation(s)
- Shasha Geng
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research
- School of Pharmaceutical Sciences
- Chongqing University
- Chongqing
- P. R. China
| | - Baojian Xiong
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research
- School of Pharmaceutical Sciences
- Chongqing University
- Chongqing
- P. R. China
| | - Yun Zhang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research
- School of Pharmaceutical Sciences
- Chongqing University
- Chongqing
- P. R. China
| | - Juan Zhang
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research
- School of Pharmaceutical Sciences
- Chongqing University
- Chongqing
- P. R. China
| | - Yun He
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research
- School of Pharmaceutical Sciences
- Chongqing University
- Chongqing
- P. R. China
| | - Zhang Feng
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research
- School of Pharmaceutical Sciences
- Chongqing University
- Chongqing
- P. R. China
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26
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Fan Y, Li X, Gao K, Liu Y, Meng X, Wu J, Hou H. Co(ii)-cluster-based metal–organic frameworks as efficient heterogeneous catalysts for selective oxidation of arylalkanes. CrystEngComm 2019. [DOI: 10.1039/c8ce02151a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three Co-cluster-based metal–organic frameworks were designed and their catalytic activities for the selective oxidation of arylalkanes were explored.
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Affiliation(s)
- Yanru Fan
- The College of Chemistry and Molecular Engineering
- Zhengzhou University
- Zhengzhou
- P. R. China
| | - Xiao Li
- The College of Chemistry and Molecular Engineering
- Zhengzhou University
- Zhengzhou
- P. R. China
| | - Kuan Gao
- The College of Chemistry and Molecular Engineering
- Zhengzhou University
- Zhengzhou
- P. R. China
| | - Yu Liu
- The College of Chemistry and Molecular Engineering
- Zhengzhou University
- Zhengzhou
- P. R. China
| | - Xiangru Meng
- The College of Chemistry and Molecular Engineering
- Zhengzhou University
- Zhengzhou
- P. R. China
| | - Jie Wu
- The College of Chemistry and Molecular Engineering
- Zhengzhou University
- Zhengzhou
- P. R. China
| | - Hongwei Hou
- The College of Chemistry and Molecular Engineering
- Zhengzhou University
- Zhengzhou
- P. R. China
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27
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Santoro S, Ferlin F, Ackermann L, Vaccaro L. C-H functionalization reactions under flow conditions. Chem Soc Rev 2019; 48:2767-2782. [PMID: 30942788 DOI: 10.1039/c8cs00211h] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
C-H functionalization technologies have progressed enormously in the last decade as testified by the great number of publications that have appeared in the literature, which are receiving great attention from researchers from different areas of expertise. While most of the protocols reported realize the C-H functionalization processes under batch conditions, there is a growing interest in the development of continuous-flow procedures aiming at increasing the performances of established methodologies or the definition of otherwise unfeasible transformations. This review summarizes the application of flow technologies for the realization of C-H functionalization reactions. According to the type of flow reactors necessary, two main general approaches are possible for the application of flow techniques, namely the use of homogeneous or heterogeneous conditions. Each example is discussed and accompanied by the description of the main features and benefits of the use of flow compared to batch conditions.
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Affiliation(s)
- Stefano Santoro
- Laboratory of Green S.O.C., Dipartimento di Chimica Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto, 8 - 06123 Perugia, Italy.
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28
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Zelenka J, Svobodová E, Tarábek J, Hoskovcová I, Boguschová V, Bailly S, Sikorski M, Roithová J, Cibulka R. Combining Flavin Photocatalysis and Organocatalysis: Metal-Free Aerobic Oxidation of Unactivated Benzylic Substrates. Org Lett 2018; 21:114-119. [PMID: 30582822 DOI: 10.1021/acs.orglett.8b03547] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We report a system with ethylene-bridged flavinium salt 2b which catalyzes the aerobic oxidation of toluenes and benzyl alcohols with high oxidation potential ( Eox > +2.5 V vs SCE) to give the corresponding benzoic acids under visible light irradiation. This is caused by the high oxidizing power of excited 2b ( E(2b*) = +2.67 V vs SCE) involved in photooxidation and by the accompanying dark organocatalytic oxygenation provided by the in situ formed flavin hydroperoxide 2b-OOH.
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Affiliation(s)
- Jan Zelenka
- Institute for Molecules and Materials , Radboud University , Heyendaalseweg 135 , 6525 AJ Nijmegen , The Netherlands
| | | | - Ján Tarábek
- Institute of Organic Chemistry and Biochemistry , Academy of Science of the Czech Republic , Flemingovo náměstí 542/2 , 16610 Prague , Czech Republic
| | | | | | | | - Marek Sikorski
- Faculty of Chemistry ; Adam Mickiewicz University in Poznan , Umultowska 89b , 61614 Poznan , Poland
| | - Jana Roithová
- Institute for Molecules and Materials , Radboud University , Heyendaalseweg 135 , 6525 AJ Nijmegen , The Netherlands
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29
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Recent Advances in Homogeneous Metal-Catalyzed Aerobic C–H Oxidation of Benzylic Compounds. Catalysts 2018. [DOI: 10.3390/catal8120640] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Csp3–H oxidation of benzylic methylene compounds is an established strategy for the synthesis of aromatic ketones, esters, and amides. The need for more sustainable oxidizers has encouraged researchers to explore the use of molecular oxygen. In particular, homogeneous metal-catalyzed aerobic oxidation of benzylic methylenes has attracted much attention. This account summarizes the development of this oxidative strategy in the last two decades, examining key factors such as reaction yields, substrate:catalyst ratio, substrate scope, selectivity over other oxidation byproducts, and reaction conditions including solvents and temperature. Finally, several mechanistic proposals to explain the observed results will be discussed.
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30
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de Souza JM, Brocksom TJ, McQuade DT, de Oliveira KT. Continuous Endoperoxidation of Conjugated Dienes and Subsequent Rearrangements Leading to C-H Oxidized Synthons. J Org Chem 2018; 83:7574-7585. [PMID: 29860826 DOI: 10.1021/acs.joc.8b01307] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have investigated the continuous flow photooxidation of several conjugated dienes and subsequent rearrangement using a practical and safe continuous-flow homemade engineered setup. End-to-end approaches involving endoperoxidation, Kornblum-DeLaMare rearrangement, and additional rearrangements are comprehensively detailed with optimization, scope, and scale-up to obtain useful hydroxyenones, furans, and 1,4-dicarbonyl building blocks.
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Affiliation(s)
- Juliana M de Souza
- Departamento de Química , Universidade Federal de São Carlos , São Carlos , SP 13565-905 , Brazil
| | - Timothy J Brocksom
- Departamento de Química , Universidade Federal de São Carlos , São Carlos , SP 13565-905 , Brazil.,Centro de Ciências Naturais e Humanas , Universidade Federal do ABC , Santo André , SP 09210-580 , Brazil
| | - D Tyler McQuade
- Department of Chemical and Life Science Engineering , Virginia Commonwealth University , Richmond , Virginia 23284-3068 , United States
| | - Kleber T de Oliveira
- Departamento de Química , Universidade Federal de São Carlos , São Carlos , SP 13565-905 , Brazil
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