1
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Stini NA, Gkizis PL, Triandafillidi I, Kokotos CG. Photocatalytic CeCl 3-Promoted C-H Alkenylation and Alkynylation of Alkanes. Chemistry 2024:e202404063. [PMID: 39636250 DOI: 10.1002/chem.202404063] [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: 11/02/2024] [Revised: 11/30/2024] [Accepted: 12/04/2024] [Indexed: 12/07/2024]
Abstract
The reemerging field of photoredox catalysis offers numerous advantages towards the development of novel, sustainable and easy-to-execute organic transformations. Herein, we report a light-triggered application of cerium complexes towards the C-H alkenylation and alkynylation of alkanes. An indirect HAT-mediated photocatalytic protocol was developed, using a cerium salt (CeCl3 ⋅ 7H2O) and a chlorine source (TBACl) as the catalytic system. A variety of cyclic and linear hydrocarbons were utilized, delivering the corresponding alkenylation or alkynylation products in good to high yields, displaying high regioselectivity. A series of mechanistic experiments were conducted.
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Affiliation(s)
- Naya A Stini
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, 15771, Panepistimiopolis, Athens, Greece
| | - Petros L Gkizis
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, 15771, Panepistimiopolis, Athens, Greece
| | - Ierasia Triandafillidi
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, 15771, Panepistimiopolis, Athens, Greece
| | - Christoforos G Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, 15771, Panepistimiopolis, Athens, Greece
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2
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Fan H, Fang Y, Yu J. Direct alkene functionalization via photocatalytic hydrogen atom transfer from C(sp 3)-H compounds: a route to pharmaceutically important molecules. Chem Commun (Camb) 2024; 60:13796-13818. [PMID: 39526464 DOI: 10.1039/d4cc05026f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2024]
Abstract
Direct functionalization of alkenes with C(sp3)-H substrates offers unique opportunities for the rapid construction of pharmaceuticals and natural products. Although significant progress has been made over the past decades, the development of green, high step-economy methods to achieve these transformations under mild conditions without the need for pre-functionalization of C(sp3)-H bonds remains a substantial challenge. Therefore, the pursuit of such methodologies is highly desirable. Recently, the direct activation of C(sp3)-H bonds via photocatalytic hydrogen atom transfer (HAT), especially from unactivated alkanes, has shown great promise. Given the potential of this approach to generate a wide range of pharmaceutically relevant compounds, this review highlights the recent advancements in the direct functionalization of alkenes through photocatalytic HAT from C(sp3)-H compounds, as well as their applications in the synthesis and diversification of drugs, natural products, and bioactive molecules, aiming to provide medicinal chemists with a practical set of tools.
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Affiliation(s)
- Hangqian Fan
- Laboratory of Pharmaceutical Engineering of Zhejiang Province, Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
| | - Yuxin Fang
- Laboratory of Pharmaceutical Engineering of Zhejiang Province, Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
| | - Jingbo Yu
- Laboratory of Pharmaceutical Engineering of Zhejiang Province, Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
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3
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Wesenberg LJ, Sivo A, Vilé G, Noël T. Ni-Catalyzed Electro-Reductive Cross-Electrophile Couplings of Alkyl Amine-Derived Radical Precursors with Aryl Iodides. J Org Chem 2024; 89:16121-16125. [PMID: 37220023 PMCID: PMC11574849 DOI: 10.1021/acs.joc.3c00859] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Indexed: 05/25/2023]
Abstract
In recent years, the "Escape-from-Flatland" trend has prompted the synthetic community to develop a set of cross-coupling strategies to introduce sp3-carbon-based fragments in organic compounds. This study presents a novel nickel-catalyzed electrochemical methodology for reductive cross-electrophile coupling. The method enables C(sp2)-C(sp3) linkages using inexpensive amine-derived radical precursors and aryl iodides. The use of electrochemistry as a power source reduces waste and avoids chemical reductants, making this approach a more sustainable alternative to traditional cross-coupling methods.
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Affiliation(s)
- Lars J Wesenberg
- Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam (UvA), Amsterdam 1098 XH, The Netherlands
| | - Alessandra Sivo
- Department of Chemistry, Materials, and Chemical Engineering "Giulio Natta", Politecnico di Milano, IT-20133 Milano, Italy
| | - Gianvito Vilé
- Department of Chemistry, Materials, and Chemical Engineering "Giulio Natta", Politecnico di Milano, IT-20133 Milano, Italy
| | - Timothy Noël
- Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam (UvA), Amsterdam 1098 XH, The Netherlands
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4
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Qu CH, Li ST, Liu JB, Chen ZZ, Tang DY, Li JH, Song GT. Site-Selective Access to Functionalized Pyrroloquinoxalinones via H-Atom Transfer from N═C sp2-H Bonds of Quinoxalinones. Org Lett 2024; 26:9244-9250. [PMID: 39440848 DOI: 10.1021/acs.orglett.4c03353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2024]
Abstract
Site-selective hydrogen atom transfer (HAT) from the N═Csp2-H bonds of quinoxaline-2(1H)-ones is a highly attractive but underdeveloped domain. Reported herein is a highly selective, practical, and economically efficient approach for facile assembly of pyrroloquinoxalinones by synergistic photocatalysis and HAT catalysis. The reaction proceeds through bromine radical-mediated HAT of quinoxalinones and imine radical addition to α-cyano-α,β-unsaturated ketones that establishes a cross-coupling/annulation cascade process, resulting in the synthesis of a series of functionalized pyrroloquinoxalinones. This protocol does not require transition metals or excess oxidants and uses easy-to-synthesize starting materials with excellent scalability and broad substrate scope. The establishment of N═Csp2 radical chemistry illustrates great potential for the synthesis of imine-containing molecules that are not possible with some traditional methods.
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Affiliation(s)
- Chuan-Hua Qu
- International Academy of Targeted Therapeutics and Innovation, Chongqing University of Arts and Sciences, 319 Honghe Avenue, Yongchuan, Chongqing 402160, China
| | - Shu-Ting Li
- International Academy of Targeted Therapeutics and Innovation, Chongqing University of Arts and Sciences, 319 Honghe Avenue, Yongchuan, Chongqing 402160, China
| | - Jian-Bo Liu
- International Academy of Targeted Therapeutics and Innovation, Chongqing University of Arts and Sciences, 319 Honghe Avenue, Yongchuan, Chongqing 402160, China
| | - Zhong-Zhu Chen
- International Academy of Targeted Therapeutics and Innovation, Chongqing University of Arts and Sciences, 319 Honghe Avenue, Yongchuan, Chongqing 402160, China
| | - Dian-Yong Tang
- International Academy of Targeted Therapeutics and Innovation, Chongqing University of Arts and Sciences, 319 Honghe Avenue, Yongchuan, Chongqing 402160, China
| | - Jia-Hong Li
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610041, China
| | - Gui-Ting Song
- International Academy of Targeted Therapeutics and Innovation, Chongqing University of Arts and Sciences, 319 Honghe Avenue, Yongchuan, Chongqing 402160, China
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5
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Kumar S, Dutta S, Cavallo L, Maity B. A Comprehensive Multireference Study of Excited-State Ni-Br Bond Homolysis in (dtbbpy)Ni II(aryl)(Br). Inorg Chem 2024; 63:20361-20371. [PMID: 39417647 DOI: 10.1021/acs.inorgchem.4c02572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2024]
Abstract
The mechanism of visible light-driven Ni-C(aryl) bond homolysis in (2,2'-bipyridine)NiII(aryl)(halide) complexes, which play a crucial role in metallaphotoredox catalysis for cross-coupling reactions, has been well studied. Differently, the theoretical understanding of Ni-halide bond homolysis remains limited. In this study, we introduce a novel electronic structural framework to elucidate the mechanisms underlying photoinduced Ni-Br bond rupture in the (dtbbpy)NiII(aryl)(Br) complex. Using multireference ab initio calculations, we characterized the excited state potential energy surfaces corresponding to metal-to-ligand charge transfer (MLCT) and ligand-to-metal charge transfer (LMCT). Our calculations reveal that the Ni-Br dissociation, triggered by an external photocatalyst, begins with the promotion of Ni(II) to a 1MLCT excited state. This state undergoes intersystem crossing with repulsive triplet surfaces corresponding to the 3MLCT and Br-to-Ni 3LMCT states, resulting in Ni-Br bond breaking via the Dexter energy transfer mechanism. In the absence of a photocatalyst, the photoexcited Ni(II) favors Ni-C(aryl) homolysis, whereas the presence of a photocatalyst promotes Ni-Br dissociation. The Ni(III) species, resulting from the oxidation of Ni(II) by the photocatalyst, was found to be unproductive toward Ni-Br or Ni-C(aryl) activation.
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Affiliation(s)
- Sanchit Kumar
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Sayan Dutta
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Luigi Cavallo
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Bholanath Maity
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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6
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Skolia E, Mountanea OG, Kokotos CG. Photochemical Aerobic Upcycling of Polystyrene Plastics. CHEMSUSCHEM 2024; 17:e202400174. [PMID: 38763906 DOI: 10.1002/cssc.202400174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/28/2024] [Accepted: 05/16/2024] [Indexed: 05/21/2024]
Abstract
Although the introduction of plastics has improved humanity's everyday life, the fast accumulation of plastic waste, including microplastics and nanoplastics, have created numerous problems with recent studies highlighting their involvement in various aspects of our lives. Upcycling of plastics, the conversion of plastic waste to high-added value chemicals, is a way to combat plastic waste that is receiving increased attention. Herein, we describe a novel aerobic photochemical process for the upcycling of real-life polystyrene-based plastics into benzoic acid. A new process employing a thioxanthone-derivative, in combination with N-bromosuccinimide, under ambient air and 390 nm irradiation is capable of upcycling real-life polystyrene-derived products in benzoic acid in yields varying from 24-54 %.
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Affiliation(s)
- Elpida Skolia
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece
| | - Olga G Mountanea
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece
| | - Christoforos G Kokotos
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece
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7
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Oliva M, Pillitteri S, Schörgenhumer J, Saito R, Van der Eycken EV, Sharma UK. Bromine radical release from a nickel-complex facilitates the activation of alkyl boronic acids: a boron selective Suzuki-Miyaura cross coupling. Chem Sci 2024:d4sc04196h. [PMID: 39371457 PMCID: PMC11450759 DOI: 10.1039/d4sc04196h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Accepted: 09/19/2024] [Indexed: 10/08/2024] Open
Abstract
In this study, without utilizing any exogenous activator or strong oxidants, we successfully employed inactivated and easily accessible alkyl boronic acids (BAs) as coupling partners in a photocatalyzed Suzuki-Miyaura reaction under batch and continuous-flow conditions. Detailed mechanistic studies suggest a unique BA activation pathway, via a plausible radical transfer event between a bromine radical (formed in situ via a photo-induced homolysis of the Ni-Br bond) and the empty p-orbital on the boron atom. Subsequently, the necessity to tune the BA oxidation potential by means of hydrogen-bonding interaction with solvents or Lewis acid-base type interactions is replaced by a novel halogen radical transfer (XRT) mechanism. The mechanistic hypothesis has been supported by both control experiments and DFT calculations.
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Affiliation(s)
- Monica Oliva
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven) Celestijnenlaan 200F B-3001 Leuven Belgium
| | - Serena Pillitteri
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven) Celestijnenlaan 200F B-3001 Leuven Belgium
| | - Johannes Schörgenhumer
- Department of Chemistry, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Riku Saito
- Department of Chemistry and Centre for Sustainable Chemistry, Ghent University Krijgslaan 281 (S3) 9000 Ghent Belgium
| | - Erik V Van der Eycken
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven) Celestijnenlaan 200F B-3001 Leuven Belgium
- Peoples' Friendship University of Russia (RUDN University) Miklukho-Maklaya Street 6 117198 Moscow Russia
| | - Upendra K Sharma
- Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, University of Leuven (KU Leuven) Celestijnenlaan 200F B-3001 Leuven Belgium
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard St. Louis MO 63121 USA
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8
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Li D, Lin M, Zhang J, Qiu C, Chen H, Xiao Z, Shen J, Zheng Y, Long J, Dai W, Wang X, Fu X, Zhang Z. Hydrophobic TaO x Species Overlayer Tuning Light-Driven Methane Chlorination with Inorganic Chlorine. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2402427. [PMID: 38751309 DOI: 10.1002/smll.202402427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 04/29/2024] [Indexed: 10/04/2024]
Abstract
Halogenated methane serves as a universal platform molecule for building high-value chemicals. Utilizing sodium chloride solution for photocatalytic methane chlorination presents an environmentally friendly method for methane conversion. However, competing reactions in gas-solid-liquid systems leads to low efficiency and selectivity in photocatalytic methane chlorination. Here, an in situ method is employed to fabricate a hydrophobic layer of TaOx species on the surface of NaTaO3. Through in-situ XPS and XANES spectra analysis, it is determined that TaOx is a coordination unsaturated species. The TaOx species transforms the surface properties from the inherent hydrophilicity of NaTaO3 to the hydrophobicity of TaOx/NaTaO3, which enhances the accessibility of CH4 for adsorption and activation, and thus promotes the methane chlorination reaction within the gas-liquid-solid three-phase system. The optimized TaOx/NaTaO3 photocatalyst has a good durability for multiple cycles of methane chlorination reactions, yielding CH3Cl at a rate of 233 µmol g-1 h-1 with a selectivity of 83%. In contrast, pure NaTaO3 exhibits almost no activity toward CH3Cl formation, instead catalyzing the over-oxidation of CH4 into CO2. Notably, the activity of the optimized TaOx/NaTaO3 photocatalyst surpasses that of reported noble metal photocatalysts. This research offers an effective strategy for enhancing the selectivity of photocatalytic methane chlorination using inorganic chlorine ions.
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Affiliation(s)
- Dongmiao Li
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Min Lin
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Jiangjie Zhang
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Chengwei Qiu
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Hui Chen
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Zhen Xiao
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Jinni Shen
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Yuanhui Zheng
- College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Jinlin Long
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Wenxin Dai
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Xuxu Wang
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Xianzhi Fu
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
| | - Zizhong Zhang
- State Key Lab of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, 350116, P. R. China
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9
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Goodwin MJ, Deetz AM, Griffin PJ, Meyer GJ. Periodic Trends in Intra-ionic Excited State Quenching by Halide. Inorg Chem 2024; 63:15772-15783. [PMID: 39120873 DOI: 10.1021/acs.inorgchem.4c01726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
The preassociation of reactants in a photoinitiated redox reaction through the use of noncovalent interactions can have a significant impact on excited state reactivity. As these noncovalent interactions render some stabilization to the associated species, they impact the kinetics and thermodynamics of photoinitiated electron transfer. Reported herein is a novel iridium(III) photocatalyst, equipped with an anion-sensitive, amide-substituted bipyridine ligand, and its reactivity with the halides (X = I-, Br-, Cl-) in acetonitrile and dichloromethane. A noteworthy periodic trend was observed, where the size and electron affinity dramatically altered the observed photoredox behavior. The binding affinity for the halides increased with decreasing ionic radius (Keq ∼103 to >106) in a polar medium but association was stoichiometric for each halide in a nonpolar medium. Evidence for the static quenching of iodide and bromide is presented while dynamic quenching was observed with all halides. These results highlight how the photophysics of halide adducts and the thermodynamics of intra-ionic photo-oxidation are impacted as a consequence of preassociation of a quencher through hydrogen bonding.
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Affiliation(s)
- Matthew J Goodwin
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Alexander M Deetz
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Paul J Griffin
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Gerald J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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10
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Tu JL, Huang B. Titanium in photocatalytic organic transformations: current applications and future developments. Org Biomol Chem 2024; 22:6650-6664. [PMID: 39118484 DOI: 10.1039/d4ob01152j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
Titanium, as an important transition metal, has garnered extensive attention in both industry and academia due to its excellent mechanical properties, corrosion resistance, and unique reactivity in organic synthesis. In the field of organic photocatalysis, titanium-based compounds such as titanium dioxide (TiO2), titanocenes (Cp2TiCl2, CpTiCl3), titanium tetrachloride (TiCl4), tetrakis(isopropoxy)titanium (Ti(OiPr)4), and chiral titanium complexes have demonstrated distinct reactivity and selectivity. This review focuses on the roles of these titanium compounds in photocatalytic organic reactions, and highlights the reaction pathways such as photo-induced single-electron transfer (SET) and ligand-to-metal charge transfer (LMCT). By systematically surveying the latest advancements in titanium-involved organic photocatalysis, this review aims to provide references for further research and technological innovation within this fast-developing field.
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Affiliation(s)
- Jia-Lin Tu
- Faculty of Arts and Sciences, Beijing Normal University, Zhuhai 519085, China.
- School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.
| | - Binbin Huang
- Faculty of Arts and Sciences, Beijing Normal University, Zhuhai 519085, China.
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11
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Li P, Tu JL, Hu AM, Zhu Y, Yin J, Guo L, Yang C, Xia W. Iron-Catalyzed Multicomponent C-H Alkylation of in Situ Generated Imines via Photoinduced Ligand-to-Metal Charge Transfer. Org Lett 2024; 26:6347-6352. [PMID: 39038192 DOI: 10.1021/acs.orglett.4c01986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Herein, we describe a novel photoinduced iron-catalyzed strategy for multicomponent C-H alkylation of in situ generated imines. By utilizing the alkyl radicals generated through iron-mediated photocatalytic C-H activation, the imines formed in situ are further subjected to addition reactions, resulting in the synthesis of various secondary and tertiary amine products. This method is simple to operate and does not require additional oxidants. It is applicable to inert alkane substrates such as cyclic alkanes, cyclic ethers, toluene, and ketones. The reaction is also compatible with various aromatic amines, alkyl amines, halogenated aromatic amines, as well as aromatic aldehydes, alkyl aldehydes, and cinnamaldehyde, among other different types of aldehydes.
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Affiliation(s)
- Pengcheng Li
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Jia-Lin Tu
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Ao-Men Hu
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Yining Zhu
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Jiawen Yin
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Lin Guo
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Chao Yang
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Wujiong Xia
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
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12
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Sharma AK, Maseras F. The Subtle Mechanism of Nickel-Photocatalyzed C(sp 3)-H Cross-Coupling. Inorg Chem 2024; 63:13801-13806. [PMID: 39018463 DOI: 10.1021/acs.inorgchem.4c01763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/19/2024]
Abstract
This computational study revises and reformulates the mechanism for the cross-coupling reaction between chlorobenzene and tetrahydrofuran catalyzed by a Ni complex with the assistance of an Ir photocatalyst. This is a representative process of transition-metal photocatalysis, and variations of it have been reported by different experimental authors. It has been also the subject of previous computational studies, which we revise and extend. Density functional theory (DFT) calculations and microkinetic modeling indicate that the most efficient mechanism takes place through an energy-transfer step and involves a NiIII complex.
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Affiliation(s)
- Akhilesh K Sharma
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), The Barcelona Institute of Science and Technology, Avenida Països Catalans 16, Tarragona 43007, Spain
| | - Feliu Maseras
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), The Barcelona Institute of Science and Technology, Avenida Països Catalans 16, Tarragona 43007, Spain
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13
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Qin J, Lei H, Gao C, Zheng Y, Zhao Y, Xia W. Light-induced ligand-to-metal charge transfer of Fe(III)-OR species in organic synthesis. Org Biomol Chem 2024. [PMID: 39011956 DOI: 10.1039/d4ob00876f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
Light-induced ligand-to-metal charge transfer (LMCT) has been utilized as a powerful strategy in various organic reactions. First-row transition metals, especially iron complexes, show good applications in this process. Fe(III)-Cl and Fe(III)-OR species are two key intermediates involved in the LMCT of iron complexes. This review highlights studies on LMCT of Fe(III)-OR species, including carboxylate-iron and alkoxy-iron species, in organic transformations. Reaction conditions, substrate scope and related mechanisms are discussed.
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Affiliation(s)
- Jie Qin
- College of Chemical and Material Engineering, Quzhou University, Quzhou 324000, China.
| | - Hong Lei
- College of Chemical and Material Engineering, Quzhou University, Quzhou 324000, China.
| | - Chuanhua Gao
- College of Chemical and Material Engineering, Quzhou University, Quzhou 324000, China.
| | - Yuewen Zheng
- College of Chemical and Material Engineering, Quzhou University, Quzhou 324000, China.
| | - Yating Zhao
- College of Chemical and Material Engineering, Quzhou University, Quzhou 324000, China.
| | - Wujiong Xia
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
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14
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Oh S, Stache EE. Recent advances in oxidative degradation of plastics. Chem Soc Rev 2024; 53:7309-7327. [PMID: 38884337 DOI: 10.1039/d4cs00407h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Oxidative degradation is a powerful method to degrade plastics into oligomers and small oxidized products. While thermal energy has been conventionally employed as an external stimulus, recent advances in photochemistry have enabled photocatalytic oxidative degradation of polymers under mild conditions. This tutorial review presents an overview of oxidative degradation, from its earliest examples to emerging strategies. This review briefly discusses the motivation and the development of thermal oxidative degradation of polymers with a focus on underlying mechanisms. Then, we will examine modern studies primarily relevant to catalytic thermal oxidative degradation and photocatalytic oxidative degradation. Lastly, we highlight some unique studies using unconventional approaches for oxidative polymer degradation, such as electrochemistry.
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Affiliation(s)
- Sewon Oh
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA
| | - Erin E Stache
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
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15
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McGhie L, Marotta A, Loftus PO, Seeberger PH, Funes-Ardoiz I, Molloy JJ. Photogeneration of α-Bimetalloid Radicals via Selective Activation of Multifunctional C1 Units. J Am Chem Soc 2024; 146:15850-15859. [PMID: 38805091 PMCID: PMC11177267 DOI: 10.1021/jacs.4c02261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/12/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024]
Abstract
Light-driven strategies that enable the chemoselective activation of a specific bond in multifunctional systems are comparatively underexplored in comparison to transition-metal-based technologies, yet desirable when considering the controlled exploration of chemical space. With the current drive to discover next-generation therapeutics, reaction design that enables the strategic incorporation of an sp3 carbon center, containing multiple synthetic handles for the subsequent exploration of chemical space would be highly enabling. Here, we describe the photoactivation of ambiphilic C1 units to generate α-bimetalloid radicals using only a Lewis base and light source to directly activate the C-I bond. Interception of these transient radicals with various SOMOphiles enables the rapid synthesis of organic scaffolds containing synthetic handles (B, Si, and Ge) for subsequent orthogonal activation. In-depth theoretical and mechanistic studies reveal the prominent role of 2,6-lutidine in forming a photoactive charge transfer complex and in stabilizing in situ generated iodine radicals, as well as the influential role of the boron p-orbital in the activation/weakening of the C-I bond. This simple and efficient methodology enabled expedient access to functionalized 3D frameworks that can be further derivatized using available technologies for C-B and C-Si bond activation.
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Affiliation(s)
- Lewis McGhie
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces, Potsdam 14476, Germany
- Department
of Chemistry and Biochemistry, Freie Universität
Berlin, Berlin 14195, Germany
| | - Alessandro Marotta
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces, Potsdam 14476, Germany
- Department
of Chemistry and Biochemistry, Freie Universität
Berlin, Berlin 14195, Germany
| | - Patrick O. Loftus
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces, Potsdam 14476, Germany
| | - Peter H. Seeberger
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces, Potsdam 14476, Germany
- Department
of Chemistry and Biochemistry, Freie Universität
Berlin, Berlin 14195, Germany
| | - Ignacio Funes-Ardoiz
- Department
of Chemistry, Instituto de Investigación Química de
la Universidad de La Rioja (IQUR), Universidad
de La Rioja Madre de Dios 53, Logroño 26004, Spain
| | - John J. Molloy
- Department
of Biomolecular Systems, Max-Planck-Institute
of Colloids and Interfaces, Potsdam 14476, Germany
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16
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Cusumano AQ, Chaffin BC, Doyle AG. Mechanism of Ni-Catalyzed Photochemical Halogen Atom-Mediated C(sp 3)-H Arylation. J Am Chem Soc 2024; 146:15331-15344. [PMID: 38778454 PMCID: PMC11246173 DOI: 10.1021/jacs.4c03099] [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] [Indexed: 05/25/2024]
Abstract
Within the context of Ni photoredox catalysis, halogen atom photoelimination from Ni has emerged as a fruitful strategy for enabling hydrogen atom transfer (HAT)-mediated C(sp3)-H functionalization. Despite the numerous synthetic transformations invoking this paradigm, a unified mechanistic hypothesis that is consistent with experimental findings on the catalytic systems and accounts for halogen radical formation and facile C(sp2)-C(sp3) bond formation remains elusive. We employ kinetic analysis, organometallic synthesis, and computational investigations to decipher the mechanism of a prototypical Ni-catalyzed photochemical C(sp3)-H arylation reaction. Our findings revise the previous mechanistic proposals, first by examining the relevance of SET and EnT processes from Ni intermediates relevant to the HAT-based arylation reaction. Our investigation highlights the ability for blue light to promote efficient Ni-C(sp2) bond homolysis from cationic NiIII and C(sp2)-C(sp3) reductive elimination from bipyridine NiII complexes. However interesting, the rates and selectivities of these processes do not account for the productive catalytic pathway. Instead, our studies support a mechanism that involves halogen atom evolution from in situ generated NiII dihalide intermediates, radical capture by a NiII(aryl)(halide) resting state, and key C-C bond formation from NiIII. Oxidative addition to NiI, as opposed to Ni0, and rapid NiIII/NiI comproportionation play key roles in this process. The findings presented herein offer fundamental insight into the reactivity of Ni in the broader context of catalysis.
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Affiliation(s)
- Alexander Q Cusumano
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Braden C Chaffin
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Abigail G Doyle
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
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17
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Kumari S, Roy S, Arora P, Kundu S. Visible light-mediated synthesis of quinazolinones and benzothiadiazine-1,1-dioxides utilizing aliphatic alcohols. Org Biomol Chem 2024; 22:4172-4178. [PMID: 38716563 DOI: 10.1039/d4ob00541d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
The activation and utilization of challenging aliphatic alcohols like methanol and ethanol is a very appealing approach to synthesize valuable organic molecules. Utilization of methanol and ethanol as a coupling partner has emerged as a valuable alternative to synthesize industrially relevant N-heterocycles because they can be easily procured from renewable sources unlike other activated coupling partners which are expensive and also unstable. Herein, a mild and metal-free photocatalytic protocol to synthesize quinazolinones and more challenging benzothiadiazine-1,1-dioxides, which is unprecedented at room temperature, is demonstrated. This methodology showcased broad substrate scope and provided important N-heterocycles more efficiently than the transition metal-based high temperature protocols. An unexplored reactivity with allyl alcohol is observed following the developed protocol. A series of control experiments were carried out to understand the mechanism.
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Affiliation(s)
- Saloni Kumari
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Souvik Roy
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Pragya Arora
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
| | - Sabuj Kundu
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
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18
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Xue M, Pan T, Shao Z, Wang W, Li H, Zhao L, Zhou X, Zhang Y. Sustainable Electrochemical Benzylic C-H Oxidation Using MeOH as an Oxygen Source. CHEMSUSCHEM 2024; 17:e202400028. [PMID: 38225209 DOI: 10.1002/cssc.202400028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 01/15/2024] [Indexed: 01/17/2024]
Abstract
New methods and strategies for the direct oxidation of benzylic C-H bonds are highly desirable, owing to the importance of ketone motifs in significant organic transformations and the synthesis of valuable molecules, including pharmaceuticals, pesticides, and fine chemicals. Herein, we describe an electrochemical benzylic C-H oxidation strategy for the synthesis of ketones using MeOH as an oxygen source. Inexpensive and safe KBr serves as both an electrolyte and a bromide radical precursor in the reaction. This transformation also offers several advantages such as mild conditions, broad functional group tolerance, and operational simplicity. Mechanistic investigations by control experiments, radical scavenging experiments, electron paramagnetic resonance (EPR), kinetic studies, cyclic voltammetry (CV), and in-situ Fourier transform infrared (FTIR) spectroscopy support a pathway involving the formation and transformation of benzyl methyl ether via hydrogen atom transfer (HAT) and single-electron transfer (SET). The practical application of our strategy is highlighted by the successful synthesis of five pharmaceuticals, namely lenperone, melperone, diphenhydramine, cinnarizine, and flunarizine.
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Affiliation(s)
- Meng Xue
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Tao Pan
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Zhichao Shao
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Wenxuan Wang
- School of Ecology and Environment, Ningxia University, 489 Helan Mountain West Road, Yinchuan, 750021, China
| | - Hu Li
- School of Ecology and Environment, Ningxia University, 489 Helan Mountain West Road, Yinchuan, 750021, China
| | - Lixing Zhao
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Xin Zhou
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
| | - Yuexia Zhang
- College of Chemistry and Chemical Engineering, Qingdao University, 308 Ningxia Road, Qingdao, 266071, China
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19
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Gu C, Li C, Minezawa N, Okazaki S, Yamaguchi K, Suzuki K. Multi-stimuli-responsive polymer degradation by polyoxometalate photocatalysis and chloride ions. NANOSCALE 2024; 16:8013-8019. [PMID: 38545655 DOI: 10.1039/d4nr00394b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Photocatalytic polymer degradation based on harnessing the abundant light energy present in the environment is one of the promising approaches to address the issue of plastic waste. In this study, we developed a multi-stimuli-responsive photocatalytic polymer degradation system facilitated by the photocatalysis of a polyoxometalate [γ-PV2W10O40]5- in conjunction with chloride ions (Cl-) as harmless and abundant stimuli. The degradation of various polymers was significantly accelerated in the presence of Cl-, which was attributed to the oxidation of Cl- by the polyoxometalate photocatalysis into a highly reactive chlorine radical that can efficiently generate a carbon-centered radical for subsequent polymer degradation. Although organic and organometallic photocatalysts decomposed under the conditions for photocatalytic polymer degradation in the presence of Cl-, [γ-PV2W10O40]5- retained its structure even under these highly oxidative conditions.
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Affiliation(s)
- Chen Gu
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo, Japan.
| | - Chifeng Li
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo, Japan.
| | - Noriyuki Minezawa
- Department of Applied Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan.
| | - Susumu Okazaki
- Department of Applied Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan.
| | - Kazuya Yamaguchi
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo, Japan.
| | - Kosuke Suzuki
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo, Japan.
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20
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Huang Y, Wang M, Liu W, Wu Q, Hu P. Unraveling the Prominent Existence of Trace Metals in Photocatalysis: Exploring Iron Impurity Effects. J Org Chem 2024; 89:4156-4164. [PMID: 38450620 DOI: 10.1021/acs.joc.4c00155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Metal impurities can complicate the identification of active catalyst species in transition metal catalysis and electrocatalysis, potentially leading to misleading findings. This study investigates the influence of metal impurities on photocatalysis. Specifically, the photocatalytic reaction of inert alkanes using chlorides without the use of an external photocatalyst was studied, achieving successful C(sp3)-H functionalization. The observations reveal that Fe and Cu impurities are challenging to avoid in a typical laboratory environment and are prominently present in normal reaction systems, and iron impurities play a dominant role in the aforementioned apparent 'metal-free' reaction. Additionally, iron exhibits significantly higher catalytic activity compared to Cu, Ce, and Ni at low metal concentrations in the photocatalytic C(sp3)-H functionalization using chlorides. Considering the widespread presence of Fe and Cu impurities in typical laboratory environments, this study serves as a reminder of their involvement in reaction processes.
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Affiliation(s)
- Yahao Huang
- Institute of Green Chemistry and Molecular Engineering, GBRCE for Functional Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Miao Wang
- Institute of Green Chemistry and Molecular Engineering, GBRCE for Functional Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Wei Liu
- Institute of Green Chemistry and Molecular Engineering, GBRCE for Functional Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Qiang Wu
- Institute of Green Chemistry and Molecular Engineering, GBRCE for Functional Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Peng Hu
- Institute of Green Chemistry and Molecular Engineering, GBRCE for Functional Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, Guangzhou 510006, P. R. China
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21
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Laporte AAH, Masson TM, Zondag SDA, Noël T. Multiphasic Continuous-Flow Reactors for Handling Gaseous Reagents in Organic Synthesis: Enhancing Efficiency and Safety in Chemical Processes. Angew Chem Int Ed Engl 2024; 63:e202316108. [PMID: 38095968 DOI: 10.1002/anie.202316108] [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: 10/24/2023] [Indexed: 12/29/2023]
Abstract
The use of reactive gaseous reagents for the production of active pharmaceutical ingredients (APIs) remains a scientific challenge due to safety and efficiency limitations. The implementation of continuous-flow reactors has resulted in rapid development of gas-handling technology because of several advantages such as increased interfacial area, improved mass- and heat transfer, and seamless scale-up. This technology enables shorter and more atom-economic synthesis routes for the production of pharmaceutical compounds. Herein, we provide an overview of literature from 2016 onwards in the development of gas-handling continuous-flow technology as well as the use of gases in functionalization of APIs.
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Affiliation(s)
- Annechien A H Laporte
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences (HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Tom M Masson
- 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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22
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Liu SH, Dong ZC, Zang ZL, Zhou CH, Cai GX. Selective α-oxidation of amides via visible-light-driven iron catalysis. Org Biomol Chem 2024; 22:1205-1212. [PMID: 38224270 DOI: 10.1039/d3ob01984e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
Hydroxyl radicals (˙OH) as one of the highly reactive species can react unselectively with a wide range of chemicals. The ˙OH radicals are typically generated under harsh conditions. Herein, we report hydroxyl radical-induced selective N-α C(sp3)-H bond oxidation of amides under greener and mild conditions via an Fe(NO3)3·9H2O catalyst inner sphere pathway upon irradiation with a 30 W blue LED light strip (λ = 455 nm) using NaBrO3 as the oxidant. This protocol exhibited high chemoselectivity and excellent functional group tolerance. A preliminary mechanism investigation demonstrated that the iron catalyst afforded hydroxyl radicals via the visible-light-induced homolysis (VLIH) of iron complexes followed by a hydrogen atom transfer (HAT) process to realize this transformation.
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Affiliation(s)
- Shu-Hong Liu
- Institute of Bioorganic & Medicinal Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China.
| | - Zhi-Chao Dong
- Institute of Bioorganic & Medicinal Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China.
| | - Zhong-Lin Zang
- Institute of Bioorganic & Medicinal Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China.
| | - Cheng-He Zhou
- Institute of Bioorganic & Medicinal Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China.
| | - Gui-Xin Cai
- Institute of Bioorganic & Medicinal Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China.
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23
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Wang M, Huang Y, Hu P. Terminal C(sp 3)-H borylation through intermolecular radical sampling. Science 2024; 383:537-544. [PMID: 38300993 DOI: 10.1126/science.adj9258] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 01/02/2024] [Indexed: 02/03/2024]
Abstract
Hydrogen atom transfer (HAT) processes can overcome the strong bond dissociation energies (BDEs) of inert C(sp3)-H bonds and thereby convert feedstock alkanes into value-added fine chemicals. Nevertheless, the high reactivity of HAT reagents, coupled with the small differences among various C(sp3)-H bond strengths, renders site-selective transformations of straight-chain alkanes a great challenge. Here, we present a photocatalytic intermolecular radical sampling process for the iron-catalyzed borylation of terminal C(sp3)-H bonds in substrates with small steric hindrance, including unbranched alkanes. Mechanistic investigations have revealed that the reaction proceeds through a reversible HAT process, followed by a selective borylation of carbon radicals. A boron-sulfoxide complex may contribute to the high terminal regioselectivity observed.
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Affiliation(s)
- Miao Wang
- Institute of Green Chemistry and Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Yahao Huang
- Institute of Green Chemistry and Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
| | - Peng Hu
- Institute of Green Chemistry and Molecular Engineering, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
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24
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Yi Y, Xi C. Organo-Photoredox Catalyzed C(sp 3 )-H Bond Arylation of Aliphatic Amides. CHEMSUSCHEM 2023:e202301585. [PMID: 38126961 DOI: 10.1002/cssc.202301585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/14/2023] [Accepted: 12/20/2023] [Indexed: 12/23/2023]
Abstract
A C(sp3 )-H bond arylation of aliphatic amides has been achieved via organophotoredox catalysis. The reaction could be realized at room temperature with visible light source and metal-free catalyst. Quinuclidine is employed as an efficient HAT reagent and a range of aliphatic amides is employed as both substrate and solvent in the reaction. This photocatalyzed transformation provides a convenient protocol to afford a board range of N-benzyl amides.
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Affiliation(s)
- Yaping Yi
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Chanjuan Xi
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, P. R. China
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25
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Ioannou DI, Capaldo L, Sanramat J, Reek JNH, Noël T. Accelerated Electrophotocatalytic C(sp 3 )-H Heteroarylation Enabled by an Efficient Continuous-Flow Reactor. Angew Chem Int Ed Engl 2023; 62:e202315881. [PMID: 37972351 DOI: 10.1002/anie.202315881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/13/2023] [Accepted: 11/16/2023] [Indexed: 11/19/2023]
Abstract
Electrophotocatalytic transformations are garnering attention in organic synthesis, particularly for accessing reactive intermediates under mild conditions. Moving these methodologies to continuous-flow systems, or flow ElectroPhotoCatalysis (f-EPC), showcases potential for scalable processes due to enhanced irradiation, increased electrode surface, and improved mixing of the reaction mixture. Traditional methods sequentially link photochemical and electrochemical reactions, using flow reactors connected in series, yet struggle to accommodate reactive transient species. In this study, we introduce a new flow reactor concept for electrophotocatalysis (EPC) that simultaneously utilizes photons and electrons. The reactor is designed with a transparent electrode and employs cost-effective materials. We used this technology to develop an efficient process for electrophotocatalytic heteroarylation of C(sp3 )-H bonds. Importantly, the same setup can also facilitate purely electrochemical and photochemical transformations. This reactor represents a significant advancement in electrophotocatalysis, providing a framework for its application in flow for complex synthetic transformations.
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Affiliation(s)
- Dimitris I Ioannou
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098, XH Amsterdam, The Netherlands
- Supramolecular and Homogeneous Catalysis Group, van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098, XH Amsterdam, The Netherlands
| | - Luca Capaldo
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098, XH Amsterdam, The Netherlands
- SynCat Lab, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124, Parma, Italy
| | - Jiri Sanramat
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098, XH Amsterdam, The Netherlands
| | - Joost N H Reek
- Supramolecular and Homogeneous Catalysis Group, van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098, XH Amsterdam, The Netherlands
| | - Timothy Noël
- Flow Chemistry Group, van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098, XH Amsterdam, The Netherlands
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26
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Fan P, Chen Z, Wang C. Nickel/Photo-Cocatalyzed Three-Component Alkyl-Acylation of Aryl-Activated Alkenes. Org Lett 2023. [PMID: 38048426 DOI: 10.1021/acs.orglett.3c03669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
Herein, we disclose a nickel/photo-cocatalyzed three-component alkyl-acylation of aryl-substituted alkenes with aldehydes and electron-withdrawing-group-activated alkyl bromides, providing straightforward access to various ketones under mild and ligand-free conditions. The photocatalyst TBADT plays a dual role in activating the acyl C-H bond of aldehydes via hydrogen atom transfer and reducing the C-Br bond of alkyl bromides via single-electron transfer. While the terminal C-C bond is forged through polarity-matched radical-type addition, nickel is likely involved in the acylation step.
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Affiliation(s)
- Pei Fan
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
- School of Chemical and Materials Engineering, Anhui Province Key Laboratory of Low Temperature Co-Fired Materials, Huainan Normal University, Huainan, Anhui 232038, P. R. China
| | - Zhe Chen
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Chuan Wang
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
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27
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Kim J, Müller S, Ritter T. Synthesis of α-Branched Enones via Chloroacylation of Terminal Alkenes. Angew Chem Int Ed Engl 2023; 62:e202309498. [PMID: 37786992 DOI: 10.1002/anie.202309498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 09/28/2023] [Accepted: 10/02/2023] [Indexed: 10/04/2023]
Abstract
Here, we show the conversion of unactivated alkenes into α-branched enones via regioselective chloroacylation with acyl chlorides. The method relies upon the initial in situ generation of chlorine radicals directly from the acyl chloride precursor under cooperative nickel/photoredox catalysis. Subsequent HCl elimination provides enones and α,β-unsaturated esters that are not accessible via the conventional acylation approaches that provide the other, linear constitutional isomer.
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Affiliation(s)
- Jungwon Kim
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Sven Müller
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany
| | - Tobias Ritter
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
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28
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Cai L, Lai Q, Zhang L, Xue G, Zhang Y, He N, Huang M, Hu S, Cai S. Visible-Light-Enabled Lanthanum-Mediated Intramolecular Epoxy-Ring Opening/Dehydrogenative Lactonization. Org Lett 2023; 25:7126-7131. [PMID: 37754837 DOI: 10.1021/acs.orglett.3c02589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
Catalytic C(sp3)-H functionalization has afforded great opportunities to prepare organic substances, facilitating the derivatization of complex drugs and natural molecules. This letter describes an efficient and practical protocol for lanthanum-catalyzed continuous epoxy-ring opening and oxidative dehydrogenative lactonization under visible-light irradiation. Notably, the lanthanum catalyst also acts as a photocatalyst while acting as a Lewis acid in this reaction; therefore, no additional photocatalyst is required. We can conveniently prepare a series of diverse isochromanones with oxygen-containing spirocyclic structural units under a balloon-oxygen atmosphere at room temperature. Mechanistic studies and control experiments reveal that the in situ-generated lanthanum bromide should be crucial in the reaction.
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Affiliation(s)
- Lina Cai
- Key Laboratory of Modern Analytical Science and Separation Technology of Fujian Province, School of Chemistry, Chemical Engineering, and Environment, Minnan Normal University, Zhangzhou 363000, China
| | - Qihong Lai
- Key Laboratory of Modern Analytical Science and Separation Technology of Fujian Province, School of Chemistry, Chemical Engineering, and Environment, Minnan Normal University, Zhangzhou 363000, China
| | - Lele Zhang
- Key Laboratory of Chemical Genomics of Guangdong Province, School of Chemical Biology and Biotechnology, Shenzhen Graduate School, Peking University, Shenzhen 518055, China
| | - Guotao Xue
- Key Laboratory of Modern Analytical Science and Separation Technology of Fujian Province, School of Chemistry, Chemical Engineering, and Environment, Minnan Normal University, Zhangzhou 363000, China
| | - Yirui Zhang
- Key Laboratory of Modern Analytical Science and Separation Technology of Fujian Province, School of Chemistry, Chemical Engineering, and Environment, Minnan Normal University, Zhangzhou 363000, China
| | - Na He
- Key Laboratory of Modern Analytical Science and Separation Technology of Fujian Province, School of Chemistry, Chemical Engineering, and Environment, Minnan Normal University, Zhangzhou 363000, China
| | - Mingqiang Huang
- Key Laboratory of Modern Analytical Science and Separation Technology of Fujian Province, School of Chemistry, Chemical Engineering, and Environment, Minnan Normal University, Zhangzhou 363000, China
| | - Shirong Hu
- Key Laboratory of Modern Analytical Science and Separation Technology of Fujian Province, School of Chemistry, Chemical Engineering, and Environment, Minnan Normal University, Zhangzhou 363000, China
| | - Shunyou Cai
- Key Laboratory of Modern Analytical Science and Separation Technology of Fujian Province, School of Chemistry, Chemical Engineering, and Environment, Minnan Normal University, Zhangzhou 363000, China
- Key Laboratory of Chemical Genomics of Guangdong Province, School of Chemical Biology and Biotechnology, Shenzhen Graduate School, Peking University, Shenzhen 518055, China
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29
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Raymenants F, Masson TM, Sanjosé-Orduna J, Noël T. Efficient C(sp 3 )-H Carbonylation of Light and Heavy Hydrocarbons with Carbon Monoxide via Hydrogen Atom Transfer Photocatalysis in Flow. Angew Chem Int Ed Engl 2023; 62:e202308563. [PMID: 37459232 DOI: 10.1002/anie.202308563] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 07/17/2023] [Indexed: 07/29/2023]
Abstract
Despite their abundance in organic molecules, considerable limitations still exist in synthetic methods that target the direct C-H functionalization at sp3 -hybridized carbon atoms. This is even more the case for light alkanes, which bear some of the strongest C-H bonds known in Nature, requiring extreme activation conditions that are not tolerant to most organic molecules. To bypass these issues, synthetic chemists rely on prefunctionalized alkyl halides or organometallic coupling partners. However, new synthetic methods that target regioselectively C-H bonds in a variety of different organic scaffolds would be of great added value, not only for the late-stage functionalization of biologically active molecules but also for the catalytic upgrading of cheap and abundant hydrocarbon feedstocks. Here, we describe a general, mild and scalable protocol which enables the direct C(sp3 )-H carbonylation of saturated hydrocarbons, including natural products and light alkanes, using photocatalytic hydrogen atom transfer (HAT) and gaseous carbon monoxide (CO). Flow technology was deemed crucial to enable high gas-liquid mass transfer rates and fast reaction kinetics, needed to outpace deleterious reaction pathways, but also to leverage a scalable and safe process.
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Affiliation(s)
- Fabian Raymenants
- Flow Chemistry Group, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Tom M Masson
- Flow Chemistry Group, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Jesús Sanjosé-Orduna
- Flow Chemistry Group, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Timothy Noël
- Flow Chemistry Group, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
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30
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Kumari S, Joshi A, Borthakur I, Kundu S. Activation of Ethanol via Conjunction of a Photocatalyst and a HAT Reagent for the Synthesis of Benzimidazoles. J Org Chem 2023; 88:11523-11533. [PMID: 37525430 DOI: 10.1021/acs.joc.3c00674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
The transformation of ethanol to value-added chemicals has tremendous potential. However, generally, harsh reaction conditions are needed for the functionalization of ethanol due to its high dehydrogenation energy. Herein, a metal-free photo-mediated activation of challenging ethanol and higher aliphatic alcohols for the synthesis of differently functionalized benzimidazoles under mild conditions is disclosed. The interplay of a photocatalyst and a HAT reagent facilitated the activation of aliphatic alcohols. A wide array of diamines with different functional groups were well tolerated, and the protocol was also extended to N-substituted diamines for the synthesis of industrially important benzimidazoles. A probable catalytic cycle was proposed based on various mechanistic studies.
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Affiliation(s)
- Saloni Kumari
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Abhisek Joshi
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Ishani Borthakur
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Sabuj Kundu
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
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31
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Meger FS, Murphy JA. Recent Advances in C-H Functionalisation through Indirect Hydrogen Atom Transfer. Molecules 2023; 28:6127. [PMID: 37630379 PMCID: PMC10459052 DOI: 10.3390/molecules28166127] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/09/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
The functionalisation of C-H bonds has been an enormous achievement in synthetic methodology, enabling new retrosynthetic disconnections and affording simple synthetic equivalents for synthons. Hydrogen atom transfer (HAT) is a key method for forming alkyl radicals from C-H substrates. Classic reactions, including the Barton nitrite ester reaction and Hofmann-Löffler-Freytag reaction, among others, provided early examples of HAT. However, recent developments in photoredox catalysis and electrochemistry have made HAT a powerful synthetic tool capable of introducing a wide range of functional groups into C-H bonds. Moreover, greater mechanistic insights into HAT have stimulated the development of increasingly site-selective protocols. Site-selectivity can be achieved through the tuning of electron density at certain C-H bonds using additives, a judicious choice of HAT reagent, and a solvent system. Herein, we describe the latest methods for functionalizing C-H/Si-H/Ge-H bonds using indirect HAT between 2018-2023, as well as a critical discussion of new HAT reagents, mechanistic aspects, substrate scopes, and background contexts of the protocols.
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Affiliation(s)
- Filip S. Meger
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, 16 Avinguda dels Països Catalans, 43007 Tarragona, Catalonia, Spain
| | - John A. Murphy
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, UK
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32
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Velasco-Rubio Á, Martínez-Balart P, Álvarez-Constantino AM, Fañanás-Mastral M. C-C bond formation via photocatalytic direct functionalization of simple alkanes. Chem Commun (Camb) 2023; 59:9424-9444. [PMID: 37417212 PMCID: PMC10392964 DOI: 10.1039/d3cc02790b] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 06/28/2023] [Indexed: 07/08/2023]
Abstract
The direct functionalization of alkanes represents a very important challenge in the goal to develop more atom-efficient and clean C-C bond forming reactions. These processes, however, are hampered by the low reactivity of the aliphatic C-H bonds. Photocatalytic processes based on hydrogen atom transfer C-H bond activation strategies have become a useful tool to activate and functionalize these inert compounds. In this article, we summarize the main achievements in this field applied to the development of C-C bond forming reactions, and we discuss the key mechanistic features that enable these transformations.
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Affiliation(s)
- Álvaro Velasco-Rubio
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, 15705 Santiago de Compostela, Spain.
| | - Pol Martínez-Balart
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, 15705 Santiago de Compostela, Spain.
| | - Andrés M Álvarez-Constantino
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, 15705 Santiago de Compostela, Spain.
| | - Martín Fañanás-Mastral
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, 15705 Santiago de Compostela, Spain.
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33
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Deetz AM, Goodwin MJ, Kober EA, Meyer GJ. Nanosecond Intra-Ionic Chloride Photo-Oxidation. Inorg Chem 2023; 62:11414-11425. [PMID: 37428627 DOI: 10.1021/acs.inorgchem.3c00970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
Transition-metal photocatalysts capable of oxidizing chloride are rare yet serve as an attractive means to controllably generate chlorine atoms, which have continued to garner the interest of researchers for notable applications in photoredox catalysis and solar energy storage. Herein, a new series of four Ir-photocatalysts with different dicationic chloride-sequestering ligands were synthesized and characterized to probe the relationship between chloride binding affinities, ion pair solution structures, and rate constants for chloride photo-oxidation in acetonitrile at room temperature. The substituents on the quaternary amines of dicationic bipyridine ligands had negligible effects on the photocatalyst excited-state reduction potential, yet dramatically influenced the affinity for chloride binding, indicating that synthetic design can be utilized to independently tune these important properties. An inverse correlation was observed between the equilibrium constant for chloride ion pairing and the rate constant for intra-ionic chloride oxidation. Exceptions to this trend suggest structural differences in the ion-paired solution structures, which were probed by 1H NMR binding experiments. This study provides new insights into light-induced oxidation of ion-paired substrates, a burgeoning approach that offers to circumvent diffusional constraints of photocatalysts with short excited-state lifetimes. Ground-state association of chloride with these photocatalysts enables intra-ionic chloride oxidation on a rapid nanosecond timescale.
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Affiliation(s)
- Alexander M Deetz
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Matthew J Goodwin
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Erin A Kober
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Gerald J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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34
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Tu JL, Hu AM, Guo L, Xia W. Iron-Catalyzed C(Sp 3)-H Borylation, Thiolation, and Sulfinylation Enabled by Photoinduced Ligand-to-Metal Charge Transfer. J Am Chem Soc 2023; 145:7600-7611. [PMID: 36958308 DOI: 10.1021/jacs.3c01082] [Citation(s) in RCA: 42] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
Catalytic C(sp3)-H functionalization has provided enormous opportunities to construct organic molecules, facilitating the derivatization of complex pharmaceutical compounds. Within this framework, direct hydrogen atom transfer (HAT) photocatalysis becomes an appealing approach to this goal. However, the viable substrates utilized in these protocols are limited, and the site selectivity shows preference to activated and thermodynamically favored C(sp3)-H bonds. Herein, we describe the development of undirected iron-catalyzed C(sp3)-H borylation, thiolation, and sulfinylation reactions enabled by the photoinduced ligand-to-metal charge transfer (LMCT) process. These reactions exhibit remarkably broad substrate scope (>150 examples in total), and most importantly, all of these three reactions show unconventional regioselectivity, with the occurrence of C(sp3)-H borylation, thiolation, and sulfinylation preferentially at the distal methyl position. The procedures are operationally simple and readily scalable and provide access to high-value products from simple hydrocarbons in one step. Mechanistic studies and control experiments indicate that the afforded site selectivity is not only relevant to the HAT species but also largely affected by the use of boron- and sulfone-based radical acceptors.
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Affiliation(s)
- Jia-Lin Tu
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Ao-Men Hu
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Lin Guo
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Wujiong Xia
- State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
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35
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Birnthaler D, Narobe R, Lopez-Berguno E, Haag C, König B. Synthetic Application of Bismuth LMCT Photocatalysis in Radical Coupling Reactions. ACS Catal 2023. [DOI: 10.1021/acscatal.2c05631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Dominik Birnthaler
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, 93053 Regensburg, Germany
| | - Rok Narobe
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, 93053 Regensburg, Germany
| | - Eliseo Lopez-Berguno
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, 93053 Regensburg, Germany
| | - Christoph Haag
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, 93053 Regensburg, Germany
| | - Burkhard König
- Institute of Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Regensburg, 93053 Regensburg, Germany
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36
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Wan T, Capaldo L, Ravelli D, Vitullo W, de Zwart FJ, de Bruin B, Noël T. Photoinduced Halogen-Atom Transfer by N-Heterocyclic Carbene-Ligated Boryl Radicals for C(sp 3)-C(sp 3) Bond Formation. J Am Chem Soc 2022; 145:991-999. [PMID: 36583709 PMCID: PMC9853867 DOI: 10.1021/jacs.2c10444] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Herein, we present a comprehensive study on the use of N-heterocyclic carbene (NHC)-ligated boryl radicals to enable C(sp3)-C(sp3) bond formation under visible-light irradiation via Halogen-Atom Transfer (XAT). The methodology relies on the use of an acridinium dye to generate the boron-centered radicals from the corresponding NHC-ligated boranes via single-electron transfer (SET) and deprotonation. These boryl radicals subsequently engage with alkyl halides in an XAT step, delivering the desired nucleophilic alkyl radicals. The present XAT strategy is very mild and accommodates a broad scope of alkyl halides, including medicinally relevant compounds and biologically active molecules. The key role of NHC-ligated boryl radicals in the operative reaction mechanism has been elucidated through a combination of experimental, spectroscopic, and computational studies. This methodology stands as a significant advancement in the chemistry of NHC-ligated boryl radicals, which had long been restricted to radical reductions, enabling C-C bond formation under visible-light photoredox conditions.
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Affiliation(s)
- Ting Wan
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Luca Capaldo
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Davide Ravelli
- PhotoGreen
Lab, Department of Chemistry, University
of Pavia, viale Taramelli 12, 27100 Pavia, Italy
| | - Walter Vitullo
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Felix J. de Zwart
- Homogeneous,
Supramolecular and Bio-inspired Catalysis Group (HomKat), van’t
Hoff Institute for Molecular Sciences (HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous,
Supramolecular and Bio-inspired Catalysis Group (HomKat), 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), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands,E-mail:
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37
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Membrane-based TBADT recovery as a strategy to increase the sustainability of continuous-flow photocatalytic HAT transformations. Nat Commun 2022; 13:6147. [PMID: 36257941 PMCID: PMC9579200 DOI: 10.1038/s41467-022-33821-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 10/04/2022] [Indexed: 11/08/2022] Open
Abstract
Photocatalytic hydrogen atom transfer (HAT) processes have been the object of numerous studies showcasing the potential of the homogeneous photocatalyst tetrabutylammonium decatungstate (TBADT) for the functionalization of C(sp3)-H bonds. However, to translate these studies into large-scale industrial processes, careful considerations of catalyst loading, cost, and removal are required. This work presents organic solvent nanofiltration (OSN) as an answer to reduce TBADT consumption, increase its turnover number and lower its concentration in the product solution, thus enabling large-scale photocatalytic HAT-based transformations. The operating parameters for a suitable membrane for TBADT recovery in acetonitrile were optimized. Continuous photocatalytic C(sp3)-H alkylation and amination reactions were carried out with in-line TBADT recovery via two OSN steps. Promisingly, the observed product yields for the reactions with in-line catalyst recycling are comparable to those of reactions performed with pristine TBADT, therefore highlighting that not only catalyst recovery (>99%, TON > 8400) is a possibility, but also that it does not happen at the expense of reaction performance.
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38
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Xu P, Daniliuc CG, Bergander K, Stein C, Studer A. Synthesis of Five-Membered Ring Systems Bearing gem-Difluoroalkenyl and Monofluoroalkenyl Substituents via Radical β-Bromo Fragmentation. ACS Catal 2022. [DOI: 10.1021/acscatal.2c03775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peng Xu
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, Münster 48149, Germany
| | - Constantin G. Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, Münster 48149, Germany
| | - Klaus Bergander
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, Münster 48149, Germany
| | - Colin Stein
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, Münster 48149, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, Münster 48149, Germany
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39
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Luridiana A, Mazzarella D, Capaldo L, Rincón JA, García-Losada P, Mateos C, Frederick MO, Nuño M, Jan Buma W, Noël T. The Merger of Benzophenone HAT Photocatalysis and Silyl Radical-Induced XAT Enables Both Nickel-Catalyzed Cross-Electrophile Coupling and 1,2-Dicarbofunctionalization of Olefins. ACS Catal 2022; 12:11216-11225. [PMID: 36158902 PMCID: PMC9486949 DOI: 10.1021/acscatal.2c03805] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/22/2022] [Indexed: 12/17/2022]
Abstract
![]()
A strategy for both
cross-electrophile coupling and 1,2-dicarbofunctionalization
of olefins has been developed. Carbon-centered radicals are generated
from alkyl bromides by merging benzophenone hydrogen atom transfer
(HAT) photocatalysis and silyl radical-induced halogen atom transfer
(XAT) and are subsequently intercepted by a nickel catalyst to forge
the targeted C(sp3)–C(sp2) and C(sp3)–C(sp3) bonds. The mild protocol is fast
and scalable using flow technology, displays broad functional group
tolerance, and is amenable to a wide variety of medicinally relevant
moieties. Mechanistic investigations reveal that the ketone catalyst,
upon photoexcitation, is responsible for the direct activation of
the silicon-based XAT reagent (HAT-mediated XAT) that furnishes the
targeted alkyl radical and is ultimately involved in the turnover
of the nickel catalytic cycle.
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Affiliation(s)
- Alberto Luridiana
- Flow Chemistry Group, Van’t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Daniele Mazzarella
- Flow Chemistry Group, Van’t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Luca Capaldo
- Flow Chemistry Group, Van’t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Juan A. Rincón
- Centro de Investigación Lilly S.A., Avda. de la Industria 30, Alcobendas-Madrid 28108, Spain
| | - Pablo García-Losada
- Centro de Investigación Lilly S.A., Avda. de la Industria 30, Alcobendas-Madrid 28108, Spain
| | - Carlos Mateos
- Centro de Investigación Lilly S.A., Avda. de la Industria 30, Alcobendas-Madrid 28108, Spain
| | - Michael O. Frederick
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, United States
| | - Manuel Nuño
- Vapourtec Ltd. Park Farm Business Centre, Fornham St Genevieve, Bury St Edmunds, Suffolk IP28 6TS, U.K
| | - Wybren Jan Buma
- Molecular Photonics, Van’t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Timothy Noël
- Flow Chemistry Group, Van’t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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40
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Masson TM, Zondag SDA, Debije MG, Noël T. Rapid and Replaceable Luminescent Coating for Silicon-Based Microreactors Enabling Energy-Efficient Solar Photochemistry. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2022; 10:10712-10717. [PMID: 35991758 PMCID: PMC9382670 DOI: 10.1021/acssuschemeng.2c03390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/21/2022] [Indexed: 06/15/2023]
Abstract
The sun is the most sustainable source of photons on the earth but is rarely used in photochemical transformations due its relatively low and variable intensity, broad wavelength range, and lack of focus. Luminescent solar concentrator-based photomicroreactors (LSC-PMs) can be an answer to all these issues, but widespread adoption is plagued by challenges associated with their complicated manufacturing. Herein, we developed a new strategy to accelerate and ease the production of LSC-PMs by depositing a thin luminescent film on commercially and widely available silicon-based microreactors. The protocol is fast and operationally simple, and the luminescent coating can be easily removed and replaced. This enables rapid tuning of the luminescent coating to fit the requirements of the photocatalytic system and to increase the photon flux inside the microreactor channels.
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Affiliation(s)
- Tom M. Masson
- 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
| | - Michael G. Debije
- Department
of Chemical Engineering and Chemistry, Stimuli-Responsive Functional
Materials & Devices, Eindhoven University
of Technology, Groene Loper 3, Bldg 14-Helix, 5600
MB Eindhoven, 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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