1
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Tu JL, Huang B. Direct C(sp 3)-H functionalization with aryl and alkyl radicals as intermolecular hydrogen atom transfer (HAT) agents. Chem Commun (Camb) 2024; 60:11450-11465. [PMID: 39268687 DOI: 10.1039/d4cc03383c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/17/2024]
Abstract
Recent years have witnessed the emergence of direct intermolecular C(sp3)-H bond functionalization using in situ generated aryl/alkyl radicals as a unique class of hydrogen atom transfer (HAT) agents. A variety of precursors have been exploited to produce these radical HAT agents under photocatalytic, electrochemical or thermal conditions. To date, viable aryl radical precursors have included aryl diazonium salts or aryl azosulfones, diaryliodonium salts, O-benzoyl oximes, aryl sulfonium salts, aryl thioesters, and aryl halides; and applicable alkyl radical sources have included tetrahalogenated methanes (e.g., CCl3Br, CBr4 and CF3I), N-hydroxyphthalimide esters, alkyl bromides, and acetic acid. This review summarizes the current advances in direct intermolecular C(sp3)-H functionalization through key HAT events with in situ generated aryl/alkyl radicals and categorizes the procedures by the specific radical precursors applied. With an emphasis on the reaction conditions, mechanisms and representative substrate scopes of these protocols, this review aims to demonstrate the current trends and future challenges of this emerging 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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2
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Hu GQ, Zhang WY, Liu YX, Liu JH, Zhao B. Visible Light-Accelerated Palladium-Catalyzed Thiocarbonylation Using Oxalic Acid Monothioester with Aryl/Alkenyl Sulfonium Salts. J Org Chem 2023; 88:14351-14356. [PMID: 37802501 DOI: 10.1021/acs.joc.3c01173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Herein, we present a decarboxylative thiocarbonylation of aryl and alkenyl sulfonium salts with oxalic acid monothioethers (OAMs), which can be achieved by visible light-accelerated palladium catalysis. Sulfonium salts are widely available, and OAM is an easily accessible and stored reagent; this mild reaction method can also be used for the synthesis of different types of thioester compounds. The reaction represents a new application of visible light-accelerated palladium catalysis in catalytic decarboxylative cross-couplings.
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Affiliation(s)
- Guo-Qin Hu
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Wen-Yan Zhang
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Yong-Xin Liu
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Jing-Hui Liu
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
| | - Bin Zhao
- School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, China
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3
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Mu Y, Jiang R, Hong Y, Hou J, Yang Z, Tang D. Acid-catalyzed synthesis of pyrazolo[4,3-c]quinolines from (1H-pyrazol-5-yl)anilines and ethers via the cleavage of C–O bond. Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.133040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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4
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Debenzylation of Benzyl-Protected Methylcellulose. POLYSACCHARIDES 2022. [DOI: 10.3390/polysaccharides3030028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Methyl cellulose and its derivatives are widely used in the food industry, cosmetics, and as construction materials. The properties of methyl celluloses (MC) strongly depend on their degrees and positions of substitution. In order to generate MCs with uncommon blocky substitution, we apply fully protected O-benzyl-O-methyl celluloses (BnMC). Such complex polysaccharide derivatives could not be deprotected completely and without shift of the composition by methods usually applied to mono- and oligosaccharides. Therefore, a facile debenzylation method was developed based on photo-initiated free-radical bromination in the presence of hydrobromic acid scavengers followed by alkaline treatment. The reaction proceeds under homogeneous conditions and without the aid of any catalyst. There is no need for expensive equipment, materials, anhydrous reagents, or running the reaction under anhydrous conditions. Reaction parameters were investigated and optimized for successful debenzylation of completely protected BnMC with degrees of methyl substitution (DSMe) around 1.9 (and DSBn around 1.1). Side-product-free and almost complete debenzylation was achieved when 1,2-epoxybutane (0.5 eq./eq. N-bromosuccinimide) and 2,6-di-tert-butylpyridine (0.5 eq./eq. N-bromosuccinimide) were used in the reaction. Furthermore, ATR-IR and 1H NMR spectroscopy confirmed the successful removal of benzyl ether groups. The method was developed to monitor the transglycosylation reaction of the BnMC with permethylated cellulose, for which the deprotection of many small samples in parallel is required. This comprises the determination of the methyl pattern in the glucosyl units by gas-liquid chromatography (GLC), as well as oligosaccharide analysis by liquid chromatography mass spectrometry (LC-MS) after perdeuteromethylation and partial hydrolysis to determine the methyl pattern in the chains. The unavoidable partial chain degradation during debenzylation does not interfere with this analytical application, but, most importantly, the DS and the methyl pattern were almost congruent for the debenzylated product and the original MC, indicating the full success of this approach The presented method provides an unprecedented opportunity for high throughput and parallel debenzylation of complicated glucans, such as BnMC (as a model compound), for analytical purposes. For comparison, debenzylation using Na/NH3 was applied to BnMC and resulted in a completely debenzylated product with a remarkably high recovery yield of 99 mol% and is, thus, the method of choice for synthetic applications, e.g., for the transglycosylation product prepared under the selected conditions in a preparative scale.
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5
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Lai M, Su F, Hu J, Wang M, Zhao M, Zhang G. Synthesis of N-Heteroarenemethyl Esters via C–C Bond Cleavage of Acyl Cyanides Under Transition Metal-Free Conditions. Front Chem 2022; 9:822625. [PMID: 35155384 PMCID: PMC8828493 DOI: 10.3389/fchem.2021.822625] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 12/15/2021] [Indexed: 01/24/2023] Open
Abstract
A practical method to synthesize N-heteroaryl esters from N-heteroaryl methanols with acyl cyanides via C–C bond cleavage without using any transition metal is demonstrated here. The use of Na2CO3/15-crown-5 couple enables access to a series of N-heteroaryl esters in high efficiency. This protocol is operationally simple and highly environmentally benign producing only cyanides as byproducts.
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6
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Kato T, Maruoka K. Selective functionalization of benzylic C-H bonds of two different benzylic ethers by bowl-shaped N-hydroxyimide derivatives as efficient organoradical catalysts. Chem Commun (Camb) 2021; 58:1021-1024. [PMID: 34951412 DOI: 10.1039/d1cc06425h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A highly efficient, site-selective benzylic C-H bond amination of two different benzylic ether substrates was described by using bowl-shaped N-hydroxyimide organoradical catalysts with diethyl azodicarboxylate. The synthetic utility of this approach is demonstrated by the subsequent transformation of the amination products into the corresponding aldehydes and alkylhydrazines.
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Affiliation(s)
- Terumasa Kato
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China.,Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou 510006, China.,Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
| | - Keiji Maruoka
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, China.,Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou 510006, China.,Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
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7
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Capaldo L, Ravelli D, Fagnoni M. Direct Photocatalyzed Hydrogen Atom Transfer (HAT) for Aliphatic C-H Bonds Elaboration. Chem Rev 2021; 122:1875-1924. [PMID: 34355884 PMCID: PMC8796199 DOI: 10.1021/acs.chemrev.1c00263] [Citation(s) in RCA: 357] [Impact Index Per Article: 119.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Direct photocatalyzed
hydrogen atom transfer (d-HAT) can be considered
a method of choice for the elaboration of
aliphatic C–H bonds. In this manifold, a photocatalyst (PCHAT) exploits the energy of a photon to trigger the homolytic
cleavage of such bonds in organic compounds. Selective C–H
bond elaboration may be achieved by a judicious choice of the hydrogen
abstractor (key parameters are the electronic character and the molecular
structure), as well as reaction additives. Different are the classes
of PCsHAT available, including aromatic ketones, xanthene
dyes (Eosin Y), polyoxometalates, uranyl salts, a metal-oxo porphyrin
and a tris(amino)cyclopropenium radical dication. The processes (mainly
C–C bond formation) are in most cases carried out under mild
conditions with the help of visible light. The aim of this review
is to offer a comprehensive survey of the synthetic applications of
photocatalyzed d-HAT.
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Affiliation(s)
- 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
| | - Maurizio Fagnoni
- PhotoGreen Lab, Department of Chemistry, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
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8
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Liu J, Wei Y, Shi M. Direct Activation of a Remote C(sp 3 )-H Bond Enabled by a Visible-Light Photosensitized Allene Moiety. Angew Chem Int Ed Engl 2021; 60:12053-12059. [PMID: 33719146 DOI: 10.1002/anie.202101266] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/02/2021] [Indexed: 12/14/2022]
Abstract
Despite allene derivatives have been always regarded as a radical accepter in traditional radical chemistry for decades, the reactivity of allene derivatives under excited state in radical chemistry was rarely explored. Herein, we wish to report an example to engage triplet-excited state of allene moiety as hydrogen-atom-transfer (HAT) partner in the activation of remote sp3 C-H bond via visible-light irradiation under mild reaction conditions with broad substrate scope and good functional-group tolerance. The reaction mechanism involving the generation of triplet excited state of allene derivative and the subsequent HAT process was supported by deuterium labeling, kinetic analysis experiments and DFT calculations.
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Affiliation(s)
- Jiaxin Liu
- State Key Laboratory of Organometallic Chemistry, University of Chinese Academy of Sciences, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Yin Wei
- State Key Laboratory of Organometallic Chemistry, University of Chinese Academy of Sciences, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
| | - Min Shi
- State Key Laboratory of Organometallic Chemistry, University of Chinese Academy of Sciences, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China
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9
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Liu J, Wei Y, Shi M. Direct Activation of a Remote C(sp
3
)–H Bond Enabled by a Visible‐Light Photosensitized Allene Moiety. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jiaxin Liu
- State Key Laboratory of Organometallic Chemistry University of Chinese Academy of Sciences Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
| | - Yin Wei
- State Key Laboratory of Organometallic Chemistry University of Chinese Academy of Sciences Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
| | - Min Shi
- State Key Laboratory of Organometallic Chemistry University of Chinese Academy of Sciences Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry Chinese Academy of Sciences 345 Lingling Road Shanghai 200032 China
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10
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Pokluda A, Anwar Z, Boguschová V, Anusiewicz I, Skurski P, Sikorski M, Cibulka R. Robust Photocatalytic Method Using Ethylene‐Bridged Flavinium Salts for the Aerobic Oxidation of Unactivated Benzylic Substrates. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202100024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Adam Pokluda
- Department of Organic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
| | - Zubair Anwar
- Faculty of Chemistry Adam Mickiewicz University in Poznań Uniwersytetu Poznańskiego 8 61–614 Poznań Poland
| | - Veronika Boguschová
- Department of Organic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
| | - Iwona Anusiewicz
- Faculty of Chemistry University of Gdańsk Wita Stwosza 63 80–308 Gdańsk Poland
| | - Piotr Skurski
- Faculty of Chemistry University of Gdańsk Wita Stwosza 63 80–308 Gdańsk Poland
| | - Marek Sikorski
- Faculty of Chemistry Adam Mickiewicz University in Poznań Uniwersytetu Poznańskiego 8 61–614 Poznań Poland
| | - Radek Cibulka
- Department of Organic Chemistry University of Chemistry and Technology, Prague Technická 5 166 28 Prague 6 Czech Republic
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11
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Sarkar S, Cheung KPS, Gevorgyan V. C-H functionalization reactions enabled by hydrogen atom transfer to carbon-centered radicals. Chem Sci 2020; 11:12974-12993. [PMID: 34123240 PMCID: PMC8163321 DOI: 10.1039/d0sc04881j] [Citation(s) in RCA: 142] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/14/2020] [Indexed: 12/12/2022] Open
Abstract
Selective functionalization of ubiquitous unactivated C-H bonds is a continuous quest for synthetic organic chemists. In addition to transition metal catalysis, which typically operates under a two-electron manifold, a recent renaissance in the radical approach relying on the hydrogen atom transfer (HAT) process has led to tremendous growth in the area. Despite several challenges, protocols proceeding via HAT are highly sought after as they allow for relatively easy activation of inert C-H bonds under mild conditions leading to a broader scope and higher functional group tolerance and sometimes complementary reactivity over methods relying on traditional transition metal catalysis. A number of methods operating via heteroatom-based HAT have been extensively reported over the past few years, while methods employing more challenging carbon analogues have been less explored. Recent developments of mild methodologies for generation of various carbon-centered radical species enabled their utilization in the HAT process, which, in turn, led to the development of remote C(sp3)-H functionalization reactions of alcohols, amines, amides and related compounds. This review covers mostly recent advances in C-H functionalization reactions involving the HAT step to carbon-centered radicals.
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Affiliation(s)
- Sumon Sarkar
- Department of Chemistry and Biochemistry, University of Texas at Dallas 800 W Campbell Rd Richardson Texas 75080 USA
| | - Kelvin Pak Shing Cheung
- Department of Chemistry and Biochemistry, University of Texas at Dallas 800 W Campbell Rd Richardson Texas 75080 USA
| | - Vladimir Gevorgyan
- Department of Chemistry and Biochemistry, University of Texas at Dallas 800 W Campbell Rd Richardson Texas 75080 USA
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12
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Fang J, Dong WL, Xu GQ, Xu PF. Photocatalyzed Metal-Free Alkylheteroarylation of Unactivated Olefins via Direct Acidic C(sp3)–H Bond Activation. Org Lett 2019; 21:4480-4485. [DOI: 10.1021/acs.orglett.9b01329] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jie Fang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Wan-Li Dong
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Guo-Qiang Xu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Peng-Fei Xu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
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13
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Revathi L, Ravindar L, Fang WY, Rakesh KP, Qin HL. Visible Light-Induced C−H Bond Functionalization: A Critical Review. Adv Synth Catal 2018. [DOI: 10.1002/adsc.201800736] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Lekkala Revathi
- State Key Laboratory of Silicate Materials for Architectures; and School of Chemistry, Chemical Engineering and Life Science; Wuhan University of Technology; 205 Luoshi Road Wuhan, Hubei Province 430070 People's Republic of China
| | - Lekkala Ravindar
- State Key Laboratory of Silicate Materials for Architectures; and School of Chemistry, Chemical Engineering and Life Science; Wuhan University of Technology; 205 Luoshi Road Wuhan, Hubei Province 430070 People's Republic of China
| | - Wan-Yin Fang
- State Key Laboratory of Silicate Materials for Architectures; and School of Chemistry, Chemical Engineering and Life Science; Wuhan University of Technology; 205 Luoshi Road Wuhan, Hubei Province 430070 People's Republic of China
| | - K. P. Rakesh
- State Key Laboratory of Silicate Materials for Architectures; and School of Chemistry, Chemical Engineering and Life Science; Wuhan University of Technology; 205 Luoshi Road Wuhan, Hubei Province 430070 People's Republic of China
| | - Hua-Li Qin
- State Key Laboratory of Silicate Materials for Architectures; and School of Chemistry, Chemical Engineering and Life Science; Wuhan University of Technology; 205 Luoshi Road Wuhan, Hubei Province 430070 People's Republic of China
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14
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Chen X, Liu M, Liu Y, Chen Y, Au CT, Yin SF. Copper-Catalyzed Esterification of N
-Heteroaryl Methanes by Oxidative Dehydrogenation. ASIAN J ORG CHEM 2018. [DOI: 10.1002/ajoc.201800421] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Xue Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics; College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 China
| | - Min Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics; College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 China
| | - Yongping Liu
- School of Basic Medicine; Hunan University of Chinese Medicine; Changsha 410208 PR China
| | - Yi Chen
- School of Basic Medicine; Hunan University of Chinese Medicine; Changsha 410208 PR China
| | - Chak-Tong Au
- College of Chemistry and Chemical Engineering; Hunan Institute of Engineering; Xiangtan 411104 Hunan China
| | - Shuang-Feng Yin
- State Key Laboratory of Chemo/Biosensing and Chemometrics; College of Chemistry and Chemical Engineering; Hunan University; Changsha 410082 China
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15
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Wang S, Liu J, Niu L, Yi H, Chiang CW, Lei A. Oxidation induced C(sp3)-O cleavage via visible-light photoredox catalysis. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.09.075] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Corrigan N, Shanmugam S, Xu J, Boyer C. Photocatalysis in organic and polymer synthesis. Chem Soc Rev 2018; 45:6165-6212. [PMID: 27819094 DOI: 10.1039/c6cs00185h] [Citation(s) in RCA: 466] [Impact Index Per Article: 77.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review, with over 600 references, summarizes the recent applications of photoredox catalysis for organic transformation and polymer synthesis. Photoredox catalysts are metallo- or organo-compounds capable of absorbing visible light, resulting in an excited state species. This excited state species can donate or accept an electron from other substrates to mediate redox reactions at ambient temperature with high atom efficiency. These catalysts have been successfully implemented for the discovery of novel organic reactions and synthesis of added-value chemicals with an excellent control of selectivity and stereo-regularity. More recently, such catalysts have been implemented by polymer chemists to post-modify polymers in high yields, as well as to effectively catalyze reversible deactivation radical polymerizations and living polymerizations. These catalysts create new approaches for advanced organic transformation and polymer synthesis. The objective of this review is to give an overview of this emerging field to organic and polymer chemists as well as materials scientists.
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Affiliation(s)
- Nathaniel Corrigan
- Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australia. and Australian Centre for NanoMedicine, School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australia
| | - Sivaprakash Shanmugam
- Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australia.
| | - Jiangtao Xu
- Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australia. and Australian Centre for NanoMedicine, School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australia
| | - Cyrille Boyer
- Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australia. and Australian Centre for NanoMedicine, School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australia
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17
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Fan WT, Li NK, Xu L, Qiao C, Wang XW. Organo-Catalyzed Asymmetric Michael-Hemiketalization-Oxa-Pictet-Spengler Cyclization for Bridged and Spiro Heterocyclic Skeletons: Oxocarbenium Ion as a Key Intermediate. Org Lett 2017; 19:6626-6629. [PMID: 29192792 DOI: 10.1021/acs.orglett.7b03341] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A Michael-hemiketalization-oxa-Pictet-Spengler cyclization has been developed for the construction of chiral bridged and spiro heterocyclic skeletons with one spiro stereogenic carbon center and two bridgehead carbon centers, utilizing cooperative catalysts of a Takemoto thiourea catalyst and a triflimide. In particular, an oxocarbenium ion acts as a key intermediate for this cyclization reaction. Additionally, biological evaluation of this type of novel structure has revealed obvious antiproliferative activity against some cancer cell lines.
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Affiliation(s)
- Wei-Tai Fan
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, and ‡College of Pharmaceutical Science, Soochow University , Suzhou 215123, People's Republic of China
| | - Nai-Kai Li
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, and ‡College of Pharmaceutical Science, Soochow University , Suzhou 215123, People's Republic of China
| | - Lumei Xu
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, and ‡College of Pharmaceutical Science, Soochow University , Suzhou 215123, People's Republic of China
| | - Chunhua Qiao
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, and ‡College of Pharmaceutical Science, Soochow University , Suzhou 215123, People's Republic of China
| | - Xing-Wang Wang
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, and ‡College of Pharmaceutical Science, Soochow University , Suzhou 215123, People's Republic of China
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18
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Cai Y, Wang J, Zhang Y, Li Z, Hu D, Zheng N, Chen H. Detection of Fleeting Amine Radical Cations and Elucidation of Chain Processes in Visible-Light-Mediated [3 + 2] Annulation by Online Mass Spectrometric Techniques. J Am Chem Soc 2017; 139:12259-12266. [PMID: 28786686 DOI: 10.1021/jacs.7b06319] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Visible-light-mediated photoredox reactions have recently emerged as a powerful means for organic synthesis and thus have generated significant interest from the organic chemistry community. Although the mechanisms of these reactions have been probed by a number of techniques such as NMR, fluorescence quenching, and laser flash photolysis and various degrees of success has been achieved, mechanistic ambiguity still exists (for instance, the involvement of the chain mechanism is still under debate) because of the lack of structural information about the proposed and short-lived intermediates. Herein, we present the detection of transient amine radical cations involved in the intermolecular [3 + 2] annulation reaction of N-cyclopropylaniline (CPA, 1) and styrene 2 by electrospray ionization mass spectrometry (ESI-MS) in combination with online laser irradiation of the reaction mixture. In particular, the reactive CPA radical cation 1+•, the reduced photocatalyst Ru(I)(bpz)3+, and the [3 + 2] annulation product radical cation 3+• are all successfully detected and confirmed by high-resolution MS. More importantly, the post-irradiation reaction with an additional substrate, isotope-labeled CPA, following photolysis of 1, 2, and Ru catalyst provides strong evidence to support the chain mechanism in the [3 + 2] annulation reaction. Furthermore, the key step of the proposed chain reaction, the oxidation of CPA 1 to amine radical cation 1+• by product radical cation 3+• (generated using online electrochemical oxidation of 3), is successfully established. Additionally, the coupling of ESI-MS with online laser irradiation has been successfully applied to probe the photostability of photocatalysts.
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Affiliation(s)
- Yi Cai
- Department of Chemistry and Biochemistry, Center of Intelligent Chemical Instrumentation, Edison Biotechnology Institute, Ohio University , Athens, Ohio 45701, United States
| | - Jiang Wang
- Department of Chemistry and Biochemistry, University of Arkansas , Fayetteville, Arkansas 72701, United States
| | - Yuexiang Zhang
- Department of Chemistry and Biochemistry, Center of Intelligent Chemical Instrumentation, Edison Biotechnology Institute, Ohio University , Athens, Ohio 45701, United States
| | - Zhi Li
- Department of Chemistry and Biochemistry, Center of Intelligent Chemical Instrumentation, Edison Biotechnology Institute, Ohio University , Athens, Ohio 45701, United States
| | - David Hu
- Department of Chemistry and Biochemistry, Center of Intelligent Chemical Instrumentation, Edison Biotechnology Institute, Ohio University , Athens, Ohio 45701, United States
| | - Nan Zheng
- Department of Chemistry and Biochemistry, University of Arkansas , Fayetteville, Arkansas 72701, United States
| | - Hao Chen
- Department of Chemistry and Biochemistry, Center of Intelligent Chemical Instrumentation, Edison Biotechnology Institute, Ohio University , Athens, Ohio 45701, United States
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Capaldo L, Ravelli D. Hydrogen Atom Transfer (HAT): A Versatile Strategy for Substrate Activation in Photocatalyzed Organic Synthesis. European J Org Chem 2017; 2017:2056-2071. [PMID: 30147436 PMCID: PMC6099384 DOI: 10.1002/ejoc.201601485] [Citation(s) in RCA: 417] [Impact Index Per Article: 59.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Indexed: 11/05/2022]
Abstract
The adoption of hydrogen atom transfer (HAT) in a photocatalytic approach, in which an excited catalyst is responsible for substrate activation, offers unique opportunities in organic synthesis, enabling the straightforward activation of R-H (R = C, Si, S) bonds in desired reagents. Either a direct strategy, based on the intrinsic reactivity of a limited number of photocatalysts in the excited state, or an indirect one, in which a photocatalytic cycle is used for the generation of a thermal hydrogen abstractor, can be exploited. This microreview summarizes the most recent advances (mainly from the last two years) in this rapidly developing area of research, collecting the selected examples according to the nature of the species promoting the HAT process. From the synthetic point of view, this area has led to the development of a plethora of strategies for C-C, C-Si, C-N, C-S, and C-halogen (particularly, fluorine) bond formation, as well as for oxidation reactions.
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Affiliation(s)
- Luca Capaldo
- PhotoGreen Lab Department of Chemistry University of Pavia Viale Taramelli 12 27100 Pavia Italy
| | - Davide Ravelli
- PhotoGreen Lab Department of Chemistry University of Pavia Viale Taramelli 12 27100 Pavia Italy
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20
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Urgoitia G, SanMartin R, Herrero MT, Domínguez E. Vanadium-Catalyzed Oxidative Debenzylation ofO-Benzyl Ethers at ppm Level. Adv Synth Catal 2016. [DOI: 10.1002/adsc.201600593] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Garazi Urgoitia
- Department of Organic Chemistry II; Faculty of Science and Technology; University of the Basque Country (UPV/EHU); Sarriena auzoa z/g 48940 Leioa Spain
| | - Raul SanMartin
- Department of Organic Chemistry II; Faculty of Science and Technology; University of the Basque Country (UPV/EHU); Sarriena auzoa z/g 48940 Leioa Spain
| | - María Teresa Herrero
- Department of Organic Chemistry II; Faculty of Science and Technology; University of the Basque Country (UPV/EHU); Sarriena auzoa z/g 48940 Leioa Spain
| | - Esther Domínguez
- Department of Organic Chemistry II; Faculty of Science and Technology; University of the Basque Country (UPV/EHU); Sarriena auzoa z/g 48940 Leioa Spain
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Hou T, Lu P, Li P. Visible-light-mediated benzylic sp3 C–H bond functionalization to C–Br or C–N bond. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.04.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Xiang M, Meng QY, Gao XW, Lei T, Chen B, Tung CH, Wu LZ. Reactivity and mechanistic insight into the cross coupling reaction between isochromans and β-keto esters through C–H bond activation under visible light irradiation. Org Chem Front 2016. [DOI: 10.1039/c5qo00412h] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The formation of a C(sp3)–C(sp3) bond next to an oxygen atom from two different C–H bonds is realized by oxidative photocatalysis.
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Affiliation(s)
- Ming Xiang
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Qing-Yuan Meng
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Xue-Wang Gao
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Tao Lei
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Bin Chen
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Chen-Ho Tung
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- P. R. China
| | - Li-Zhu Wu
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials
- Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- P. R. China
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Liu M, Chen T, Yin SF. Copper-catalysed aerobic oxidative esterification of N-heteroaryl methanes with alcohols. Catal Sci Technol 2016. [DOI: 10.1039/c5cy02069g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Efficient copper-catalysed aerobic oxidative esterification of N-heteroaryl methanes with alcohols has been developed. A variety of N-heteroaryl esters including those with functional groups are produced in good to excellent yields under the present reaction conditions.
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Affiliation(s)
- Min Liu
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- Hunan University
- Changsha 410082
- China
| | - Tieqiao Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- Hunan University
- Changsha 410082
- China
| | - Shuang-Feng Yin
- State Key Laboratory of Chemo/Biosensing and Chemometrics
- College of Chemistry and Chemical Engineering
- Hunan University
- Changsha 410082
- China
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Xiang M, Meng QY, Li JX, Zheng YW, Ye C, Li ZJ, Chen B, Tung CH, Wu LZ. Activation of CH Bonds through Oxidant-Free Photoredox Catalysis: Cross-Coupling Hydrogen-Evolution Transformation of Isochromans and β-Keto Esters. Chemistry 2015; 21:18080-4. [DOI: 10.1002/chem.201503361] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Indexed: 12/21/2022]
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Angnes RA, Li Z, Correia CRD, Hammond GB. Recent synthetic additions to the visible light photoredox catalysis toolbox. Org Biomol Chem 2015; 13:9152-67. [PMID: 26242759 DOI: 10.1039/c5ob01349f] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The boom in visible light photoredox catalysis (VLPC) research has demonstrated that this novel synthetic approach is here to stay. VLPC enables reactive radical intermediates to be catalytically generated at ambient temperature, a feat not generally allowed through traditional pyrolysis- or radical initiator-based methodologies. VLPC has vastly extended the range of substrates and reaction schemes that have been traditionally the domain of radical reactions. In this review the photophysics background of VLPC will be briefly discussed, followed by a report on recent inroads of VLPC into decarboxylative couplings and radical C-H functionalization of aromatic compounds. The bulk of the review will be dedicated to advances in synergistic catalysis involving VLPC, namely the combination of photoredox catalysis with organocatalysis, including β-functionalization of carbonyl groups, functionalization of weak aliphatic C-H bonds, and anti-Markovnikov hydrofunctionalization of alkenes; dual catalysis with gold or with nickel, photoredox catalysis as an oxidation promoter in transition metal catalysis, and acid-catalyzed enantioselective radical addition to π systems.
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Affiliation(s)
- Ricardo A Angnes
- Chemistry Institute, State University of Campinas - Unicamp C.P. 6154, CEP. 13083-970, Campinas, São Paulo, Brazil
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