1
|
Chen J, Tan C, Rodrigalvarez J, Zhang S, Martin R. Site-Selective Distal C(sp 3)-H Bromination of Aliphatic Amines as a Gateway for Forging Nitrogen-Containing sp 3 Architectures. Angew Chem Int Ed Engl 2024; 63:e202406485. [PMID: 38770612 DOI: 10.1002/anie.202406485] [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: 04/05/2024] [Revised: 05/03/2024] [Accepted: 05/20/2024] [Indexed: 05/22/2024]
Abstract
Herein, we disclose a new strategy that rapidly and reliably incorporates bromine atoms at distal, secondary C(sp3)-H sites in aliphatic amines with an excellent and predictable site-selectivity pattern. The resulting halogenated building blocks serve as versatile linchpins to enable a series of carbon-carbon and carbon-heteroatom bond-formations at remote C(sp3) sites, thus offering a new modular and unified platform that expediates the access to advanced sp3 architectures possessing valuable nitrogen-containing saturated heterocycles of interest in medicinal chemistry settings.
Collapse
Affiliation(s)
- Jinhong Chen
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
- Universitat Rovira i Virgili, Departament de Química Analítica i Química Orgànica, c/Marcel ⋅ lí Domingo, 1, 43007, Tarragona, Spain
| | - Clarence Tan
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
| | - Jesus Rodrigalvarez
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
| | - Shuai Zhang
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
- Universitat Rovira i Virgili, Departament de Química Analítica i Química Orgànica, c/Marcel ⋅ lí Domingo, 1, 43007, Tarragona, Spain
| | - Ruben Martin
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluïs Companys, 23, 08010, Barcelona, Spain
| |
Collapse
|
2
|
Goodwin MJ, Deetz AM, Griffin PJ, Meyer GJ. Periodic Trends in Intra-ionic Excited State Quenching by Halide. Inorg Chem 2024. [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.
Collapse
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
| |
Collapse
|
3
|
Michelas M, Wimberger L, Boyer C. A General Approach for Photo-Oxidative Degradation of Various Polymers. Macromol Rapid Commun 2024:e2400358. [PMID: 39008823 DOI: 10.1002/marc.202400358] [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: 05/17/2024] [Revised: 06/26/2024] [Indexed: 07/17/2024]
Abstract
The escalating demand for plastics has resulted in a surge of plastic waste worldwide, posing a monumental environmental challenge. To address this issue, a versatile photo-oxidative degradation method applicable to seven distinct polymer families is proposed, comprising poly(isobutyl vinyl ether) (PIBVE), poly(2,3-dihydrofuran) (PDHF), poly(vinyl acetate) (PVAc), poly(n-butyl acrylate) (PBA), poly(methyl acrylate) (PMA), poly(vinyl chloride) (PVC), poly(dimethyl acrylamide) (PDMA), poly(ethylene oxide) (PEO), poly(oligo(ethylene glycol) methyl ether acrylate) (PEGMEA), and even poly(methyl methacrylate) (PMMA). This method employs photo-mediated hydrogen atom transfer (HAT) followed by oxidation to promote polymer degradation. This reaction is carried out under aerobic condition in the presence of iron trichloride (FeCl3) as a photocatalyst in combination with low-intensity purple light irradiation. The process can degrade up to 97% of the polymer in less than 3 h. This degradation process can be easily controlled by switching the light off, which allows for precise modulation of the degradation rate, enhancing the effectiveness of the method. Overall, this method provides a sustainable method for degrading various polymer types with low energy input.
Collapse
Affiliation(s)
- Maxime Michelas
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Laura Wimberger
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Cyrille Boyer
- School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| |
Collapse
|
4
|
Treacy SM, Rovis T. Photoinduced Ligand-to-Metal Charge Transfer in Base-Metal Catalysis. SYNTHESIS-STUTTGART 2024; 56:1967-1978. [PMID: 38962497 PMCID: PMC11218547 DOI: 10.1055/s-0042-1751518] [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: 07/05/2024]
Abstract
The absorption of light by photosensitizers has been shown to offer novel reactive pathways through electronic excited state intermediates, complementing ground state mechanisms. Such strategies have been applied in both photocatalysis and photoredox catalysis, driven by generating reactive intermediates from their long-lived excited states. One developing area is photoinduced ligand-to-metal charge transfer (LMCT) catalysis, in which coordination of a ligand to a metal center and subsequent excitation with light results in the formation of a reactive radical and a reduced metal center. This mini review concerns the foundations and recent developments in ligand-to-metal charge transfer in transition metal catalysis focusing on the organic transformations made possible through this mechanism.
Collapse
Affiliation(s)
- S M Treacy
- Columbia University, Department of Chemistry, 3000 Broadway, Havemeyer Hall, New York, NY 10027, USA
| | - T Rovis
- Columbia University, Department of Chemistry, 3000 Broadway, Havemeyer Hall, New York, NY 10027, USA
| |
Collapse
|
5
|
Venkatraman RK, Tolba AH, Sølling TI, Cibulka R, El-Zohry AM. Ultrafast Events of Photoexcited Iron(III) Chloride for Activation of Benzylic C-H Bonds. J Phys Chem Lett 2024; 15:6202-6208. [PMID: 38836909 DOI: 10.1021/acs.jpclett.4c01116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
The usage of rare-earth-metal catalysts in the synthesis of organic compounds is widespread in chemical industries but is limited owing to its environmental and economic costs. However, recent studies indicate that abundant-earth metals like iron(III) chloride can photocatalyze diverse organic transformations using blue-light LEDs. Still, the underlying mechanism behind such activity is debatable and controversial, especially in the absence of ultrafast spectroscopic results. To address this urgent challenge, we performed femtosecond time-resolved electronic absorption spectroscopy experiments of iron(III) chloride in selected organic solvents relevant to its photocatalytic applications. Our results show that the long-lived species [Fe(II) ← Cl•]* is primarily responsible for both oxidizing the organic substrate and reducing molecular oxygen through the diffusion process, leading to the final product and regenerating the photocatalyst rather than the most widely proposed free chloride radical (Cl•). Our study will guide the rational design of efficient earth-abundant photocatalysts.
Collapse
Affiliation(s)
- Ravi Kumar Venkatraman
- Ultrafast Laser Spectroscopy Lab Center for Integrative Petroleum Research, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
| | - Amal Hassan Tolba
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic
- Chemistry Department, Faculty of Science, Assiut University, Assiut 2074020, Egypt
| | - Theis I Sølling
- Ultrafast Laser Spectroscopy Lab Center for Integrative Petroleum Research, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
| | - Radek Cibulka
- Department of Organic Chemistry, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague, Czech Republic
| | - Ahmed M El-Zohry
- Ultrafast Laser Spectroscopy Lab Center for Integrative Petroleum Research, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
| |
Collapse
|
6
|
Kachore A, Aggarwal V, Bala E, Singh H, Guleria S, Sharma S, Pathan S, Saima, Selvaraj M, Assiri MA, Kumar Verma P. Recent Advances in Direct Regioselective C-H Chlorination at Aromatic and Aliphatic. Chem Asian J 2024:e202400391. [PMID: 38825568 DOI: 10.1002/asia.202400391] [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: 04/22/2024] [Revised: 05/31/2024] [Accepted: 05/31/2024] [Indexed: 06/04/2024]
Abstract
Direct installation of key functionalities in a molecule through C-H bond activation is one of the thrust areas as well as challenging task in organic synthesis. Particularly, introduction of chlorine in a molecule imparts additional benefits for further functionalizations as well as improves the electronic behaviour such as lipophilicity and polarity towards drug development process. The chlorinated molecules have also been established as efficient biologically relevant scaffolds. Current manuscript has been focused on the direct installation of the chlorine atom at various aromatic and aliphatic positions to produce functional molecules. The key highlight of the manuscript belongs to the site selectivity (regioselectivity) for the installation of chlorine functionality. Manuscript describes the advanced methods developed for the direct C-H chlorination reactions and further simplified for the chlorination reactions at various positions including aromatic (o-, m-, and p-), benzylic, heteroaromatic, and aliphatic positions. Directing groups (DGs) and the coordination with the catalyst is the key for the enhancement of regioselectivities during direct C-H chlorination reactions.
Collapse
Affiliation(s)
- Ankit Kachore
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Varun Aggarwal
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Ekta Bala
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Hemant Singh
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Saksham Guleria
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Sakshi Sharma
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Sameer Pathan
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Saima
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
| | - Manickam Selvaraj
- Department of Chemistry, Faculty of Science, King Khalid University, PO Box 9004, 61413, Abha, Saudi Arabia
- Research Centre for Advanced Materials Science (RCAMS), King Khalid University, PO Box 9004, Abha, 61413, Saudi Arabia
| | - Mohammed A Assiri
- Department of Chemistry, Faculty of Science, King Khalid University, PO Box 9004, 61413, Abha, Saudi Arabia
- Research Centre for Advanced Materials Science (RCAMS), King Khalid University, PO Box 9004, Abha, 61413, Saudi Arabia
| | - Praveen Kumar Verma
- School of Advanced Chemical Sciences, Shoolini University of Biotechnology and Management Sciences, 173229, Solan, H.P., India
- Department of Oral and Maxillofacial Surgery, Saveetha Dental College and Hospitals, SIMATS, Saveetha University, 600077, Chennai, Tamil Nadu, India
| |
Collapse
|
7
|
May AM, Dempsey JL. A new era of LMCT: leveraging ligand-to-metal charge transfer excited states for photochemical reactions. Chem Sci 2024; 15:6661-6678. [PMID: 38725519 PMCID: PMC11079626 DOI: 10.1039/d3sc05268k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 04/02/2024] [Indexed: 05/12/2024] Open
Abstract
Ligand-to-metal charge transfer (LMCT) excited states are capable of undergoing a wide array of photochemical reactions, yet receive minimal attention compared to other charge transfer excited states. This work provides general criteria for designing transition metal complexes that exhibit low energy LMCT excited states and routes to drive photochemistry from these excited states. General design principles regarding metal identity, oxidation state, geometry, and ligand sets are summarized. Fundamental photoreactions from these states including visible light-induced homolysis, excited state electron transfer, and other photoinduced chemical transformations are discussed and key design principles for enabling these photochemical reactions are further highlighted. Guided by these fundamentals, this review outlines critical considerations for the future design and application of coordination complexes with LMCT excited states.
Collapse
Affiliation(s)
- Ann Marie May
- Department of Chemistry, University of North Carolina at Chapel Hill Chapel Hill North Carolina 27599-3290 USA
| | - Jillian L Dempsey
- Department of Chemistry, University of North Carolina at Chapel Hill Chapel Hill North Carolina 27599-3290 USA
| |
Collapse
|
8
|
Wenzel JO, Werner J, Allgaier A, van Slageren J, Fernández I, Unterreiner AN, Breher F. Visible-Light Activation of Diorganyl Bis(pyridylimino) Isoindolide Aluminum(III) Complexes and Their Organometallic Radical Reactivity. Angew Chem Int Ed Engl 2024; 63:e202402885. [PMID: 38511969 DOI: 10.1002/anie.202402885] [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: 02/08/2024] [Revised: 03/14/2024] [Accepted: 03/14/2024] [Indexed: 03/22/2024]
Abstract
We report on the synthesis and characterization of a series of (mostly) air-stable diorganyl bis(pyridylimino) isoindolide (BPI) aluminum complexes and their chemistry upon visible-light excitation. The redox non-innocent BPI pincer ligand allows for efficient charge transfer homolytic processes of the title compounds. This makes them a universal platform for the generation of carbon-centered radicals. The photo-induced homolytic cleavage of the Al-C bonds was investigated by means of stationary and transient UV/Vis spectroscopy, spin trapping experiments, as well as EPR and NMR spectroscopy. The experimental findings were supported by quantum chemical calculations. Reactivity studies enabled the utilization of the aluminum complexes as reactants in tin-free Giese-type reactions and carbonyl alkylations under ambient conditions, which both indicated radical-polar crossover behavior. A deeper understanding of the physical fundamentals and photochemical process was provided, furnishing in turn a new strategy to control the reactivity of bench-stable aluminum organometallics.
Collapse
Affiliation(s)
- Jonas O Wenzel
- Karlsruhe Institute of Technology (KIT), Institute of Inorganic Chemistry (AOC), Engesserstraße 15, 76131, Karlsruhe, Germany
| | - Johannes Werner
- Karlsruhe Institute of Technology (KIT), Institute of Physical Chemistry (IPC), Fritz-Haber-Weg 2, 76131, Karlsruhe, Germany
| | - Alexander Allgaier
- University of Stuttgart, Institute of Physical Chemistry, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Joris van Slageren
- University of Stuttgart, Institute of Physical Chemistry, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Israel Fernández
- Universidad Complutense de Madrid, Facultad de Ciencias Químicas, 28040, Madrid, Spain
| | - Andreas-Neil Unterreiner
- Karlsruhe Institute of Technology (KIT), Institute of Physical Chemistry (IPC), Fritz-Haber-Weg 2, 76131, Karlsruhe, Germany
| | - Frank Breher
- Karlsruhe Institute of Technology (KIT), Institute of Inorganic Chemistry (AOC), Engesserstraße 15, 76131, Karlsruhe, Germany
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Langer DL, Oh S, Stache EE. Selective poly(vinyl ether) upcycling via photooxidative degradation with visible light. Chem Sci 2024; 15:1840-1845. [PMID: 38303945 PMCID: PMC10829002 DOI: 10.1039/d3sc05613a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/22/2023] [Indexed: 02/03/2024] Open
Abstract
Poly(vinyl ethers) (PVEs) have many applications, such as adhesives, lubricants, and anticorrosive agents, thanks to their elastic, nonirritating, and chemically inert properties. The recycling of PVEs remains largely underexplored, and current methods lack generality towards other polymer classes. Thus, the chemical upcycling of PVE into small molecule feedstocks would provide an alternative approach to combat these current issues. Here, we report a visible light-mediated method of upcycling poly(isobutyl vinyl ether) (PIBVE) into small molecules via photooxidative degradation using chlorine or bromine radicals. PIBVE can be degraded to low molecular weight oligomers within 2 h, producing good yields of alcohols, aldehydes, and carboxylic acids. Mechanistic studies suggest that hydrogen atom transfer (HAT) from the backbone or the side chain leads to small molecule generation via oxidative cleavages. Additionally, this protocol was applied to a copolymer of poly(methyl acrylate-co-isobutyl vinyl ether) to demonstrate the preference for the degradation of polymers bearing more electron-rich C-H bonds through a judicious choice of abstraction agent. Ultimately, we show that photooxidative degradation enables the selective chemical upcycling of PVEs as a method of plastic waste valorization.
Collapse
Affiliation(s)
- Darren L Langer
- Department of Chemistry and Chemical Biology, Cornell University Ithaca New York 14853 USA
| | - Sewon Oh
- Department of Chemistry and Chemical Biology, Cornell University Ithaca New York 14853 USA
| | - Erin E Stache
- Department of Chemistry and Chemical Biology, Cornell University Ithaca New York 14853 USA
- Department of Chemistry, Princeton University Princeton New Jersey 08544 USA
| |
Collapse
|
11
|
Su Y, Cao K, Lu Y, Meng Q, Dai Q, Luo X, Lu H, Wu Z, Weng X. Surface-Phosphorylated Ceria for Chlorine-Tolerance Catalysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1369-1377. [PMID: 38048160 DOI: 10.1021/acs.est.3c06878] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
An improved fundamental understanding of active site structures can unlock opportunities for catalysis from conceptual design to industrial practice. Herein, we present the computational discovery and experimental demonstration of a highly active surface-phosphorylated ceria catalyst that exhibits robust chlorine tolerance for catalysis. Ab initio molecular dynamics (AIMD) calculations and in situ near-ambient pressure X-ray photoelectron spectroscopy (in situ NAP-XPS) identified a predominantly HPO4 active structure on CeO2(110) and CeO2(111) facets at room temperature. Importantly, further elevating the temperature led to a unique hydrogen (H) atom hopping between coordinatively unsaturated oxygen and the adjacent P═O group of HPO4. Such a mobile H on the catalyst surface can effectively quench the chlorine radicals (Cl•) via an orientated reaction analogous to hydrogen atom transfer (HAT), enabling the surface-phosphorylated CeO2-supported monolithic catalyst to exhibit both expected activity and stability for over 68 days during a pilot test, catalyzing the destruction of a complex chlorinated volatile organic compound industrial off-gas.
Collapse
Affiliation(s)
- Yuetan Su
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
| | - Kexin Cao
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
| | - Yunhao Lu
- Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China
| | - Qingjie Meng
- School of Civil & Environmental Engineering and Geography Science, Ningbo University, Ningbo 315211, P. R. China
| | - Qiguang Dai
- Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Xueqing Luo
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311200, P. R. China
| | - Hanfeng Lu
- Institute of Catalytic Reaction Engineering, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, P. R. China
| | - Zhongbiao Wu
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- Zhejiang Provincial Engineering Research Centre of Industrial Boiler & Furnace Flue Gas Pollution Control, 388 Yuhangtang Road, Hangzhou 310058, P. R. China
| | - Xiaole Weng
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, P. R. China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311200, P. R. China
| |
Collapse
|
12
|
Zhong PF, Tu JL, Zhao Y, Zhong N, Yang C, Guo L, Xia W. Photoelectrochemical oxidative C(sp 3)-H borylation of unactivated hydrocarbons. Nat Commun 2023; 14:6530. [PMID: 37845202 PMCID: PMC10579347 DOI: 10.1038/s41467-023-42264-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 10/04/2023] [Indexed: 10/18/2023] Open
Abstract
Organoboron compounds are of high significance in organic synthesis due to the unique versatility of boryl substituents to access further modifications. The high demand for the incorporation of boryl moieties into molecular structures has witnessed significant progress, particularly in the C(sp3)-H borylation of hydrocarbons. Taking advantage of special characteristics of photo/electrochemistry, we herein describe the development of an oxidative C(sp3)-H borylation reaction under metal- and oxidant-free conditions, enabled by photoelectrochemical strategy. The reaction exhibits broad substrate scope (>57 examples), and includes the use of simple alkanes, halides, silanes, ketones, esters and nitriles as viable substrates. Notably, unconventional regioselectivity of C(sp3)-H borylation is achieved, with the coupling site of C(sp3)-H borylation selectively located in the distal methyl group. Our method is operationally simple and easily scalable, and offers a feasible approach for the one-step synthesis of high-value organoboron building blocks from simple hydrocarbons, which would provide ample opportunities for drug discovery.
Collapse
Affiliation(s)
- Ping-Fu Zhong
- State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Jia-Lin Tu
- State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Yating Zhao
- College of Chemical and Material Engineering, Quzhou University, Quzhou, 324000, China
| | - Nan Zhong
- State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Chao Yang
- State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China
| | - Lin Guo
- State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
| | - Wujiong Xia
- State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China.
| |
Collapse
|
13
|
De Kreijger S, Elias B, Troian-Gautier L. Chloride, Bromide, and Iodide Photooxidation in Acetonitrile/Water Mixtures Using Binuclear Iridium(III) Photosensitizers. Inorg Chem 2023; 62:16196-16202. [PMID: 37734153 DOI: 10.1021/acs.inorgchem.3c02648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/23/2023]
Abstract
Two iridium(III) binuclear photosensitizers, [Ir(dFCF3ppy)2(N-N)Ir(dFCF3ppy)2]2+, where N-N is tetrapyrido[3,2-a:2',3'-c:3″,2″-h:2‴,3‴-j]phenazine (Ir-TPPHZ) and 1,4,5,8-tetraazaphenanthrene[9,10-b]-1,4,5,8,9,12-hexaazatriphenylene (Ir-TAPHAT) are reported for iodide, bromide, and chloride photooxidation in acetonitrile and acetonitrile/water mixtures using blue-light irradiation. Excited-state reduction potentials Ered* of +2.02 and +2.09 V vs NHE were determined for Ir-TPPHZ and Ir-TAPHAT, respectively. Both photosensitizers' excited states were efficiently quenched by iodide, bromide, and chloride with quenching rate constants in the (3.5-9.2) × 1010 and (0.0036-2.9) × 1010 M-1 s-1 ranges in neat acetonitrile and acetonitrile/water mixtures, respectively. Nanosecond transient absorption spectroscopy provided unambiguous evidence of reductive excited-state electron transfer, with all halides in the solvent mixtures containing up to 50% water. Cage-escape yields were large (55-96%) in acetonitrile and dropped below 32% in 50:50 acetonitrile/water mixtures.
Collapse
Affiliation(s)
- Simon De Kreijger
- Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), UCLouvain, Place Louis Pasteur 1, Box L4.01.02, B-1348 Louvain-la-Neuve, Belgium
| | - Benjamin Elias
- Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), UCLouvain, Place Louis Pasteur 1, Box L4.01.02, B-1348 Louvain-la-Neuve, Belgium
| | - Ludovic Troian-Gautier
- Institut de la Matière Condensée et des Nanosciences (IMCN), Molecular Chemistry, Materials and Catalysis (MOST), UCLouvain, Place Louis Pasteur 1, Box L4.01.02, B-1348 Louvain-la-Neuve, Belgium
| |
Collapse
|
14
|
Zhang Q, An B, Lei Y, Gao Z, Zhang H, Xue S, Jin X, Xu W, Wu Z, Wu M, Yang X, Wu W. Cl 2 ⋅ - Mediates Direct and Selective Conversion of Inert C(sp 3 )-H Bonds into Aldehydes/Ketones. Angew Chem Int Ed Engl 2023; 62:e202304699. [PMID: 37409373 DOI: 10.1002/anie.202304699] [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: 04/03/2023] [Revised: 06/29/2023] [Accepted: 07/05/2023] [Indexed: 07/07/2023]
Abstract
Developing new reactive pathway to activate inert C(sp3 )-H bonds for valuable oxygenated products remains a challenge. We prepared a series of triazine conjugated organic polymers to photoactivate C-H into aldehyde/ketone via O2 →H2 O2 →⋅OH→Cl⋅→Cl2 ⋅- . Experiment results showed Cl2 ⋅- could successively activate C(sp3 )-H more effectively than Cl⋅ to generate unstable dichlorinated intermediates, increasing the kinetic rate ratio of dichlorination to monochlorination by a factor of 2,000 and thus breaking traditional dichlorination kinetic constraints. These active intermediates were hydrolyzed into aldehydes or ketones easily, when compared with typical stable dichlorinated complexes, avoiding chlorinated by-product generation. Moreover, an integrated two-phase system in an acid solution strengthened the Cl2 ⋅- mediated process and inhibited product overoxidation, where the conversion rate of toluene reached 16.94 mmol/g/h and the selectivity of benzaldehyde was 99.5 %. This work presents a facile and efficient approach for selective conversion of inert C(sp3 )-H bonds using Cl2 ⋅- .
Collapse
Affiliation(s)
- Qinhua Zhang
- State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Bo An
- State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Yu Lei
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, China
| | - Zhixiao Gao
- State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Haonan Zhang
- State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Sheng Xue
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, 266021, P. R. China
| | - Xin Jin
- State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Wengang Xu
- State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Zihan Wu
- State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Mingbo Wu
- State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| | - Xin Yang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, China
| | - Wenting Wu
- State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
| |
Collapse
|
15
|
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: 7] [Impact Index Per Article: 7.0] [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.
Collapse
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
| |
Collapse
|
16
|
Yang Y, Yu X, He N, Huang X, Song X, Chen J, Lin J, Jin Y. FeCl 3-catalyzed oxidative amidation of benzylic C-H bonds enabled by a photogenerated chlorine-radical. Chem Commun (Camb) 2023; 59:10299-10302. [PMID: 37551442 DOI: 10.1039/d3cc03186a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
Herein, we report the development of iron-catalyzed benzylic C-H oxidative amidation reactions via photoinduced ligand-to-metal charge transfer (LMCT). These reactions exhibit a broad substrate scope (60 examples) and offer operationally simple, scalable procedures for accessing valuable products from methylarenes in a single step. Mechanistic studies and control experiments confirm the participation of a photogenerated chlorine radical in facilitating the hydrogen atom transfer (HAT) from the benzylic C-H bond to initiate the reaction.
Collapse
Affiliation(s)
- Yingying Yang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research & Development of Natural Products, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China.
| | - Xianglin Yu
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research & Development of Natural Products, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China.
| | - Na He
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research & Development of Natural Products, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China.
| | - Xinxiang Huang
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research & Development of Natural Products, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China.
| | - Xizhong Song
- Jianxi Zhiheng Hall Chinese Herbal Medicine Co. Ltd., Jianxi, 331200, P. R. China.
| | - Jingbo Chen
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research & Development of Natural Products, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China.
| | - Jun Lin
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research & Development of Natural Products, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China.
| | - Yi Jin
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan Provincial Center for Research & Development of Natural Products, School of Pharmacy, Yunnan University, Kunming, 650091, P. R. China.
| |
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
Marr ZY, Thapa Magar R, Fournier B, Benedict JB, Rack JJ. Photocrystallography of [Ru(bpy) 2(dmso) 2] 2+ reveals an O-bonded metastable state. Chem Sci 2023; 14:7279-7284. [PMID: 37416725 PMCID: PMC10321476 DOI: 10.1039/d3sc01526b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/06/2023] [Indexed: 07/08/2023] Open
Abstract
We report the first instance of observing the phototriggered isomerization of dmso ligands on a bis sulfoxide complex, [Ru(bpy)2(dmso)2], in the crystalline solid state. The solid-state UV-vis spectrum of the crystal demonstrates an increase in optical density around 550 nm after irradiation, which is consistent with the solution isomerization results. Digital images of the crystal before and after irradiation display a notable color change (pale orange to red) and cleavage occurs along planes, (1̄01) and (100), during irradiation. Single crystal X-ray diffraction data also confirms that isomerization is occurring throughout the lattice and a structure that contains a mix of the S,S and O,O/S,O isomer was attained from a crystal irradiated ex situ. In situ irradiation XRD studies reveal that the percentage of the O-bonded isomer increases as a function of 405 nm exposure time.
Collapse
Affiliation(s)
- Zoe Y Marr
- Department of Chemistry, The State University of New York at Buffalo Buffalo NY 14260 USA
| | - Rajani Thapa Magar
- Department of Chemistry and Chemical Biology, University of New Mexico Albuquerque NM 87131-001 USA
| | - Bertrand Fournier
- Institut Galien Paris-Saclay, CNRS UMR 8612, Université Paris-Saclay 91400 Orsay France
- Université Paris-Saclay, CentraleSupélec, CNRS, Laboratoire SPMS 91190 Gif-sur-Yvette France
| | - Jason B Benedict
- Department of Chemistry, The State University of New York at Buffalo Buffalo NY 14260 USA
| | - Jeffrey J Rack
- Department of Chemistry and Chemical Biology, University of New Mexico Albuquerque NM 87131-001 USA
| |
Collapse
|
20
|
Chang L, Wang S, An Q, Liu L, Wang H, Li Y, Feng K, Zuo Z. Resurgence and advancement of photochemical hydrogen atom transfer processes in selective alkane functionalizations. Chem Sci 2023; 14:6841-6859. [PMID: 37389263 PMCID: PMC10306100 DOI: 10.1039/d3sc01118f] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 05/11/2023] [Indexed: 07/01/2023] Open
Abstract
The selective functionalization of alkanes has long been recognized as a prominent challenge and an arduous task in organic synthesis. Hydrogen atom transfer (HAT) processes enable the direct generation of reactive alkyl radicals from feedstock alkanes and have been successfully employed in industrial applications such as the methane chlorination process, etc. Nevertheless, challenges in the regulation of radical generation and reaction pathways have created substantial obstacles in the development of diversified alkane functionalizations. In recent years, the application of photoredox catalysis has provided exciting opportunities for alkane C-H functionalization under extremely mild conditions to trigger HAT processes and achieve radical-mediated functionalizations in a more selective manner. Considerable efforts have been devoted to building more efficient and cost-effective photocatalytic systems for sustainable transformations. In this perspective, we highlight the recent development of photocatalytic systems and provide our views on current challenges and future opportunities in this field.
Collapse
Affiliation(s)
- Liang Chang
- School of Pharmacy, Nanjing University of Chinese Medicine Nanjing 210023 China
| | - Shun Wang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai 200032 China
| | - Qing An
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai 200032 China
| | - Linxuan Liu
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai 200032 China
| | - Hexiang Wang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai 200032 China
| | - Yubo Li
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai 200032 China
| | - Kaixuan Feng
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai 200032 China
| | - Zhiwei Zuo
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences Shanghai 200032 China
| |
Collapse
|
21
|
de Groot LHM, Ilic A, Schwarz J, Wärnmark K. Iron Photoredox Catalysis-Past, Present, and Future. J Am Chem Soc 2023; 145:9369-9388. [PMID: 37079887 PMCID: PMC10161236 DOI: 10.1021/jacs.3c01000] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
Photoredox catalysis of organic reactions driven by iron has attracted substantial attention throughout recent years, due to potential environmental and economic benefits. In this Perspective, three major strategies were identified that have been employed to date to achieve reactivities comparable to the successful noble metal photoredox catalysis: (1) Direct replacement of a noble metal center by iron in archetypal polypyridyl complexes, resulting in a metal-centered photofunctional state. (2) In situ generation of photoactive complexes by substrate coordination where the reactions are driven via intramolecular electron transfer involving charge-transfer states, for example, through visible-light-induced homolysis. (3) Improving the excited-state lifetimes and redox potentials of the charge-transfer states of iron complexes through new ligand design. We seek to give an overview and evaluation of recent developments in this rapidly growing field and, at the same time, provide an outlook on the future of iron-based photoredox catalysis.
Collapse
Affiliation(s)
- Lisa H M de Groot
- Centre for Analysis and Synthesis, Lund University, Lund SE-22100, Sweden
| | - Aleksandra Ilic
- Centre for Analysis and Synthesis, Lund University, Lund SE-22100, Sweden
| | - Jesper Schwarz
- Centre for Analysis and Synthesis, Lund University, Lund SE-22100, Sweden
| | - Kenneth Wärnmark
- Centre for Analysis and Synthesis, Lund University, Lund SE-22100, Sweden
| |
Collapse
|
22
|
Huo L, Li X, Zhao Y, Li L, Chu L. Site- and Stereoselective Synthesis of Alkenyl Chlorides by Dual Functionalization of Internal Alkynes via Photoredox/Nickel Catalysis. J Am Chem Soc 2023; 145:9876-9885. [PMID: 37072001 DOI: 10.1021/jacs.3c02748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Herein, we report a redox-neutral and atom-economical protocol to synthesize valuable alkenyl chlorides from unactivated internal alkynes and abundant organochlorides via photoredox and nickel catalysis. This protocol enables the site- and stereoselective addition of organochlorides to alkynes via chlorine photoelimination-initiated sequential hydrochlorination/remote C-H functionalization. The protocol is compatible with a wide range of medicinally relevant heteroaryl, aryl, acid, and alkyl chlorides for efficiently producing γ-functionalized alkenyl chlorides, exhibiting excellent regioselectivities and stereoselectivities. Late-stage modifications and synthetic manipulations of the products and preliminary mechanistic studies are also presented.
Collapse
Affiliation(s)
- Liping Huo
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Center for Advanced Low-Dimension Materials, Donghua University, Shanghai 201620, China
| | - Xiaofang Li
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Center for Advanced Low-Dimension Materials, Donghua University, Shanghai 201620, China
| | - Yaheng Zhao
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Center for Advanced Low-Dimension Materials, Donghua University, Shanghai 201620, China
| | - Ling Li
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Center for Advanced Low-Dimension Materials, Donghua University, Shanghai 201620, China
| | - Lingling Chu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Center for Advanced Low-Dimension Materials, Donghua University, Shanghai 201620, China
| |
Collapse
|
23
|
Panda C, Anny-Nzekwue O, Doyle LM, Gericke R, McDonald AR. Evidence for a High-Valent Iron-Fluoride That Mediates Oxidative C(sp 3)-H Fluorination. JACS AU 2023; 3:919-928. [PMID: 37006763 PMCID: PMC10052241 DOI: 10.1021/jacsau.3c00021] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 06/19/2023]
Abstract
[FeII(NCCH3)(NTB)](OTf)2 (NTB = tris(2-benzimidazoylmethyl)amine, OTf = trifluoromethanesulfonate) was reacted with difluoro(phenyl)-λ3-iodane (PhIF2) in the presence of a variety of saturated hydrocarbons, resulting in the oxidative fluorination of the hydrocarbons in moderate-to-good yields. Kinetic and product analysis point towards a hydrogen atom transfer oxidation prior to fluorine radical rebound to form the fluorinated product. The combined evidence supports the formation of a formally FeIV(F)2 oxidant that performs hydrogen atom transfer followed by the formation of a dimeric μ-F-(FeIII)2 product that is a plausible fluorine atom transfer rebound reagent. This approach mimics the heme paradigm for hydrocarbon hydroxylation, opening up avenues for oxidative hydrocarbon halogenation.
Collapse
|
24
|
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: 30] [Impact Index Per Article: 30.0] [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.
Collapse
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
| |
Collapse
|
25
|
Xu S, Ping Y, Li W, Guo H, Su Y, Li Z, Wang M, Kong W. Enantioselective C(sp 3)-H Functionalization of Oxacycles via Photo-HAT/Nickel Dual Catalysis. J Am Chem Soc 2023; 145:5231-5241. [PMID: 36812098 DOI: 10.1021/jacs.2c12481] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The selective functionalization of ubiquitous but inert C-H bonds is highly appealing in synthetic chemistry, but the direct transformation of hydrocarbons lacking directing groups into high-value chiral molecules remains a formidable challenge. Herein, we develop an enantioselective C(sp3)-H functionalization of undirected oxacycles via photo-HAT/nickel dual catalysis. This protocol provides a practical platform for the rapid construction of high-value and enantiomerically enriched oxacycles directly from simple and abundant hydrocarbon feedstocks. The synthetic utility of this strategy is further demonstrated in the late-stage functionalization of natural products and the synthesis of many pharmaceutically relevant molecules. Experimental and density functional theory calculation studies provide detailed insights into the mechanism and the origin of enantioselectivity for the asymmetric C(sp3)-H functionalization.
Collapse
Affiliation(s)
- Sheng Xu
- The Institute for Advanced Studies and Hongyi Honor College, Wuhan University, Wuhan 430072, China
| | - Yuanyuan Ping
- The Institute for Advanced Studies and Hongyi Honor College, Wuhan University, Wuhan 430072, China
| | - Wei Li
- The Institute for Advanced Studies and Hongyi Honor College, Wuhan University, Wuhan 430072, China
| | - Haoyun Guo
- The Institute for Advanced Studies and Hongyi Honor College, Wuhan University, Wuhan 430072, China
| | - Yinyan Su
- The Institute for Advanced Studies and Hongyi Honor College, Wuhan University, Wuhan 430072, China
| | - Ziyang Li
- The Institute for Advanced Studies and Hongyi Honor College, Wuhan University, Wuhan 430072, China
| | - Minyan Wang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Wangqing Kong
- The Institute for Advanced Studies and Hongyi Honor College, Wuhan University, Wuhan 430072, China
| |
Collapse
|
26
|
Huang H, Jing X, Deng J, Meng C, Duan C. Enzyme-Inspired Coordination Polymers for Selective Oxidization of C(sp 3)-H Bonds via Multiphoton Excitation. J Am Chem Soc 2023; 145:2170-2182. [PMID: 36657380 DOI: 10.1021/jacs.2c09348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Nature's blueprint provides the fundamental principles for expanding the use of abundant metals in catalysis; however, mimicking both the structure and function of copper enzymes simultaneously in one artificial system for selective C-H bond oxidation faces marked challenges. Herein, we report a new approach to the assembly of artificial monooxygenases utilizing a binuclear Cu2S2Cl2 cluster to duplicate the identical structure and catalysis of the CuA enzyme. The designed monooxygenase Cu-Cl-bpyc facilitates well-defined redox potential that initially activated O2via photoinduced electron transfer, and generated an active chlorine radical via a ligand-to-metal charge transfer (LMCT) process from the consecutive excitation of the in situ formed copper(II) center. The chlorine radical abstracts a hydrogen atom selectively from C(sp3)-H bonds to generate the radical intermediate; meanwhile, the O2•- species interacted with the mimic to form mixed-valence species, giving the desired oxidization products with inherent product selectivity of copper monooxygenases and recovering the catalyst directly. This enzymatic protocol exhibits excellent recyclability, good functional group tolerance, and broad substrate scope, including some biological and pharmacologically relevant targets. Mechanistic studies indicate that the C-H bond cleavage was the rate-determining step and the cuprous interactions were essential to stabilize the active oxygen species. The well-defined structural characters and the fine-modified catalytic properties open a new avenue to develop robust artificial enzymes with uniform and precise active sites and high catalytic performances.
Collapse
Affiliation(s)
- Huilin Huang
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian116024, China
| | - Xu Jing
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian116024, China
| | - Jiangtao Deng
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian116024, China
| | - Changgong Meng
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian116024, China
| | - Chunying Duan
- State Key Laboratory of Fine Chemicals, Zhang Dayu School of Chemistry, Dalian University of Technology, Dalian116024, China
| |
Collapse
|
27
|
Abstract
The emergence of modern photocatalysis, characterized by mildness and selectivity, has significantly spurred innovative late-stage C-H functionalization approaches that make use of low energy photons as a controllable energy source. Compared to traditional late-stage functionalization strategies, photocatalysis paves the way toward complementary and/or previously unattainable regio- and chemoselectivities. Merging the compelling benefits of photocatalysis with the late-stage functionalization workflow offers a potentially unmatched arsenal to tackle drug development campaigns and beyond. This Review highlights the photocatalytic late-stage C-H functionalization strategies of small-molecule drugs, agrochemicals, and natural products, classified according to the targeted C-H bond and the newly formed one. Emphasis is devoted to identifying, describing, and comparing the main mechanistic scenarios. The Review draws a critical comparison between established ionic chemistry and photocatalyzed radical-based manifolds. The Review aims to establish the current state-of-the-art and illustrate the key unsolved challenges to be addressed in the future. The authors aim to introduce the general readership to the main approaches toward photocatalytic late-stage C-H functionalization, and specialist practitioners to the critical evaluation of the current methodologies, potential for improvement, and future uncharted directions.
Collapse
Affiliation(s)
- Peter Bellotti
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149Münster, Germany
| | - Huan-Ming Huang
- School of Physical Science and Technology, ShanghaiTech University, 201210Shanghai, China
| | - Teresa Faber
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149Münster, Germany
| | - Frank Glorius
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149Münster, Germany
| |
Collapse
|
28
|
An Q, Xing YY, Pu R, Jia M, Chen Y, Hu A, Zhang SQ, Yu N, Du J, Zhang Y, Chen J, Liu W, Hong X, Zuo Z. Identification of Alkoxy Radicals as Hydrogen Atom Transfer Agents in Ce-Catalyzed C-H Functionalization. J Am Chem Soc 2023; 145:359-376. [PMID: 36538367 DOI: 10.1021/jacs.2c10126] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The intermediacy of alkoxy radicals in cerium-catalyzed C-H functionalization via H-atom abstraction has been unambiguously confirmed. Catalytically relevant Ce(IV)-alkoxide complexes have been synthesized and characterized by X-ray diffraction. Operando electron paramagnetic resonance and transient absorption spectroscopy experiments on isolated pentachloro Ce(IV) alkoxides identified alkoxy radicals as the sole heteroatom-centered radical species generated via ligand-to-metal charge transfer (LMCT) excitation. Alkoxy-radical-mediated hydrogen atom transfer (HAT) has been verified via kinetic analysis, density functional theory (DFT) calculations, and reactions under strictly chloride-free conditions. These experimental findings unambiguously establish the critical role of alkoxy radicals in Ce-LMCT catalysis and definitively preclude the involvement of chlorine radical. This study has also reinforced the necessity of a high relative ratio of alcohol vs Ce for the selective alkoxy-radical-mediated HAT, as seemingly trivial changes in the relative ratio of alcohol vs Ce can lead to drastically different mechanistic pathways. Importantly, the previously proposed chlorine radical-alcohol complex, postulated to explain alkoxy-radical-enabled selectivities in this system, has been examined under scrutiny and ruled out by regioselectivity studies, transient absorption experiments, and high-level calculations. Moreover, the peculiar selectivity of alkoxy radical generation in the LMCT homolysis of Ce(IV) heteroleptic complexes has been analyzed and back-electron transfer (BET) may have regulated the efficiency and selectivity for the formation of ligand-centered radicals.
Collapse
Affiliation(s)
- Qing An
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.,State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yang-Yang Xing
- Center of Chemistry for Frontier Technologies, Department of Chemistry, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310007, China.,Beijing National Laboratory for Molecular Sciences, Zhongguancun North First Street NO. 2, Beijing 100190, China.,Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang, China
| | - Ruihua Pu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Menghui Jia
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Yuegang Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Anhua Hu
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Shuo-Qing Zhang
- Center of Chemistry for Frontier Technologies, Department of Chemistry, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310007, China.,Beijing National Laboratory for Molecular Sciences, Zhongguancun North First Street NO. 2, Beijing 100190, China.,Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang, China
| | - Na Yu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jianbo Du
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.,State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yanxia Zhang
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jinquan Chen
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Weimin Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xin Hong
- Center of Chemistry for Frontier Technologies, Department of Chemistry, State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310007, China.,Beijing National Laboratory for Molecular Sciences, Zhongguancun North First Street NO. 2, Beijing 100190, China.,Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Westlake University, 18 Shilongshan Road, Hangzhou 310024, Zhejiang, China
| | - Zhiwei Zuo
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| |
Collapse
|
29
|
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
| |
Collapse
|
30
|
Site- and enantioselective cross-coupling of saturated N-heterocycles with carboxylic acids by cooperative Ni/photoredox catalysis. Nat Commun 2023; 14:125. [PMID: 36624097 PMCID: PMC9829739 DOI: 10.1038/s41467-023-35800-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 01/02/2023] [Indexed: 01/11/2023] Open
Abstract
Site- and enantioselective cross-coupling of saturated N-heterocycles and carboxylic acids-two of the most abundant and versatile functionalities-to form pharmaceutically relevant α-acylated amine derivatives remains a major challenge in organic synthesis. Here, we report a general strategy for the highly site- and enantioselective α-acylation of saturated N-heterocycles with in situ-activated carboxylic acids. This modular approach exploits the hydrogen-atom-transfer reactivity of photocatalytically generated chlorine radicals in combination with asymmetric nickel catalysis to selectively functionalize cyclic α-amino C-H bonds in the presence of benzylic, allylic, acyclic α-amino, and α-oxy methylene groups. The mild and scalable protocol requires no organometallic reagents, displays excellent chemo-, site- and enantioselectivity, and is amenable to late-stage diversification, including a modular synthesis of previously inaccessible Taxol derivatives. Mechanistic studies highlight the exceptional versatility of the chiral nickel catalyst in orchestrating (i) catalytic chlorine elimination, (ii) alkyl radical capture, (iii) cross-coupling, and (iv) asymmetric induction.
Collapse
|
31
|
Singer RA, Monfette S, Bernhardson D, Tcyrulnikov S, Hubbell AK, Hansen EC. Recent Advances in Nonprecious Metal Catalysis. Org Process Res Dev 2022. [DOI: 10.1021/acs.oprd.2c00310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Robert A. Singer
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Sebastien Monfette
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - David Bernhardson
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Sergei Tcyrulnikov
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Aran K. Hubbell
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Eric C. Hansen
- Pfizer Chemical Research and Development, Pfizer Inc., Groton, Connecticut 06340, United States
| |
Collapse
|
32
|
Xu P, Su W, Ritter T. Decarboxylative sulfoximination of benzoic acids enabled by photoinduced ligand-to-copper charge transfer. Chem Sci 2022; 13:13611-13616. [PMID: 36507153 PMCID: PMC9682917 DOI: 10.1039/d2sc05442f] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/01/2022] [Indexed: 11/16/2022] Open
Abstract
Sulfoximines are synthetically important scaffolds and serve important roles in drug discovery. Currently, there is no solution to decarboxylative sulfoximination of benzoic acids; although thoroughly investigated, limited substrate scope and harsh reaction conditions still hold back traditional thermal aromatic decarboxylative functionalization. Herein, we realize the first decarboxylative sulfoximination of benzoic acids via photo-induced ligand to copper charge transfer (copper-LMCT)-enabled decarboxylative carbometalation. The transformation proceeds under mild reaction conditions, has a broad substrate scope, and can be applied to late-stage functionalization of complex small molecules.
Collapse
Affiliation(s)
- Peng Xu
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm Platz 1D-45470 Mülheim an der RuhrGermany
| | - Wanqi Su
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm Platz 1D-45470 Mülheim an der RuhrGermany,Institute of Organic Chemistry, RWTH Aachen UniversityLandoltweg 152074 AachenGermany
| | - Tobias Ritter
- Max-Planck-Institut für KohlenforschungKaiser-Wilhelm Platz 1D-45470 Mülheim an der RuhrGermany
| |
Collapse
|
33
|
Gao Z, Mu J, Zhang J, Huang Z, Lin X, Luo N, Wang F. Hydrogen Bonding Promotes Alcohol C-C Coupling. J Am Chem Soc 2022; 144:18986-18994. [PMID: 36216790 DOI: 10.1021/jacs.2c07410] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photocatalytic C-C bond formation coupled with H2 production provides a sustainable approach to producing carbon-chain-prolonged chemicals and hydrogen energy. However, the involved radical intermediates with open-shell electronic structures are highly reactive, experiencing predominant oxidative or reductive side reactions in semiconductors. Herein, we demonstrate that hydrogen bonding on the catalyst surface and in the bulk solution can inhibit oxidation and reverse reaction of α-hydroxyethyl radicals (αHRs) in photocatalytic dehydrocoupling of ethanol over Au/CdS. Intentionally added water forms surface hydrogen bonds with adsorbed αHRs and strengthens the hydrogen bonding between αHRs and ethanol while maintaining the flexibility of radicals in solution, thereby allowing for αHRs' desorption from the Au/CdS surface and their stabilization by a solvent. The coupling rate of αHR increases by 2.4-fold, and the selectivity of the target product, 2,3-butanediol (BDO), increases from 37 to 57%. This work manifests that nonchemical bonding interactions can steer the reaction paths of radicals for selective photocatalysis.
Collapse
Affiliation(s)
- Zhuyan Gao
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian116023, China.,University of Chinese Academy of Sciences, Beijing100049, China
| | - Junju Mu
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian116023, China
| | - Jian Zhang
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian116023, China
| | - Zhipeng Huang
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian116023, China.,University of Chinese Academy of Sciences, Beijing100049, China
| | - Xiangsong Lin
- School of Materials and Textile Engineering, Jiaxing University, Jiaxing314001, China
| | - Nengchao Luo
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian116023, China
| | - Feng Wang
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian116023, China
| |
Collapse
|
34
|
Li P, Deetz AM, Hu J, Meyer GJ, Hu K. Chloride Oxidation by One- or Two-Photon Excitation of N-Phenylphenothiazine. J Am Chem Soc 2022; 144:17604-17610. [DOI: 10.1021/jacs.2c07107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pengju Li
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, P. R. China
| | - Alexander M. Deetz
- Department of Chemistry, University of North Carolina at Chapel Hill, Murray Hall 2202B, Chapel Hill, North Carolina 27599-3290, United States
| | - Jiaming Hu
- Department of Materials Science, Fudan University, Shanghai 200433, P. R. China
| | - Gerald J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Murray Hall 2202B, Chapel Hill, North Carolina 27599-3290, United States
| | - Ke Hu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 220 Handan Road, Shanghai 200433, P. R. China
| |
Collapse
|
35
|
Juliá F. Ligand‐to‐Metal Charge Transfer (LMCT) Photochemistry at 3d‐Metal Complexes: An Emerging Tool for Sustainable Organic Synthesis. ChemCatChem 2022. [DOI: 10.1002/cctc.202200916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Fabio Juliá
- Institute of Chemical Research of Catalonia: Institut Catala d'Investigacio Quimica Chemistry Av Paisos Catalans, 16 43007 Tarragona SPAIN
| |
Collapse
|
36
|
Niu B, Sachidanandan K, Cooke MV, Casey TE, Laulhé S. Photoinduced C(sp 3)-H Chalcogenation of Amide Derivatives and Ethers via Ligand-to-Metal Charge-Transfer. Org Lett 2022; 24:4524-4529. [PMID: 35729078 DOI: 10.1021/acs.orglett.2c01505] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A photoinduced, iron(III) chloride-catalyzed C-H activation of N-methyl amides and ethers leads to the formation of C-S and C-Se bonds via a ligand-to-metal charge transfer (LMCT) process. This methodology converts secondary and tertiary amides, sulfonamides, and carbamates into the corresponding amido-N,S-acetal derivatives in good yields. Mechanistic work revealed that this transformation proceeds through a hydrogen atom transfer (HAT) involving chlorine radical intermediates.
Collapse
Affiliation(s)
- Ben Niu
- Department of Chemistry & Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Krishnakumar Sachidanandan
- Department of Chemistry & Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Maria Victoria Cooke
- Department of Chemistry & Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Taylor E Casey
- Department of Chemistry & Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| | - Sébastien Laulhé
- Department of Chemistry & Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202, United States
| |
Collapse
|
37
|
Bonciolini S, Noël T, Capaldo L. Synthetic Applications of Photocatalyzed Halogen‐radical mediated Hydrogen Atom Transfer for C−H Bond Functionalization. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200417] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Stefano Bonciolini
- University of Amsterdam: Universiteit van Amsterdam Van 't Hoff Institute for Molecular Sciences NETHERLANDS
| | - Timothy Noël
- University of Amsterdam: Universiteit van Amsterdam Van 't Hoff Institute for Molecular Sciences NETHERLANDS
| | - Luca Capaldo
- University of Amsterdam: Universiteit van Amsterdam Van 't Hoff Institute for Molecular Sciences Science Park 904 1098 XH Amsterdam NETHERLANDS
| |
Collapse
|
38
|
Gérard EF, Yadav V, Goldberg DP, de Visser SP. What Drives Radical Halogenation versus Hydroxylation in Mononuclear Nonheme Iron Complexes? A Combined Experimental and Computational Study. J Am Chem Soc 2022; 144:10752-10767. [PMID: 35537044 PMCID: PMC9228086 DOI: 10.1021/jacs.2c01375] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
Nonheme iron halogenases
are unique enzymes in nature that selectively
activate an aliphatic C–H bond of a substrate to convert it
into C–X (X = Cl/Br, but not F/I). It is proposed that they
generate an FeIII(OH)(X) intermediate in their catalytic
cycle. The analogous FeIII(OH) intermediate in nonheme
iron hydroxylases transfers OH• to give alcohol
product, whereas the halogenases transfer X• to
the carbon radical substrate. There remains significant debate regarding
what factors control their remarkable selectivity of the halogenases.
The reactivity of the complexes FeIII(BNPAPh2O)(OH)(X) (X = Cl, Br) with a secondary carbon radical (R•) is described. It is found that X• transfer occurs
with a secondary carbon radical, as opposed to OH• transfer with tertiary radicals. Comprehensive computational studies
involving density functional theory were carried out to examine the
possible origins of this selectivity. The calculations reproduce the
experimental findings, which indicate that halogen transfer is not
observed for the tertiary radicals because of a nonproductive equilibrium
that results from the endergonic nature of these reactions, despite
a potentially lower reaction barrier for the halogenation pathway.
In contrast, halogen transfer is favored for secondary carbon radicals,
for which the halogenated product complex is thermodynamically more
stable than the reactant complex. These results are rationalized by
considering the relative strengths of the C–X bonds that are
formed for tertiary versus secondary carbon centers. The computational
analysis also shows that the reaction barrier for halogen transfer
is significantly dependent on secondary coordination sphere effects,
including steric and H-bonding interactions.
Collapse
Affiliation(s)
- Emilie F Gérard
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom.,Department of Chemical Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Vishal Yadav
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - David P Goldberg
- Department of Chemistry, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, United States
| | - Sam P de Visser
- Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom.,Department of Chemical Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| |
Collapse
|
39
|
Shu X, Zhong D, Lin Y, Qin X, Huo H. Modular Access to Chiral α-(Hetero)aryl Amines via Ni/Photoredox-Catalyzed Enantioselective Cross-Coupling. J Am Chem Soc 2022; 144:8797-8806. [PMID: 35503417 DOI: 10.1021/jacs.2c02795] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Chiral α-aryl N-heterocycles are commonly found in natural products, pharmaceutical agents, and chiral catalysts but remain challenging to access via asymmetric catalysis. Herein, we report a general and modular approach for the direct enantioselective α-arylation of saturated azacycles and acyclic N-alkyl benzamides via nickel/photoredox dual catalysis. This process exploits the hydrogen atom transfer ability of photoeliminated chlorine radicals to convert azacycles to the corresponding α-amino alkyl radicals that then are coupled with ubiquitous and inexpensive (hetero)aryl chlorides. These coupling reactions require no oxidants or organometallic reagents, feature feedstock starting materials, a broad substrate scope, and high enantioselectivities, and are applicable to late-stage diversification of medicinally relevant complex molecules. Mechanistic studies suggest that the nickel catalyst uncommonly plays multiple roles, accomplishing chlorine radical generation, α-amino radical capture, cross-coupling, and asymmetric induction.
Collapse
Affiliation(s)
- Xiaomin Shu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - De Zhong
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yanmei Lin
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiao Qin
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Haohua Huo
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| |
Collapse
|
40
|
Cagan DA, Bím D, Silva B, Kazmierczak NP, McNicholas BJ, Hadt RG. Elucidating the Mechanism of Excited-State Bond Homolysis in Nickel-Bipyridine Photoredox Catalysts. J Am Chem Soc 2022; 144:6516-6531. [PMID: 35353530 PMCID: PMC9979631 DOI: 10.1021/jacs.2c01356] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ni 2,2'-bipyridine (bpy) complexes are commonly employed photoredox catalysts of bond-forming reactions in organic chemistry. However, the mechanisms by which they operate are still under investigation. One potential mode of catalysis is via entry into Ni(I)/Ni(III) cycles, which can be made possible by light-induced, excited-state Ni(II)-C bond homolysis. Here, we report experimental and computational analyses of a library of Ni(II)-bpy aryl halide complexes, Ni(Rbpy)(R'Ph)Cl (R = MeO, t-Bu, H, MeOOC; R' = CH3, H, OMe, F, CF3), to illuminate the mechanism of excited-state bond homolysis. At given excitation wavelengths, photochemical homolysis rate constants span 2 orders of magnitude across these structures and correlate linearly with Hammett parameters of both bpy and aryl ligands, reflecting structural control over key metal-to-ligand charge-transfer (MLCT) and ligand-to-metal charge-transfer (LMCT) excited-state potential energy surfaces (PESs). Temperature- and wavelength-dependent investigations reveal moderate excited-state barriers (ΔH‡ ∼ 4 kcal mol-1) and a minimum energy excitation threshold (∼55 kcal mol-1, 525 nm), respectively. Correlations to electronic structure calculations further support a mechanism in which repulsive triplet excited-state PESs featuring a critical aryl-to-Ni LMCT lead to bond rupture. Structural control over excited-state PESs provides a rational approach to utilize photonic energy and leverage excited-state bond homolysis processes in synthetic chemistry.
Collapse
Affiliation(s)
- David A. Cagan
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Daniel Bím
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Breno Silva
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States,Department of Chemistry and Biochemistry, Suffolk University, Boston, Massachusetts 02108, United States
| | - Nathanael P. Kazmierczak
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Brendon J. McNicholas
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Ryan G. Hadt
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States,Corresponding Author:
| |
Collapse
|
41
|
Yamane M, Kanzaki Y, Mitsunuma H, Kanai M. Titanium(IV) Chloride-Catalyzed Photoalkylation via C(sp 3)-H Bond Activation of Alkanes. Org Lett 2022; 24:1486-1490. [PMID: 35166548 DOI: 10.1021/acs.orglett.2c00138] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Despite the sophistication of C-H functionalization as one of the most powerful tools in organic synthesis, methodology for performing hydrogen-atom transfer of unactivated alkanes remains rather scarce. Herein, we describe chlorine radical-catalyzed C(sp3)-H photoalkylation using titanium(IV) chloride via a ligand-to-metal charge transfer process. Enabled by the unique properties of this abundant metal salt, the reaction not only effected the coupling of various alkanes with radical acceptors but also was shown to be applicable to direct photoalkylation of aromatic ketones.
Collapse
Affiliation(s)
- Mina Yamane
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yamato Kanzaki
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Harunobu Mitsunuma
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Motomu Kanai
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| |
Collapse
|
42
|
Bell JD, Robb I, Murphy JA. Highly selective α-aryloxyalkyl C–H functionalisation of aryl alkyl ethers. Chem Sci 2022; 13:12921-12926. [DOI: 10.1039/d2sc04463c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 10/15/2022] [Indexed: 11/21/2022] Open
Abstract
We report highly selective photocatalytic functionalisations of alkyl groups in aryl alkyl ethers with a range of electron-poor alkenes using an acridinium catalyst with a phosphate base and irradiation with visible light (456 nm or 390 nm).
Collapse
Affiliation(s)
- Jonathan D. Bell
- Department of Pure and Applied Chemistry, 295 Cathedral Street, Glasgow G1 1XL, UK
| | - Iain Robb
- Department of Pure and Applied Chemistry, 295 Cathedral Street, Glasgow G1 1XL, UK
| | - John A. Murphy
- Department of Pure and Applied Chemistry, 295 Cathedral Street, Glasgow G1 1XL, UK
| |
Collapse
|
43
|
Zhang X, Zeng R. Neutrally Photoinduced MgCl2-Catalyzed Alkenylation and Imidoylation of Alkanes. Org Chem Front 2022. [DOI: 10.1039/d2qo01003h] [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
We report a practical protocol for oxidation of the chloride ion (Cl-) to chlorine radical (Cl.) via a photoinduced MgCl2 catalysis, avoiding the use of strong acid, formal oxidant, and...
Collapse
|