1
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Geniller L, Ben Kraim H, Clot E, Taillefer M, Jaroschik F, Prieto A. Metal-Free Decarboxylative Allylation of Oxime Esters under Light Irradiation. Chemistry 2024; 30:e202401494. [PMID: 38785147 DOI: 10.1002/chem.202401494] [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: 04/17/2024] [Revised: 05/07/2024] [Accepted: 05/24/2024] [Indexed: 05/25/2024]
Abstract
Allylation reactions, often used as a key step for constructing complex molecules and drug candidates, typically rely on transition-metal (TM) catalysts. Even though TM-free radical allylations have been developed using allyl-stannanes, -sulfides, -silanes or -sulfones, much less procedures have been reported using simple and commercially available allyl halides, that are used for the preparation of the before-mentioned allyl derivatives. Here, we present a straightforward photocatalytic protocol for the decarboxylative allylation of oxime esters using allyl bromide derivatives under metal-free and mild conditions. This methodology yields a diverse variety of functionalized molecules including several pharmaceutically relevant molecules.
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Affiliation(s)
- Lilian Geniller
- ICGM, University of Montpellier, CNRS, ENSCM, 34000, Montpellier, France
| | - Hiba Ben Kraim
- ICGM, University of Montpellier, CNRS, ENSCM, 34000, Montpellier, France
| | - Eric Clot
- ICGM, University of Montpellier, CNRS, ENSCM, 34000, Montpellier, France
| | - Marc Taillefer
- ICGM, University of Montpellier, CNRS, ENSCM, 34000, Montpellier, France
| | - Florian Jaroschik
- ICGM, University of Montpellier, CNRS, ENSCM, 34000, Montpellier, France
| | - Alexis Prieto
- ICGM, University of Montpellier, CNRS, ENSCM, 34000, Montpellier, France
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2
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Manickavasagam G, He C, Lin KYA, Saaid M, Oh WD. Recent advances in catalyst design, performance, and challenges of metal-heteroatom-co-doped biochar as peroxymonosulfate activator for environmental remediation. ENVIRONMENTAL RESEARCH 2024; 252:118919. [PMID: 38631468 DOI: 10.1016/j.envres.2024.118919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 04/02/2024] [Accepted: 04/10/2024] [Indexed: 04/19/2024]
Abstract
The escalation of global water pollution due to emerging pollutants has gained significant attention. To address this issue, catalytic peroxymonosulfate (PMS) activation technology has emerged as a promising treatment approach for effectively decontaminating a wide range of pollutants. Recently, modified biochar has become an increasingly attractive as PMS activator. Metal-heteroatom-co-doped biochar (MH-BC) has emerged as a promising catalyst that can provide enhanced performance over heteroatom-doped and metal-doped biochar due to the synergism between metal and heteroatom in promoting PMS activation. Therefore, this review aims to discuss the fabrication pathways (i.e., internal vs external doping and pre-vs post-modification) and key parameters (i.e., source of precursors, synthesis methods, and synthesis conditions) affecting the performance of MH-BC as PMS activator. Subsequently, an overview of all the possible PMS activation pathways by MH-BC is provided. Subsequently, Also, the detection, identification, and quantification of several reactive species (such as, •OH, SO4•-, O2•-, 1O2, and high valent oxo species) generated in the catalytic PMS system by MH-BC are also evaluated. Lastly, the underlying challenges associated with poor stability, the lack of understanding regarding the interaction between metal and heteroatom during PMS activation and quantification of radicals in multi-ROS system are also deliberated.
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Affiliation(s)
| | - Chao He
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - Kun-Yi Andrew Lin
- Department of Environmental Engineering & Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, 250, Kuo-Kuang Road, Taichung, Taiwan; Institute of Analytical and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Mardiana Saaid
- School of Chemical Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Wen-Da Oh
- School of Chemical Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia.
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3
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Grunshaw T, Wood SH, Sproules S, Parrott A, Nordon A, Shapland PDP, Wheelhouse KMP, Tomkinson NCO. A Mechanistic Investigation of the N-Hydroxyphthalimide Catalyzed Benzylic Oxidation Mediated by Sodium Chlorite. J Org Chem 2024; 89:7933-7945. [PMID: 38748510 PMCID: PMC11165572 DOI: 10.1021/acs.joc.4c00583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 05/02/2024] [Accepted: 05/06/2024] [Indexed: 06/13/2024]
Abstract
A detailed investigation into the mechanistic course of N-hydroxyphthalimide catalyzed oxidation of benzylic centers using sodium chlorite as the stoichiometric oxidant is reported. Through a combination of experimental, spectroscopic, and computational techniques, the transformation is interrogated, providing improved reaction conditions and an enhanced understanding of the mechanism. Performing the transformation in the presence of acetic acid or a pH 4.5 buffer leads to extended reaction times but improves the catalyst lifetime, leading to the complete consumption of the starting material. Chlorine dioxide is identified as the active oxidant that is able to oxidize the N-hydroxyphthalimide anion to the phthalimide-N-oxyl radical, the proposed catalytically active species, which is able to abstract a hydrogen atom from the substrate. A second molecule of chlorine dioxide reacts with the resultant radical and, after loss of hypochlorous acid, leads to the observed product. Through a broad variety of techniques including UV/vis, EPR and Raman spectroscopy, isotopic labeling, and the use of radical traps, evidence for the mechanism is presented that is supported through electronic structural calculations.
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Affiliation(s)
- Thomas Grunshaw
- Department
Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, Glasgow G1 1XL, U.K.
- GlaxoSmithKline
R&D, Gunnels Wood
Road, Stevenage SG1 2NY, U.K.
| | - Susanna H. Wood
- Department
Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, Glasgow G1 1XL, U.K.
| | - Stephen Sproules
- School
of Chemistry, University of Glasgow, Glasgow G12 8QQ, U.K.
| | - Andrew Parrott
- Department
Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, Glasgow G1 1XL, U.K.
| | - Alison Nordon
- Department
Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, Glasgow G1 1XL, U.K.
| | | | | | - Nicholas C. O. Tomkinson
- Department
Pure and Applied Chemistry, Thomas Graham Building, University of Strathclyde, Glasgow G1 1XL, U.K.
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4
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Pei BB, Wang J, Ji J, Chen Q, Wang CQ, Feng C. Radical Decarboxylation-Initiated S H2' Reaction of β,β-Difluoroenol Sulfonates: Access to α,α-Difluoroketones. Org Lett 2024. [PMID: 38796776 DOI: 10.1021/acs.orglett.4c01555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2024]
Abstract
Reported herein is a novel radical decarboxylation-initiated SH2' reaction of β,β-difluoroenol sulfonates. This transformation is characterized by mild reaction conditions, a broad substrate scope, and late-stage modification of drug molecules, providing general and mechanistically distinct access to bioactive and synthetically versatile α,α-difluoroketones. Preliminary mechanistic studies demonstrate that this reaction proceeds through a succession of silver-mediated decarboxylative radical generation and radical-addition-induced β-elimination of the sulfonyl radical.
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Affiliation(s)
- Bing-Bing Pei
- Technical Institute of Fluorochemistry (TIF), Institute of Advanced Synthesis (IAS), School of Chemistry and Molecular Engineering, State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, 30 South Puzhu Road, Nanjing, Jiangsu 211816, China
| | - Jiali Wang
- Technical Institute of Fluorochemistry (TIF), Institute of Advanced Synthesis (IAS), School of Chemistry and Molecular Engineering, State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, 30 South Puzhu Road, Nanjing, Jiangsu 211816, China
| | - Jiuyang Ji
- Capital Construction Office, Nanjing Tech University, 30 South Puzhu Road, Nanjing, Jiangsu 211816, China
| | - Qing Chen
- Technical Institute of Fluorochemistry (TIF), Institute of Advanced Synthesis (IAS), School of Chemistry and Molecular Engineering, State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, 30 South Puzhu Road, Nanjing, Jiangsu 211816, China
| | - Cheng-Qiang Wang
- Technical Institute of Fluorochemistry (TIF), Institute of Advanced Synthesis (IAS), School of Chemistry and Molecular Engineering, State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, 30 South Puzhu Road, Nanjing, Jiangsu 211816, China
| | - Chao Feng
- Technical Institute of Fluorochemistry (TIF), Institute of Advanced Synthesis (IAS), School of Chemistry and Molecular Engineering, State Key Laboratory of Material-Oriented Chemical Engineering, Nanjing Tech University, 30 South Puzhu Road, Nanjing, Jiangsu 211816, China
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5
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Mydy LS, Hungerford J, Chigumba DN, Konwerski JR, Jantzi SC, Wang D, Smith JL, Kersten RD. An intramolecular macrocyclase in plant ribosomal peptide biosynthesis. Nat Chem Biol 2024; 20:530-540. [PMID: 38355722 PMCID: PMC11049724 DOI: 10.1038/s41589-024-01552-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/12/2024] [Indexed: 02/16/2024]
Abstract
The biosynthetic dogma of ribosomally synthesized and posttranslationally modified peptides (RiPP) involves enzymatic intermolecular modification of core peptide motifs in precursor peptides. The plant-specific BURP-domain protein family, named after their four founding members, includes autocatalytic peptide cyclases involved in the biosynthesis of side-chain-macrocyclic plant RiPPs. Here we show that AhyBURP, a representative of the founding Unknown Seed Protein-type BURP-domain subfamily, catalyzes intramolecular macrocyclizations of its core peptide during the sequential biosynthesis of monocyclic lyciumin I via glycine-tryptophan crosslinking and bicyclic legumenin via glutamine-tyrosine crosslinking. X-ray crystallography of AhyBURP reveals the BURP-domain fold with two type II copper centers derived from a conserved stapled-disulfide and His motif. We show the macrocyclization of lyciumin-C(sp3)-N-bond formation followed by legumenin-C(sp3)-O-bond formation requires dioxygen and radical involvement based on enzyme assays in anoxic conditions and isotopic labeling. Our study expands enzymatic intramolecular modifications beyond catalytic moiety and chromophore biogenesis to RiPP biosynthesis.
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Affiliation(s)
- Lisa S Mydy
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA.
| | - Jordan Hungerford
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Desnor N Chigumba
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
| | | | - Sarah C Jantzi
- Plasma Chemistry Laboratory, Center for Applied Isotope Studies, University of Georgia, Athens, GA, USA
| | - Di Wang
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Janet L Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Roland D Kersten
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA.
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6
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Xie Z, Cao B, Zhao J, Liu M, Lao Y, Luo H, Zhong Z, Xiong X, Wei W, Zou T. Ion Pairing Enables Targeted Prodrug Activation via Red Light Photocatalysis: A Proof-of-Concept Study with Anticancer Gold Complexes. J Am Chem Soc 2024; 146:8547-8556. [PMID: 38498689 DOI: 10.1021/jacs.4c00408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Photocatalysis has found increasing applications in biological systems, for example, in localized prodrug activation; however, high-energy light is usually required without giving sufficient efficiency and target selectivity. In this work, we report that ion pairing between photocatalysts and prodrugs can significantly improve the photoactivation efficiency and enable tumor-targeted activation by red light. This is exemplified by a gold-based prodrug (1d) functionalized with a morpholine moiety. Such a modification causes 1d to hydrolyze in aqueous solution, forming a cationic species that tightly interacts with anionic photosensitizers including Eosin Y (EY) and Rose Bengal (RB), along with a significant bathochromic shift of absorption tailing to the far-red region. As a result, a high photoactivation efficiency of 1d by EY or RB under low-energy light was found, leading to an effective release of active gold species in living cells, as monitored by a gold-specific biosensor (GolS-mCherry). Importantly, the morpholine moiety, with pKa ∼6.9, in 1d brings in a highly pH-sensitive and preferential ionic interaction under a slightly acidic condition over the normal physiological pH, enabling tumor-targeted prodrug activation by red light irradiation in vitro and in vivo. Since a similar absorption change was found in other morpholine/amine-containing clinic drugs, photocages, and precursors of reactive labeling intermediates, it is believed that the ion-pairing strategy could be extended for targeted activation of different prodrugs and for mapping of an acidic microenvironment by low-energy light.
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Affiliation(s)
- Zhiying Xie
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, State Key Laboratory of Anti-Infective Drug Discovery and Development, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Bei Cao
- Warshel Institute for Computational Biology, and General Education Division, The Chinese University of Hong Kong, Shenzhen 518172, China
- School of Education Sciences, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou 511453, China
| | - Jing Zhao
- State Key Laboratory of Coordination Chemistry, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Moyi Liu
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, State Key Laboratory of Anti-Infective Drug Discovery and Development, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Yuhan Lao
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, State Key Laboratory of Anti-Infective Drug Discovery and Development, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Hejiang Luo
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, State Key Laboratory of Anti-Infective Drug Discovery and Development, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Zhi Zhong
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, State Key Laboratory of Anti-Infective Drug Discovery and Development, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Xiaolin Xiong
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, State Key Laboratory of Anti-Infective Drug Discovery and Development, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
| | - Wei Wei
- State Key Laboratory of Coordination Chemistry, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Taotao Zou
- Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, State Key Laboratory of Anti-Infective Drug Discovery and Development, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China
- Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications, Jinan University, Guangzhou 510632, China
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7
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Liu HZ, Shu XX, Huang M, Wu BB, Chen JJ, Wang XS, Li HL, Yu HQ. Tailoring d-band center of high-valent metal-oxo species for pollutant removal via complete polymerization. Nat Commun 2024; 15:2327. [PMID: 38485966 PMCID: PMC10940690 DOI: 10.1038/s41467-024-46739-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 03/07/2024] [Indexed: 03/18/2024] Open
Abstract
Polymerization-driven removal of pollutants in advanced oxidation processes (AOPs) offers a sustainable way for the simultaneous achievement of contamination abatement and resource recovery, supporting a low-carbon water purification approach. However, regulating such a process remains a great challenge due to the insufficient microscopic understanding of electronic structure-dependent reaction mechanisms. Herein, this work probes the origin of catalytic pollutant polymerization using a series of transition metal (Cu, Ni, Co, and Fe) single-atom catalysts and identifies the d-band center of active site as the key driver for polymerization transfer of pollutants. The high-valent metal-oxo species, produced via peroxymonosulfate activation, are found to trigger the pollutant removal via polymerization transfer. Phenoxyl radicals, identified by the innovative spin-trapping and quenching approaches, act as the key intermediate in the polymerization reactions. More importantly, the oxidation capacity of high-valent metal-oxo species can be facilely tuned by regulating their binding strength for peroxymonosulfate through d-band center modulation. A 100% polymerization transfer ratio is achieved by lowering the d-band center. This work presents a paradigm to dynamically modulate the electronic structure of high-valent metal-oxo species and optimize pollutant removal from wastewater via polymerization.
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Affiliation(s)
- Hong-Zhi Liu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China
| | - Xiao-Xuan Shu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China
| | - Mingjie Huang
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China.
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, China.
| | - Bing-Bing Wu
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Jie-Jie Chen
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China.
| | - Xi-Sheng Wang
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Hui-Lin Li
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, China.
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8
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Zhao Z, Laps S, Gichtin JS, Metanis N. Selenium chemistry for spatio-selective peptide and protein functionalization. Nat Rev Chem 2024; 8:211-229. [PMID: 38388838 DOI: 10.1038/s41570-024-00579-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2024] [Indexed: 02/24/2024]
Abstract
The ability to construct a peptide or protein in a spatio-specific manner is of great interest for therapeutic and biochemical research. However, the various functional groups present in peptide sequences and the need to perform chemistry under mild and aqueous conditions make selective protein functionalization one of the greatest synthetic challenges. The fascinating paradox of selenium (Se) - being found in both toxic compounds and also harnessed by nature for essential biochemical processes - has inspired the recent exploration of selenium chemistry for site-selective functionalization of peptides and proteins. In this Review, we discuss such approaches, including metal-free and metal-catalysed transformations, as well as traceless chemical modifications. We report their advantages, limitations and applications, as well as future research avenues.
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Affiliation(s)
- Zhenguang Zhao
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
| | - Shay Laps
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Jacob S Gichtin
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Norman Metanis
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
- Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, Israel.
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9
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Teye-Kau JHG, Ayodele MJ, Pitre SP. Vitamin B 12 -Photocatalyzed Cyclopropanation of Electron-Deficient Alkenes Using Dichloromethane as the Methylene Source. Angew Chem Int Ed Engl 2024; 63:e202316064. [PMID: 38015966 DOI: 10.1002/anie.202316064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 11/30/2023]
Abstract
The cyclopropyl group is of great importance in medicinal chemistry, as it can be leveraged to influence a range of pharmaceutical properties in drug molecules. This report describes a Vitamin B12 -photocatalyzed approach for the cyclopropanation of electron-deficient alkenes using dichloromethane (CH2 Cl2 ) as the methylene source. The reaction proceeds in good to excellent yields under mild conditions, has excellent functional group compatibility, and is highly chemoselective. The scope could also be extended to the preparation of D2 -cyclopropyl and methyl-substituted cyclopropyl adducts starting from CD2 Cl2 and 1,1-dichloroethane, respectively.
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Affiliation(s)
- John Hayford G Teye-Kau
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences, Stillwater, OK 74078, USA
| | - Mayokun J Ayodele
- Weaver Labs LLC, 1110 S. Innovation Way Dr., #130, Stillwater, OK 74074, USA
| | - Spencer P Pitre
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences, Stillwater, OK 74078, USA
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10
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Gu X, Wang T, Yan K. Solvent-Free Mechanoradical-Mediated Minisci-Type C-H Alkylation of N-Heteroarenes. Org Lett 2023; 25:7287-7292. [PMID: 37787464 DOI: 10.1021/acs.orglett.3c02480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
An environmentally friendly new C-H alkylation method of N-heteroarenes facilitated by mechanochemistry is described. Under solvent-free ball-milling, mechanoradicals (SO4•-) were generated from persulfate via in situ homolysis in the solid state, at as low as -50 °C. These highly oxidizing radicals readily transform alkyl trifluoroborate salts to their corresponding carbon-based radicals for subsequent C-C bond formation with N-heterocycles. Mechanistic studies unambiguously confirmed the involvement of both oxygen- and alkyl-radical-based intermediates.
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Affiliation(s)
- Xiang Gu
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - Taoyong Wang
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
| | - KaKing Yan
- School of Physical Science and Technology, ShanghaiTech University, 201210 Shanghai, China
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11
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Wan Q, Chen K, Dong X, Ruan X, Yi H, Chen S. Elucidating the Underlying Reactivities of Alternating Current Electrosynthesis by Time-Resolved Mapping of Short-Lived Reactive Intermediates. Angew Chem Int Ed Engl 2023; 62:e202306460. [PMID: 37593930 DOI: 10.1002/anie.202306460] [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: 05/08/2023] [Revised: 08/14/2023] [Accepted: 08/17/2023] [Indexed: 08/19/2023]
Abstract
Alternating current (AC) electrolysis is an emerging field in synthetic chemistry, however its mechanistic studies are challenged by the effective characterization of the elusive intermediate processes. Herein, we develop an operando electrochemical mass spectrometry platform that allows time-resolved mapping of stepwise electrosynthetic reactive intermediates in both direct current and alternating current modes. By dissecting the key intermediate processes of electrochemical functionalization of arylamines, the unique reactivities of AC electrosynthesis, including minimizing the over-oxidation/reduction through the inverse process, and enabling effective reaction of short-lived intermediates generated by oxidation and reduction in paired electrolysis, were evidenced and verified. Notably, the controlled kinetics of reactive N-centered radical intermediates in multistep sequential AC electrosynthesis to minimize the competing reactions was discovered. Overall, this work provides direct evidence for the mechanism of AC electrolysis, and clarifies the underlying reasons for its high efficiency, which will benefit the rational design of AC electrosynthetic reactions.
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Affiliation(s)
- Qiongqiong Wan
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
| | - Kaixiang Chen
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
| | - Xin Dong
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
| | - Xianqin Ruan
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
| | - Hong Yi
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
| | - Suming Chen
- The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, P. R. China
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12
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Abstract
Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R1R2N-O•. The spin distribution over the nitroxide N and O atoms contributes to the thermodynamic stability of these radicals. The presence of bulky N-substituents R1 and R2 prevents nitroxide radical dimerization, ensuring their kinetic stability. Despite their reactivity toward various transient C radicals, some nitroxides can be easily stored under air at room temperature. Furthermore, nitroxides can be oxidized to oxoammonium salts (R1R2N═O+) or reduced to anions (R1R2N-O-), enabling them to act as valuable oxidants or reductants depending on their oxidation state. Therefore, they exhibit interesting reactivity across all three oxidation states. Due to these fascinating properties, nitroxides find extensive applications in diverse fields such as biochemistry, medicinal chemistry, materials science, and organic synthesis. This review focuses on the versatile applications of nitroxides in organic synthesis. For their use in other important fields, we will refer to several review articles. The introductory part provides a brief overview of the history of nitroxide chemistry. Subsequently, the key methods for preparing nitroxides are discussed, followed by an examination of their structural diversity and physical properties. The main portion of this review is dedicated to oxidation reactions, wherein parent nitroxides or their corresponding oxoammonium salts serve as active species. It will be demonstrated that various functional groups (such as alcohols, amines, enolates, and alkanes among others) can be efficiently oxidized. These oxidations can be carried out using nitroxides as catalysts in combination with various stoichiometric terminal oxidants. By reducing nitroxides to their corresponding anions, they become effective reducing reagents with intriguing applications in organic synthesis. Nitroxides possess the ability to selectively react with transient radicals, making them useful for terminating radical cascade reactions by forming alkoxyamines. Depending on their structure, alkoxyamines exhibit weak C-O bonds, allowing for the thermal generation of C radicals through reversible C-O bond cleavage. Such thermally generated C radicals can participate in various radical transformations, as discussed toward the end of this review. Furthermore, the application of this strategy in natural product synthesis will be presented.
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Affiliation(s)
- Dirk Leifert
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, 48149 Münster, Germany
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13
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Sun B, Li W, Liu Q, Zhang G, Mo F. Transition metal-free visible light photoredox-catalyzed remote C(sp 3)-H borylation enabled by 1,5-hydrogen atom transfer. Commun Chem 2023; 6:156. [PMID: 37488210 PMCID: PMC10366130 DOI: 10.1038/s42004-023-00960-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 07/17/2023] [Indexed: 07/26/2023] Open
Abstract
The borylation of unreactive carbon-hydrogen bonds is a valuable method for transforming feedstock chemicals into versatile building blocks. Here, we describe a transition metal-free method for the photoredox-catalyzed borylation of unactivated C(sp3)-H bond, initiated by 1,5-hydrogen atom transfer (HAT). The remote borylation was directed by 1,5-HAT of the amidyl radical, which was generated by photocatalytic reduction of hydroxamic acid derivatives. The method accommodates substrates with primary, secondary and tertiary C(sp3)-H bonds, yielding moderate to good product yields (up to 92%) with tolerance for various functional groups. Mechanistic studies, including radical clock experiments and DFT calculations, provided detailed insight into the 1,5-HAT borylation process.
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Affiliation(s)
- Beiqi Sun
- School of Materials Science and Engineering, Peking University, Yiheyuan Road, Beijing, 100871, China
- College of Engineering, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Wenke Li
- College of Engineering, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Qianyi Liu
- College of Engineering, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Gaoge Zhang
- College of Engineering, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Fanyang Mo
- School of Materials Science and Engineering, Peking University, Yiheyuan Road, Beijing, 100871, China.
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14
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Lu Y, Zhang J, Duan X, Yang B, Zhao C, Gu L, Chen C, Zhu H, Ye Y, Luo Z, Zhang Y. K 2S 2O 8-Mediated Radical Cyclization of 1,6-Enyne for the Synthesis of Diiodonated γ-Lactams. J Org Chem 2023; 88:2393-2403. [PMID: 36715636 DOI: 10.1021/acs.joc.2c02818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A novel and convenient K2S2O8-mediated diiodo cyclization of 1,6-enynes for the facile synthesis of functionalized γ-lactam derivatives has been developed. This reaction features mild and transition-metal-free conditions, which offer a green and efficient entry to synthetically important γ-lactam scaffolds. Mechanistic studies suggest that iodide radicals initiate the cascade cyclic transformation.
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Affiliation(s)
- Yuling Lu
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. of China
| | - Jiale Zhang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. of China
| | - Xianxian Duan
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. of China
| | - Boyi Yang
- Department of Forensic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chunhua Zhao
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. of China
| | - Lianghu Gu
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. of China
| | - Chunmei Chen
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. of China
| | - Hucheng Zhu
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. of China
| | - Ying Ye
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. of China
| | - Zengwei Luo
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. of China
| | - Yonghui Zhang
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation. School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, P. R. of China
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15
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Wen M, Spotte-Smith EWC, Blau SM, McDermott MJ, Krishnapriyan AS, Persson KA. Chemical reaction networks and opportunities for machine learning. NATURE COMPUTATIONAL SCIENCE 2023; 3:12-24. [PMID: 38177958 DOI: 10.1038/s43588-022-00369-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/08/2022] [Indexed: 01/06/2024]
Abstract
Chemical reaction networks (CRNs), defined by sets of species and possible reactions between them, are widely used to interrogate chemical systems. To capture increasingly complex phenomena, CRNs can be leveraged alongside data-driven methods and machine learning (ML). In this Perspective, we assess the diverse strategies available for CRN construction and analysis in pursuit of a wide range of scientific goals, discuss ML techniques currently being applied to CRNs and outline future CRN-ML approaches, presenting scientific and technical challenges to overcome.
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Affiliation(s)
- Mingjian Wen
- Chemical and Biomolecular Engineering, University of Houston, Houston, TX, USA
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Evan Walter Clark Spotte-Smith
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - Samuel M Blau
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Matthew J McDermott
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA
| | - Aditi S Krishnapriyan
- Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA
- Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA, USA
| | - Kristin A Persson
- Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA.
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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