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Search for "mechanisms" in Full Text gives 673 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

  • Nian Li,
  • Ruzal Sitdikov,
  • Ajit Prabhakar Kale,
  • Joost Steverlynck,
  • Bo Li and
  • Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

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  • electrochemical transformations. Detailed reaction conditions, such as electrolyte, electrode material, and the use of constant current or constant voltage, are presented. Additionally, we discuss the mechanisms of some representative reactions and provide selected examples of LSF of relevant bioactive compounds
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Published 09 Oct 2024

Machine learning-guided strategies for reaction conditions design and optimization

  • Lung-Yi Chen and
  • Yi-Pei Li

Beilstein J. Org. Chem. 2024, 20, 2476–2492, doi:10.3762/bjoc.20.212

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  • extensive effort. This involves complex parameter optimization, meticulous validation against experimental data, and careful consideration of diverse reaction conditions and possible reaction mechanisms [28][29]. Although some studies employ transition-state (TS) theory to simulate activation energies and
  • reaction mechanisms. These models are particularly valuable in areas where experimental data are sparse or challenging to obtain, thereby extending the range of ML applications in chemistry. Educating the next generation of chemists, engineers, and data scientists in both ML and chemical synthesis is
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Published 04 Oct 2024

Asymmetric organocatalytic synthesis of chiral homoallylic amines

  • Nikolay S. Kondratyev and
  • Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

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  • , an observation that is in good agreement with previously obtained data on bisurea catalysts [36]. To further distinguish between the SN1 and SN2 mechanisms, the authors performed an in silico simulation of the non-catalysed reaction to determine the possible potential energy surface and found that
  • –Sakurai reaction of allyltrimethylsilane with N-Fmoc aldimines. The pyrrolidine unit gem-methyl group conformational control in the squaramide-based catalyst [34]. The energetic difference between the transition states of the two proposed modes of the reaction (SN1 and SN2 mechanisms). The concerted SN2
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Published 16 Sep 2024

Hydrogen-bond activation enables aziridination of unactivated olefins with simple iminoiodinanes

  • Phong Thai,
  • Lauv Patel,
  • Diyasha Manna and
  • David C. Powers

Beilstein J. Org. Chem. 2024, 20, 2305–2312, doi:10.3762/bjoc.20.197

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  • the combination of synthetically tunable iodine-centered electrophilicity and the diversity of substrate functionalization mechanisms that can be accessed [1][2]. Large families of iodine(III)- and iodine(V)-based reagents have been developed – including iodobenzene diacetate (PhI(OAc)2, PIDA
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Published 11 Sep 2024

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

  • Stefan P. Schmid,
  • Leon Schlosser,
  • Frank Glorius and
  • Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

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  • effect studies and isotopic substitution experiments revealed multiple different mechanisms of enantioinduction for the respective combinations. To rationalise relevant interactions, MLR models were trained on subsets of the data set. For each different mechanism of enantioinduction previously elucidated
  • organocatalysis, we expect a steady increase in studies aiming to bridge the gaps between different reactions that are mechanistically transferable via ML. Using this strategy, it is possible to both increase the available data (since more reactions are considered), as well as investigate more general mechanisms
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Published 10 Sep 2024

Computational toolbox for the analysis of protein–glycan interactions

  • Ferran Nieto-Fabregat,
  • Maria Pia Lenza,
  • Angela Marseglia,
  • Cristina Di Carluccio,
  • Antonio Molinaro,
  • Alba Silipo and
  • Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

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  • numerous biological processes, ranging from cellular recognition to immune response modulation. Understanding the intricate details of these interactions is crucial for deciphering the molecular mechanisms underlying various physiological and pathological conditions. Computational techniques have emerged
  • proteins versatility places them at the core of almost every biological event, including cell–cell communication and regulation of immune responses. In the majority of cases, these mechanisms are significantly influenced by the molecular interactions occurring between glycans and receptor proteins. A well
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Published 22 Aug 2024

Cage-like microstructures via sequential Ugi reactions in aqueous emulsions

  • Rita S. Alqubelat,
  • Yaroslava A. Menzorova and
  • Maxim A. Mironov

Beilstein J. Org. Chem. 2024, 20, 2078–2083, doi:10.3762/bjoc.20.179

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  • principle, two possible mechanisms were considered: (1) Soft CMC/chitosan gel particles interacted with the surface and flattened to form discs. (2) When particles were deposited on the surface, they did not completely cover it, forming a network. In this work, we tested these hypotheses and found arguments
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Published 22 Aug 2024

Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies

  • Beatrice E. Jones,
  • Camille Blayo,
  • Jake L. Greenfield,
  • Matthew J. Fuchter,
  • Nathan Cowieson and
  • Rachel C. Evans

Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176

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  • mechanisms of structural changes using in-situ light irradiation with rapid, time-resolved data collection. However, X-ray irradiation has been shown previously to induce Z-to-E isomerisation of Azo-PS, which can lead to inaccuracies in the measured photostationary state. Here, we investigate the effect of
  • brilliance of synchrotron X-ray sources enables the mechanisms of structural changes in PS to be studied, using in-situ light irradiation with time-resolved data collection. For example, Tribet and co-workers used this approach to explore the kinetics of micellisation and dissolution of cationic Azo-PS, both
  • irradiation with SAXS was used to determine the mechanisms for morphology changes in AzoTAB and AAPTAB systems on Z–E isomerisation. A concentration of 50 mM in water was chosen for these experiments, as this is well above the critical micelle concentration (CMC) for both surfactants (CMC in water for (E
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Published 14 Aug 2024

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

  • Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

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  • ].· Synthesis of 1,2,3-thiadiazoles [64]. Synthesis of 5-thioxo-1,2,4-triazolium inner salts [65]. Synthesis of 1-aminotetrazoles [66]. C(sp2)–H functionalization of aldehyde-derived hydrazones: general mechanisms. C(sp2)–H functionalization of benzaldehyde diphenyl hydrazone [68][69]. Phosphorylation of
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Published 14 Aug 2024

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

  • Pengcheng Lu,
  • Luis Juarez,
  • Paul A. Wiget,
  • Weihe Zhang,
  • Krishnan Raman and
  • Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

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  • -carboxylate (6) and the use of density functional theory (DFT) to evaluate their mechanisms. Over thirty N1- and N2-alkylated products were isolated in over 90% yield regardless of the conditions. DFT calculations suggest a chelation mechanism produces the N1-substituted products when cesium is present and
  • other non-covalent interactions (NCIs) drive the N2-product formation. Methyl 1H-indazole-7-carboxylate (18) and 1H-indazole-3-carbonitrile (21) were also subjected to the reaction conditions and their mechanisms were evaluated. The N1- and N2-partial charges and Fukui indices were calculated for
  • -3 as a bidentate ligand to the Na+ cation from NaH. The tight ion pair would direct alkylation under conditions A to N1. As this and other postulations exist, we explored the possible mechanisms of each reaction conditions computationally. All calculations were performed in implicit THF at the
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Published 09 Aug 2024

Electrochemical radical cation aza-Wacker cyclizations

  • Sota Adachi and
  • Yohei Okada

Beilstein J. Org. Chem. 2024, 20, 1900–1905, doi:10.3762/bjoc.20.165

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  • cations that offer unique reactivities as intermediates in various bond-formation processes. Such intermediates can potentially take part in both radical and ionic bond formation; however, the mechanisms involved are complicated and not fully understood. Herein, we report electrochemical radical cation
  • different, their creative use may pave the way for complementary bond formation. This merging is unique and such intermediates could potentially take part in both radical and ionic bond formation. However, the mechanisms involved can be complicated and are not fully understood. Alkenes and styrenes are
  • expected to proceed via radical cations, there are several interpretations of the mechanisms involved, since radical and ionic cyclizations are both possible. In this context, electrochemical and photochemical aza-Wacker cyclizations have provided interesting models for mechanistic discussion (Scheme 2
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Published 05 Aug 2024

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

  • Cristina Martini,
  • Muhammad Idham Darussalam Mardjan and
  • Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

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Published 01 Aug 2024

Discovery of antimicrobial peptides clostrisin and cellulosin from Clostridium: insights into their structures, co-localized biosynthetic gene clusters, and antibiotic activity

  • Moisés Alejandro Alejo Hernandez,
  • Katia Pamela Villavicencio Sánchez,
  • Rosendo Sánchez Morales,
  • Karla Georgina Hernández-Magro Gil,
  • David Silverio Moreno-Gutiérrez,
  • Eddie Guillermo Sanchez-Rueda,
  • Yanet Teresa-Cruz,
  • Brian Choi,
  • Armando Hernández Garcia,
  • Alba Romero-Rodríguez,
  • Oscar Juárez,
  • Siseth Martínez-Caballero,
  • Mario Figueroa and
  • Corina-Diana Ceapă

Beilstein J. Org. Chem. 2024, 20, 1800–1816, doi:10.3762/bjoc.20.159

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  • compounds. For example, the discovery of teixobactin [8] has paved the way for developing antibiotics with innovative mechanisms of action. Similarly, the discovery of halicin, a molecule identified through a machine learning-based approach, has shown promise as a broad-spectrum antimicrobial agent
  • peptides, coupled with their successful production in E. coli [30], has driven research to consider them a source for new antibiotics, as supported by the present study. Identifying the genetic and biochemical mechanisms underlying the production of compounds is of utmost importance in developing effective
  • Clostridia are the human and animal microbiota and soil for both anaerobic and aerotolerant organisms. We interpret a lack of effect on C. difficile, an intestinal clinical isolate, due to either the presence of resistance mechanisms or the fact that these peptides evolved to be active against soil
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Published 30 Jul 2024

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

  • Ryo Tanifuji and
  • Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

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  • intermolecular Diels–Alder reactions with 34 or other dienophiles, leading to a diverse array of bisorbicillinoids. Based on the crystal structure of TropB, a homologous enzyme of SorbC, Narayan and co-workers have intensively elucidated that the detailed mechanisms of the oxidative dearomatization catalyzed by
  • crystallographic structures of MaDA (6JQH) and MaDA-3 (7E2V) provided insights into the mechanisms of different stereoselectivities in the Diels–Alder reactions [56]. In 2014, the same group led by Lei also reported the total synthesis of kuwanon J (59) and related natural products. In their earlier fully chemical
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Published 23 Jul 2024

Oxidation of benzylic alcohols to carbonyls using N-heterocyclic stabilized λ3-iodanes

  • Thomas J. Kuczmera,
  • Pim Puylaert and
  • Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 1677–1683, doi:10.3762/bjoc.20.149

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  • reagents offer a viable alternative to traditional aryl-λ5-iodane-based oxidants, although further studies are necessary to fully understand their reaction mechanisms. Experimental General procedure for oxidation of benzylic alcohols 1a (700 µmol, 201 mg, 1.40 equiv), benzylic alcohol (3, 500 µmol, 1.00
  • ) in MeCN (2.5 mL), respectively, were stirred at 60 °C for 2.5 h and quenched with Me2S (1.40 mmol). Possible reaction mechanisms via the formation of a) a Cl(I) species and b) the formation of an alkoxyiodane IIb. Both are initialized by the activated iodane I-OH, which was observed as c) I-OMe
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Published 19 Jul 2024

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

  • Maria-Paula Schröder,
  • Isabel P.-M. Pfeiffer and
  • Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

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  • oxygen-independent coproporphyrinogen-III oxidase (CPO). B) Catalytic mechanisms of rSAM-mediated methylation are depicted exemplary for class B (TsrM) and class C (TbtI) RiPP MTs. The three-dimensional structures of the rSAM C-MTs TsrM with bound cobalamin and [4Fe-4S] cluster (PDB ID: 6WTE (https
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Published 18 Jul 2024

Divergent role of PIDA and PIFA in the AlX3 (X = Cl, Br) halogenation of 2-naphthol: a mechanistic study

  • Kevin A. Juárez-Ornelas,
  • Manuel Solís-Hernández,
  • Pedro Navarro-Santos,
  • J. Oscar C. Jiménez-Halla and
  • César R. Solorio-Alvarado

Beilstein J. Org. Chem. 2024, 20, 1580–1589, doi:10.3762/bjoc.20.141

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  • energy than our proposed species. The reaction mechanisms are described in detail in this work and were found to be in excellent agreement with the experimental yield. These initial results confirmed that our proposed mechanism was energetically favored and therefore more plausible compared to
  • reactions, we explored different pathways of the reaction mechanisms for the ortho-halogenation using 2-naphthol as a model substrate (Scheme 2). In such a way, we found a reaction pathway that was energetically favored. Based on our successful procedure for chlorination, we also developed an efficient
  • TS2 is energetically less favored (ΔG‡ = 16.2 kcal/mol, see Supporting Information File 1 for details of the explored chlorination and bromination mechanisms). Additionally, for this mechanism, we identified that the formation of TS4 has the highest energy barrier (ΔG‡ = 20.2 kcal/mol), becoming a
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Published 15 Jul 2024

Benzylic C(sp3)–H fluorination

  • Alexander P. Atkins,
  • Alice C. Dean and
  • Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

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  • publications by the Doyle and Musacchio groups in 2021 and 2022 demonstrated the effective use of photochemical oxidative radical-polar crossover mechanisms to achieve this. The Doyle group reported the use of an iridium-catalysed system in this context with Et3N·3HF as the fluoride source (Figure 32) [83
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Published 10 Jul 2024

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

  • Yu Fan,
  • Ahmed El Rhaz,
  • Stéphane Maisonneuve,
  • Emilie Gillon,
  • Maha Fatthalla,
  • Franck Le Bideau,
  • Guillaume Laurent,
  • Samir Messaoudi,
  • Anne Imberty and
  • Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

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  • the leading cause of morbidity and mortality in cystic fibrosis and immunocompromised patients and as one of the leading causes of nosocomial infections [1]. Due to the existence of numerous molecular mechanisms conferring resistance to multiple classes of antibiotics, therapeutic options are
  • -isomer is twice better than for its Z-counterpart for the S-linked compound 3 and three times better for the O-glycoside 1. Even though the other compounds do not exhibit significant variations of affinities between E- and Z-isomers, a closer look at the thermodynamic values indicates that the mechanisms
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Published 03 Jul 2024

Bioinformatic prediction of the stereoselectivity of modular polyketide synthase: an update of the sequence motifs in ketoreductase domain

  • Changjun Xiang,
  • Shunyu Yao,
  • Ruoyu Wang and
  • Lihan Zhang

Beilstein J. Org. Chem. 2024, 20, 1476–1485, doi:10.3762/bjoc.20.131

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  • stereochemical outcomes of KRs. These updated fingerprint motifs for stereochemical prediction not only enhance our understanding of the enzymatic mechanisms governing stereocontrol but also facilitate accurate stereochemical prediction and genome mining of polyketides derived from modular cis-AT PKSs. Keywords
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Published 02 Jul 2024

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

  • Mithu Roy,
  • Bitan Sardar,
  • Itu Mallick and
  • Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

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  • of novel synthetic strategies. It has expanded the scope of available synthetic methods and contributed to the synthesis of complex molecules with high efficiency and selectivity. Ongoing research in this field continues to explore new catalysts, photosensitizers, and reaction mechanisms to further
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Published 14 Jun 2024

Computation-guided scaffold exploration of 2E,6E-1,10-trans/cis-eunicellanes

  • Zining Li,
  • Sana Jindani,
  • Volga Kojasoy,
  • Teresa Ortega,
  • Erin M. Marshall,
  • Khalil A. Abboud,
  • Sandra Loesgen,
  • Dean J. Tantillo and
  • Jeffrey D. Rudolf

Beilstein J. Org. Chem. 2024, 20, 1320–1326, doi:10.3762/bjoc.20.115

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  • (1) [6]. In 1, the C2–C3 and C6–C7 alkenes are E-configured, with the latter alkene configuration being conserved in all known eunicellane cyclization mechanisms. The first trans-eunicellane synthase, AlbS from the biosynthesis of albireticulone in Streptomyces albireticuli [10], was also identified
  • chemically-induced cationic cyclization mechanisms, we performed quantum chemical calculations [mPW1PW91/6–31+G(d/p)/SMD(chloroform)] [13][14][15][16][17][18][19][20] to obtain the relative free energies of the cationic intermediates and transition states that interconvert them, as well as the relative free
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Published 07 Jun 2024

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

  • Jinmin Gao,
  • Liyuan Li,
  • Shijie Shen,
  • Guomin Ai,
  • Bin Wang,
  • Fang Guo,
  • Tongjian Yang,
  • Hui Han,
  • Zhengren Xu,
  • Guohui Pan and
  • Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

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  • monomeric structure of AlpJ shares similarities with the dimeric cofactor-independent anthrone oxygenases, such as ActVA-Orf6 [13], the structural intricacies governing the accommodation of these two distinct mechanisms warrant further investigation. The current findings indicate that both 8 and 1 can serve
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Published 23 May 2024

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

  • Mohd Farhan Ansari,
  • Atul Kumar Maurya,
  • Abhishek Kumar and
  • Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

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Published 21 May 2024

Light on the sustainable preparation of aryl-cored dibromides

  • Fabrizio Roncaglia,
  • Alberto Ughetti,
  • Nicola Porcelli,
  • Biagio Anderlini,
  • Andrea Severini and
  • Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

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  • ion in aqueous acidic media (Equation 1) [43]. Its practical implementation is surprisingly simple as standard aqueous HBr and H2O2 solutions are effective. The generated bromine can be involved in different chemical mechanisms, such as an Ar-SE (Equation 2) [44] or a radical substitution on activated
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Published 14 May 2024
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