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Search for "manganese" in Full Text gives 91 result(s) in Beilstein Journal of Organic Chemistry.

Menadione: a platform and a target to valuable compounds synthesis

  • Acácio S. de Souza,
  • Ruan Carlos B. Ribeiro,
  • Dora C. S. Costa,
  • Fernanda P. Pauli,
  • David R. Pinho,
  • Matheus G. de Moraes,
  • Fernando de C. da Silva,
  • Luana da S. M. Forezi and
  • Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

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  • manganese(II) naphthenate (MnPc)-catalyzed oxidation of 16 to furnish 10 in 60% yield with 75.6% conversion and 80% selectivity (Table 1, entry 8) [54]. The MnPc catalyst improves the stability of H2O2 and thus promotes a selective oxidation [54]. The approach developed by Beller’s group, which applied a
  • oxidizing agent in the presence of a mixture of chromium(III) and manganese(II) salts to furnish product 10 in 70% yield (Table 1, entry 16) [62]. The authors proposed that the oxidation involves an initial ozonation of the transition metal salts, which then oxidized substrate 16 to the desired product 10
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Published 11 Apr 2022

Site-selective reactions mediated by molecular containers

  • Rui Wang and
  • Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

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  • substrate 26 was first modified at the hydroxy groups through esterification with a designed acid moiety possessing a p-tert-butylphenyl group and transformed to the corresponding model substrate 27. The catalyst H used here was a manganese(III)-bounded porphyrin module carrying four β-cyclodextrin units at
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Published 14 Mar 2022

Earth-abundant 3d transition metals on the rise in catalysis

  • Nikolaos Kaplaneris and
  • Lutz Ackermann

Beilstein J. Org. Chem. 2022, 18, 86–88, doi:10.3762/bjoc.18.8

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  • laboratories calls for a critical analysis of these methods to enable an efficient transition of these methods. Hence, manganese-catalyzed C–H functionalization for late-stage functionalizations of biomolecules and drug-like scaffolds are summarized [8]. Likewise, 3d transition metal-catalyzed C–H
  • allow for indirected C–H transformations and herein, homolytic C–H cleavages are described for transformative manganese-catalyzed brominations of tertiary C–H bonds [14]. Finally, electrooxidation enabled the site-selective alkynylation of tetrahydroisoquinolines within a TEMPO/copper regime [15]. As
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Editorial
Published 07 Jan 2022

Recent advances and perspectives in ruthenium-catalyzed cyanation reactions

  • Thaipparambil Aneeja,
  • Cheriya Mukkolakkal Abdulla Afsina,
  • Padinjare Veetil Saranya and
  • Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 37–52, doi:10.3762/bjoc.18.4

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  • single-step. The proposed mechanism is depicted in Scheme 26. Xiao and co-workers developed an environmentally benign strategy for the oxidative cyanation of differently substituted alcohols using a manganese oxide nanorod-supported ruthenium catalyst (Scheme 27) [49]. They also evaluated the efficiency
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Published 04 Jan 2022

Iron-catalyzed domino coupling reactions of π-systems

  • Austin Pounder and
  • William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

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Published 07 Dec 2021

Facile and innovative catalytic protocol for intramolecular Friedel–Crafts cyclization of Morita–Baylis–Hillman adducts: Synergistic combination of chiral (salen)chromium(III)/BF3·OEt2 catalysis

  • Karthikeyan Soundararajan,
  • Helen Ratna Monica Jeyarajan,
  • Raju Subimol Kamarajapurathu and
  • Karthik Krishna Kumar Ayyanoth

Beilstein J. Org. Chem. 2021, 17, 2186–2193, doi:10.3762/bjoc.17.140

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  • convinced us to explore them as suitable chiral Lewis acid catalysts for the Friedel–Crafts cyclization of MBH adducts. Mononuclear(salen) complexes of aluminium, chromium, manganese and cobalt were chosen and screened for the current investigation. Results and Discussion To evaluate the scope of the
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Published 26 Aug 2021

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

  • Renato L. Carvalho,
  • Amanda S. de Miranda,
  • Mateus P. Nunes,
  • Roberto S. Gomes,
  • Guilherme A. M. Jardim and
  • Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

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  • could help expanding the currently available methods in organic synthesis. Manganese-catalyzed C–H activation Manganese is the twelfth most abundant element in the Earth’s crust and the third most abundant transition metal after iron and titanium [126]. The valence electron configuration of elemental
  • manganese is 3d54s2 with a high redox potential due to the high number of available oxidation states (−3 to +7), allowing the formation of compounds with a coordination number of up to 7 [127]. These properties associated with a low toxicity and low cost make manganese a metal with great potential in
  • organometallic chemistry and catalysis [128]. The first example of a stoichiometric manganese-mediated C–H activation, reported by Stone, Bruce, and co-workers (1970) [129], was an ortho-metalation in azobenzenes. In recent years, with the expansion of the C–H activation field, manganese catalysts have been
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Published 30 Jul 2021

Sustainable manganese catalysis for late-stage C–H functionalization of bioactive structural motifs

  • Jongwoo Son

Beilstein J. Org. Chem. 2021, 17, 1733–1751, doi:10.3762/bjoc.17.122

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  • organic synthesis. Among the 3d metals, manganese catalysts have gained increasing attention for late-stage diversification due to the sustainability, cost-effectiveness, ease of operation, and reduced toxicity. Herein, we summarize recent manganese-catalyzed late-stage C–H functionalization reactions of
  • biologically active small molecules and complex peptides. Keywords: bioactive molecules; 3d transition metals; late-stage functionalization; manganese catalyst; sustainable catalysis; Introduction Manganese, a 3d transition metal, allows for a potentially ideal sustainable catalytic system because of the
  • natural abundance, cost-effectiveness, and low toxicity. In addition, it presents variable oxidation states (−3 to +7), which enable diverse catalytically active manganese complexes, providing characteristic reaction profiles. Since the first pioneering manganese-mediated reaction for accessing
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Published 26 Jul 2021

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

  • Guido Gambacorta,
  • James S. Sharley and
  • Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

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Published 18 May 2021

Manganese/bipyridine-catalyzed non-directed C(sp3)–H bromination using NBS and TMSN3

  • Kumar Sneh,
  • Takeru Torigoe and
  • Yoichiro Kuninobu

Beilstein J. Org. Chem. 2021, 17, 885–890, doi:10.3762/bjoc.17.74

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  • gram scale. The introduced bromine atom can be converted into fluorine and allyl groups. Keywords: bromination; C–H transformation; hydrogen abstraction; manganese; radical; Introduction Organic halides are versatile precursors for various synthetic protocols and are frequently used to introduce a
  • -position of an oxazoline or amide is selectively activated using a copper or palladium catalyst. Manganese is one of the most abundant and nontoxic transition metals found in the earth’s crust and its corresponding complexes and salts are useful in synthetic organic reactions [29][30][31][32][33][34][35
  • reported the manganese-porphyrin-catalyzed chlorination and bromination of C(sp3)−H bonds, respectively (Scheme 1d). Groves et al. also reported the manganese-salen-catalyzed fluorination of benzylic C(sp3)−H bonds [49]. Although these methods are efficient, they have a limited substrate scope
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Published 22 Apr 2021

Valorisation of plastic waste via metal-catalysed depolymerisation

  • Francesca Liguori,
  • Carmen Moreno-Marrodán and
  • Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

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Published 02 Mar 2021

Mesoionic tetrazolium-5-aminides: Synthesis, molecular and crystal structures, UV–vis spectra, and DFT calculations

  • Vladislav A. Budevich,
  • Sergei V. Voitekhovich,
  • Alexander V. Zuraev,
  • Vadim E. Matulis,
  • Vitaly E. Matulis,
  • Alexander S. Lyakhov,
  • Ludmila S. Ivashkevich and
  • Oleg A. Ivashkevich

Beilstein J. Org. Chem. 2021, 17, 385–395, doi:10.3762/bjoc.17.34

Graphical Abstract
  • -containing alkylation reagents [27]. Very recently, this aminide was found to be a suitable ligand for manganese complexes [28] and used as the agent for the preparation of salts with high energy density [29]. Also, it is worth noting that today only a few examples of mesoionic tetrazole aminide X-ray
  • -aminide ligand in a manganese complex [29], being the only structurally characterized complex with a neutral 1,3-dialkyltetrazolium-5-aminide. Therefore, it is of interest to compare the structural data for this compound with those obtained for compound 8a to find the influence of the complexation on the
  • ligand structure. As can be seen, the bond lengths of the free 1,3-di-tert-butyltetrazolium-5-aminide 8a and the ligand in the manganese complex are rather close. Nevertheless, the following structural differences attract attention. In the complex, the endocyclic N1–C5 and N4–C5 bonds are shorter, but
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Published 08 Feb 2021

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

  • Sergey V. Norkov,
  • Anton V. Cherkasov,
  • Andrey S. Shavyrin,
  • Maxim V. Arsenyev,
  • Viacheslav A. Kuropatov and
  • Vladimir K. Cherkasov

Beilstein J. Org. Chem. 2021, 17, 273–282, doi:10.3762/bjoc.17.26

Graphical Abstract
  • the supplementary crystallographic data for this paper. These data are provided free of charge by The Cambridge Crystallographic Data Centre: http://www.ccdc.cam.ac.uk/structures. Samples for EPR spectroscopy Alkali metal, thallium, hydrogen semiquinonates as well as manganese carbonyl semiquinonates
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Published 27 Jan 2021

Recent developments in enantioselective photocatalysis

  • Callum Prentice,
  • James Morrisson,
  • Andrew D. Smith and
  • Eli Zysman-Colman

Beilstein J. Org. Chem. 2020, 16, 2363–2441, doi:10.3762/bjoc.16.197

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Published 29 Sep 2020

Regioselective cobalt(II)-catalyzed [2 + 3] cycloaddition reaction of fluoroalkylated alkynes with 2-formylphenylboronic acids: easy access to 2-fluoroalkylated indenols

  • Tatsuya Kumon,
  • Miroku Shimada,
  • Jianyan Wu,
  • Shigeyuki Yamada and
  • Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 2193–2200, doi:10.3762/bjoc.16.184

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  • ][32]. Therefore, we also accomplished the synthesis of 2-fluoroalkylated indenone and indanone by simple reactions (Scheme 3). An allylic oxidation was carried out with 10 equiv of manganese dioxide in dichloromethane as the solvent at 0 °C for 30 minutes, leading to the corresponding 2
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Published 04 Sep 2020

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

  • Lucas Guillemard and
  • Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

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  • ]. Targeting more sustainable protocols, a manganese catalyst was selected to trigger the coupling between an aryldiazonium salt and simple (hetero)aryls. A unique reactivity was obtained under irradiation with blue LEDs and a continuous-flow process allowed achieving higher reactivity. Under the optimized
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Published 21 Jul 2020

Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

  • Carlos H. Escalante,
  • Eder I. Martínez-Mora,
  • Carlos Espinoza-Hicks,
  • Alejandro A. Camacho-Dávila,
  • Fernando R. Ramos-Morales,
  • Francisco Delgado and
  • Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

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  • ]indole-1,3-diones 9 were submitted to aromatization to generate the corresponding tetrahydropyrrolo[3,4-e]indole-1,3-diones 21 (Table 4). When 9e was treated with manganese oxide [32] at 25 or 100 °C for 24 h, no reaction occurred and the starting material was recovered (Table 4, entries 1 and 2
  • ). Derivative 21c was also prepared by the oxidation of 9h with manganese oxide at higher temperature, but the yield was lower (Table 4, entry 5). As part of our interest in further functionalizing octahydropyrrolo[3,4-e]indole-1,3-diones 9, formylation was herein investigated under usual Vilsmeier–Haack
  • using manganese oxide or DDQ as the oxidizing reagents, or even including Pd/C at high temperatures (250 °C) [45], failed to obtain the series of indoles 23. It is likely that the electron withdrawing effect of the formyl group at the C-7 position counterbalance the delocalization direction of the
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Published 17 Jun 2020

Oxime radicals: generation, properties and application in organic synthesis

  • Igor B. Krylov,
  • Stanislav A. Paveliev,
  • Alexander S. Budnikov and
  • Alexander O. Terent’ev

Beilstein J. Org. Chem. 2020, 16, 1234–1276, doi:10.3762/bjoc.16.107

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  • Cu(ClO4)2 afforded a better yield of the C–O coupling product 48 then the manganese-based oxidants in this case (Scheme 17) [94]. A radical mechanism was suggested. The copper(II) ion reacts with oxime 19 to generate iminoxyl radical 20 and also forms complex 49 with dinitrile 47. Interaction of
  • oxidation of α,β-unsaturated oxime 109’. As a result, 5-endo-trig cyclization affording hydroxyisoxazoline 110’ in good yield was observed. Another approach to the synthesis of hydroxy-substituted isoxazolines 113 is the manganese(III) acetylacetonate catalyzed reaction of β,γ-unsaturated oximes 112 with
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Published 05 Jun 2020

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

  • Esteban P. Urriolabeitia,
  • Pablo Sánchez,
  • Alexandra Pop,
  • Cristian Silvestru,
  • Eduardo Laga,
  • Ana I. Jiménez and
  • Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

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  • chromatography (TLC) was performed on Macherey-Nagel Polygram® SIL G/UV254 silica gel on polyester sheets, with manganese-activated zinc silicate with green fluorescence for short-wave UV (254 nm) and special inorganic fluorescent pigment with blue fluorescence for long-wave UV (366 nm) as indicators. Fluka
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Published 25 May 2020

Targeted photoswitchable imaging of intracellular glutathione by a photochromic glycosheet sensor

  • Xianzhi Chai,
  • Hai-Hao Han,
  • Yi Zang,
  • Jia Li,
  • Xiao-Peng He,
  • Junji Zhang and
  • He Tian

Beilstein J. Org. Chem. 2019, 15, 2380–2389, doi:10.3762/bjoc.15.230

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  • integrate these functions into one molecule. By taking advantages of both redox-active/high loading features of two-dimensional (2D) manganese dioxide (MnO2) and dynamic fluorescence photoswitching of photochromic sensors, we here design a hybrid photochromic MnO2 glycosheet (Glyco-DTE@MnO2) to achieve the
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Published 07 Oct 2019

Functionalization of 4-bromobenzo[c][2,7]naphthyridine via regioselective direct ring metalation. A novel approach to analogues of pyridoacridine alkaloids

  • Benedikt C. Melzer,
  • Alois Plodek and
  • Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2304–2310, doi:10.3762/bjoc.15.222

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  • added at C-5 of 4-chloro- (9a) and 4-fluorobenzo[c][2,7]naphthyridine (9b) as well as the 4-carboxamide 9c to give 5-substituted-5,6-dihydro derivatives, which were readily aromatized with manganese dioxide [13]. Further functionalization was performed by Stille cross coupling of a 4-chloro intermediate
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Published 26 Sep 2019

Recent advances in transition-metal-catalyzed incorporation of fluorine-containing groups

  • Xiaowei Li,
  • Xiaolin Shi,
  • Xiangqian Li and
  • Dayong Shi

Beilstein J. Org. Chem. 2019, 15, 2213–2270, doi:10.3762/bjoc.15.218

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  • Groves [82] developed two manganese catalysts for the fluorination of C(sp3)–H bonds (Scheme 38). On the one hand, they employed a manganese porphyrin to catalyze the oxidative aliphatic C–H fluorination with iodosylbenzene (PhIO) as a stoichiometric oxidant. A variety of substrates, including simple
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Published 23 Sep 2019

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

  • Gagandeep Kour Reen,
  • Ashok Kumar and
  • Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

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  • a rich library of compounds with good yields except 5-bromo, 4-methyl and 3-methyl substitution on 2-AP with 41, 45 and 49% yield, respectively. Meng et al. have used copper supported on manganese oxide-based octahedral molecular sieves OMS-2 (CuOx/OMS-2) as a heterogeneous catalytic system for a
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Published 19 Jul 2019

Insertion of [1.1.1]propellane into aromatic disulfides

  • Robin M. Bär,
  • Gregor Heinrich,
  • Martin Nieger,
  • Olaf Fuhr and
  • Stefan Bräse

Beilstein J. Org. Chem. 2019, 15, 1172–1180, doi:10.3762/bjoc.15.114

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  • opening of 1 with Grignard reagents enables the synthesis of aryl and some alkyl-substituted BCPs and a subsequent cross-coupling reaction [5][18]. To provide bicyclo[1.1.1]pentylamine as a building block in large-scale syntheses, Bunker et al. developed a synthesis of hydrazine BCP via a manganese
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Published 28 May 2019

Oxidative radical ring-opening/cyclization of cyclopropane derivatives

  • Yu Liu,
  • Qiao-Lin Wang,
  • Zan Chen,
  • Cong-Shan Zhou,
  • Bi-Quan Xiong,
  • Pan-Liang Zhang,
  • Chang-An Yang and
  • Quan Zhou

Beilstein J. Org. Chem. 2019, 15, 256–278, doi:10.3762/bjoc.15.23

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  • olefins and cyclopropanols) over the last 20 years. Review Oxidative radical ring-opening and cyclization of methylenecyclopropanes (MCPs) In 2004, Huang and co-workers reported the first manganese(III) acetate-mediated radical ring-opening and cyclization of methylenecyclopropanes (MCPs, 1) with malonic
  • another molecule Mn(OAc)3 [48]. Later, Shi et al. demonstrated an oxidative annulation of MCPs 1 with 1,3-dicarbonyl compounds 7 using manganese(III) catalysis under room temperature conditions, which afforded 4,5-dihydrofuran derivatives 8 as [3 + 2] annulation products (cyclopropyl retained adducts) in
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Published 28 Jan 2019
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