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Search for "manganese" in Full Text gives 77 result(s) in Beilstein Journal of Organic Chemistry.

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

  • Carlos R. Azpilcueta-Nicolas and
  • Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

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  • reductant, which can be an organic reductant, such as tetrakis(N,N-dimethylamino)ethylene (TDAE) or Hantzsch ester (HE), or a metal such as zinc (Zn0) or manganese (Mn0). Upon fragmentation, radical species 12 is captured by the oxidative addition complex 125, giving rise to NiIII complex 126. The cross
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Published 21 Feb 2024

Selectivity control towards CO versus H2 for photo-driven CO2 reduction with a novel Co(II) catalyst

  • Lisa-Lou Gracia,
  • Philip Henkel,
  • Olaf Fuhr and
  • Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

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  • ]. Among the most employed earth-abundant metal-based PS, Cu(I) complexes have the first place, not only in artificial photosynthesis, but also in a large variety of photo(redox)catalyses [12][13][14][15][16][17]. On the other hand, several complexes based on 3d transition metals, like manganese [18], iron
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Published 17 Nov 2023

Tying a knot between crown ethers and porphyrins

  • Maksym Matviyishyn and
  • Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

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  • of coordination compounds of copper(II), iron(II/III), manganese(II), nickel(II), and cobalt(II) with 9-Zn and 9-Cu was demonstrated. The emission quenching was rationalised considering the binding of the transition metal within the crown ether cavity. No quenching was observed upon the addition of
  • iron(II) and manganese(II) complexes with similar compositions. Interestingly, by-products incorporating the [2 + 2] macrocycles were isolated from the reaction mixtures targeting 16-Fe, 18a-Fe and 16-Mn, 18a-Mn (Figure 13) [67]. The helical geometry of [16-M]2 was attributed to the inherent
  • flexibility of macrocyclic ligands, as demonstrated by X-ray molecular structures. The helicates consisted of two metal centres, namely cobalt, manganese, or iron, each coordinated by two nitrogens and oxygen donors of the ligand. The metal centres adopted distorted octahedral geometries with slight
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Published 27 Oct 2023

Radical ligand transfer: a general strategy for radical functionalization

  • David T. Nemoto Jr,
  • Kang-Jie Bian,
  • Shih-Chieh Kao and
  • Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

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  • behavior of P450 oxygenases encouraged early work on site-selective C–H functionalization [20]. Throughout their studies, it was found that manganese could perform the same HAT and RLT steps as iron at heme active sites. Groves developed the manganese tetramesitylporphine catalyst V (Scheme 2), which was
  • found to be capable of functionalizing specific C–H bonds to numerous functionalities, including C–F [21][22], C–N3 [23], and C–Cl bonds [24][25]. Upon these remarkable observations, methodologies involving manganese–porphyrin catalysts have been developed over the years. These methods take advantage of
  • the power of RLT to install a variety of medicinally relevant groups, largely mirroring the selectivity of CYP450s. Intriguingly, studies by Groves have revealed earth abundant iron and manganese to be particularly privileged for this application of RLT, a major advantage for sustainable method
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Published 15 Aug 2023
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  • sacrificial donors [40]. More recently, other groups have published the electrochemical hydrogenation of carbonyl compounds using more earth-abundant electrocatalysts. For instance, Siewert and co-worker used a manganese complex as an electrocatalyst for the chemoselective carbonyl hydrogenation [41
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Published 08 Aug 2023

Strategies in the synthesis of dibenzo[b,f]heteropines

  • David I. H. Maier,
  • Barend C. B. Bezuidenhoudt and
  • Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

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  • . Knell et al. [40][41] reported a comparison of several catalysts, which included potassium-promoted iron, cobalt and manganese oxide catalysts, for the synthesis of 1a. Industrially, 1a is produced by the vapour phase dehydration of 2a over an iron/potassium/chromium catalyst system (Scheme 4) [42]. 2
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Published 22 May 2023

Combining the best of both worlds: radical-based divergent total synthesis

  • Kyriaki Gennaiou,
  • Antonios Kelesidis,
  • Maria Kourgiantaki and
  • Alexandros L. Zografos

Beilstein J. Org. Chem. 2023, 19, 1–26, doi:10.3762/bjoc.19.1

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  • generation of radicals from carbonyl reduction [18] but also manganese(III) acetate as a convenient one-electron oxidant [19]. The next twenty years, the field continued to flourish mainly by way of the decipherment of hydrogen atom transfer (HAT) mechanisms, which led to the establishment of several
  • ) [30]. HAT reductions of the C9–C11 alkene followed to deliver arisugacin F (35), phenylpyropene C (36), pyripyropene E (38), and phenylpyropene F (41). The steric bulk of the manganese catalyst employed suppressed the undesired reaction with tetrasubstituted alkenes and led to the exclusive reaction
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Published 02 Jan 2023

Design, synthesis, and evaluation of chiral thiophosphorus acids as organocatalysts

  • Karen R. Winters and
  • Jean-Luc Montchamp

Beilstein J. Org. Chem. 2022, 18, 1471–1478, doi:10.3762/bjoc.18.154

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  • -catalyzed hydrophosphinylation [45]. The key heterocyclization of 11 into 12 was accomplished using silver-promoted homolytic aromatic substitution [46], which was superior to our own manganese methodology (43% yield) [36]. Copper-catalyzed arylation [34] of 12 with iodobenzene and 4-nitroiodobenzene gave
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Published 17 Oct 2022

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

  • Artem N. Semakin,
  • Ivan S. Golovanov,
  • Yulia V. Nelyubina and
  • Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

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  • dynamic covalent libraries [25]. TAAD can be covalently bound to a polymer matrix through the nucleophilic nitrogen N(1) that was used to prepare scavengers of boronic acids [25]. Also, TAAD was demonstrated to serve as a scorpionate-type ligand for manganese and iron leading to complexes with the metal
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Published 11 Oct 2022

Electrochemical vicinal oxyazidation of α-arylvinyl acetates

  • Yi-Lun Li,
  • Zhaojiang Shi,
  • Tao Shen and
  • Ke-Yin Ye

Beilstein J. Org. Chem. 2022, 18, 1026–1031, doi:10.3762/bjoc.18.103

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  • have reported a manganese dioxide-catalyzed radical azidation of enol acetates to afford the corresponding azidoketones using dioxygen as the oxidant (Scheme 1A) [14]. The adoption of electrosynthesis in green and sustainable redox transformations has been experiencing a dynamic renaissance [15][16][17
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Published 12 Aug 2022

Synthesis of odorants in flow and their applications in perfumery

  • Merlin Kleoff,
  • Paul Kiler and
  • Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

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  • oxidant (Scheme 8B) [39]. The process is performed at 120 °C at 10 bar with a residence time of 6 min, and catalyzed homogenously utilizing the established “MC-system” (manganese/cobalt/bromide) in a heated tube reactor. Remarkably, acetophenone is obtained in a good yield of 66% and in 96% purity without
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Published 27 Jun 2022

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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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

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  • -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

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  • 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
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