Search results

Search for "electron transfer" in Full Text gives 327 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

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

Graphical Abstract
  • , signaling the binding of HFIP to 2c enhanced the electron transfer kinetics between the hypervalent iodine reagent and the electrode [45]. Further additions of HFIP further increased the current response and shifted the peak potential, with 10 µL and 15 µL of HFIP showing responses with Epr at −1.55 V and
PDF
Album
Supp Info
Full Research Paper
Published 11 Sep 2024

Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties

  • Shakeel Alvi and
  • Rashid Ali

Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186

Graphical Abstract
  • electron transfer processes etc. [26][27][28]. On the other front, doping with heteroatom(s) to the truxene skeleton drastically modulate its unique physical as well as chemical properties besides the geometrical structure, as well [29]. After successful construction of truxene and its asymmetrical isomer
PDF
Album
Supp Info
Full Research Paper
Published 29 Aug 2024

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

  • Akiya Ogawa and
  • Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

Graphical Abstract
  • quinoxaline synthesis was reported to proceed by irradiation with visible light in the presence of dibenzylamine ((PhCH2)2NH, MeCN, rt, blue LED) [64]. This reaction involves a visible-light-induced single electron transfer (SET) process. An efficient radical cascade cyclization has also been reported, in
PDF
Album
Perspective
Published 26 Aug 2024

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

  • Ignaz Betcke,
  • Alissa C. Götzinger,
  • Maryna M. Kornet and
  • Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

Graphical Abstract
  • agrochemical uses of pyrazoles [13] include insecticides [14], herbicides [15], and fungicides [16]. Furthermore, they are widely applied for the assembly of supramolecular ensembles [17] and molecular systems capable of photoinduced electron transfer [18]. Due to their pertinent photophysical properties [19
PDF
Album
Review
Published 16 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

Graphical Abstract
  • formation of dimeric side products. Cyclic voltammetry analysis suggested an initial anodic single electron transfer (SET) to radical cation 5, cyclization and deprotonation. Subsequent SET oxidation in solution by 5 led to cation 7. Final deprotonation furnished aromatic cycle 4. In 2022, Zhang et al
  • that potassium iodide would serve as an electromediator to oxidize the hydrazone through an inner-sphere electron transfer. Moreover, the electrolysis proceeded more efficiently in the presence of ammonium acetate since (i) the acetate anion would serve as a base to facilitate the oxidation of the
PDF
Album
Review
Published 14 Aug 2024

Development of a flow photochemical process for a π-Lewis acidic metal-catalyzed cyclization/radical addition sequence: in situ-generated 2-benzopyrylium as photoredox catalyst and reactive intermediate

  • Masahiro Terada,
  • Zen Iwasaki,
  • Ryohei Yazaki,
  • Shigenobu Umemiya and
  • Jun Kikuchi

Beilstein J. Org. Chem. 2024, 20, 1973–1980, doi:10.3762/bjoc.20.173

Graphical Abstract
  • intramolecular cyclization followed by proto-demetalation with trifluoroacetic acid (TFA). In catalytic cycle II, photoexcitation of the generated 2-benzopyrylium intermediates A under light irradiation facilitates single-electron transfer (SET) from benzyltrimethylsilane derivatives 2 as the donor molecule
PDF
Album
Supp Info
Full Research Paper
Published 13 Aug 2024

Novel oxidative routes to N-arylpyridoindazolium salts

  • Oleg A. Levitskiy,
  • Yuri K. Grishin and
  • Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2024, 20, 1906–1913, doi:10.3762/bjoc.20.166

Graphical Abstract
  • negative potentials. The pyridoindazolium salt reduction is also sensitive to the presence of a base since the electron transfer is followed by a protonation chemical step. Indeed, a bulk electrolysis of amine A1 in the presence of 2,6-lutidine gave much better (60%) yield of salt S1. Additionally, the
PDF
Album
Supp Info
Full Research Paper
Published 07 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

Graphical Abstract
  • ). For example, Moeller reported electrochemical reactions under basic conditions, which were proposed to proceed via radicals [16][17][18]. Xu also reported electrochemical reactions via radicals, which were generated through proton-coupled electron transfer [19]. On the other hand, Yoon reported
PDF
Album
Supp Info
Letter
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

Graphical Abstract
PDF
Album
Review
Published 01 Aug 2024

Synthesis of polycyclic aromatic quinones by continuous flow electrochemical oxidation: anodic methoxylation of polycyclic aromatic phenols (PAPs)

  • Hiwot M. Tiruye,
  • Solon Economopoulos and
  • Kåre B. Jørgensen

Beilstein J. Org. Chem. 2024, 20, 1746–1757, doi:10.3762/bjoc.20.153

Graphical Abstract
  • are quite the same for all compounds. The oxidation is initiated by an electron transfer from the substrate where the substrate will loose an electron more easily [42], and the free electron pairs of the hydroxy group are usually more difficult to ionize than π-electrons of the aromatic systems [52
  • Information File 1). Naphthalene-1-ol (1b) gave a well-defined oxidation peak at 0.95 V (vs Fe/Fe+) while naphthalene-2-ol (1a) showed an oxidation peak at 1.14 V (vs Fe/Fe+). The oxidation peak potential difference between 1b and 1a was 190 mV. PAHs undergo rapid irreversible chemical reactions upon electron
  • transfer [50]. Unsubstituted PAHs display multielectron oxidation, but one-electron waves occur with electron-donating substituents in suitable positions. Panizza et al. [38] observed two one-electron oxidations in their cyclic voltammetry studies of 1a in water and proposed the formation of a naphthyloxy
PDF
Album
Supp Info
Full Research Paper
Published 24 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

Graphical Abstract
  • in the concerted transfer of an electron and a proton from the benzylic substrate resulting in the benzylic radical II – pathway [A] [67]. This radical can also be accessed via sequential oxidative single-electron-transfer (SET) and proton-transfer (PT) steps (pathway [B]), or concerted proton
  • -coupled electron transfer (PCET) (pathway [C]). Benzylic radicals can then react with FAT reagents to give the desired benzyl fluoride products [66][68]. Several photochemical benzylic fluorination methodologies proposed to proceed via radical pathways have been reported. Chen and co-workers published a
  • functional groups on the aromatic ring and adjacent to the benzylic position. Mechanistic investigations suggested an initial electron transfer to generate a radical cation en route to the intermediate benzylic radical, rather than a HAT process, however, the authors did not distinguish between a stepwise
PDF
Album
Review
Published 10 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

Graphical Abstract
  • triggered to carry out energy transfer and electron transfer or proton-coupled electron transfer when it absorbs light of an appropriate wavelength (Figure 2). These processes generate highly reactive species, such as radical cations or anions, which can initiate the desired organic transformations
PDF
Album
Review
Published 14 Jun 2024

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation

  • Kosuke Yamamoto,
  • Kazuhisa Arita,
  • Masami Kuriyama and
  • Osamu Onomura

Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116

Graphical Abstract
  • intermediates through a single-electron transfer process [26][27][28][29][30][31]. In particular, electroreductive transformations have recently received renewed attention from modern synthetic chemists as a safer protocol than conventional methods using chemical reductants such as metal hydride species [32][33
  • the additional electron transfer to form the corresponding anions is a highly favorable pathway due to the more positive reduction potential of radicals than that of the starting halides [38], employing redox mediators enables the generated aryl radicals to participate in radical arylation reactions
  • single-electron reduction at the cathode to generate the radical anion species (1,3-DCB•−), which might act as a mediator to produce the radical anion 1•− through the homogeneous electron transfer in the bulk solution (representative reduction peak potential: 1a, Ep = −1.98 V vs SCE in MeCN [59]; 1c, Ep
PDF
Album
Supp Info
Letter
Published 10 Jun 2024

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

  • Johannes Rocker,
  • Till J. B. Zähringer,
  • Matthias Schmitz,
  • Till Opatz and
  • Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

Graphical Abstract
  • catalyst in the sulfonylation/arylation of styrenes and as a triplet sensitizer in energy transfer catalysis. The singlet lifetime is sufficiently long to exploit the exceptional excited state reduction potential for the activation of 4-cyanopyridine. Photoinduced electron transfer generating the radical
  • mechanism of the recently reported sulfonylation/arylation [45][46] reaction using laser flash photolysis (LFP). LFP is a powerful spectroscopic tool in photocatalysis that allows us not only to distinguish between energy and electron transfer but also to detect transient triplet states and radicals
  • photocatalyst (PC•+/PC = +1.12 V vs SCE) is then regenerated by an electron transfer from sodium p-toluenesulfinate (TsNa) (Ts•/Ts− = +0.70 V vs SCE) closing the photocatalytic cycle [45]. Unlike other prominent photocatalysts, little to nothing is known about the reactivity, the photophysical properties or the
PDF
Album
Supp Info
Full Research Paper
Published 28 May 2024

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

  • Vishnu Selladurai and
  • Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

Graphical Abstract
  • structure of aniline, o-anisidine, and methyl anthranilate were optimized using the B3LYP/6-31G(d,p) basis set. Oxidative electron transfer from an arylamine to SeO2 was the first step in the oxidation process. This step was especially crucial for the polymerization of arylamines. Hence, we proposed that
PDF
Album
Supp Info
Full Research Paper
Published 27 May 2024

Advancements in hydrochlorination of alkenes

  • Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

Graphical Abstract
  • state thereof, denoted with an asterisk, possessing a reduction potential of 2.0 V versus SCE (saturated calomel electrode). Subsequently, this excited state undergoes quenching through photoinduced electron transfer (PET) with styrene 5. The resulting vinyl radical cation exhibits electrophilicity at
  • . The acridinium ion 161 now takes on the additional role of a phase-transfer catalyst, facilitating the transport of the chloride ion into the lipophilic alkene phase. Subsequently, under irradiation with blue LEDs, the acridinium cation 161 and the chloride anion engage in a single-electron-transfer
PDF
Album
Review
Published 15 Apr 2024

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

  • Geng-Xin Liu,
  • Xiao-Ting Jie,
  • Ge-Jun Niu,
  • Li-Sheng Yang,
  • Xing-Lin Li,
  • Jian Luo and
  • Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

Graphical Abstract
  • , hydride shift process, and photoinduced homolytic cleavage of the C–Pd bond, furnishing hybrid α-ester alkylpalladium radical I. In path b, upon irradiation with blue light, photoexcited Pd(0)Ln* reduces ethyl diazoacetate (1a) to Pd-radical species I by a proton-coupled electron transfer (PCET) process
PDF
Album
Supp Info
Full Research Paper
Published 27 Mar 2024

Enhanced reactivity of Li+@C60 toward thermal [2 + 2] cycloaddition by encapsulated Li+ Lewis acid

  • Hiroshi Ueno,
  • Yu Yamazaki,
  • Hiroshi Okada,
  • Fuminori Misaizu,
  • Ken Kokubo and
  • Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

Graphical Abstract
  • experimental and theoretical approaches, we clarified the range of applicable substrates for the thermal [2 + 2] cycloaddition of Li+@C60, highlighting the expanded scope of this straightforward and selective functionalization method. Keywords: electron transfer; fullerene; ion-endohedral fullerene; Lewis
  • thermal [2 + 2] cycloaddition. The [2 + 2] cycloaddition reactions of empty C60 have been known to proceed with unsaturated substrates having HOMO levels suitable for the thermal or photoinduced single-electron-transfer (SET) process (Scheme 1) [14][15][16][17][18][19][20][21][22][23]. Although the
PDF
Album
Supp Info
Full Research Paper
Published 25 Mar 2024

Switchable molecular tweezers: design and applications

  • Pablo Msellem,
  • Maksym Dekthiarenko,
  • Nihal Hadj Seyd and
  • Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

Graphical Abstract
  • [4]pyrroles [73]. The electrochemical properties of the host–guest system are modulated by a thermally induced electron transfer (ET) that generates the charge separation state [PrS-TTF-C4P•+/Li+@C60•−]. This behavior was first reported with Cl− as an allosteric regulator but was then described with
  • allosterically regulated host–guest systems to catalysis or magnetic properties. Redox switchable molecular tweezers One of the cleanest stimuli for supramolecular switching is electron transfer. Besides photoswitching, the undeniable advantages of redox switching are the absence of chemical waste and the fact
PDF
Album
Review
Published 01 Mar 2024

Enhanced host–guest interaction between [10]cycloparaphenylene ([10]CPP) and [5]CPP by cationic charges

  • Eiichi Kayahara,
  • Yoshiyuki Mizuhata and
  • Shigeru Yamago

Beilstein J. Org. Chem. 2024, 20, 436–444, doi:10.3762/bjoc.20.38

Graphical Abstract
  • suggested the partial electron transfer from [10]CPP to [5]CPP2+ in the complex, and this charge-transfer (CT) interaction is most likely the origin of the higher association constant of the dicationic complex than the neutral one. Keywords: charge-transfer; cycloparaphenylene; dication; host–guest
  • regardless of the oxidation state of the starting CPPs. Thus, when neutral [5]CPP was mixed with [10]CPP2+ (SbCl6−)2, only the signals at 8.0 and 5.3 ppm corresponding to [10]CPP⊃[5]CPP2+ were observed (Figure 1c, path B), suggesting a quick electron transfer from [5]CPP to [10]CPP2+ has occurred. The same
  • stabilized by in-plane aromaticity, the single-electron transfer from [10]CPP to [5]CPP2+ to form [10]CPP•+⊃[5]CPP•+ is energetically unfavorable. The association constant (Ka) between [10]CPP⊃[5]CPP2+ [B(C6F5)4−]2 in 1,1,2,2-tetrachloroethane-d2 (TCE-d2) at 50 °C was determined to be 1.07 × 103 L·mol−1 by
PDF
Album
Supp Info
Letter
Published 23 Feb 2024

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

  • Periklis X. Kolagkis,
  • Eirini M. Galathri and
  • Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

Graphical Abstract
PDF
Album
Review
Published 22 Feb 2024

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

Graphical Abstract
  • many applications as radical precursors. Mechanistically, NHPI esters undergo a reductive decarboxylative fragmentation to provide a substrate radical capable of engaging in diverse transformations. Their reduction via single-electron transfer (SET) can occur under thermal, photochemical, or
  • fragmentation of 8 affords a radical species 9 in a constructive step towards initiating the radical reaction, a principal competing step is back-electron transfer (BET) to return the closed shell starting materials (Scheme 2B). A recent study showed comparable rates for fragmentation (8 ± 5 × 105 s−1) and BET
  • hydrogen atom transfer (HAT) or sequential electron transfer and proton transfer (ET/PT) steps. Alternatively, redox-neutral transformations can be envisioned using catalytic reductants, which can enable a complementary scope of downstream functionalizations (Scheme 2B). In this perspective, we present an
PDF
Album
Perspective
Published 21 Feb 2024

Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

  • Kazuhiro Okamoto,
  • Naoki Shida and
  • Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

Graphical Abstract
  • hydroamination reaction products via a proton-coupled electron transfer (PCET) mechanism. Cyclic voltammetry (CV) analysis indicated that the chemoselectivity was derived from the size of the hydrogen bond complex, which consisted of the carbamate substrate and phosphate base, and could be controlled using
  • 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as an additive. These results provide fundamental insights for the design of PCET-based redox reaction systems under electrochemical conditions. Keywords: amidyl radical; cyclic voltammetry; electrosynthesis; hydroamination; proton coupled electron transfer
  • ; Introduction Proton-coupled electron transfer (PCET) enables the generation of various radical species under ambient conditions (Figure 1, top) [1]. In PCET processes, hydrogen bond formation between weak bases and acidic X–H bonds (X = N, O, C) is a key step, which is followed by concerted proton- and
PDF
Album
Supp Info
Full Research Paper
Published 12 Feb 2024

Photochromic derivatives of indigo: historical overview of development, challenges and applications

  • Gökhan Kaplan,
  • Zeynel Seferoğlu and
  • Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

Graphical Abstract
  • ] providing a detailed analysis of the synthetic methods and describing all types of the photochemical reactions of indigo derivatives (E–Z photoisomerization, photoinduced proton and electron transfer), our review is focused on the photoswitchable indigo derivatives undergoing the E–Z photoisomerization in
PDF
Album
Review
Published 07 Feb 2024
Graphical Abstract
  • physicochemical properties of the family of these compounds that have been investigated is provided to clarify their potential for future applications. Keywords: click chemistry; donor–acceptor conjugate; intramolecular charge transfer; photoluminescence; photoinduced electron transfer; Introduction Push–pull
  • to the presence of competitive processes, such as energy or electron transfer. Trolez et al. investigated the photoluminescence properties of various fluorophore-containing TCBDs synthesized via reactions between ynamides and TCNE [139]. The study revealed that numerous fluorenyl derivatives and
  • arising from hydrogen bonding and π–π stacking interactions. In contrast, when 75 is incorporated into a nanocomposite with polystyrene serving as the matrix, luminescent properties are observed [141]. Photoinduced intramolecular energy and electron transfer Exploiting the electron-accepting property of
PDF
Album
Review
Published 22 Jan 2024
Other Beilstein-Institut Open Science Activities