Electrochemical synthesis of cyclic biaryl λ³-bromanes from 2,2’-dibromobiphenyls

• Andrejs Savkins and
• Igors Sokolovs

Beilstein J. Org. Chem. 2025, 21, 451–457, doi:10.3762/bjoc.21.32

• diarylbromonium species by direct anodic oxidation of 2,2'-dibromo-1,1'-biphenyl. The electrochemical method provides access to a range of symmetrically and non-symmetrically substituted cyclic biaryl λ3-bromanes in moderate yields. Keywords: anodic oxidation; cyclic biaryl λ3-bromane; cyclic voltammetry

Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• 1600–1550 cm−1 triplet. This result is fully compatible with the presence of the two rather overlapped (i.e., with similar energies) one-electron oxidations in the cyclic voltammetry of 2. The spectral resemblances for 2•+ and 22+ might also indicate that the positive charge is mainly gathered by the

• Electrochemistry Cyclic voltammetry experiments were conducted with a three-electrode geometry operating with a glassy carbon as the working electrode. A Pt-coil counter electrode. and an Ag wire, as the pseudo-reference, were used. Potential values are given with respect to the ferrocene/ferrocenium (Fc/Fc

Recent advances in electrochemical copper catalysis for modern organic synthesis

• Yemin Kim and
• Won Jun Jang

Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9

• desired annulation products. Moreover, the same products were generated using alkynyl carboxylic acids instead of terminal alkynes via decarboxylative C–H alkynylation and annulation. Cyclic voltammetry (CV) studies exhibited an oxidative current at 0.95 V vs SCE in the presence of the Cu(II) salt, base

Synthesis, structure and π-expansion of tris(4,5-dehydro-2,3:6,7-dibenzotropone)

• Yongming Xiong,
• Xue Lin Ma,
• Shilong Su and
• Qian Miao

Beilstein J. Org. Chem. 2025, 21, 1–7, doi:10.3762/bjoc.21.1

• in 3, which consume the energy of the excited state. Figure 4 shows the UV–vis absorption spectrum of 3 in cyclohexane with the absorption edge at 561 nm and its emission spectrum with a peak at 580 nm. In the test windows of cyclic voltammetry (Supporting Information File 1, Figure S1), 3 exhibits

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• frontier orbitals. Electrochemical studies The electrochemical properties of the dyes were investigated by square wave voltammetry (SWV) and cyclic voltammetry (CV) and the data are summarised in Table 1, with the plots shown in Figure 6. All the materials exhibit at least one reversible reduction and two

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

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• starting mercapto-substituted heterocycles were studied. Based on cyclic voltammetry data, the starting compounds can be arranged in increasing order of the anodic peak potentials: 5-(3-pyridyl)-1,2,4-triazole-3-thiol (0.87 V) < 2-mercapto-4-phenylthiazole (0.94 V) < 3-nitropyridine-2-thiol (1.18 V

• ) < 1,3,4-oxadiazole derivatives (1.37–1.39 V). The redox properties of catechols 1–9 were studied by cyclic voltammetry (CV) (Table 1). In the anodic area, the electrochemical profile for catechol thioethers 1–5 represents two successive irreversible oxidative stages. The first two-electron peak is

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

• iminoiodinanes for the metal-free aziridination of unactivated olefins. 1H NMR and cyclic voltammetry (CV) studies indicate that hydrogen-bonding between HFIP and the iminoiodinane generates an oxidant capable of direct NGT to unactivated olefins. Stereochemical scrambling during aziridination of 1,2

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

• 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

• hydrazones initiated with the SET anodic oxidation of the hydrazone and deprotonation to form the N-centered radical 10. After aza-cyclization on the aromatic ring, a second SET oxidation and deprotonation delivered the heterocycle 9. This mechanism was supported by cyclic voltammetry analysis of a model

• of aromatic aldehyde-derived hydrazones regardless of their electronic properties as well as aliphatic-aldehyde derived hydrazones. Cyclic voltammetry analysis showed that thiocyanate salt 96 possesses a lower oxidation potential than the hydrazone 95. As such, the authors proposed the anodic

Radical reactivity of antiaromatic Ni(II) norcorroles with azo radical initiators

• Siham Asyiqin Shafie,
• Ryo Nozawa,
• Hideaki Takano and
• Hiroshi Shinokubo

Beilstein J. Org. Chem. 2024, 20, 1967–1972, doi:10.3762/bjoc.20.172

• CH2Cl2 were examined using cyclic voltammetry (Figure 4). Macrocycle 2a exhibited one reversible oxidation wave at 0.44 V and two reversible reduction waves at −0.85 V and −1.14 V. The electrochemical HOMO–LUMO gap of 2a is 1.29 V, which is larger than that of 1a (1.08 V) [2]. DFT calculations We next

Synthesis and characterization of 1,2,3,4-naphthalene and anthracene diimides

• Adam D. Bass,
• Daniela Castellanos,
• Xavier A. Calicdan and
• Dennis D. Cao

Beilstein J. Org. Chem. 2024, 20, 1767–1772, doi:10.3762/bjoc.20.155

• undergo reversible chemical reduction processes, as determined by cyclic voltammetry in CH2Cl2 solvent (Figure 4). There are two factors at play. The imide substitution is impactful as the N-phenyl derivatives are roughly by 100 mV easier to reduce than the N-hexyl analogs. The anthracene scaffold also

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

• . The specific quinones formed were guided by the position of an initial hydroxy group on the polycyclic aromatic hydrocarbon. An available para-position in the PAPs gave p-quinones, while hydroxy groups in the 2- or 3-position led to o-quinones. The substrates were analysed by cyclic voltammetry for

• estitmation of the HOMO/LUMO energies to shed more light on this transformation. The easy separation of the supporting electrolyte from the product will allow recycling and makes this a green transformation. Keywords: acetal formation; cyclic voltammetry; flow electrochemistry; green oxidation; polycyclic

• dimers, which indicates a radical intermediate [36]. Swenton and co-workers [37] established evidence for the phenoxonium ion (Scheme 1), and were further able to divert the reaction into forming ortho-oxidation due to steric hindrance (Scheme 2). Cyclic voltammetry studies of the oxidation of 2-naphthol

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

• ·2HF proved to be the best of the HF·amine reagents screened. The reaction was conducted under constant potential conditions, using cyclic voltammetry prior to electrolysis to determine the appropriate oxidation potential required for each substrate. Under these conditions, yields of up to 65% were

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• molecular orbital (LUMO). To understand the electron affinity of t-Bu-FIDS, cyclic voltammetry was conducted. The cyclic voltammogram of t-Bu-FIDS in o-DCB showed reversible reduction waves at E1/2 = −1.14 V and −1.51 V (vs Fc/Fc+), as shown in Figure 3. Both the first and second reduction potentials of t

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• of 1 with the HOMO of 2a should be considered. Electrochemical measurements of 3 Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements were conducted to evaluate the electronic effects of the silylene addends in 3 (Figure 9). The oxidation processes of 3 were shown to be

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• obtained from absorbance spectra, taken as the photon energy corresponding to the cut-off wavelength (Table 1). Subsequently, preliminary electrochemical studies were performed with selected DCPQs and corresponding DPQD counterparts using cyclic voltammetry (Figure S1, Supporting Information File 1

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

• yield of multiadducts compared to previously reported functionalizations of Li+@C60. The reason can be explained by the difference in electron-accepting ability between the monoadduct and pristine Li+@C60 investigated by cyclic voltammetry (Figure 5). Both products exhibited reversible first and second

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

• . However, the low solubility and stability of the dication in polar solvents prevented confirmation of the solvent effect. To clarify the additional interaction in the complex, the electrochemical analysis of the [10]CPP⊃[5]CPP2+[B(C6F5)4–]2 was examined by using cyclic voltammetry, which was performed in

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

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

• ] (Scheme 7A). Cyclic voltammetry measurements of a model NHPI ester showed a shift in its reduction potential from –1.79 V to –1.51 V (vs SCE in MeCN) in the presence of In(OTf)3. As such, it was hypothesized that the Lewis acid lowers the LUMO of the NHPI ester via interaction with the oxygen lone pair in

• photocatalytic radical-mediated dearomatization, with H2O serving as the nucleophile [54] (Scheme 9A). Despite the presence of H2O in the reaction, the reduction of 38 to its corresponding radical anion 39 could occur without the need for hydrogen-bonding (Scheme 9B). Cyclic voltammetry measurements of NHPI

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• short-term heating of the melted reactants at 220–250 °C is described, and the compounds were characterized by means of single-crystal X-ray crystallography, NMR, UV–vis, and IR spectroscopy, as well as cyclic voltammetry. The reaction with o-amino-, o-hydroxy-, and o-mercapto-substituted arylamines

• ]oxazino[2,3-b]phenothiazine 10c (Figure 7) were bathochromically shifted by about 50 nm relative to those of the quinoxaline[2,3-b]phenoxazines 6. The electrochemical behavior of compounds 4a–h, 5a–c, 6a,b, and 10c was studied using cyclic voltammetry (CV). As exemplified by the CV curves (Figure S12

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• hydride resulted in the formation of the oxepine ring by a double substitution reaction, to yield the desired dinaphthooxepine 33. The non-planar character of dinaphthooxepine bisimides was confirmed by X-ray crystal structure, and stability towards thermal or photoactivation was also established. Cyclic

• voltammetry studies revealed that reduction of dinaphthooxepine 33 proceeds irreversibly, giving rise to a new chemical species (Figure 2), and this was further confirmed by chemical reduction in the presence of decamethylcobaltocene CoCp*2 at room temperature. Using two equivalents of this 1-electron

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

• 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

• -alkylation, whereas the use of AcOH provided N-alkylated product 3 (Table 1, entries 5 and 6). When acetonitrile (MeCN) was used as the solvent, cyclized dimer 4 was obtained (Table 1, entry 7). Next, 1 was subjected to cyclic voltammetry (CV) measurements under varying conditions (Figure 2). An oxidation

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• expanded by pyrrolo annelation. The optical and redox properties of these compounds, in some cases carbon-rich, were studied by UV–vis absorption spectroscopy and cyclic voltammetry. Synthetically, the work explores IF diones or fluorenone as central building blocks by subjecting the carbonyl groups to a

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• of the compounds are sensitive to the medium. Cyclic voltammetry measurements indicate good hole-blocking and electron-injecting properties due to their high ionization potentials. Photoelectron spectroscopy and time-of-flight measurements reveal good electron-transporting properties for one of the

• derivatives 6–9. Their 5% weight loss temperatures (Td) ranged from 433 to 493 °C (Figure 5a and Table 1). Electrochemical properties The electrochemical properties of compounds 6–9 were studied by cyclic voltammetry (CV) selecting the electrochemical window from −1.6 to 1.7 V and the CV data were corrected

• delayed fluorescence. The optical band gaps of the compounds were determined to be 2.74–2.8 eV, while cyclic voltammetry measurements demonstrated that the compounds possess excellent hole-blocking properties due to their high ionization potentials. Moreover, they exhibited appropriate electron-injecting