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

• 2023, the Mei group reported the C(sp3)–H alkenylation of THIQs with acrolein by a combination of Cu/TEMPO and electrooxidation (Figure 6) [52]. CV experiments demonstrated that TEMPO was a suitable redox mediator, and on/off experiments confirmed that the reaction continued even without electrolysis

• , yielding an α-aryloxylation product 37. After their investigation of Cu-catalyzed electrochemical reactions, the same group further developed synergistic Cu/Ni catalysis for the stereodivergent electrooxidation of benzoxazolyl acetate (Figure 10) [59]. In this catalytic system, copper and nickel activate

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

• of the substrate. The formed radical reacts with t-BuOOH to produce the corresponding ketone, with tert-butanol as a byproduct (Scheme 7). A closely related transformation was developed by Cheng and Xu in 2020 for the electrooxidation of methylarenes to aromatic acetals [15]. With this method

• arenes via palladium-catalyzed electrooxidation, further showcasing the versatility and potential of this approach in organic synthesis (Scheme 42b) [58]. These methodologies underline the expanding role of palladium catalysis in electrochemical transformations, offering robust strategies for the

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

• the electrochemical properties of functionalized catechols allows one to suggest the mechanism of their electrooxidation, establish electron transfer centers, and predict antioxidant activity based on electrochemical data. To determine electron-transfer centers, the oxidation potentials of the

• heterocycle moiety. The formation of intramolecular hydrogen bonds between the OH group and the pyridine ring facilitates the electrooxidation process (1.,0 V) (Supporting Information File 1, Figure S21) for catechol thioether 5. The second oxidation peak is shifted to the anodic region due to the influence

• maximum at λ = 412 nm which is characteristic for sterically hindered o-benzoquinones. The proposed scheme for the electrooxidation of catechols 6–9 is presented in Scheme 3. Based on the current intensities of the second anodic peaks for compounds 6–8 with a 1,3,4-oxadiazole-2-thione ring (Figure 8 for 7

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

• oxidation of N-arylhydrazone by electrogenerated iodide radical (Scheme 11) [50]. In parallel, the group of Yuan achieved the electrosynthesis of 1,3,5-trisubstituted 1,2,4-triazoles 67 from arylhydrazines 64, aldehydes 65 and primary amines 66. Iodine-mediated electrooxidation of in situ-generated aldehyde

• -diphenylethylene proceeded with similar efficiency, thereby excluding any radical pathway. As such, it was proposed that the catalytic electrooxidation of iodide (ENH4I = 0.41 V and 0.75 V vs Ag/AgCl in dimethylacetamide for I−/I3− and I3−/I2 redox couples) into iodine provided a green and mild tool to in situ

• electromediator for synthesising α-diazoketones 139 in good yields. The electrolysis was performed at low temperature in a divided cell equipped with a platinum anode and a nickel cathode. It was not possible to isolate the diazo compounds arising from the electrooxidation of 4,4’-dimethylbenzilhydrazone and 4,4

Electrochemical formal homocoupling of sec-alcohols

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

Beilstein J. Org. Chem. 2022, 18, 1062–1069, doi:10.3762/bjoc.18.108

• alcohol derivatives. The present transformations smoothly proceed in a simple undivided cell under constant current conditions without the use of external chemical oxidants/reductants, and transition-metal catalysts. Keywords: alcohols; dimerization; electrooxidation; electroreduction; paired

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

• 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

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• . Recent advances in anodic cyclization reactions along with their detailed mechanistic rationale have been studied in details in an article published by Moeller’s group [45]. Herein, we present a systematic description of electrooxidation reactions where asymmetry has been induced by means of chiral

• modification of anodes. As in case of asymmetric electroreduction, the prime reasonable entry in the area of asymmetric electrooxidation using chemically modified electrode was made by a successive work by Miller’s group in 1976. Using modified graphite electrodes, they successfully reported anodic oxidation

• electrooxidation in the aqueous phase. The [Br+] thus generated oxidizes the N-oxyl/N-hydroxy species, leading to the formation of the N-oxoammonium species in CH2Cl2. The nucleophilic addition of racemic 63 to this N-oxoammonium species might further generate 65 and a steric hindered environment would favor the

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• glycol electrooxidation. For glycerol, a similar study was conducted by Ferreira et al. [14] on PdRh electrodeposits showing that the glycerol oxidation route follows a pathway involving the consumption rather than production of H2O once the initially present OH− ions are consumed. Finally, the

• reactions of small organic molecules, studies of the cation impact on the formed products are rather scarce. Sitta et al. [32] revealed an analogous trend as Strmcnik et al. [24], i.e., increasing current densities for ethylene glycol electrooxidation over Pt in the order Li+ < Na+ < K+. They used IR

• in the electrolyte by blocking surface sites that are required for the carbon bond cleavage. To the best of our knowledge, there are no studies focusing on the cation effect on the glycerol electrooxidation reaction using Pd-based materials. With respect to FC applications and the electrosynthesis of

An alternative to hydrogenation processes. Electrocatalytic hydrogenation of benzophenone

• Cristina Mozo Mulero,
• Alfonso Sáez,
• Jesús Iniesta and
• Vicente Montiel

Beilstein J. Org. Chem. 2018, 14, 537–546, doi:10.3762/bjoc.14.40

• analysis (TGA). Cathodes were prepared using Pd electrocatalytic loadings (LPd) of 0.2 and 0.02 mg cm−2. The anode consisted of hydrogen gas diffusion for the electrooxidation of hydrogen gas, and a 117 Nafion exchange membrane acted as a cationic polymer electrolyte membrane. Benzophenone solution was

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45

• hydrophobic part. The preferential sites of cholesterol electrooxidation are shown in Figure 1. These are the hydroxy group at C3, the C5–C6 double bond, the allylic positions (particularly C7), and the tertiary positions (mainly in the side chain at C25). The multiple potential sites of chemical or

• material) as the main product in addition to other products (e.g. 15-oxo 5, 16-oxo 6 and other oxo-steroids). The electrooxidation of cholesterol derivatives also produced ketones but the detailed product analysis was not reported. It seems that the active species for the ketone formation in Gif systems is

• source since no additives were employed. The observed results may be explained by assuming a cathodic reduction of dichloromethane to chloride ions, followed by their diffusion to the anodic compartment, and electrooxidation to chlorine which reacted with cholesterol. An efficient electrochemical

3α,5α-Cyclocholestan-6β-yl ethers as donors of the cholesterol moiety for the electrochemical synthesis of cholesterol glycoconjugates

• Aneta M. Tomkiel,
• Adam Biedrzycki,
• Jolanta Płoszyńska,
• Dorota Naróg,
• Andrzej Sobkowiak and
• Jacek W. Morzycki

Beilstein J. Org. Chem. 2015, 11, 162–168, doi:10.3762/bjoc.11.16

• glycoconjugates from 3β-hydroxy-Δ5-steroids (sterols). The method consists of electrooxidation of a proper cholesterol derivative in the presence of an unactivated sugar with a free hydroxy group at the anomeric position (formation of glycosides) or at any other position (preferentially a primary position) that

• the cyclic voltammogram for 6β-(4-hydroxyphenyloxy)-3α,5α-cyclocholestane (6g) shows two additional anodic peaks at 0.88 V and 1.45 V (curve e, brown). The existence of these peaks is probably connected with electrooxidation of the substituents. It is worth to notice that in the case of 6f and 6g the

• in Scheme 3. The proposed formation of disteroidal oxonium ions accounts for an alkyl (aryl) group transfer from C-6 to C-3. Interestingly, the isomerization itself is not an electrochemical reaction. Electrooxidation is needed only to initiate the whole process, i.e., to generate the homoallylic

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• electrochemical oxidation of unfunctionalised amides (last comprehensively reviewed in 1984 by Prof. T. Shono) [10] to N-acyliminium ion intermediates and their application to synthetic challenges. The Shono electrooxidation route to N-acyliminium intermediates Shono and colleagues reported the first direct

• spatially addressable electrolysis platform’s (SAEP) [56]. This technique has been used to prepare both parallel and combinatorial libraries using Shono-type oxidation on a microarray. Some technical aspects of anodic alkoxylation have been patented [57]. The use of the Shono-type electrooxidation in

• multiple branches of synthetic organic chemistry The enantioselective electrooxidation of sec-alcohols mediated by azabicyclo-N-oxyls has been reported by Onomura and colleagues [58][59]. The azabicyclo-N-oxyl oxidation mediators were themselves prepared by anodic methoxylation. A chiral example of the