Formaldehyde surrogates in multicomponent reactions

• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

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

• asymmetric C(sp3)–H alkynylation of tertiary cyclic amines by merging Cu(II)/TEMPO catalysis with electrochemistry to yield chiral C1-alkynylated tetrahydroisoquinolines (THIQs) (Figure 5) [50]. As a co-catalytic redox mediator, TEMPO plays an essential role in the formation of iminium intermediate 15 and in

• 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

• employing electricity as an oxidant (Figure 11) [60]. Mechanistic studies have indicated that n-Bu4NI acts as a redox mediator at the anode, and the electron transfer between the copper complex and the iodine radical is the rate-determining step. The author proposed a catalytic cycle, as illustrated in

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

• ) as the redox mediator, this method showed excellent tolerance across various arenes and alkenes. The selective LSF of biorelevant complex molecules demonstrated significant potential for drug exploration (Scheme 42a). One year later, the same group disclosed the dehydrogenative cross-coupling of two

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

• conditions. The key to success is the use of 1,3-dicyanobenzene as a redox mediator and visible-light irradiation, which effectively suppresses the formation of simple reduction, i.e., hydrodehalogenation, products to afford the desired products in good to high yields. Mechanistic investigations proposed

• hydroarylation with (hetero)aryl halides using 1,3-dicyanobenzene as a redox mediator under visible-light irradiation. Results and Discussion We began the investigation of the electroreductive hydroarylation using methyl 4-chlorobenzoate (1a) and methyl acrylate (2a) as model substrates (Table 1). After

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• generate alkyl radicals for surface modification [161]. Electrochemical surface modification also works for inert PTFE surfaces in the presence of a 2,2’-dipyridyl redox mediator [162]. Photons and high-energy charged particles can transfer their energy to bound electrons in atoms, exciting the electron to

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• artificial photosynthesis. Systems for photocatalytic carbon dioxide reduction are optimized using sacrificial electron donors. One strategy for coupling carbon dioxide reduction and water oxidation to achieve artificial photosynthesis is to use a redox mediator, or recyclable electron donor. This review

• sacrificial electron donors, and for researchers interested in designing new redox mediator and recyclable electron donor species. Keywords: artificial photosynthesis; photocatalysis; redox couple; sacrificial electron donor; solar fuels; Introduction Artificial photosynthesis research has resulted in the

• water splitting, sacrificial electron donors are used as an electron source to act as a placeholder for NADPH and the water-splitting reaction. To recouple water splitting and carbon dioxide reduction the sacrificial donors need to be replaced by redox mediators. A redox mediator is a compound or

Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface

• Kendra Drayton-White,
• Siyue Liu,
• Yu-Chia Chang,
• Sakashi Uppal and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156

• inserting a functionalized electrode into a solution containing a redox mediator. The mediator is oxidized at the electrodes in the array and reduced at a remote counter electrode. This results in a current that can be measured at each electrode in the array. The protein target is then added to the solution

• functionalized electrode into a solution containing a redox mediator and then monitoring the current associated with a redox mediator. The method is different relevant to the traditional methods lacking the polymer surface in that the current is dependent on changes to the polymer coating; a situation that can

• details) containing ferrocene carboxylic acid as a redox mediator. Initially, the array was placed in a solution containing the smallest concentration of Gαi1 and then a current measured for the mediator at the electrodes in the array. The solution was then removed, replaced with a mediator/buffer

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH₄I

• Shang-Feng Yang,
• Pei Li,
• Zi-Lin Fang,
• Sen Liang,
• Hong-Yu Tian,
• Bao-Guo Sun,
• Kun Xu and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

• and Life, Beijing University of Technology, Beijing 100124, China 10.3762/bjoc.18.130 Abstract The electrochemical preparation of 2-aminothiazoles has been achieved by the reaction of active methylene ketones with thioureas assisted by ᴅʟ-alanine using NH4I as a redox mediator. The electrochemical

Cathodic generation of reactive (phenylthio)difluoromethyl species and its reactions: mechanistic aspects and synthetic applications

• Sadanobu Iwase,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2022, 18, 872–880, doi:10.3762/bjoc.18.88

• place. Thus, it was found that o-phthalonitrile should work as an electron transfer catalyst, i.e., a redox mediator. On the bases of the cyclic voltammetric measurements, the cathodic reduction of 1 was carried out at a constant potential using o-phthalonitrile as mediator. As shown in Scheme 5, the

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• developments, which enables a diverse range of previously inaccessible organic transformations in milder reaction conditions [31][32][33][34][35][36][37][38][39][40]. Here, by absorbing visible light, a photocatalyst can function as a single-electron redox mediator through an oxidative or reductive quenching

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

• formation of (S)-63 over (R)-63. Hence, (S)-63 would be converted to ketone 62 via hydride transfer, whereas (R)-63 might be predominantly retained. Very recently, Wirth’s group demonstrated the use of chiral iodoarene 67 as a redox mediator for the electrochemical lactonization of diketo acid derivatives

Functional panchromatic BODIPY dyes with near-infrared absorption: design, synthesis, characterization and use in dye-sensitized solar cells

• Quentin Huaulmé,
• Cyril Aumaitre,
• Outi Vilhelmiina Kontkanen,
• David Beljonne,
• Alexandra Sutter,
• Gilles Ulrich,
• Renaud Demadrille and
• Nicolas Leclerc

Beilstein J. Org. Chem. 2019, 15, 1758–1768, doi:10.3762/bjoc.15.169

• devices sensitized with BOD-TTPA-alk are slightly higher compared to the ones prepared out of BOD-TTPA. This could be explained by the presence of the alkyl chains on the TPA units that are known to prevent the redox mediator to interact with the TiO2 surface thus reducing the probability to observe a

Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• electrosynthesis. Keywords: cyclic voltammetry; ferrocene; paramagnetic NMR spectroscopy; redox mediator; spectroelectrochemistry; Introduction Since its discovery, ferrocene (FcH) has been established as versatile redox-active building block [1][2][3]. Ferrocene can be reversibly oxidized to the 17 valence

• reactions [29], borylations of arenediazonium salts [30] and in C–H imidation reactions of (hetero)arenes [31] (Scheme 1b,c). Ferrocene has been used as redox mediator for the electrochemical modification of carbon surfaces via electrochemical oxidation of carboxylates [32][33], as mediator for

• application as redox mediator (Scheme 2) [55][56]. Ferrocenyl esters 1–4 are synthetically accessible via the acids of 1 [45][46], 2 [57], 3 and 4 [54] in a direct selective metalation of ferrocene [54][57][58][59][60], quenching with carbon dioxide, followed by esterification [45][46][47][48][54]. The 1,1

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• of 4 equivalents of the thiol is needed for the reaction. The authors addressed this limitation in a later report (vide infra). Functional groups like alcohols, Boc-protected amines, carbonyls, esters and halides are tolerated. One year later, Yoon and co-workers described a redox mediator concept

• apply cysteine-containing glutathione for the reaction with a series of highly functionalized alkenes to form the respective sulfide adducts with yields up to 99%. This concept attracted attention from different fields of chemistry. Boyer and co-workers for example applied the redox mediator accelerated

• concept [32] (Scheme 4b) [34]. They first introduced alkene moieties to the chemically inert lignin structure by esterification of the hydroxy groups of lignin with 4-pentenoic acid. Subsequent radical thiol–ene reaction with aliphatic thiols, using [Ru(bpy]3Cl2 as photocatalyst and p-toluidine as redox

A hybrid electron donor comprising cyclopentadithiophene and dithiafulvenyl for dye-sensitized solar cells

• Gleb Sorohhov,
• Chenyi Yi,
• Michael Grätzel,
• Silvio Decurtins and
• Shi-Xia Liu

Beilstein J. Org. Chem. 2015, 11, 1052–1059, doi:10.3762/bjoc.11.118

• % with cobalt tris(bipyridine)-based redox mediator. With iodide/triiodide as redox shuttle, both devices based on dye 1 and dye 2 showed higher photocurrent densities of 9.26 mA cm−2 and 12.26 mA cm−2, respectively. However, they showed lower photovoltages of 485 mV and 493 mV. As a result, in the

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

• radicals from the cation pool method [24][25]. Indirect electrolysis methods The only indirect anodic oxidation method to perform the Shono-oxidation with a thiophenyl electroauxiliary has been reported by Fuchigami and co-workers [36]. Using a catalytic triarylamine redox mediator, anodic

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• of 2,3-dihydrobenzofuran structures 43 via double-mediatory Wacker-type cyclization of alkenyl phenols 42 [61]. Pd(OAc)2 was used to catalyze the cyclization while TEMPO served as redox mediator for the electrochemical regeneration of the catalytically active Pd(II) species. In contrast to

• . described an indirect electrochemical method for the generation of 2-substituted benzoxazoles from Schiff bases (Scheme 19) [64]. Using 20 mol % NaI as redox mediator, the electrolysis is conducted under galvanostatic conditions in an undivided cell. A two-phase system composed of a sodium carbonate buffer

• converted with α- and β-pinene to form euglobal model compounds 55 and 56. The electrolysis was carried out in an undivided cell under potentiostatic conditions with a CH3NO2/Et4NOTs electrolyte. DDQ was employed as a redox mediator, allowing for operation at a relatively low electrode potential of 0.45 V

Coupled chemo(enzymatic) reactions in continuous flow

• Ruslan Yuryev,
• Simon Strompen and
• Andreas Liese

Beilstein J. Org. Chem. 2011, 7, 1449–1467, doi:10.3762/bjoc.7.169

• both in discontinuous- and continuous-operation modes (Scheme 5) [26]. Cellobiose dehydrogenase was applied to catalyze the oxidation of 12, while laccase was used as a regenerating enzyme coupled by the redox mediator 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). In continuous-flow