Enantioselective radical chemistry: a bright future ahead

• Anna C. Renner,
• Sagar S. Thorat,
• Hariharaputhiran Subramanian and
• Mukund P. Sibi

Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174

• abundance, low cost, less toxicity, and existence of multiple oxidation states (I, II, and III) make copper an essential transition metal for catalytic purposes [60][61]. The fact that copper, like other transition metals, has multiple oxidation states makes it an excellent redox catalyst. Owing to the

• was the use of ferrocene as a redox mediator, which played an important role in preventing substrate decomposition under the electrochemical conditions. An electrochemical method enabled regio- and enantioselective radical reactions of silyl polyenolates with racemic α-branched esters, yielding

Pathway economy in cyclization of 1,n-enynes

• Hezhen Han,
• Wenjie Mao,
• Bin Lin,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173

• enabling more efficient utilization of limited raw materials [1][2]. Two years later, Wender proposed “step economy” advocating optimized synthetic routes and strategies to minimize the number of steps required for constructing target molecules [3][4]. In 2008, “redox economy” was introduced by Baran [5

• ]. Similar to “atom and step economies”, this concept emphasizes prioritizing the minimization of redox manipulations during synthesis to achieve linear and stable progression of oxidation states in intermediates. In recent years, “pot economy” and “time economy” were proposed by Hayashi, underscoring the

• circumvents cumbersome late-stage functional group manipulations and perfectly aligns with the principles of step economy, time economy, and redox economy. Over the past few decades, chemists have rapidly directed this efficient synthetic paradigm toward diverse targets by skillfully regulating reaction

Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings

• Lifen Peng,
• Ting Wang,
• Zhiwen Yuan,
• Bin Li,
• Zilong Tang,
• Xirong Liu,
• Hui Li,
• Guofang Jiang,
• Chunling Zeng,
• Henry N. C. Wong and
• Xiao-Shui Peng

Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166

• transformations far from thermodynamic equilibria have emerged abundantly with the consideration of green chemistry [89][90][91][92]. Redox-active organic compounds, transition metal coordinating compounds and even an electrode surface were commonly employed as catalysts in the electrochemical transformations [93

• ]. Besides, electrochemical cyclization of alkynes is also an important access towards indoles. In 2016, Xu reported the electrochemical intramolecular coupling of urea derivatives to form substituted indoles (Scheme 1) [162]. Using [Cp2Fe] (5 mol %) as the redox catalyst, the intramolecular coupling of

• cationic resonance G quickly. The nucleophilic attack of D2O formed H, which underwent dedeuteration and elimination of DI to form 30a with reduction of deuterated water to generate deuteroxyl ions (OD−) and deuterium gas (D2) at the cathode. This method, using iodide salts as electrolyte and redox

C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

• Meerwein–Ponndorf–Verley reduction, while acetaldehyde is generated in situ by ethanol oxidation (Scheme 50). The equilibrium allows furfural to be simultaneously converted into furfuryl alcohol and 3-(2-furyl)acrolein in one pot through a redox reaction. The highest mass conversion rate of furfural can

Multicomponent reactions IV

• Thomas J. J. Müller and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2082–2084, doi:10.3762/bjoc.21.163

• a strong emphasis on heterocycle synthesis. Beyond traditional condensation-based approaches, mechanistically innovative crossovers – linking metal catalysis with radical chemistry and, more recently, with photo(redox) catalysis – are opening entirely new avenues for MCR development. Finally, seven

Bioinspired total syntheses of natural products: a personal adventure

• Zhengyi Qin,
• Yuting Yang,
• Nuran Yan,
• Xinyu Liang,
• Zhiyu Zhang,
• Yaxuan Duan,
• Huilin Li and
• Xuegong She

Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160

• approach. This key reaction mimics the plausible biosynthetic pathway and demonstrates great efficiency and sole diastereoselectivity, showcasing the plausibility of the biosynthetic proposal. Further redox manipulations of the last olefin and deprotection ultimately provided chabranol. To clearly confirm

• oxa-carbenium cation triggered by an acid to proceed a Friedel–Crafts reaction to afford the dibenzocyclooctene skeleton. On the other hand, eupomatilone would undergo redox transformations to generate another oxa-carbenium cation to undergo a Friedel–Crafts reaction to form a spirocyclic skeleton

Photochemical reduction of acylimidazolium salts

• Michael Jakob,
• Nick Bechler,
• Hassan Abdelwahab,
• Fabian Weber,
• Janos Wasternack,
• Leonardo Kleebauer,
• Jan P. Götze and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153

• acid derivative substrates [16]. Over the last few years, a wide range of valuable NHC-catalyzed transformations have also been developed that incorporate redox steps. As an enamine species, single-electron oxidation of a Breslow intermediate is comparatively favored with the resulting open shell

• direct excitation of the benzoylazolium salt with the excited state species 1*, which subsequently reacts with TESH. Comparison of the redox potential of the silane (+1.54 V vs ferrocene) with the estimated excited-state potential of the azolium salt 1* (+1.70 V vs ferrocene) suggest that direct electron

Enantioselective desymmetrization strategy of prochiral 1,3-diols in natural product synthesis

• Lihua Wei,
• Rui Yang,
• Zhifeng Shi and
• Zhiqiang Ma

Beilstein J. Org. Chem. 2025, 21, 1932–1963, doi:10.3762/bjoc.21.151

• diastereoselectivity. Compound 288 was then treated with Co(acac)2, 1,1,3,3-tetramethyldisiloxane (TMDSO), and O2 in degassed iPrOH, undergoing a hydrogen-atom-transfer (HAT)-initiated redox radical cascade to give pentacyclic alcohol 289, which was converted to C18/19 diol 290 in two steps. To differentiate the two

Synthesis of N-doped chiral macrocycles by regioselective palladium-catalyzed arylation

• Shuhai Qiu and
• Junzhi Liu

Beilstein J. Org. Chem. 2025, 21, 1917–1923, doi:10.3762/bjoc.21.149

• -bridged structural analogs of [1n]metacyclophanes. In comparison to all-carbon [1n]metacyclophanes, the incorporation of N atoms endows them with unique features, such as enhanced molecular dynamics and tunable redox property, positioning them as key precursors to construct organic high-spin materials [20

Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs

• Almaz A. Zagidullin,
• Emil R. Bulatov,
• Mikhail N. Khrizanforov,
• Damir R. Davletshin,
• Elvina M. Gilyazova,
• Ivan A. Strelkov and
• Vasily A. Miluykov

Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148

• alkylating agents 1–3. The motivation behind these experiments was to explore whether these compounds, which individually exhibit no appreciable redox activity in the potential window applied, can chemically modify (alkylate) serum albumin and thus suppress its characteristic oxidation peaks. Human serum

• themselves exhibit no discernible redox activity in this potential range when tested in the absence of HSA. Consequently, any changes in the recorded voltammogram could be attributed to the interaction (alkylation) of albumin rather than to new electrochemical processes arising directly from the compounds

Stereoselective electrochemical intramolecular imino-pinacol reaction: a straightforward entry to enantiopure piperazines

• Margherita Gazzotti,
• Fabrizio Medici,
• Valerio Chiroli,
• Laura Raimondi,
• Sergio Rossi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2025, 21, 1897–1908, doi:10.3762/bjoc.21.147

• voltammetry measurements were also carried out in order to evaluate the electrochemical redox properties of the species involved in the process and to provide evidence for the behavior of the monoprotonated and the bisprotonated diimines, 3a and 4a (Scheme 8). The cyclic voltammogram of the starting diimine

Research progress on calixarene/pillararene-based controlled drug release systems

• Liu-Huan Yi,
• Jian Qin,
• Si-Ran Lu,
• Liu-Pan Yang,
• Li-Li Wang and
• Huan Yao

Beilstein J. Org. Chem. 2025, 21, 1757–1785, doi:10.3762/bjoc.21.139

• times. This bis-vesicle structure possesses the following intelligent responsive characteristics: (1) temperature sensitivity originating from the enthalpy-driven nature of the host–guest interaction; (2) redox responsiveness due to the reversible electron transfer of MVC12; (3) competitive complexation

• making the system sensitive to cyclodextrins. Experiments have confirmed that this carrier can efficiently encapsulate DOX and trigger drug release through multiple stimuli, demonstrating good potential for anticancer therapy in vitro. This intelligent delivery system, integrating temperature, redox, and

Photocatalysis and photochemistry in organic synthesis

• Timothy Noël and
• Bartholomäus Pieber

Beilstein J. Org. Chem. 2025, 21, 1645–1647, doi:10.3762/bjoc.21.128

• ) transition, resulting in a long-lived charge-separated species. In this excited state, [Ru(bpy)3]Cl2 is both a more potent oxidant and reductant than in its ground state. This reactivity, in combination with the reversible redox behavior of the metal complex, enables reductive or oxidative quenching cycles

Thermodynamic equilibrium between locally excited and charge transfer states in perylene–phenothiazine dyads

• Issei Fukunaga,
• Shunsuke Kobashi,
• Yuki Nagai,
• Hiroki Horita,
• Hiromitsu Maeda and
• Yoichi Kobayashi

Beilstein J. Org. Chem. 2025, 21, 1577–1586, doi:10.3762/bjoc.21.121

• energy gap between them. Phenothiazine (PTZ) and perylene (Pe) are well-known molecular components for designing π-orthogonal D–A systems [13][14][15]. PTZ is an excellent electron donor due to its strong electron-donating ability and redox tunability, while Pe is often used as a robust acceptor

Azobenzene protonation as a tool for temperature sensing

• Antti Siiskonen,
• Sami Vesamäki and
• Arri Priimagi

Beilstein J. Org. Chem. 2025, 21, 1528–1534, doi:10.3762/bjoc.21.115

• emerged as staple building blocks in smart materials, from light-responsive norbornadienes in molecular solar thermal energy storage [2] to pH-sensitive spiropyrans in cell imaging [3], and redox-active viologens in memory junctions [4]. Among the different molecular switches azobenzenes stand out due to

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• versatile scaffolds for chiral optoelectronic applications. The incorporation of nitrogen enables precise modulation of electronic structures, redox characteristics, and intermolecular interactions, thereby enhancing performance in circularly polarized luminescence (CPL), thermally activated delayed

• fluorescence (TADF), and chiral sensing. Notably, recent developments have yielded π-extended, structurally robust, and stimuli-responsive azahelicenes exhibiting record-high dissymmetry factors (|gabs| and |glum|), elevated CPL brightness (BCPL), and efficient integration into CPL-OLEDs and redox-switchable

• structures, enhance solubility, and expand functional diversity [6]. Substituting carbon atoms with electron-deficient nitrogen atoms introduces new opportunities to fine-tune redox potentials, charge-transport behavior, and intermolecular interactions [7]. These modifications have proven especially valuable

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

• Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

• (89%). Interestingly, the fusion of two azulene units at peri-position induces the significant orbital interaction, resulting in a very narrow HOMO–LUMO gap in 172. Consequently, 172 exhibits NIR absorption properties (λmax = 1180 nm, tail to 1720 nm) and reversible redox behaviours (electrochemical

Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

• Jiangfei Chen,
• Yi-Lin Qu,
• Ming Yuan,
• Xiang-Mei Wu,
• Heng-Pei Jiang,
• Ying Fu and
• Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

• radical C, which adds to the N-arylacrylamide, followed by intramolecular cyclization and deprotonation to form the final products 19. To further expand the radical difunctionalization toolbox, electrochemical approaches have emerged as a green and efficient alternative, offering precise redox control

• employed as a redox catalyst, Na2CO3 as a base, and n-Bu4NBF4 as the electrolyte, all participating in an undivided electrolytic cell with a reticulated vitreous carbon (RVC) anode and a platinum (Pt) cathode at a constant current of 10 mA, in a co-solvent mixture of MeOH/THF 2:1 for 3 hours to deliver the

• selection, solvents, and current density, the best results were obtained using tetrabutylammonium bromide as the catalyst in CH₃CN, with a low catalyst loading of 2 mol %, and palladium wire as the cathode, yielding the target compound in 81% yield. This study capitalized on the use of bromide ions as redox

Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates

• Alexander S. Budnikov,
• Igor B. Krylov,
• Fedor K. Monin,
• Valentina M. Merkulova,
• Alexey I. Ilovaisky,
• Liu Yan,
• Bing Yu and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96

• -centered radical from diisopropyl H-phosphonate (2a). In addition, the anion affects the redox properties of the copper ion, and thus the optimal choice is important to achieve both sufficient oxidative properties and catalyst recycling by reoxidation with O2. The employment of Mn(acac)3 and FeCl3, which

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

• addition, the method could be scaled up to a gram scale. Redox-driven ylide reactions have gained increasing attention to tackle several disadvantages of traditional ylide-type reactions, such as use of reagents in excess and harsh reaction conditions. For example, Werner and co-workers (2019) reported a

• catalytic Wittig reaction using phosphetane oxide 412 as redox cycling catalyst using silanes as the reductant to convert aldehydes and α-bromoesters into the corresponding cinnamate esters 44, 154, and 413. The reaction proceeds via formation of nucleophilic phosphane 414 (Scheme 87A) [147]. Moreover

Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts

• Katy Medrano-Uribe,
• Jorge Humbrías-Martín and
• Luca Dell’Amico

Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76

• is a particular interest in the obtainment of organic molecules with well-balanced redox potentials in the excited state that can act as bimodal photocatalysts, facilitating their use in oxidative and reductive quenching cycles. In this sense, it is crucial to understand the molecule's structure

• absorption profile in the visible region, ii) a long lifetime of the excited states, and iii) balanced redox potentials in both the ground and excited states [7]. In 2018, Zeitler and her collaborators conducted an innovative and in-depth study on modulating the photochemical properties of a family of donor

• –acceptor cyanoarenes [8]. They employed various nitrogen donor molecules attached to diversely substituted acceptor cores. This systematic approach allowed the authors to develop new organic photocatalysts (PCs) with strong reductive or oxidative properties based on the different redox potentials. Although

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• Electrochemical reaction cells When a redox reaction occurs indirectly, chemical energy is transformed into electrical energy. A device that facilitates this conversion is known as an electrochemical cell. Electrochemical reaction cells are divided into two primary categories: galvanic (voltaic) and electrolytic

• . They consist of two electrodes – anode (where oxidation occurs) and cathode (where reduction occurs) – immersed in an electrolyte. Galvanic cell The redox reaction occurs spontaneously in these cells, converting chemical energy into electrical energy. The potential difference between the two electrodes

• resistance, and maintain ion balance (e.g., LiClO4, n-Bu4NBF4), and active electrolytes, which participate directly in redox reactions, acting as oxidizing or reducing agents (e.g., H2SO4, Et4NOH). Choosing the proper electrolyte affects reaction efficiency, selectivity, and overall performance. Electrodes

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

• Olesja Koleda,
• Janis Sadauskis,
• Darja Antonenko,
• Edvards Janis Treijs,
• Raivis Davis Steberis and
• Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

• decarboxylation/cyclization conditions, and the respective 2-aminoproline derivatives 6a–c were obtained in 49–75% yield. Redox-sensitive 4-anisoyl and 4-cyanobenzoyl groups-containing monoesters 9d,e are also suitable as substrates as evidenced by the formation of 6d,e in 38–63% yields. Not only N-tosylates

Photocatalyzed elaboration of antibody-based bioconjugates

• Marine Le Stum,
• Eugénie Romero and
• Gary A. Molander

Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49

• selectivity and the preservation of sensitive biological structures when appropriate redox potentials of photocatalysts are applied to the targeted amino acid. Additional advantages of photoinduced reactions include the ability to perform the reactions rapidly (typically <15 minutes). It was only in the late

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

• [17][18]. An important drawback of this solvent is the difficulty of its removal from the reaction crude, and extractions with water are commonly employed before purification. Depending on the reaction conditions, DMSO can be transformed into different products, e.g., under redox conditions, DMSO can