Substituent effects in N-acetylated phenylazopyrazole photoswitches

• Radek Tovtik,
• Dennis Marzin,
• Pia Weigel,
• Stefano Crespi and
• Nadja A. Simeth

Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66

• higher to equal ΦE→Z. Interestingly, for R = Me and H, we recorded higher QYs in NMe-PAPs than in NAc-PAPs (22% and 45% for R = H and R = Me in NMe-PAP vs 14% and 44% for the acetylated ones). In contrast to the excitation of the π→π* state in NAc-PAPs, the isomerization process varies in efficiency when

Synthesis and photoinduced switching properties of C₇-heteroatom containing push–pull norbornadiene derivatives

• Daniel Krappmann and
• Andreas Hirsch

Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64

• , it is essential not only to achieve a high storage density and good quantum efficiency for the isomerization process but also to ensure large half-lifes and durability in switching reliability [20]. By making structural adjustments to the parent carbon scaffold, it is possible to target specific

Regioselective formal hydrocyanation of allenes: synthesis of β,γ-unsaturated nitriles with α-all-carbon quaternary centers

• Seeun Lim,
• Teresa Kim and
• Yunmi Lee

Beilstein J. Org. Chem. 2025, 21, 800–806, doi:10.3762/bjoc.21.63

• , bromo, trifluoromethyl, or methoxy groups on the phenyl ring, were smoothly converted into β,γ-unsaturated nitriles 3t–x with high efficiency. Particularly, allenes 1y and 1z containing benzodioxane or naphthalene moieties were well-tolerated under these reaction conditions, affording nitriles 3y and 3z

• reaction conditions, broad functional group compatibility, and high efficiency, enabling the synthesis of new and versatile functionalized β,γ-unsaturated nitriles containing α-all-carbon quaternary centers with exceptional selectivity. The practicality of this approach was validated through gram-scale

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

• efficiency of reactions [14][15][16][17][18][19][20][21]. Organophosphorous compounds are essential materials with broad applications in medicinal chemistry, synthesis, agriculture, as ligands, and intermediates to prepare complex compounds. Due to their importance, scientists have introduced many studies in

• reduction occur in separate compartments, separated by a diaphragm or salt bridge, to prevent reactant mixing and improve efficiency (e.g., Daniel cell). However, in undivided cells, both reactions occur in a single compartment without separation, resulting in a more straightforward design but potentially

• lower efficiency (e.g., some electrolytic cells). Role of electrolytes in organic electrochemical reactions Electrolytes are crucial for conductivity and reaction stability in organic electrochemical reactions. They are categorized as supporting electrolytes, which enhance conductivity, reduce

New advances in asymmetric organocatalysis II

• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 766–769, doi:10.3762/bjoc.21.60

• describes the enantioselective Michael addition of pyrazoline-5-ones to α,β-unsaturated ketones. The enantioselectivity and chemical efficiency of this transformation were achieved with a cinchona-alkaloid-derived primary-amine–Brønsted acid composite [22]. A good demonstration of how organocatalysis

Copper-catalyzed domino cyclization of anilines and cyclobutanone oxime: a scalable and versatile route to spirotetrahydroquinoline derivatives

• Qingqing Jiang,
• Xinyi Lei,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2025, 21, 749–754, doi:10.3762/bjoc.21.58

• significantly lower yields of 3aa (Table 1, entry 2). Replacing the Cu(TFA)2 catalyst with other copper sources, such as cuprous chloride (CuCl), cuprous thiocyanate (CuSCN), copper bromide (CuBr2), copper trifluoromethanesulfonate (Cu(OTf)2), and copper powder resulted in diminished reaction efficiency (Table

Synthesis of HBC fluorophores with an electrophilic handle for covalent attachment to Pepper RNA

• Raphael Bereiter and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 727–735, doi:10.3762/bjoc.21.56

• (8), MsOc3HBC (14), and MsOc3HBC-vinyl (22)) as reported previously [11]. Nine more HBC derivatives with altered handle lengths and different electrophilic groups are introduced in this study. Furthermore, we include an evaluation of the efficiency of all reactive fluorophores (previously introduced

Recent advances in allylation of chiral secondary alkylcopper species

• Minjae Kim,
• Gwanggyun Kim,
• Doyoon Kim,
• Jun Hee Lee and
• Seung Hwan Cho

Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51

• scope and efficiency of these reactions. A notable advancement came from Knochel's introduction of dialkylzinc reagents in 1999, which substantially broadened the range of applicable organometallic compounds [23]. Subsequent significant progress was achieved independently by Feringa and Alexakis through

• into a powerful and versatile tool in asymmetric synthesis, capable of employing a wide array of organometallic reagents that furnish the desired compounds with high efficiency and selectivity. The regioselective asymmetric construction of stereogenic carbon centers from prochiral allylic substrates

• regioselectivity (SN2/SN2' = >99:1). The reaction with 3-methylbut-2-en-1-yl bromide (15) was particularly noteworthy, as it exhibited superior selectivity compared to the corresponding phosphates. The high efficiency of this protocol was demonstrated through the synthesis of various functionalized alkenes with

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

• , NaOAc) did not improve the efficiency of the anodic decarboxylation/cyclization reaction (Table 1, entries 2–4). Even though the amount of hemiaminal 10a was slightly reduced, the formation of amino acid ester 11a as side product was observed in the crude reaction mixture (Table 1, entries 2–4). The

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

• strategy maximizes the efficiency and specificity of functionalization, representing a significant advancement in the selective modification of antibodies. This method demonstrated an innovative mode of selectivity, even though some drawbacks remain. For example, the 1-methyl-4-arylurazole used in these

• transformations targeted toward a variety of diverse canonical amino acids would introduce more versatility, efficiency, and convenience in the construction of these increasingly important structural units. Cautionary considerations Photoredox chemistry offers a powerful approach for the targeted modification of

Total synthesis of (±)-simonsol C using dearomatization as key reaction under acidic conditions

• Xiao-Yang Bi,
• Xiao-Shuai Yang,
• Shan-Shan Chen,
• Jia-Jun Sui,
• Zhao-Nan Cai,
• Yong-Ming Chuan and
• Hong-Bo Qin

Beilstein J. Org. Chem. 2025, 21, 601–606, doi:10.3762/bjoc.21.47

• reductive elimination with Zn/AcOH and spontaneous oxy-Michael addition. This route largely enhances the synthetic efficiency and shortens the number of synthetic steps. The whole synthesis route involves 8 steps and affords the final product in a total yield of 13%, which could be the shortest synthesis

Sequential two-step, one-pot microwave-assisted Urech synthesis of 5-monosubstituted hydantoins from L-amino acids in water

• Wei-Jin Chang,
• Sook Yee Liew,
• Thomas Kurz and
• Siow-Ping Tan

Beilstein J. Org. Chem. 2025, 21, 596–600, doi:10.3762/bjoc.21.46

• . Additionally, the reaction proceeds efficiently without the need for toxic or moisture-sensitive reagents, further making it suitable for large-scale applications. The shorter reaction time (less than 2 hours) also contributes to improve energy efficiency when compared to traditional methods. These factors

• demonstrate that the process can be effectively scaled up, particularly in industries that prioritize sustainability and operational efficiency. In terms of green chemistry principles, this approach already meets several key goals, such as reducing the use of hazardous reagents and solvents, increasing

• reaction efficiency, and minimizing waste. Future studies can quantitatively evaluate these aspects using established metrics such as E-factor, atom economy, and reaction mass efficiency. These indicators will provide a more comprehensive evaluation of the environmental sustainability of the reaction and

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

• temperatures, no specifically prepared solvents), one-pot, batch processes leading to tandem or cascade reactions, resource efficiency through the application of the 12 principles of Green Chemistry, and readily available starting materials such as waste materials from food production processes [1][2][3]. In

• reported using an alternative synthetic strategy [92], but lower efficiency in terms of yields, number of steps, and scope compared to this multicomponent methodology. Inspired by this previous work, Sharma et al. improved the reaction for free and immobilized glyoxylic acid, with and without acid

Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• irradiation conditions. Inefficient intersystem crossing (or complete lack thereof) and short singlet-state lifetimes can both affect the efficiency of a photoreaction [20]. Crystal packing Similar to Cl2B, the potentially reactive double bonds in Me2B are coplanar and parallel, with a torsion angle of 0(0

Synthesis of N-acetyl diazocine derivatives via cross-coupling reaction

• Thomas Brandt,
• Pascal Lentes,
• Jeremy Rudtke,
• Michael Hösgen,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2025, 21, 490–499, doi:10.3762/bjoc.21.36

• Abstract Diazocines are photoswitches derived from azobenzenes by bridging the two phenyl rings in ortho position with a CH2CH2 group forming an eight membered (diazocine) ring. Diazocine is superior to most azobenzenes in almost all photophysical properties (switching efficiency, quantum yield

• azobenzene is that the switching efficiency decreases sharply with increasing water content in the solvent. In a recently published paper, we reported that replacing one CH2 group in the bridge with NCOCH3 not only confers intrinsic water solubility, but also largely eliminates the problem of reduced

• switching efficiency in aqueous solutions. In order to investigate the chemistry of this promising photoswitch and to unlock further applications, we now investigate strategies for the synthesis of derivatives, which are based on cross-coupling reactions. Fourteen vinyl-, aryl-, cyano-, and amino

Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• bacterial as well as eukaryotic aspartyl-, asparaginyl-, histidyl- and tyrosyl-tRNA isoacceptors bearing the G34U35N36 anticodon motif [1]. Like other tRNA anticodon modifications, queuosine has been shown to increase translational fidelity and efficiency [2]. Structurally, queuosine and preQ1 (compound 1

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• hydrogen-atom transfer or solvolysis are often observed. A technological solution to cope with the Beer–Lambert law was offered by flow chemistry [19][20][21] by employing microreactors with reduced optical paths to enhance irradiation efficiency [22][23][24]. Photon-limited reactions, whose efficiency is

• the surface area of the solids and, therefore, irradiation efficiency. UV lamps (e.g., medium-pressure Hg lamps) are typically used for irradiation, thus requiring specialized safety equipment. While it offers some control over pressure and duration, manual grinding suffers from inconsistencies due to

• in enhancing the mixing efficiency and increasing the exposure of the surface of the reaction mixture to light. Additionally, the formation of compound 8.2 was associated with the observation of an initial molten state of the mixture, which could have promoted single-electron-transfer processes that

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• , chemists have made use of selectively reactive chemicals by handling them, individually, in unreactive bottles. Meanwhile, Nature has learned to convert mixtures of unreactive chemicals by handling them in selectively reactive bottles (enzymes). Only the latter approach offers the efficiency, rate

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

Synthesis, characterization, antimicrobial, cytotoxic and carbonic anhydrase inhibition activities of multifunctional pyrazolo-1,2-benzothiazine acetamides

• Ayesha Saeed,
• Shahana Ehsan,
• Muhammad Zia-ur-Rehman,
• Erin M. Marshall,
• Sandra Loesgen,
• Abdus Saleem,
• Simone Giovannuzzi and
• Claudiu T. Supuran

Beilstein J. Org. Chem. 2025, 21, 348–357, doi:10.3762/bjoc.21.25

• to weak antimicrobial efficiency against E. coli, and C. albicans (see Figure S43 in Supporting Information File 1). These experiments showed that compounds 7b and 7h have potential antistaphylococcal activity. Microbroth dilution assays [52] were performed for the determination of MIC (minimum

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• become a powerful approach for achieving sustainable chemical transformations, combining high efficiency with energy-saving, mild conditions. By harnessing the deeper penetration and selectivity of red and near-infrared light, this method minimizes the side reactions typical of higher-energy sources

• states. In this section, the document highlights applications of these complexes in reactions like ring-closing metathesis and polymerization, where red light’s deeper penetration enhances yields and efficiency, particularly for large-scale reactions. The second section broadens the focus to explore

• efficiency of photoredox-catalyzed reactions. Absorption in the red region opens up innovative opportunities for photochemical transformations. First, the employed photon has the lowest energy in the electromagnetic spectrum of visible light, which allows for safer laboratory conditions in terms of

Heteroannulations of cyanoacetamide-based MCR scaffolds utilizing formamide

• Marios Zingiridis,
• Danae Papachristodoulou,
• Despoina Menegaki,
• Konstantinos G. Froudas and
• Constantinos G. Neochoritis

Beilstein J. Org. Chem. 2025, 21, 217–225, doi:10.3762/bjoc.21.13

• convergent chemistry characterized by diversity, complexity and efficiency. MCRs are compatible with C1 chemistry due to the generally great tolerance of different functional groups. They have been mostly employed in the synthesis of oxazolidinones and oxazinanones utilizing CO2 and CO [4][16][17][18][19][20

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

• Seungmin Lee,
• Minsuk Kim,
• Hyewon Han and
• Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

• motifs such as a benzofuran, indazole, and quinoline were also shown to undergo the desired Markovnikov amidation with high efficiency (23j–l). Several mechanistic experiments were performed to rationalize the reaction pathways. As shown in Figure 7, copper hydride, generated from a copper precatalyst

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

• functionalization of highly complex and diverse molecules, such as those of pharmaceuticals and natural products, has provided new retrosynthetic disconnections for complex compounds, contributing to improved resource efficiency [41][42][43][44][45][46]. Recently, the merging of C–H activation and electrochemistry

Cu(OTf)₂-catalyzed multicomponent reactions

• Sara Colombo,
• Camilla Loro,
• Egle M. Beccalli,
• Gianluigi Broggini and
• Marta Papis

Beilstein J. Org. Chem. 2025, 21, 122–145, doi:10.3762/bjoc.21.7

• , also in regio- and stereoselective processes. The interest for these strategies arises from the cost-effectiveness as one-pot processes, the ease of application and the great efficiency when directed to the synthesis of biologically active compounds. Plausible general catalytic activation for ionic or