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

• an electrophilic handle for the covalent attachment of the ligand to the RNA. The simplicity of the underlying design of irreversibly bound ligand–RNA complexes has provided a new impetus in the fields of covalent RNA labeling and RNA drugging. Here, we present short and robust synthetic routes for

• , DPQ1) and haloalkyl-modified preQ1 and DPQ1. B) The ligand classes of XcnpreQ1 and XcnDPQ1 allow specific formation of covalent small molecule–RNA complexes as has been recently demonstrated (see ref. [4]). Electrophile (E). Three-step syntheses of preQ1 (1) and DPQ1 (2). For the synthesis of m6preQ1

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

• observed in dilute solutions because of the formation of aggregates perturbing electronic transitions [51][52][53]. Moreover, at high concentrations, the formation of electron donor–acceptor (EDA) complexes [54] or exciplexes is expected to be favored, and the effect of mechanical forces on these is worth

• zinc cations to align 1.1 through the formation of hydrogen-bonded coordination complexes. Thus, when a single crystal of the [Zn(bpe)2(H2O)4](NO3)2·8/3H2O·2/3bpe complex was exposed to UV irradiation (dark blue phosphor lamps, λ = 350 nm) for 25 h, only 46% conversion to 1.2 was observed via 1H NMR

• instead of 2 h in a row) proved beneficial to minimize heat accumulation resulting in product decomposition. Next, the authors proved the generality of mechanoluminescence by performing the sulfonylation of alkenes via EDA-complexes photochemistry (Scheme 12B). Thus, when a mixture of 1,1-diphenylethylene

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• sensitivity of in situ obtained complexes 9 and 10 with CN− to different cations. It appeared that the addition of an equivalent amount of Hg(ClO4)2 to an acetonitrile solution selectively and completely restores the initial absorption and fluorescence spectra (Scheme 3). Thus, the obtained compounds

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

• diverse catalyst types and applications. The first section is dedicated to metal-based photocatalysts. Complexes involving metals such as osmium and ruthenium, have dominated red-light photoredox catalysis because of their ability to absorb low-energy photons and sustain redox cycles via stable excited

• 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

• photocatalysts, such as helical carbenium ions and advanced nitrobenzofuran derivatives for applications in phototherapy and controlled drug release, underscoring the potential of red-light photocatalysis in biomedicine. Review Red-light photocatalysis with metal-based complexes Metal-based complexes naturally

Quantifying the ability of the CF₂H group as a hydrogen bond donor

• Matthew E. Paolella,
• Daniel S. Honeycutt,
• Bradley M. Lipka,
• Jacob M. Goldberg and
• Fang Wang

Beilstein J. Org. Chem. 2025, 21, 189–199, doi:10.3762/bjoc.21.11

• this way, we were able to determine the HB donation ability of CF2H-containing compounds on a single scale. As shown in Figure 5, we determined dissociation constants (Kd) of n-Bu3PO···HB donor complexes, revealing several general trends. First, we found that CF2H groups attached to an extended

• , with other easily accessible parameters. We first calculated the Gibbs free energy of formation (ΔGcalc) of the HB complexes of HB donors with trimethylphosphine oxide (Me3PO), which models n-Bu3PO as a hydrogen bond acceptor, and compared these values with experimental data. We realized that such an

• –vis spectroscopic titrations with Reichardt’s dye, and (iii) 1H NMR titrations using n-Bu3PO as a reference HB acceptor. Our studies revealed that the 1H NMR titrations, although tedious, offered reliable binding affinity data for HB complexes involving neutral and cationic donor molecules. This

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

• (Figure 15) [70]. In this catalytic system, catalytic amounts of Cu(sBOX) (L3) and Co(salen) complexes promote the formation of chiral nitriles 89 in the presence of PhSiH3 (88) as the hydride source and TMSCN (21) as the cyanide source via the effective sequential addition of a hydrogen atom and a CN

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

• possible to exclude its action also as Lewis acid. Confirming this dual activity, it should be noted that copper triflate can rarely be replaced by other copper salts or complexes to obtain the same results. In general, catalyst switching does not work with copper triflate, thus supporting its unique

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• from certain plant species (Figure 1) [12]. The acenaphthylene-fused thiophene-based heteroarene 3 is another heterocyclic fluoranthene analogue, which was used as an organic semiconductor in transistors [13]. The synthesis and coordination complexes of the acenaphthylene-fused N-heterocyclic (NHC

Giese-type alkylation of dehydroalanine derivatives via silane-mediated alkyl bromide activation

• Perry van der Heide,
• Michele Retini,
• Fabiola Fanini,
• Giovanni Piersanti,
• Francesco Secci,
• Daniele Mazzarella,
• Timothy Noël and
• Alberto Luridiana

Beilstein J. Org. Chem. 2024, 20, 3274–3280, doi:10.3762/bjoc.20.271

• photochemistry has introduced new ways of generating radicals like photoredox catalysis and via electron donor–acceptor (EDA) complexes [10][11][12][13]. These advances, coupled with modern electrochemical methods, chemical reactor engineering and light emitting diodes (LED), have eliminated the need for thermal

Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts

• Mandeep K. Chahal

Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257

• solutions [18]. Similarly, Burns and co-workers reported di- and tetra-urea picket porphyrins highlighting, the impact of buried solvent molecules, such as DMSO, on the selectivity, affinity, and stoichiometry of anion binding [19]. Iron complexes of tetra-urea picket porphyrins further demonstrate how

• functional versatility [44], and many of these resulting metal complexes are catalytically active [45][46][47]. These synthetic metalloporphyrins take inspiration from biological systems, such as hemes (iron complexes), chlorophylls (magnesium complexes), and vitamin B12 (cobalt complex). Contrary to

• macrocycles as electrocatalysts Development of efficient renewable technologies is a driving force in the efforts to achieve sustainability with the same or even increasing demands for energy worldwide. In this context, transition-metal complexes of tetraazamacrocycles (N4-macrocycle) such as porphyrins

Tailored charge-neutral self-assembled L₂Zn₂ container for taming oxalate

• David Ocklenburg and
• David Van Craen

Beilstein J. Org. Chem. 2024, 20, 3007–3015, doi:10.3762/bjoc.20.250

• metallocontainers which are formed by metal-driven self-assembly have become especially popular to bind various kinds of anions since such systems offer easy to tune confinements. Usually, the utilized complexes are net positive which makes them ideal hosts for anions [56][57][58][59][60][61][62][63]. However, the

• be volatile to simplify complex purification. Second, the solubility of the neutral host complexes usually needs to be improved by the installation of solubility groups, which must be considered during ligand design. The biggest strength of metallocages and metallocontainers, whether they are

• coordinating or which can act as good chelating ligands [65]. The latter holds true for oxalate as shortest dicarboxylate anion which likely forms complexes with all sorts of metals [66][67]. In fact, oxalate’s ideal ligand character is one reason for the aforementioned diseases and this property poses a fatal

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• of allylic peroxidation 2, 4 and 5 were observed (Scheme 4) [24]. Similar transformations were reported later using CuCl as the catalyst [39]. Later, Gade with coauthors demonstrated the allylic peroxidation of cyclohexane with TBHP using the alkylperoxocobalt(III) complexes [Co(BPI)(OAc)(OO-t-Bu

• -t-Bu)2. Allylic peroxidation of 3-substituted prop-1-ene-1,3-diyldibenzenes 8 was performed with TBHP as the oxidant/peroxidation agent and with Cu2O as the catalyst [42] (Scheme 6). The proposed mechanism of peroxides 9 formation does not include peroxo–copper complexes and begins with the

• formation of peroxide 9. The enantioselective peroxidation of alkenes 10 with TBHP with the formation of the optically active products 11 was carried out in good yields and low ee by the use of in situ-generated chiral bisoxazoline–copper(I) complexes (Scheme 7) [43]. Studying the oxidation of α-pinene (12

Multicomponent synthesis of α-branched amines using organozinc reagents generated from alkyl bromides

• Baptiste Leroux,
• Alexis Beaufils,
• Federico Banchini,
• Olivier Jackowski,
• Alejandro Perez-Luna,
• Fabrice Chemla,
• Marc Presset and
• Erwan Le Gall

Beilstein J. Org. Chem. 2024, 20, 2834–2839, doi:10.3762/bjoc.20.239

• nucleophilic organozincate complexes (e.g., LiBuZnBrCl), which is a well-established process in THF [29][30]. Due to the hygroscopic character of LiCl and the necessity to determine the amount of organozinc by iodolysis [20] in order to adjust the stoichiometry of the reagents for the multicomponent coupling

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• , highly sensitive chemosensors via a facile synthetic route/method, we have explored three chelates for lanthanide ions (DO3A, 2,6-pyridinedicarboxylic acid and DO2A), resulting in complexes with different overall charges. Additionally we have explored two copper(II) binding groups (di(2-picolyl)amine and

• aqueous hydrogen sulfide and 100 ppb for gaseous hydrogen sulfide [16]. However, due to the limited aqueous solubility and ligand dissociation of this chemosensor, and to the weakly luminescent bis species at usable concentrations, we extended this work to the lanthanide–macrocycle binary complexes [Ln

• not exhibit any discernible increase in luminescence. As far as we are aware, there are only three reports of lanthanide-based probes for the detection of gaseous hydrogen sulfide. Two are the europium(III) complexes from our group ([Eu(triazole-DPA)3·Cu]3+ and [Eu(DO2A)(triazole-DPA)·Cu]+), which are

C–C Coupling in sterically demanding porphyrin environments

• Liam Cribbin,
• Brendan Twamley,
• Nicolae Buga,
• John E. O’ Brien,
• Raphael Bühler,
• Roland A. Fischer and
• Mathias O. Senge

Beilstein J. Org. Chem. 2024, 20, 2784–2798, doi:10.3762/bjoc.20.234

• one, may have slowed down the protodeboronation process, as substrates with electron-withdrawing groups are postulated to increase the Lewis acidity of the boronic acid, which may allow an increased incidence of protodeboronation to occur. It is also known that aryl–B(Pin) complexes have a greater

• porphyrins Nonplanar porphyrins are known to form supramolecular assemblies [6], either through hydrogen-bonding networks or through π–π interactions. Examples of this can be seen in the trapping of Keggin-type heteropolyoxometalate (POM) through nonplanar Mo(V)–porphyrin complexes [58], or porphyrin

Computational design for enantioselective CO₂ capture: asymmetric frustrated Lewis pairs in epoxide transformations

• Maxime Ferrer,
• Iñigo Iribarren,
• Tim Renningholtz,
• Ibon Alkorta and
• Cristina Trujillo

Beilstein J. Org. Chem. 2024, 20, 2668–2681, doi:10.3762/bjoc.20.224

• considered were calculated using Equation 4 and Equation 5, respectively, where H(A) stands for the enthalpy of the FLP, H(H+) for the enthalpy of the proton, H(F−) for the enthalpy of the fluoride ion, and H([A-H+]) and H([A-F−]) for the enthalpies of the complexes formed between the FLP and a proton and a

Deciphering the mechanism of γ-cyclodextrin’s hydrophobic cavity hydration: an integrated experimental and theoretical study

• Stiliyana Pereva,
• Stefan Dobrev,
• Tsveta Sarafska,
• Valya Nikolova,
• Silvia Angelova,
• Tony Spassov and
• Todor Dudev

Beilstein J. Org. Chem. 2024, 20, 2635–2643, doi:10.3762/bjoc.20.221

• hydrogen bonding, although generally not dominant, can influence the complex formation as well [5]. Cyclodextrins form inclusion complexes with polar and non-polar substances of various aggregate states. This incredible versatility, combined with the enhanced stability against oxidation, as well as

• process. An occupancy of up to 7 hydration water molecules has been found and a comparison between α-CD, β-CD, and γ-CD hydration mechanisms is provided. Results and Discussion Nonhydrated γ-CD As with the other two cyclodextrins (α- and β-), before proceeding to the complexes with water, we considered

• the other complexes only two options were modelled (Figure 2, n = 2–7, structures a and b). The first water molecule can bind to the narrow rim (n = 1; Figure 2, structures a–c) or the wide rim (n = 1; Figure 2, structures d and e). All attempts to position single water molecule in the cavity or near

Efficient modification of peroxydisulfate oxidation reactions of nitrogen-containing heterocycles 6-methyluracil and pyridine

• Alfiya R. Gimadieva,
• Yuliya Z. Khazimullina,
• Aigiza A. Gilimkhanova and
• Akhat G. Mustafin

Beilstein J. Org. Chem. 2024, 20, 2599–2607, doi:10.3762/bjoc.20.219

• in two different ways: with metallophthalocyanine catalysts present and by including hydrogen peroxide as a co-oxidant (Scheme 1). Metal–phthalocyanine complexes (PcM) are recognized as catalysts for gentle, particular oxidation reactions under aerobic [14] and H2O2-based conditions [15][16][17][18

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• cations [21]. Moreover, ion-pairing assemblies of 1a+ and the π-electronic receptor–anion complexes as pseudo-π-electronic anions exhibited electric conductive properties [22][23][24][25]. The structures and electronic states of ions directly affect the arrangement of constituent ions in the assemblies

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

• benzylic position (Scheme 31). 1.3.2 Co-assisted anodic oxidation. In 2021, Xu and colleagues developed an electrocatalytic approach for the intramolecular oxidative allylic amination and C–H alkylation using cobalt–salen complexes as catalysts [43]. In this reaction, the cobalt catalyst [Co(II)] is first

• complex compounds (Scheme 35). In addition, Niu and coworkers reported a similar work on a cobalt-electrocatalyzed atroposelective C–H annulation of benzamides with acetylenes [48]. 1.3.3 Ni-assisted anodic oxidation: Apart from cobalt, nickel complexes have also been applied in anionic oxidations and

Evaluating the halogen bonding strength of a iodoloisoxazolium(III) salt

• Dominik L. Reinhard,
• Anna Schmidt,
• Marc Sons,
• Julian Wolf,
• Elric Engelage and
• Stefan M. Huber

Beilstein J. Org. Chem. 2024, 20, 2401–2407, doi:10.3762/bjoc.20.204

• abstractions, e.g. to activate gold chloride complexes [18][19]. Therefore, besides the development of new bidentate catalyst motifs, we were still interested in the optimization of these “simpler” derivatives. Thus, we designed a new catalyst motif [20] featuring an isoxazole ring, XB donor 7Z, and compared

• preactivation process between the XB donor, the gold complex, or the amide can be assumed. Such a sigmoidal curve for this reaction has also been observed in one of the previous studies on the XB activation of gold complexes [15]. The prototypic iodolium 1BArF showed significantly better results reaching ≈85

• ]. For all catalyst systems, decomposition of the −BArF24 anion was observed via 1H and 19F NMR spectroscopy, which is known to happen in the presence of activated gold complexes [29]. The stability of the DAI cations was checked with 1H NMR: the characteristic doublets belonging to the respective

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

• derivatives are used as ligands in the synthesis of metal complexes (Ni(II), Pd(II), Pt(II), Cu(I), Ag(I) etc.) exhibiting antibacterial and antitumor activity [34]. In most cases, polyfunctional catechol thioethers were obtained by Michael reaction via the interaction of o-, p-benzoquinone and the

• of complexes 5 and 8 do not contain any solvent molecules, while the unit cell of crystals 6·0.5CH3CN contains one acetonitrile molecule per two catechol molecules. The nitro-substituted pyridine group in 5 is disordered in two positions. The X-ray structure of catechol 5 is shown in Figure 1, and

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

• and type II’ β-hairpin. Even though the latter was consistently lower in ground state energy (up to 6 kcal/mol for some catalysts), predictive models for enantioselectivity were found for both catalyst conformers in separate MLR models. For organophosphorous ligands of transition metal complexes, the

• the ML model by being considered as a nucleophile or electrophile, depending on the reaction mechanism. Descriptors allowed for the inclusion of a variety of co-catalysts, ranging from Fe-piano stool complexes to copper complexes. The consideration of co-catalysis into model development further

gem-Difluorination of carbon–carbon triple bonds using Brønsted acid/Bu₄NBF₄ or electrogenerated acid

• Mizuki Yamaguchi,
• Hiroki Shimao,
• Kengo Hamasaki,
• Keiji Nishiwaki,
• Shigenori Kashimura and
• Kouichi Matsumoto

Beilstein J. Org. Chem. 2024, 20, 2261–2269, doi:10.3762/bjoc.20.194

• the use of HF or its complexes as a reagent. These reactions seem to proceed via the formation of the vinyl fluoride as the intermediate [25][26][27][28]. In the first example, Olah and co-workers reported the reaction of terminal alkynes with HF/pyridine (Olah reagent) (Figure 1, reaction 1) [29][30

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• -covalent electron pair, making it impossible to generate boron radicals by homolysis via the n–σ* transition. In addition, since boron has an empty orbital, it forms ate complexes when Lewis base compounds coexist. As the result, the boryl groups of the ate complexes are bulky and often cause steric

• hindrance. However, several examples of isocyanide insertion reactions into B–H and B–B bonds are known. For example, isocyanides coordinate to diborane (B2H6) or trialkylboranes (BR'3) to form Lewis acid–base complexes (RNC→BH3 or RNC→BR'3), but these complexes are thermally labile, and hydrogen or alkyl

• Lewis acid–base complexes (t-BuNC→BH3) to generate the corresponding isocyanide–boryl radicals 17 (t-BuNC→BH2•), which can be observed by ESR (Scheme 10b) [47]. However, the synthetic application of this boryl radical has not been investigated. Among the cyclic diboron compounds, a series of five