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

• Laurin Flemmich Ronald Micura Institute of Organic Chemistry, Center for Molecular Biosciences Innsbruck (CMBI), Innrain 80-82, 6020 Innsbruck, Austria 10.3762/bjoc.21.35 Abstract The preQ1 cIass-I riboswitch aptamer can utilize 7-aminomethyl-7-deazaguanine (preQ1) ligands that are equipped with

• such reactive preQ1 and (2,6-diamino-7-aminomethyl-7-deazapurine) DPQ1 ligands. The readily accessible key intermediates of preQ0 and DPQ0 (both bearing a nitrile moiety instead of the aminomethyl group) were reduced to the corresponding 7-formyl-7-deazapurine counterparts. These readily undergo

• vitro and in living cells using rationally designed electrophile-tethered derivatives of preQ1 (1) and its Watson–Crick diamino-faced counterpart DPQ1 (2, Scheme 1A). These ligands (compound classes 3 and 4, Scheme 1A) were tailored to target a conserved guanine nucleobase within a natural preQ1-binding

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

• spectroscopy (Scheme 1). During the reaction progress, the C=C bonds of bpe ligands undergo pedal-like motion prior to photodimerization [63]. For the single-crystal irradiation, the slow reactivity can be attributed to the hindered pedal motion in the single crystals, likely due to the presence of

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

• the cage framework to polarize adjacent aryl–hydrogen bonds in the ligands by enough to coordinate and activate substrates (Figure 5E) [190]. Here, the use of bulky counteranions reinforces the cationic cage interior, which is enhanced further by use of lower polarity solvents, and the pKa of confined

• transform the ligands can result in changes in cage topology distribution [204]. Self-assembly can also prescribe limitations on the symmetry of cages [36]. Notably, Clever has recently reported the first Pd2(ABCD) MOC [205], which may signal the possibility of using low-symmetry cavities [206][207][208

• -based porous organic cages have been a popular choice for study [377][379][406][407][408], as have MOCs [208][376][386]. Much focus remains on the prediction (and automation) [409] of the formation of cavities by probing combinations of, e.g., amines/aldehydes or metals/ligands to identify structures

Unraveling aromaticity: the dual worlds of pyrazole, pyrazoline, and 3D carborane

• Zahra Noori,
• Miquel Solà,
• Clara Viñas,
• Francesc Teixidor and
• Jordi Poater

Beilstein J. Org. Chem. 2025, 21, 412–420, doi:10.3762/bjoc.21.29

• , exceptional thermal and chemical stability, and robust synthetic versatility [16][17] – make carborane derivatives essential components in various fields. These include pharmaceuticals [18][19][20][21][22], boron neutron capture therapy (BNCT) [23][24][25][26], organometallic ligands [27], and functional

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

• own a large span of colors depending on the nature of the metal and the ligands but also on the various oxidation states these compounds can attain. This property results on the absorption of a visible-light photon complementary to the observed color and has been extensively exploited in photoredox

• of lower-energy photons in second- and third-row transition metals compared to their first-row counterparts [13]. These phenomena are specifically improved when potent π-acceptor ligands are used due to their low-energy π* antibonding orbitals resulting in a bathochromic shift of the MLCT absorption

• -row d6 metal complexes such as Fe(II) complexes and positions Cr(0) as a promising alternative in photoredox applications under low-energy red-light conditions. The enhanced performance of these Cr(0) complexes is attributed to their strong ligand field, provided by the isocyanide ligands, which

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

• enantioselectivity is the introduction of serine-derived bisoxazoline ligands L8 (sBOX). Upon coordination with a copper catalyst, these ligands present second-sphere ester groups, which facilitate the additional stabilization of noncovalent interactions at the penta-coordinated Cu(III) intermediate 82 in the

• reactions of copper catalysts without ligands face limitations owing to slow electron transfer kinetics, irreversible copper plating, and competing substrate oxidation. To overcome these challenges, Sevov et al. developed a ligand-free, Cu-catalyzed electrochemical Chan–Lam coupling using a ferrocenium salt

Nickel-catalyzed cross-coupling of 2-fluorobenzofurans with arylboronic acids via aromatic C–F bond activation

• Takeshi Fujita,
• Haruna Yabuki,
• Ryutaro Morioka,
• Kohei Fuchibe and
• Junji Ichikawa

Beilstein J. Org. Chem. 2025, 21, 146–154, doi:10.3762/bjoc.21.8

• , entry 3). Reducing the catalyst loading to 5 mol % slightly affected the yield of 3bb, which was 90% (Table 1, entry 4). Next, we evaluated various additives with 5 mol % of Ni(cod)2 to stabilize regenerated zero-valent nickel species (Table 1, entries 5–8). While phosphine ligands such as triphenyl

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

• counteranion. The use of a carbamate among the substrates instead of the amine allowed the synthesis of propargylcarbamates 11. This reaction, effective only for the aromatic aldehydes, did not require other co-catalysts or ligands (Scheme 8) [21]. Three-component reactions of alkynes, alkyltrifluoroborates

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

• compounds comprising a stereogenic plane or axis is much less developed. Axially chiral compounds are well known as chiral ligands in asymmetric catalysis, with notable examples of binaphthyl-based derivatives such as BINAP, SEGPHOS, or binaphthyl-based phosphoric acid derivatives, which are among the

• purities, solid yields and very good diastereomeric ratios. The hydroxy group present in products 156 and 158 could be transformed to provide axially chiral phosphines that could be utilized as chiral ligands in transition-metal-catalyzed reactions. Testing both substrates 156 and 158 for conformational

Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

• supplied a flowing stream of 12 selectable solvents, an autosampler that injected microliter amounts of preselected reaction mixtures, and an LC–MS device for product characterization. Approximately 5,760 reactions were screened across a selection of 11 ligands, seven bases, and four solvents, along with

Chemical glycobiology

• Elisa Fadda,
• Rachel Hevey,
• Benjamin Schumann and
• Ulrika Westerlind

Beilstein J. Org. Chem. 2025, 21, 8–9, doi:10.3762/bjoc.21.2

• . [12] in the context of photoswitchable ligands to the lectin LecA. Staying in the theme of lectin characterization, Lundstrøm et al. study the glycan binding profile of CMA1 originating from melon [13]. A time that sees great opportunities in computational biology also breeds innovative applications

Reactivity of hypervalent iodine(III) reagents bearing a benzylamine with sulfenate salts

• Beatriz Dedeiras,
• Catarina S. Caldeira,
• José C. Cunha,
• Clara S. B. Gomes and
• M. Manuel B. Marques

Beilstein J. Org. Chem. 2024, 20, 3281–3289, doi:10.3762/bjoc.20.272

• ]; (ii) the incorporation of the iodine atom in the 5-membered heterocycle [10]; and (iii) the trans effect, due to the interaction of the hypervalent bonds established by the axial ligands, where iodine orbitals are shared with both heteroatoms [11]. As a result, benziodoxol(on)es have found application

Intramolecular C–H arylation of pyridine derivatives with a palladium catalyst for the synthesis of multiply fused heteroaromatic compounds

• Yuki Nakanishi,
• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2024, 20, 3256–3262, doi:10.3762/bjoc.20.269

• . The addition of ligand improved the yield of 2a as shown in Table 1, entries 7–10. Among several ligands, including Buchwald-type phosphines L1–L4 [33] examined, it was found that the use CyJohnPhos (L3) afforded the cyclized product in 90% yield and the reaction with PPh3 (L4) as a ligand was also

Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• contributed to the development of promising ligands in recent years. Rather than providing an exhaustive overview, this review aims to highlight key studies that address major CNS pathologies, relevant drug targets, and various MCR approaches. We have carefully selected representative articles and apologize

• , traumatic brain injuries, and brain tumors. Finally, in elderhood, seizures are often linked to primary craniocephalic trauma, brain tumors, and neurodegenerative disorders [23]. This review centers on five neurological disorders where ligands obtained using multicomponent reactions (MCRs) have been

• representative articles and extend our apologies to authors whose important works may not be included. By focusing on these studies, we aim to present a clear and concise view of current research directions and significant advancements in the field. Review Ligands targeting CNS diseases obtained from MCR

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

• metal-free porphyrins. 1.1 Calix[4]pyrrole macrocycles as organocatalysts Calix[4]pyrroles act as versatile ligands in supramolecular chemistry and have been widely studied as binding hosts for various guests such as anions, ion pairs, or neutral compounds [4][30][31], ligands for p-block elements, as

• well as transition and rare-earth metals [32][33]. There are many comprehensive reviews covering these two areas along with the connection of these ligands to supramolecular and medicinal chemistry [34][35][36]. In addition, calix[4]pyrroles, due to the presence of four accessible inner NHs and well

• activity in electrocatalytic HER [123]. Although free base corrole ligands demonstrated activity in HER, they were unstable in trifluoroacetic acid (TFA), a common proton source, leading to rapid degradation during catalysis. Subsequently, the same group introduced metal-free xanthene-bridged biscorroles

Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond

• Thomas Ma and
• John Chu

Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253

• , they serve as ligands for chelating iron in siderophores. Because ferric cations (Fe3+) mostly exist as insoluble solids in the Earth crust, most microorganisms produce and secrete siderophores to scavenge this scarce resource from their surroundings [67]. Whereas siderophores do not always contain

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

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• significant as it circumvents the use of costly and hazardous metals and ligands which are commercially not available. In order to obtain a variety of synthetically desirable tetrasubstituted α-aryl-α-fluoroacetoacetamides 7, Zaheer et al. disclosed a straightforward, metal-free technique for the α-arylation

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• antitumor effects were related to the inhibition of the survival pathway of c-Jun and JNK2 (Jun N-terminal kinase). In an additional study, it was shown that treatment with derivative E-β-46b results in an increase of melanoma cell sensitivity for death ligands and allows to overcome resistance against

Synthesis and antimycotic activity of new derivatives of imidazo[1,2-a]pyrimidines

• Dmitriy Yu. Vandyshev,
• Daria A. Mangusheva,
• Khidmet S. Shikhaliev,
• Kirill A. Scherbakov,
• Oleg N. Burov,
• Alexander D. Zagrebaev,
• Tatiana N. Khmelevskaya,
• Alexey S. Trenin and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2024, 20, 2806–2817, doi:10.3762/bjoc.20.236

• fingerprints (IFP) between the docking ligands and the protein shows that, similar to the reference ligand voriconazole, the compounds interact with the protein through hydrophobic interactions with hydrophobic residues of the protein and the formation of coordination bonds with the haem iron (Table 3). At the

• pocket formed by residues Y122, L508, F504 and I373. The superposition of the selected and docked ligands reveals that compounds 4a–e are arranged in an identical manner, whereas the position of compound 5e, particularly tetrahydroimidazo[1,2-a]pyrimidine, is significantly disparate (Figure 5B

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

• compared to the 85 °C used in the synthesis of the para-equivalent 26 gave no conversion and was accompanied by the formation of palladium black [49]. No reactivity was observed by either TLC or mass spectrometry when switching back to Pd2(dba)3 with three different ligands SPhos, XantPhos, and Rac-Binap

• observed with the β-ethyl CH3 resonances splitting into two separate chemical environments; however, the identity of the product synthesized was not fully characterized. In future, if reactivity for OET-o-BrPPs were to be further explored a larger library of ligands whether biphenyl-based or other could be

Copper-catalyzed yne-allylic substitutions: concept and recent developments

• Shuang Yang and
• Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

• stereocenter of the product is controlled by the catalyst. A single crystal of Cu(I) was investigated by X-ray and proved to be the dicopper complex, while the Cu(II) catalyst was revealed as mononuclear copper coordinated with two ligands. Further kinetic isotope experiments and nonlinear relationship studies

• showed that the reaction exhibits a negative nonlinear effect, while the kinetic experiments indicate that a mono-copper catalyst might be involved in the rate-limiting step. They speculated that the observed nonlinear effect might arise from the existence of both the inactive homo-dimer of ligands and

Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones

• Ruben Manuel Figueira de Abreu,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228

• -Flight (TOF) LC–MS. The solvent, toluene, was purchased as dry solvent and applied without further purification. Other reagents, catalysts, ligands, acids, and bases were used as purchased from commercial suppliers. Column chromatography was performed on Merck Silica gel 60 (particle size 63–200 μm

Synthesis of fluoroalkenes and fluoroenynes via cross-coupling reactions using novel multihalogenated vinyl ethers

• Yukiko Karuo,
• Keita Hirata,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 2691–2703, doi:10.3762/bjoc.20.226

• previous study by Thorand [44], we performed the reaction between fluorine-containing vinyl ether 1a and 1.05 equiv of trimethylsilylacetylene (5a) to afford the corresponding enyne 3a in 55% yield (Table 2, entry 1). Cross-coupling utilizing a palladium(II) catalysts containing phosphine ligands produced

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

• placement/locality of these water molecules in α-, β-, and γ-CDs is a matter of continuing debate. The water ligands could be coordinated inside the cavity or around either rim. Note that CDs retain some water molecules (numbers and position depending on the nature of the guest molecule) after the inclusion