Synthetic approach to borrelidin fragments: focus on key intermediates

• Yudhi Dwi Kurniawan,
• Zetryana Puteri Tachrim,
• Teni Ernawati,
• Faris Hermawan,
• Ima Nurasiyah and
• Muhammad Alfin Sulmantara

Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91

• starting material 155a. Encouragingly, the addition of an extra 5 mol % of the catalyst followed by further heating for 28 hours successfully converted the remaining 155a into 156a, which was isolated in 54% yield. A trace amount of an unwanted dimer of 155a was also detected. In contrast, different

• results were obtained when compound 155b was used. Addition of 5 mol % catalyst produced the expected macrocyclic product and dimer 157 in yields of 24 and 22%, respectively, while a significant amount of unreacted 155b (26%) remained under these conditions. Conclusion In summary, this review has examined

Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• centered between the primary faces of two adjacent β-CD molecules, while DBC was nested inside the barrel-shaped cavity of a β-CD head-to-head dimer (Figure 4). Noteworthy, K+ ions were absent in the crystal superstructures, which was explained by the authors as the possible result of protons replacing K

Supramolecular assembly of hypervalent iodine macrocycles and alkali metals

• Krishna Pandey,
• Lucas X. Orton,
• Grayson Venus,
• Waseem A. Hussain,
• Toby Woods,
• Lichang Wang and
• Kyle N. Plunkett

Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87

• distance between O18–Li of 1.918 Å. The overall structure is a bent dimer with the two phenylalanine HIM structures arranged in close geometry with a O6–Li–O18 bond angle of 98.83°. In contrast, the Na+-incorporated co-crystal structure is different than the Li+ co-crystal, even though the unit cell is

Dicarboxylate recognition based on ultracycle hosts through cooperative hydrogen bonding and anion–π interactions

• Wen-Hui Mi,
• Teng-Yu Huang,
• Xu-Dong Wang,
• Yu-Fei Ao,
• Qi-Qiang Wang and
• De-Xian Wang

Beilstein J. Org. Chem. 2025, 21, 884–889, doi:10.3762/bjoc.21.72

• binding model, with two-step binding constants of K11 = 259 M−1 and K12 = 251 M−1, implying that B4aH can accommodate two C22− anions as a dimer within its cavity [29]. Malonate (C32−) and succinate (C42−) exhibited irregular titration curves (Figure 2c), and no reliable binding constants could be

• obtained using either 1:1 or 1:2 binding models. This is likely due to their intermediate size of chain lengths, which are neither long enough for 1:1 binding nor capable of squeezing a dimer for 1:2 complexation. Notably, the unsubstituted ultracycle B4 [31] without the pendant OH groups on the lower rim

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• photoirradiation of the ANTH solution, a set of new resonances (δ = 6.92 (m, 2H), 6.81 (m, 2H), and 4.55 (s, 1H) ppm) appeared and increased in intensity relative to the ANTH resonances. The new photoproduct was identified as a dimer, dianthracene, which had previously been shown to form under anaerobic UV

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

• a [2 + 2] cycloaddition reaction, with approximately 20% yield of the dimer in the crystal. This was particularly notable, given that the compound had spent minimal time in solution with limited exposure to visible light, and no exposure to ultraviolet light. To further explore this phenomenon, we

• packing mode. Extra precautions were taken to shield the compounds from light during synthesis, purification, and storage. After crystallizing each bimane, a vial containing multiple crystals was selected for irradiation studies. Cl2B (B), which showed 5% presence of the [2 + 2] dimer after

• crystallography, was irradiated, resulting in Cl2B (C), which showed approximately 18% dimer formation, while no dimerization was observed in the Me2B and Me4B (C) samples (see experimental section for details). The initial presence of the [2 + 2] dimer in the Cl2B (A) sample can be attributed to improper

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

• coordinative bonds on one side and hydrogen bonds on the other. Surprisingly, when the crystals were manually ground for 5 min before irradiation, the conversion to dimer 1.2 remarkably increased to 88% in only 4 h of UV irradiation time. Overall, the role of manual grinding was not only to increase the

• shaking a 1:1 mixture of chalcone (4.1) and 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol (4.2) with a test-tube shaker under irradiation with a high-pressure Hg lamp, the [2 + 2] syn-head-to-tail dimer product 4.3 was obtained selectively in 80% yield after 10 h (Scheme 4) [66]. In detail, 4.2 works as a

Synthesis and characterizations of highly luminescent 5-isopropoxybenzo[rst]pentaphene

• Islam S. Marae,
• Jingyun Tan,
• Rengo Yoshioka,
• Zakaria Ziadi,
• Eugene Khaskin,
• Serhii Vasylevskyi,
• Ryota Kabe,
• Xiushang Xu and
• Akimitsu Narita

Beilstein J. Org. Chem. 2025, 21, 270–276, doi:10.3762/bjoc.21.19

• singlet (S1) state [21]. Notably, a dimer of BPP, 5,5'-bibenzo[rst]pentaphene (BBPP), exhibited an enhanced PLQY of 44% through intensity borrowing from its bright S2 state as well as intriguing symmetry-breaking charge transfer between two BPP units. Moreover, the substitution of BPP with two electron

Efficient synthesis of fluorinated triphenylenes with enhanced arene–perfluoroarene interactions in columnar mesophases

• Yang Chen,
• Jiao He,
• Hang Lin,
• Hai-Feng Wang,
• Ping Hu,
• Bi-Qin Wang,
• Ke-Qing Zhao and
• Bertrand Donnio

Beilstein J. Org. Chem. 2024, 20, 3263–3273, doi:10.3762/bjoc.20.270

• derivatives: the in situ prepared 2Li-BP5/6 was reacted with F5/6 to yield the symmetrical discotic dimers, G55/G66 respectively, in an average yield of 42–45% (Scheme 1). The reaction of 2Li-BP8 with F4 was also successfully tested, and allowed the preparation of the unsymmetrical discotic dimer G48

• spectra. Their LUMO electron density maps distribute across to the side arm for F1 (−1.88 eV; −1.78 eV for PH1) and to the other triphenylene core for the dimer G11 (−1.78 eV). The π-conjugation of excited states results in a difference of their HOMO and LUMO energy levels: the fluorine dimer G11

• along the main axes: ORTEP diagram showing 50% thermal ellipsoid probability: carbon (gray), fluorine (green), and hydrogen (white). POM textures, observed between crossed polarizers of Janus and dimer, F6, F12, G66, and G48, respectively, as representative examples. More images can be seen in

C–H Trifluoromethylthiolation of aldehyde hydrazones

• Victor Levet,
• Balu Ramesh,
• Congyang Wang and
• Tatiana Besset

Beilstein J. Org. Chem. 2024, 20, 2883–2890, doi:10.3762/bjoc.20.242

• expected product was detected (Scheme 4C). Having in mind that in the presence of an oxidant, the SCF3 dimer (SCF3)2 might be generated, an additional test was realized. In the presence of NCS in THF, AgSCF3 was converted into the corresponding dimer in 5 min (monitored by 19F NMR). Then, the reaction was

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

• 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 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

• allylpalladium chloride dimer or bis(triphenylphosphine)palladium dichloride were used as catalyst, the reaction proceeded with the same yield as that in Table 1, entry 4 (entries 7 and 8). Utilizing palladium catalyst such as bis(triphenylphosphine)palladium dichloride, all these reactions could convert 1a into

• low yields of 3a (Table 2, entries 2 and 3). In the case of palladium(II), which produced good yields of the Suzuki–Miyaura cross-coupling products, only a small amount of 3a was obtained (Table 2, entries 4–8). In particular, when the allylpalladium dichloride dimer was used, Sonogashira coupling

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

• appears unfavorable in comparison to a single water dimer and single water molecules located on the narrow rim (γ-CD–3H2O (b)). The first layer of water molecules is filled by three water molecules in the plane of the narrow rim, and the fourth incoming guest is displaced into the cavity upon optimization

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

• proximally located PCCp− units formed a partially stacked dimer with a stacking distance of 3.43 Å. The B(C6F5)4− and PCCp− ion pairs with the nearest set of ion pairs showed the Etot values of −115.1 and −100.7 kcal/mol, respectively, with Ees/Edisp values of −48.6/−73.7 and −51.5/−54.9 kcal/mol

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

• = 10.9139(1) Å, c = 24.3668(3) Å, β = 95.601(1)°) and a density of 2.01865 g/cm3. Two units of the cationic XB donor form a dimer, which is bridged via two bromide ions (Figure 2). As usual for DAI salts, two XB axes are found on the elongations of the C–I bonds. On the one trans to the isoxazolium unit

• ). Halogen bonding dimer found in the crystal structure of 7Br. Ellipsoids are shown at 50% probability (carbon: grey, nitrogen: blue, oxygen: red, bromine: orange, iodine: purple) and hydrogen atoms are shown in standard ball-and-stick model (white). Halogen and hydrogen bonding is indicated dashed. 1H NMR

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• concerted SN2 mechanism or SN1 mechanism with the allyl nucleophile addition step as rate-determining. Interestingly, the authors observed a 0.55 order in the catalyst, which indicates that a substantial part of the catalyst forms a hydrogen-bonded dimer with Kdiss ≈ 1000 M−1 when not in the catalytic cycle

Synthesis and reactivity of the di(9-anthryl)methyl radical

• Tomohiko Nishiuchi,
• Kazuma Takahashi,
• Yuta Makihara and
• Takashi Kubo

Beilstein J. Org. Chem. 2024, 20, 2254–2260, doi:10.3762/bjoc.20.193

• unit allows for spin localization at the 10-position of anthracene through C–C bond rotation, resulting in a tail-to-tail σ-dimer (Figure 1b). The σ-dimer exhibits an equilibrium state between the monomer radical and the σ-dimer in solution, and mechano-stimulus-induced C–C bond fission in the solid

• activation barrier is only 2.94 kcal mol−1 (Supporting Information File 1, Figure S3). Thus, these two structures are likely in equilibrium and rapidly exchange with each other in solution. The energy difference between DAntM dimer (head-to-head σ-dimer) and DAntM radical monomer was also evaluated, showing

• that the dimer form is energetically preferable by about 3.97 kcal mol−1 (Supporting Information File 1, Figure S2). In VT-ESR measurements at low temperatures, the ESR signal integral decreased with cooling (Supporting Information File 1, Figure S4). However, even at 190 K, the relative signal

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

Radical reactivity of antiaromatic Ni(II) norcorroles with azo radical initiators

• Siham Asyiqin Shafie,
• Ryo Nozawa,
• Hideaki Takano and
• Hiroshi Shinokubo

Beilstein J. Org. Chem. 2024, 20, 1967–1972, doi:10.3762/bjoc.20.172

• toluene (Scheme 1). The reaction smoothly proceeded to afford dialkylated macrocycle 2a in 92% yield. In addition to 2a, monoalkylated product 3a and dipyrrin dimer 4a were obtained as minor products in 4% and 3% yield, respectively. The structure of 2a was unambiguously confirmed by single-crystal X-ray

Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• = 2.24 nm could be attributed to the longer molecular axis of DA11 in dimer form, while that at d = 0.36 nm originated from π–π stacking of the DASA motif. Consistently, diffraction from the longer molecular axis of DA10 in dimer form was shorter (d = 2.19 nm) than that of DA11, revealing the subtle

• at 1.50 nm and 1.45 nm, respectively (Figure S11b and Figure S12b, Supporting Information File 1), revealing the shortened longer molecular axis of DA7 and DA6 in dimer form compared to DA11 and DA10. The observed major diffraction peaks of DA7 and DA6 macroscopic soft scaffolds also originated from

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• , formed the product 93 in 36–59% yield along with the overoxidized compound 95, and the dimer 94 as byproducts. However, upon reaction with methanol under acidic conditions, the product 93 and the dimer 94 underwent a smooth transformation to the methyl acetal in high yields. Similar exposure of the

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• contraction reactions, yielding a benzofluorene intermediate 4 and the dimer 5, both featuring a kinamycin skeleton (Scheme 1) [11][12]. Recent investigations unveiled the catalytic activity of the O-methyltransferase-like protein AlpH, which catalyzes a unique SAM-independent coupling of ʟ-glutamylhydrazine

• the spontaneous formation of a limited quantity of 1 derived from 8, we detected the generation of products, including the previously characterized benzofluorene intermediate 4 and benzofluorene dimer 5, alongside a novel compound, designated as 10 (Figure 1, trace d). High-resolution mass

• formation of product 4, which through a presumed radical-mediated reaction could spontaneously convert to the dimer 5. Additionally, compound 12 had the potential to be oxidized to hydroquinone–kinobscurinone 10, a proposed precursor of kinobscurinone. When employing 1 as the substrate, such cofactor

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• respect to the carbonyl groups (Figure 6b) and 5.25° concerning peripheral rings 1 and 3 (Figure 6c). The unit cell is composed of a dimer of 2b held together by intermolecular N–H∙∙∙N and C–H∙∙∙O=C H-bonds with average distances of 2.30 Å and 2.28 Å, respectively (Figure 6d and 6e). The herringbone

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• ). As previously reported, Vs NnlA exhibited two major peaks, a lower molecular weight peak consistent with a dimer and a second peak consistent with a large oligomer [21]. By contrast, the chromatograms of the purified Ps, Mr, Ms, and Pd NnlA were dominated by a single peak ranging in molecular mass

• not change in samples containing reduced Vs NnlA compared with samples without Vs NnlA. Additionally, NO2− was not formed in these samples (Table S4, Supporting Information File 1). Alpha-fold model of NnlA A model of the Vs NnlA dimer was produced using AlphaFold2, which allows for predicting the

• °C in deoxygenated 30 mM tricine buffer at pH 7.5. Alpha-fold model of Vs NnlA dimer (cyan) overlayed with Pseudomonas aeruginosa (grey; PDB: 3VOL [35][36]) to estimate the position and orientation of the heme cofactor. Conserved residues in the distal heme pocket are labeled. Conserved basic

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• bisalkynylplatinum(II)–terpyridine clips [54]. The dimer showed photocatalytic activity in the photooxidation of a secondary amine to the corresponding imine that could be deactivated and reactivated by opening or closing the tweezers. Variations on multidentate N-donor ligands have also been developed by Lehn and