The high potential of methyl laurate as a recyclable competitor to conventional toxic solvents in [3 + 2] cycloaddition reactions

• Ayhan Yıldırım and
• Mustafa Göker

Beilstein J. Org. Chem. 2025, 21, 2389–2415, doi:10.3762/bjoc.21.184

• optimized [3 + 2] cycloaddition conditions. The primary strategy for the selection of these compounds as catalysts is predicated on their capacity to function as H-bond acceptors and/or H-bond donors. As has been documented in previous research, imine-based templates or [2]rotaxane that possess an amide

Conformational effects on iodide binding: a comparative study of flexible and rigid carbazole macrocyclic analogs

• Guang-Wei Zhang,
• Yong Zhang,
• Le Shi,
• Chuang Gao,
• Hong-Yu Li and
• Lei Xue

Beilstein J. Org. Chem. 2025, 21, 2369–2375, doi:10.3762/bjoc.21.181

• iodine ions, which is consistent with the conclusions reached by our NMR titration. The binding constants of the complexes (K), KPBG = (1.387 ± 0.02363) × 105 M−1, KWDG= (6.089 ± 0.3320) × 103 M−1 were measured (Tables S1 and S2 in Supporting Information File 1), indicating that both acceptors had strong

• peaks appeared, indicating that photoelectron transfer occurred between iodine ions and the macrocycles [27][28], and fluorescence quenching was due to the photoinduced electron transfer (PET) effect between iodine ions and acceptors, resulting in non-radiative dissipation of excited state energy rather

Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates

• Gyöngyvér Pusztai,
• László Poszávácz,
• Anna Vincze,
• András Marton,
• Ahmed Qasim Abdulhussein,
• Judit Halász,
• András Dancsó,
• Gyula Simig,
• György Tibor Balogh and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169

• File 1, Figures S1–S3). Based on their calculated physicochemical properties, all compounds satisfied Lipinski’s Rule of Five suggested by Wager et al. [34] (molecular weight < 500 Da, logP < 5, number of hydrogen-bond donors < 5, number of hydrogen-bond acceptors < 10) [35], and the topological polar

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

• picoseconds to several years. The presence of heteroatoms also introduces H-bond donors and acceptors and metal coordination sites [11]. Like azobenzenes, E–Z isomerisation of azoheteroarenes can be triggered by light irradiation, while Z–E isomerisation proceeds through irradiation with a different

• presence of H-bond acceptors [102][104][107]. The presence and the nature of the H-bond can be identified by 1H NMR spectroscopy since the N–H proton has a characteristic chemical shift depending on the H-bond acceptor [101]. Arylhydrazones based on pyridine have been intensively studied since the H-bond

• between hydrazone and pyridine can be broken by protonation with an acid and even by metal coordination, rendering these compounds photo- and acidochromic (Scheme 31) [102]. The equilibrium can also be modulated by introducing hydrogen-bond acceptors in R1 [107] or by introducing substituents to the

Approaches to stereoselective 1,1'-glycosylation

• Daniele Zucchetta and
• Alla Zamyatina

Beilstein J. Org. Chem. 2025, 21, 1700–1718, doi:10.3762/bjoc.21.133

• advances in 1,1′-glycosylation and provides an overview of selected glycosylation strategies, including those aimed at forming α,β-, β,β-, and α,α-1,1′-glycosidic linkages. Particular emphasis is placed on the challenges of achieving stereoselectivity with lactol glycosyl acceptors, which commonly exist as

• exploiting the participation effect of the neighboring protecting group [43][44], employing anomeric lactols as acceptors is more complex as lactols with the desired configuration are frequently difficult to obtain (e.g., through anomerization). In addition to the nature of the leaving group and promoter

• formation of an α-glycoside on the donor side [54]. On the acceptor side, the β-configuration was favored due to steric hindrance from the C-2 phthalimido group in the triacetylated GalN-lactol acceptors 6 or 3,4-di-O-benzylated acceptors 8, resulting in kinetically controlled formation of β,α-1,1

Structural analysis of stereoselective galactose pyruvylation toward the synthesis of bacterial capsular polysaccharides

• Tsun-Yi Chiang,
• Mei-Huei Lin,
• Chun-Wei Chang,
• Jinq-Chyi Lee and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2025, 21, 1671–1677, doi:10.3762/bjoc.21.131

• position. Additionally, THF was used as a solvent to enhance the α-selectivity of the reaction [41][42][43]. Next, while both compounds 8 and 9 can act as acceptors, compound 9, a primary alcohol, exhibits greater nucleophilicity. Using the TolSCl/AgOTf promoter system at −70 °C, the β-linked disaccharide

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

• in the presence of electron donors and acceptors. Furthermore, [Ru(bpy)3]Cl2 can engage in Förster and Dexter energy transfer processes, enabling the transfer of excited-state energy to molecules that do not themselves absorb visible light. This versatility is arguably the reason for the tremendous

Tautomerism and switching in 7-hydroxy-8-(azophenyl)quinoline and similar compounds

• Lidia Zaharieva,
• Vera Deneva,
• Fadhil S. Kamounah,
• Nikolay Vassilev,
• Ivan Angelov,
• Michael Pittelkow and
• Liudmil Antonov

Beilstein J. Org. Chem. 2025, 21, 1404–1421, doi:10.3762/bjoc.21.105

• CH3 group) and 3 leads to destabilization of K, while placing a substituent in positions 5 (weakly) and 6 stabilizes it. The effect on position 4 is mixed – electron donors stabilize the K form, while acceptors rise its energy. All substituents in position 8 stabilize K, but the effect of the

• acceptors is more pronounced. The effect of the amino group is stronger comparing to NMe2 due to the steric hindrance in the latter. Since in 1 the azo group, an acceptor, is placed on position 8, it is also expended to bring additional inherent stabilization of the 1K tautomer. The effect of the

• donors in the phenyl ring, while N–NH is a donor, favored by acceptors in Ph [3][7][89]. Following this model, a suitable substitution in the Ph ring of 1 can stabilize or destabilized KE and KK in respect to E and K. This opens an additional channel for fulfilling the requirements for a clean switching

High-pressure activation for the solvent- and catalyst-free syntheses of heterocycles, pharmaceuticals and esters

• Kelsey Plasse,
• Valerie Wright,
• Guoshu Xie,
• R. Bernadett Vlocskó,
• Alexander Lazarev and
• Béla Török

Beilstein J. Org. Chem. 2025, 21, 1374–1387, doi:10.3762/bjoc.21.102

• the phenomena [17]. In addition, due to the availability of commercially accessible instruments, the applications of HHP in synthetic chemistry have expanded in the past decades. The studied reactions include hydrogenation [18], the addition of enamines to Michael acceptors [19], enantioselective

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

• base [5]. In fact, its hydrogen-bond-accepting ability is even stronger than that of the other 3-, 5- and 6-membered cyclic ethers, as well as the carbonyls of aldehydes, ketones, esters and carbonates [6][7][8]. The only better carbonyl-based hydrogen-bond acceptors are amides, carbamates and ureas [9

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

• the system. In 2024, Liang’s group reported the replacement of N-arylacrylamides with 7-fluoro-3-homoallylquinazolin-4-ones, which are tethered to an alkenyl group at the nitrogen atom and function as radical acceptors (Scheme 17). This approach effectively facilitated photoelectrocatalytic

On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

• Daniel Straub,
• Markus Gross,
• Mona E. Arnold,
• Julia Zolg and
• Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

• functionalization with a much broader variety of donors (and even acceptors) than is possible through a radical-mediated nucleophilic aromatic substitution (SRN1, see also below) [3][46][47]. The I-TTM has a maximum emission at λem = 578 nm and a ϕ of 3% (in cyclohexane), indicating that the symmetry does not seem

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

• of D–A structures makes them the ideal structures to further understand the structure–property relationship of D–A molecules for optimizing their photocatalytic performance by simpler modification of the different D–A subunits. In particular, D–A structures featuring sulfur-based acceptors and

• nitrogen donors have gained increasing attention for their use as photoredox catalysts. This study introduces a new family of D–A molecules by exploring various sulfur-based acceptors and nitrogen donors, including a novel tribenzo[b,d,f]azepine (TBA) unit and 5H-dibenz[b,f]azepine (IMD). Our findings

• diverse scaffolds have been reported in the literature, the identification and use of novel PCs with tunable and diverse optical and redox properties can pave the way to uncharted reactivity. In this context, sulfur-based cores, widely used as acceptors in photoelectric materials [9][10][11][12][13][14

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

• acids. Rather, halides with enhanced electrophilic potency, such as α-halocarbonyls [14][15][16], nitrogen (half-)mustards [17][18], or epoxides [19][20], Michael acceptors [17], carbamates [17], imidazolides [17], squarates [17], and diaziridines [17] (the latter requiring photoactivation) have been

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

• [329][330][331], superbases [332][333][334][335][336], or non-specific arrays of hydrogen-bond donors [337]/acceptors [338]. Advances in post-assembly modifications [339] have recently allowed stable organic cages featuring endohedral (internally directed) functionality [340][341], or metals [342][343

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

• affecting any other acetyl or benzoyl groups in the substrate. However, the use of chloroacetyl groups being highly electron-withdrawing in nature, significantly reduces the reactivity of the glycosyl donors, and also undergoes transesterification migration reactions with less nucleophilic acceptors. So, to

• [130]. The group has shown the formation of 1,2-trans glycosides with both carbohydrate-based and non-carbohydrate-based aglycons and carbohydrate acceptors in high yield. Continuing with the carbonyl-mediated glycosylation protocol, Wang et al. showed the application of the photolabile 2-(2

• as a protecting group [153] for the C-2 position which successfully formed a six-membered ring intermediate via neighbouring group participation to form completely selective 1,2-cis glycosylated products with a range of carbohydrate acceptors. The formation of ring intermediate and glycosylating

Streamlined modular synthesis of saframycin substructure via copper-catalyzed three-component assembly and gold-promoted 6-endo cyclization

• Asahi Kanno,
• Ryo Tanifuji,
• Satoshi Yoshida,
• Sota Sato,
• Saori Maki-Yonekura,
• Kiyofumi Takaba,
• Jungmin Kang,
• Kensuke Tono,
• Koji Yonekura and
• Hiroki Oguri

Beilstein J. Org. Chem. 2025, 21, 226–233, doi:10.3762/bjoc.21.14

• - and E- rings serve as hydrogen bond (HB) donors/acceptors to facilitate DNA alkylation at C21. UV–vis absorption (gray solid line), the emission spectrum (blue solid line), and the corresponding excitation spectrum (blue dashed line) of the imidate 18 in CHCl3 (c = 100 μM). aQuantum yield (Φfl

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

• provide information about binding affinity or energy, particularly between HB donors and acceptors as molecular entities rather than as a collection of separate functional groups. In contrast, NMR titration experiments quantify the binding affinities and energies between CF2H-containing molecules and n

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

• porphyrin macrocycle contains two Ns and two NHs (from two pyrrolenine and two pyrrole units), both of which can act as supramolecular H-bond donor and acceptors and can promote metal-free catalysis. Additionally, due to their synthetic versatility, these macrocycles can be further functionalized to add

• that function as hydrogen-bond donors and acceptors. Additionally, the nitrogen atoms in the pyrrole units of the porphyrin structure can also act as Lewis bases, capable of donating electron pairs. These properties enable tetrapyrrolic macrocycles to act as effective binding sites or catalytically

gem-Difluorovinyl and trifluorovinyl Michael acceptors in the synthesis of α,β-unsaturated fluorinated and nonfluorinated amides

• Monika Bilska-Markowska,
• Marcin Kaźmierczak,
• Wojciech Jankowski and
• Marcin Hoffmann

Beilstein J. Org. Chem. 2024, 20, 2946–2953, doi:10.3762/bjoc.20.247

• , we observed a striking illustration of this phenomenon. A Michael addition involving gem-difluorovinyl and trifluorovinyl acceptors was successfully achieved, demonstrating high stereoselectivity. This selectivity was further elucidated through theoretical calculations. Using this methodology, a

• series of new α,β-unsaturated amides, both fluorinated and nonfluorinated, were synthesized. Keywords: gem-difluorovinyl Michael acceptors; Michael addition; trifluorovinyl Michael acceptors; α,β-unsaturated amides; Introduction The Michael reaction, characterized by the addition of stable carbon

• advancements have broadened the scope of Michael donors and acceptors to encompass fluorine-containing compounds, enhancing the reaction's utility in synthesizing fluorinated derivatives [7][8]. Shibata and colleagues pioneered the use of fluorinated Michael donors, notably achieving enantioselective addition

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• enhanced push–pull effect in this molecule due to the presence of a stronger acceptor. Furthermore, the energy of the LUMO of compound 3 is comparable to reported PDI-based acceptors which have been used in OPVs with PCE > 7% [34]. Crystallographic study Needle-shape crystals of compound 3b suitable for

• (EAs) of −4.11 eV, −4.09 eV, and −4.15 eV. Consequently, the estimated Efund are 1.27, 1.25 and 1.25 eV for 3a, 3b, and 3c, respectively. The EA value is in a similar range (from −3.70 to −4.30 eV) of some of the most widely used fullerene-based acceptors such as PC60BM and PC70BM [35], which suggests

• that the three materials might function effectively as electron acceptors. OFET device studies The electrical characteristics were confirmed by the fabrication of OFETs. Compounds 3a–c were deposited by spin-coating onto n-doped Si/SiO2/Au substrates. The device performance parameters are summarised in

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

• been widely investigated in the past decades for application as fluorescent dyes [3][4][5], chirality inducers [6][7][8], acceptors for photoinduced electron transfer (PET) [9][10], and components of supramolecular assemblies [11][12][13][14]. Owing to the stable π-electronic systems showing unique

Synthesis and conformational analysis of pyran inter-halide analogues of ᴅ-talose

• Olivier Lessard,
• Mathilde Grosset-Magagne,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2024, 20, 2442–2454, doi:10.3762/bjoc.20.208

• 15: d = 2.356 Å) and with F3 and H4 (13: d = 2.867 Å, 14: d = 2.849 Å, and 15: d = 2.886 Å). Does the halogen at C4 contribute to the stabilization within the crystal lattice? To answer this question, we have to look at the behavior of halogens as hydrogen bond acceptors (X···H) and nonbonding

Stereoselective mechanochemical synthesis of thiomalonate Michael adducts via iminium catalysis by chiral primary amines

• Michał Błauciak,
• Dominika Andrzejczyk,
• Błażej Dziuk and
• Rafał Kowalczyk

Beilstein J. Org. Chem. 2024, 20, 2313–2322, doi:10.3762/bjoc.20.198

• Discussion Based on our previous experiences with low-reactive Michael acceptors [29], initial attempts were carried out using bifunctional squaramides, derivatives of cinchona. However, up to 45% yield of the desired product was obtained with poor enantioselectivity (14%, Scheme 2). Considering the

• %) and moderate enantioselectivity (68%). Moreover, the steric bias in proximity (E2, Scheme 3) or the subunit of the conjugated system (E3) of acceptors revealed the nucleophiles (1 and 3) were unable to reach the reactive center or to form a stable bond. Interestingly, when the reaction with bis

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• ] cycloaddition–retroelectrocyclization (CA-RE) between electron-rich alkynes and electron-deficient olefins [8]. The [2 + 2] CA-RE click reactions were employed to produce a variety of functional materials, such as nonlinear optical chromophores [9][10], super acceptors [11][12], ion sensing D–A systems [13