Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B

• Horst Weber,
• Kim-Thao Tran-Cong,
• Bernhard Mayer,
• Guido J. Reiss,
• Iryna S. Konovalova,
• Marc S. Appelhans,
• Kenneth R. Wood and
• Claus M. Passreiter

Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39

• the elucidation of the reaction mechanism and the synthesis of new compounds with possible biological activity. Experimental General Detailed experimental procedures are described in [1]. Instrumentation NMR spectra were recorded on Bruker ARX 300 or AVANCE DMX 600 NMR spectrometers (Bruker, Karlsruhe

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• intense chiroptical responses, including mirror-image CD and strong CPL with |glum| values up to 0.0026 and CPL brightness approaching 30.8 M−1 cm−1. A plausible reaction mechanism: cyclic voltammetry (CV) analyses of hydroxycarbazole derivative 3 and 2-naphthol derivatives 4; DFT-based calculations of

Recent advances in the cleavage of non-activated amides

• Eun-Sol Choi and
• Hyo-Jun Lee

Beilstein J. Org. Chem. 2026, 22, 352–369, doi:10.3762/bjoc.22.23

• bioactive compounds underwent smooth esterification with TFE to give the corresponding 2,2,2-trifluoroethyl esters 82–85 in high yields. To elucidate the reaction mechanism, cyclic voltammetry experiments, control reactions, and DFT calculations were conducted. At the anode, bromide ions are oxidized to

Ring contraction and ring expansion reactions in terpenoid biosynthesis and their application to total synthesis

• Nicolas Kratena,
• Nicolas Heinzig and
• Peter Gärtner

Beilstein J. Org. Chem. 2026, 22, 289–343, doi:10.3762/bjoc.22.21

Spirobarbiturates with a pyrrolizidine moiety: synthesis, structure and biological evaluation

• Arthur A. Puzyrkov,
• Andrew S. Drachuk,
• Ekaterina A. Popova,
• Alexander V. Stepakov and
• Vitali M. Boitsov

Beilstein J. Org. Chem. 2026, 22, 274–288, doi:10.3762/bjoc.22.20

• unable to isolate individual products either by chromatography or by recrystallization. The proposed reaction mechanism is shown in Scheme 5, where it can be seen that the intermediate azomethine ylide, acting as a 1,3-dipole, undergoes a [3 + 2] cycloaddition with N-substituted maleimides 3a–p. The

Advances in Zr-mediated radical transformations and applications to total synthesis

• Hiroshige Ogawa and
• Hugh Nakamura

Beilstein J. Org. Chem. 2026, 22, 71–87, doi:10.3762/bjoc.22.3

• method applied to secondary alkyl chlorides, both acyclic (44h) and cyclic (44i and 44j), as well as to benzyl chlorides derived from bioactive molecules such as fenofibrate (44k) and celestoride (44l), all of which furnished the corresponding dimers in excellent yields. The proposed reaction mechanism

Sustainable electrochemical synthesis of aliphatic nitro-NNO-azoxy compounds employing ammonium dinitramide and their in vitro evaluation as potential nitric oxide donors and fungicides

• Alexander S. Budnikov,
• Nikita E. Leonov,
• Michael S. Klenov,
• Andrey A. Kulikov,
• Igor B. Krylov,
• Timofey A. Kudryashev,
• Aleksandr M. Churakov,
• Alexander O. Terent’ev and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2025, 21, 2739–2754, doi:10.3762/bjoc.21.211

• nucleophilic substitution of –ONO2 groups. To clarify the reaction mechanism, cyclic voltammetry (CV) studies were conducted. CV curves of cyclohexanone oxime (S1), 1-bromo-1-nitrosocyclohexane (S2), 1-chloro-1-nitrosocyclohexane (S3), 1-nitrosocyclohexyl acetate (S4), 1-nitro-1-nitrosocyclohexane (1c), 1

• product nitro-NNO-azoxy propane 2a exhibits an oxidation peak at +1.68 V (Figure 2, pink curve). Despite the lower oxidation potential of 2a, we speculate that an excess of ADN suppresses competitive oxidation of the reaction product. To gain insight into the reaction mechanism, control experiments were

• studied reaction was also carried out under controlled potential conditions (Scheme 4, reaction 2) at E ≈ 1.8 V for 2.0 F per mol 1a. In this case, the formation of 2a was observed in a 68% yield. To gain insight into the reaction mechanism of the discovered nitro-NNO-azoxylation process quantum chemical

Mechanistic insights into hydroxy(tosyloxy)iodobenzene-mediated ditosyloxylation of chalcones: a DFT study

• Jai Parkash,
• Sangeeta Saini,
• Vaishali Saini,
• Omkar Bains and
• Raj Kamal

Beilstein J. Org. Chem. 2025, 21, 2703–2715, doi:10.3762/bjoc.21.208

• nature of para-substituents on the reaction mechanism. The substituents considered in the study include -OCH3, -SCH3, -Cl and -NO2 groups. For these chalcones, different possible pathways at various steps during the reaction are investigated leading to formation of α,β-ditosyloxy ketones and β,β

• -substituted carbonyl compound (compound C – vicinal product). By systematically varying the substituent (-X) on para-position of the aryl group, the influence of different electron-donating and electron-withdrawing groups on the reaction mechanism of these modified chalcone compounds is studied

• , the detailed calculated reaction mechanism differs. Scheme 2 and Scheme 3 depicts the reaction mechanism for these two possible cases, i.e., when X is electron-donating and electron-withdrawing, respectively. Figure 1 depicts the free energy reaction profile for the chalcone with X = -SCH3. The

Tandem hydrothiocyanation/cyclization of CF₃-iminopropargyl alcohols with NaSCN in the presence of AcOH

• Ruslan S. Shulgin,
• Ol’ga G. Volostnykh,
• Anton V. Stepanov,
• Igor’ A. Ushakov,
• Alexander V. Vashchenko and
• Olesya A. Shemyakina

Beilstein J. Org. Chem. 2025, 21, 2694–2702, doi:10.3762/bjoc.21.207

• (c, d) reaction mixtures in MeCN. Examples of hydrothiocyanation/cyclization of alkynes. Plausible reaction mechanism. Oxidation of isothiazolium thiocyanate 2a. Screening of reaction conditions. Scope of iminopropargyl alcohols 1. Supporting Information Supporting Information File 10: Full

Thiazolidinones: novel insights from microwave synthesis, computational studies, and potentially bioactive hybrids

• Luan A. Martinho,
• Victor H. J. G. Praciano,
• Guilherme D. R. Matos,
• Claudia C. Gatto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2025, 21, 2618–2636, doi:10.3762/bjoc.21.203

• decrease in yields (Table 1, entries 19–21). To confirm the critical role of ethylenediamine in the reaction mechanism, an experiment without its presence was conducted, resulting in only 2% of the desired product (Table 1, entry 22). With the optimized reaction conditions established, this methodology was

• analyses. Limitations of the EDA-catalyzed Knoevenagel reactions for the synthesis of rhodanine or thiazolidine-2,4-dione derivatives. Plausible reaction mechanism for the EDA-catalyzed Knoevenagel condensation reactions. Substrate scope of the HPW-catalyzed GBB reactions. Synthesis of imidazo[1,2-a

Assembly strategy for thieno[3,2-b]thiophenes via a disulfide intermediate derived from 3-nitrothiophene-2,5-dicarboxylate

• Roman A. Irgashev

Beilstein J. Org. Chem. 2025, 21, 2489–2497, doi:10.3762/bjoc.21.191

• thiophene, promoting further study of these structures and reaction mechanism. 1H NMR spectroscopy of the obtained mixture provided the first key information about its nature, namely the presence of two major products 2 and 3, both of which showed three characteristic singlets with signal integration 1:3:3

• , necessitates consideration of a reaction mechanism beyond straightforward nucleophilic substitution of the nitro group in ester 1. Although the initial reaction probably involves a nucleophilic attack by the S-nucleophile on the activated thiophene ring, resulting in displacement of the nitro group, the

• subsequent fate of the intermediate appears to be critical. Based on our observations and literature data, a probable reaction mechanism was proposed. The initial nucleophilic substitution of the nitro group in ester 1 by the AcS− anion yields the S-acetyl derivative (intermediate A) and NO2− anion. The key

Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings

• Lifen Peng,
• Ting Wang,
• Zhiwen Yuan,
• Bin Li,
• Zilong Tang,
• Xirong Liu,
• Hui Li,
• Guofang Jiang,
• Chunling Zeng,
• Henry N. C. Wong and
• Xiao-Shui Peng

Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166

• in 89% and 63% yield, respectively. Based on the results of control experiments and the previous reports [186], a plausible reaction mechanism was deduced. Firstly, treatment of [RuCl2(p-cymene)]2 with NaOAc afforded the ruthenium diacetate species A, which underwent complexation with 4 and

• ][194][195][196][197][198][199][200], the authors proposed a possible reaction mechanism. For the synthesis of 11a in Pt plate electrodes, two-electron anodic oxidation of I− formed I+. Addition of I+ to C≡C in 10 resulted in the production of A. Meanwhile, continuous reduction of H2O at the cathode

• oxidative cyclization of 2-alkynylaniline 16 and diselenide 17 occurred to form desired 3-selenylindole 18 in satisfactory yields with wide substance scope. Based on control experiments and previous references [203], a possible reaction mechanism was outlined. Firstly, the anodic oxidation of 17a formed

C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

• ) [71]. The Bobleter and Feather groups investigated the reaction mechanism of the conversion of these C3 compounds. The acid-catalyzed equilibrium between 1,3-dihydroxy-2-propane and 2,3-dihydroxypropanal involves an ene-triol intermediate which leads to methylglyoxal by a dehydration reaction at

Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics

• Leticia A. Gomes and
• Steven A. Lopez

Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156

• offers new insights into the reaction mechanism, showing that inverted housane/diradical forms initially in the ground state and can thermally convert into retained housane. This finding represents a significant shift in mechanistic understanding, highlighting the importance of incorporating dynamical

Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis

• Rasma Kroņkalne,
• Rūdolfs Beļaunieks,
• Armands Sebris,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154

• chemoselectivity towards diene formation (Table 1, entries 15 and 16). In accordance with the proposed reaction mechanism (Scheme 2), an equimolar amount of protons is generated in the reaction, which would likely induce the formation of additional side-products either by protodecupration [27] or the acid

Photochemical reduction of acylimidazolium salts

• Michael Jakob,
• Nick Bechler,
• Hassan Abdelwahab,
• Fabian Weber,
• Janos Wasternack,
• Leonardo Kleebauer,
• Jan P. Götze and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153

• substrate (Figure 1b). This led to the successful development of a novel dual NHC/light-mediated reduction process using either the simple tertiary amine, NEt(iPr)2 (DIPEA) or the widely available silane HSiEt3, as the only reductant. Moreover, interesting insights into the reaction mechanism supported by

• 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN), which has been commonly employed in dual NHC/photoredox-catalyzed coupling reactions, cleanly provided the fully reduced species in 50% 1H NMR yield (Table 1, entry 19). Comments on the reaction mechanism At this stage of the study, our

• attention turned to a consideration of the reaction mechanism. As has been well documented in the photoredox literature [47][48][49][50][51][52][53], excitation of a photocatalyst ([PC]) in the presence of DIPEA can result in reductive quenching of the excited state, affording the corresponding

Stereoselective electrochemical intramolecular imino-pinacol reaction: a straightforward entry to enantiopure piperazines

• Margherita Gazzotti,
• Fabrizio Medici,
• Valerio Chiroli,
• Laura Raimondi,
• Sergio Rossi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2025, 21, 1897–1908, doi:10.3762/bjoc.21.147

• on a 0.1 mmol scale. Proposed reaction mechanism. Cyclic voltammetry investigation. Cyclic voltammetry of a 0.325 M solution of Et4NBF4 in DMF (light-blue line). Cyclic voltammetry of diimine 1a (10 mM) recorded in a 0.325 M solution of Et4NBF4 in DMF (dark-blue line). Cyclic voltammetry of diimine

Chiral phosphoric acid-catalyzed asymmetric synthesis of helically chiral, planarly chiral and inherently chiral molecules

• Wei Liu and
• Xiaoyu Yang

Beilstein J. Org. Chem. 2025, 21, 1864–1889, doi:10.3762/bjoc.21.145

• removing the less soluble racemic products. Detailed studies were conducted to explore the reaction mechanism, focusing specifically on the role of the 2-acylanilines 73 as co-catalysts. Based on the experimental results and previous research, a plausible mechanism was proposed. Isomerization of substrates

Fe-catalyzed efficient synthesis of 2,4- and 4-substituted quinolines via C(sp²)–C(sp²) bond scission of styrenes

• Prafull A. Jagtap,
• Manish M. Petkar,
• Vaishnavi R. Sawant and
• Bhalchandra M. Bhanage

Beilstein J. Org. Chem. 2025, 21, 1799–1807, doi:10.3762/bjoc.21.142

• protocol, a set of control experiments was conducted to gain insight into the reaction mechanism, as depicted in Scheme 4. To clarify the significance of oxidative conditions, the standard reaction was initially conducted under an inert atmosphere by replacing oxygen with nitrogen (reaction 1). Under these

• reaction mixture was stirred at 120 °C for 24 hours, resulting in the formation of 27% of 3a along with 33% of 3a′. To further investigate the role of the solvent in the reaction mechanism, a deuterium-labeling experiment was performed by reacting 1a with 2a in deuterated methanol (CD3OD) under standard

• . Plausible reaction mechanism. Optimization of reaction conditions.a Supporting Information Supporting Information File 24: Experimental section, characterization of synthesized compounds, and copies of spectra. Funding P.A.J. gratefully acknowledges the Chhatrapati Shahu Maharaj Research Training and

Synthesis of chiral cyclohexane-linked bisimidazolines

• Changmeng Xi,
• Qingshan Sun and
• Jiaxi Xu

Beilstein J. Org. Chem. 2025, 21, 1786–1790, doi:10.3762/bjoc.21.140

• -protected amino group. On the basis of the previous report [28], a possible reaction mechanism is presented in Scheme 3. The reaction of triphenylphosphine oxide and triflic anhydride first generates an activating agent, the Hendrickson reagent (A). The amide in cyclohexane-1,2-dicarboxamides 4

• )-cyclohexane-1,2-dicarboxylic acid followed by the Hendrickson reagent-mediated final cyclization. Bisoxazoline and bisimidazoline ligands. Synthesis of chiral cyclohexane-linked bisimidazoline ligands. Attempted synthesis of chiral cyclohexane-linked bisimidazoline 5h. Proposed reaction mechanism. Synthesis

Preparation of a furfural-derived enantioenriched vinyloxazoline building block and exploring its reactivity

• Madara Darzina,
• Anna Lielpetere and
• Aigars Jirgensons

Beilstein J. Org. Chem. 2025, 21, 1737–1741, doi:10.3762/bjoc.21.136

• potent gonadotropin-releasing hormone receptor antagonists with potential application as anticancer drugs [25] and as nucleoside analogs with antiviral potency [26]. According to the reaction mechanism proposed by Elliott et al., the aza-Diels–Alder reaction of vinyloxazoline S-6 with TsNCO is a step

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

• functional and protecting groups on the pyranose scaffold can profoundly influence the reaction mechanism, toggling it between SN2 and SN1 pathways [104][105]. Supporting this, the torsional restriction imparted by the 4,6-O-benzylidene group in 2-azido-substituted GlcN lactols was found to favor the

Continuous-flow-enabled intensification in nitration processes: a review of technological developments and practical applications over the past decade

• Feng Zhou,
• Chuansong Duanmu,
• Yanxing Li,
• Jin Li,
• Haiqing Xu,
• Pan Wang and
• Kai Zhu

Beilstein J. Org. Chem. 2025, 21, 1678–1699, doi:10.3762/bjoc.21.132

• processes, as opposed to statistical models that rely solely on empirical relationships between experimental factors and outcomes. While kinetics modeling enables extrapolation of reaction predictions beyond experimentally tested conditions, it demands substantial expertise in reaction mechanism elucidation

Catalytic asymmetric reactions of isocyanides for constructing non-central chirality

• Jia-Yu Liao

Beilstein J. Org. Chem. 2025, 21, 1648–1660, doi:10.3762/bjoc.21.129

• the reaction, the resulting deacylated compound 20 could be recovered in almost quantitative yield without any erosion of the enantiopurity. A possible reaction mechanism for this Pd-catalyzed three-component reaction was proposed (Scheme 3b). As shown, the reaction started with the oxidative addition

• between β-ketoester 30 and di-tert-butyl azodicarboxylate (31), and the corresponding product 32 was obtained in 99% yield with 88% ee. A plausible reaction mechanism was proposed for this CPA-catalyzed enantioselective Groebke–Blackburn–Bienaymé reaction. As illustrated in Scheme 5b, the imine

General method for the synthesis of enaminones via photocatalysis

• Paula Pérez-Ramos,
• Raquel G. Soengas and
• Humberto Rodríguez-Solla

Beilstein J. Org. Chem. 2025, 21, 1535–1543, doi:10.3762/bjoc.21.116

• semipreparative scale for the reaction of 3-bromochromone (7a, 5.0 mmol) to afford enaminone 9a in a 68% isolated yield (Scheme 3). In terms of the reaction mechanism, TEMPO completely inhibited the reaction, implying the possibility of a radical intermediate in the reaction (Scheme 4A). Moreover, the TEMPO