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

• methoxymethyl group cleavage, O-to-N rearrangement, and isomerization of the double bond. An oxazoline ring formation in the resulting unsaturated amides provided the corresponding enantioenriched vinyloxazoline. The reactivity of the electron-deficient double bond in the vinyloxazoline was explored in several

• ][24] (Scheme 1). The proposed strategy relied on the N-deprotection of the intermediate ester 3d inducing O-to-N rearrangement to form amide 5 as a precursor of vinyloxazoline 6. For this purpose, Alloc (allyloxycarbonyl) turned out to be a suitable N-protecting group as it was compatible with the

Transition-state aromaticity and its relationship with reactivity in pericyclic reactions

• Israel Fernández

Beilstein J. Org. Chem. 2025, 21, 1613–1626, doi:10.3762/bjoc.21.125

• Cope rearrangements [20]. More recently, Alabugin and co-workers reported that the gold(I)-catalyzed propargyl rearrangement depicted in Scheme 1b also follows a concerted oxonia Claisen pathway (via an aromatic TS) rather than through a higher barrier 6-endo-dig cyclization [21], which provides

• reactions between t-BuN3 and [Au]CP complex (black lines) and the analogous process involving [Mg]CP complex and projected onto the N···P bond-forming distance. (a) Diels–Alder cycloaddition reaction between butadiene and ethylene. (b) Gold(I)-catalyzed propargyl rearrangement. Representative

Thermodynamic equilibrium between locally excited and charge transfer states in perylene–phenothiazine dyads

• Issei Fukunaga,
• Shunsuke Kobashi,
• Yuki Nagai,
• Hiroki Horita,
• Hiromitsu Maeda and
• Yoichi Kobayashi

Beilstein J. Org. Chem. 2025, 21, 1577–1586, doi:10.3762/bjoc.21.121

• . Conversely, the deceleration of the early component (6.2 ps vs 2.4 ps for PTZ(TPA)2), likely associated with solvent reorientation, may be explained by the larger dipole rearrangement induced by excitation in this asymmetric molecular framework, which in turn requires more time for the reorganization of the

Ambident reactivity of enolizable 5-mercapto-1H-tetrazoles in trapping reactions with in situ-generated thiocarbonyl S-methanides derived from sterically crowded cycloaliphatic thioketones

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Marcin Palusiak,
• Heinz Heimgartner,
• Marta Denel-Bobrowska and
• Agnieszka B. Olejniczak

Beilstein J. Org. Chem. 2025, 21, 1508–1519, doi:10.3762/bjoc.21.113

• publications [15], or/and from secondary processes, like an intramolecular rearrangement. Taking into account the postulated basicity (and nucleophilicity) of thiocarbonyl S-methanides 1 derived from cycloaliphatic thioketones [6], the initiating step of these processes can be presented as protonation of the

• depends on both steric factors in 11 and the electronic structure of the reactive anion 12. In general, growing steric hindrance prefers the S-attack and, very likely, hinders rearrangement leading to thioaminals 9. This hypothesis is supported by the fact that no formation of products 9 is observed with

• initial products are thioaminals 9, which under the reaction conditions or later on, during the storage in CDCl3 solution, undergo an intramolecular rearrangement presented in Scheme 7. Moreover, the differences observed in the structures of products obtained in reactions with structurally similar

Heterologous biosynthesis of cotylenol and concise synthesis of fusicoccane diterpenoids

• Ye Yuan,
• Zhenhua Guan,
• Xue-Jie Zhang,
• Nanyu Yao,
• Wenling Yuan,
• Yonghui Zhang,
• Ying Ye and
• Zheng Xiang

Beilstein J. Org. Chem. 2025, 21, 1489–1495, doi:10.3762/bjoc.21.111

• (7) and R (8) (Scheme 1). The secondary hydroxy group of brassicicene I was selectively TBS-protected in the presence of TBSOTf and 2,6-lutidine to give compound 13 in 93% yield. Then, compound 13 underwent oxidative rearrangement with PCC to afford ketone 14 in 61% yield. Under Luche reduction

Wittig reaction of cyclobisbiphenylenecarbonyl

• Taito Moribe,
• Junichiro Hirano,
• Hideaki Takano,
• Hiroshi Shinokubo and
• Norihito Fukui

Beilstein J. Org. Chem. 2025, 21, 1454–1461, doi:10.3762/bjoc.21.107

• . Consequently, figure-eight molecules often exhibit fascinating properties, such as unusual rearrangement reactions [9] and efficient circularly polarized luminescence (CPL) [10][11][12]. Cyclobisbiphenylenecarbonyl (CBBC) 1 is a figure-eight macrocycle, which is readily synthesized from commercially available

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• for high-efficiency chiral optoelectronic and quantum materials. In 2024, Kivala’s group selectively synthesized highly distorted [6]helicenes 29a and 29b incorporating azocine units via a regioselective Beckmann rearrangement from oxime precursor 29c [43] (Table 8). For comparative evaluation, the

• optoelectronic materials. In 2022, Furuta’s group developed a one-pot synthetic protocol to access (NH)-phenanthridinone derivatives and chiral amide-functionalized [7]helicene-like molecules 67a,b from biaryl dicarboxylic acids, employing a Curtius rearrangement followed by basic hydrolysis [81] (Table 23

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

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

• Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

• by a naphthalene-to-azulene rearrangement. The alternative radical cation mechanism has a higher energy barrier than the arenium cation-mediated reaction. Notably, only one of the pentagon–heptagon pairs exhibits an azulene-like electronic structure and aromaticity, as confirmed by the analysis of

• ]. Instead, products of a skeletal arrangement of one azulene moiety 121 and two azulene moieties 122 were isolated in low yields (1% and 4%, respectively). Plausible mechanisms of such a cyclopenta[ef]heptalene to phenanthrene rearrangement were proposed by the authors and involve the arenium ion pathway or

• (Scheme 24). Further heating on the Au(111) surface led to products with partial skeletal rearrangement, driven by intramolecular structural strain. Both nanographenes, 186 and 187, contain six formal azulene subunits and exhibit nearly planar geometry. However, theoretical analysis of NICS values

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

A multicomponent reaction-initiated synthesis of imidazopyridine-fused isoquinolinones

• Ashutosh Nath,
• John Mark Awad and
• Wei Zhang

Beilstein J. Org. Chem. 2025, 21, 1161–1169, doi:10.3762/bjoc.21.92

• intermediate 7, the carbonyl oxygen interacts with AlCl₃, enhancing the electrophilicity and promoting the rearrangement to form stable oxonium ions. The removal of water from 7 is facilitated by protonation, producing reactive carbocations which undergo dehydrative aromatization to produce products 8

Investigations of amination reactions on an antimalarial 1,2,4-triazolo[4,3-a]pyrazine scaffold

• Henry S. T. Smith,
• Ben Giuliani,
• Kanchana Wijesekera,
• Kah Yean Lum,
• Sandra Duffy,
• Aaron Lock,
• Jonathan M. White,
• Vicky M. Avery and
• Rohan A. Davis

Beilstein J. Org. Chem. 2025, 21, 1126–1134, doi:10.3762/bjoc.21.90

• mixtures were separated by silica flash column chromatography, and in some cases, were subsequently separated by HPLC where required. All reactions gave easily isolated product in high purity (≥95%), with yields ranging from 18% to 87%. No ipso-substituted products, and no triazole–imidazole rearrangement

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

• nitrilium salt 92 followed by carboxylate attack (93) and Mumm rearrangement (Scheme 27) [63]. Furthermore, Maruoka and co-workers (2020) developed a one-pot transamidation reaction catalyzed by Cu via acid fluoride 48 (Scheme 28) [64]. In this work, single-electron transfer (SET) between Selectfluor and

Recent total synthesis of natural products leveraging a strategy of enamide cyclization

• Chun-Yu Mi,
• Jia-Yuan Zhai and
• Xiao-Ming Zhang

Beilstein J. Org. Chem. 2025, 21, 999–1009, doi:10.3762/bjoc.21.81

• reduction, and epoxidation delivered compound 33 with the required oxidation level of the cyclopentane ring. In the final stages, Meinwald rearrangement/hemiketalization in a step-wise procedure, followed by amide reduction, completed the total synthesis of (−)-cephalotine B. Alternatively, after benzylic

• oxidation, the Meinwald rearrangement/aldol reaction gave rise to the bridge cyclic intermediate 35, which can finally be converted into both (−)-fortuneicyclidin A and (−)-fortuneicyclidin B. Polycyclization Cyclization/Pictet–Spengler reaction The hexahydropyrrolo[2,1-a]isoquinoline or tetrahydropyrrolo

Studies on the syntheses of β-carboline alkaloids brevicarine and brevicolline

• Benedek Batizi,
• Patrik Pollák,
• András Dancsó,
• Péter Keglevich,
• Gyula Simig,
• Balázs Volk and
• Mátyás Milen

Beilstein J. Org. Chem. 2025, 21, 955–963, doi:10.3762/bjoc.21.79

• ammonium derivative 14 with the potassium salt of compound 15 resulted in the ring-opened derivative 16. Removal of the benzylthiocarbonyl moiety, then Beckmann rearrangement of the oxime obtained from ketone 17 and subsequent cyclization gave β-carboline derivative 18, which was dehydrogenated and

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• functionalized indoles. When treated with acid (BF3·E2O), the intermediate 2-methylene-3-aminoindoline 69 undergoes an aza-Cope rearrangement to form 2-benzylindole 70; when treated with a base (Cs2CO3), this intermediate undergoes a 1,3-proton migration process to convert back to 3-aminoindole 71. The possible

Synthesis and photoinduced switching properties of C₇-heteroatom containing push–pull norbornadiene derivatives

• Daniel Krappmann and
• Andreas Hirsch

Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64

• intermediates in total [29][30] and bio-synthesis protocols [31], e.g., in inositol chemistry [32] or towards aminocyclitols [33]. The potential of these compounds as functional photoswitches was primarily assessed in the 1960s and 1970s by Prinzbach and co-workers, who identified a variety of rearrangement

• Bansal and co-workers [44] revealed the potential formation of aza-QC derivatives at low temperatures. However, isolation of these derivatives proved difficult, as rapid rearrangement to azepine analogues occurred at temperatures exceeding 0 °C. On the basis of the quadricyclane or azepine structure

• formation of O-QC2 was achieved after 15 minutes (Supporting Information File 1). Next, thermally induced back-conversion to Q-NBD2 was attempted by heating the sample to 50 °C overnight. This process resulted in the initial formation of O-UnS2, followed by further rearrangement, consistent with the

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• (Scheme 30). The experimental results showed that product c was initially formed and then continuously transformed into product d via the phospho-Fries rearrangement. This transformation was completed in the presence of Et3N within 5 hours. Additionally, an excess of S8 and (EtO)2P(O)H likely inhibits the

• occurrence of this rearrangement. Electrochemical Se–P bond formation In another study, Gu et al. [71] reported electrochemical P–Se bond formation of the reaction of elemental Se with diethyl phosphonate and aromatic compounds. In this method, potassium iodide acts as a key additive. The reaction is carried

Development and mechanistic studies of calcium–BINOL phosphate-catalyzed hydrocyanation of hydrazones

• Carola Tortora,
• Christian A. Fischer,
• Sascha Kohlbauer,
• Alexandru Zamfir,
• Gerd M. Ballmann,
• Jürgen Pahl,
• Sjoerd Harder and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2025, 21, 755–765, doi:10.3762/bjoc.21.59

• rearrangement under mild conditions [6], and the Nazarov-type electrocyclization of alkenyl aryl carbinols [7]. Exploiting the ease with which calcium forms hydrides, hydrogenation of aldimines, transfer hydrogenation of alkenes, and even deuteration of benzene by an SNAr mechanism, have been recently achieved

Sequential two-step, one-pot microwave-assisted Urech synthesis of 5-monosubstituted hydantoins from L-amino acids in water

• Wei-Jin Chang,
• Sook Yee Liew,
• Thomas Kurz and
• Siow-Ping Tan

Beilstein J. Org. Chem. 2025, 21, 596–600, doi:10.3762/bjoc.21.46

• copper(I)-catalyzed reactions (48–71%) [13] and the four-component Ugi reaction [14] yields 48–71% and 27–67%, respectively. In addition, pyroglutamates with isocyanates, which provide exceptionally high yields (97–99%) [15], and dipeptides have been utilized in triflate-activated Mumm’s rearrangement

Formaldehyde surrogates in multicomponent reactions

• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

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

• light irradiation, undergoing rearrangement and photodegradation, so there may be a risk of degradation if irradiation using UV light is tried. Alternatively, the lack of a [2 + 2] cycloaddition of Me2B, may be due to its photophysical properties not allowing for a reaction to occur, rather than the

Molecular diversity of the reactions of MBH carbonates of isatins and various nucleophiles

• Zi-Ying Xiao,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2025, 21, 286–295, doi:10.3762/bjoc.21.21

• Figure 1 and Figure 2, it can be found that the C=C bond is located in the unit of the pyrrolidine-2,5-dione, while the scaffold of indolin-2-one is connected via a C–C single bond with the unit of the pyrrolidine-2,5-dione. Therefore, an allyl rearrangement must proceed in the reaction process, which is

• used in the reaction, a direct Michael addition of the arylamine to the C=C bond of the maleimide unit and sequential elimination of carbon dioxide and tert-butoxide ion gives the intermediate B, which in turn undergoes an allylic rearrangement to afford the product 5. In this process, no extra

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

• four-step process involves allylation, Claisen rearrangement, isomerization, and oxidative dimerization. Each reaction step was optimized independently by using either online HPLC or in-line benchtop NMR spectroscopy to afford an overall yield of 67% in 66 iterative experiments over four linear

Controlled oligomerization of [1.1.1]propellane through radical polarity matching: selective synthesis of SF₅- and CF₃SF₄-containing [2]staffanes

• Jón Atiba Buldt,
• Wang-Yeuk Kong,
• Yannick Kraemer,
• Masiel M. Belsuzarri,
• Ansh Hiten Patel,
• James C. Fettinger,
• Dean J. Tantillo and
• Cody Ross Pitts

Beilstein J. Org. Chem. 2024, 20, 3134–3143, doi:10.3762/bjoc.20.259

• contrast to P212121 in the low temperature phase (LTP). Note that the b-axis is roughly 1/5 of the c-axis observed at 90 K (the axial rearrangement is due to the change in space group). To discern the approximate temperature of the phase transition, the unit cell was measured in 20 K increments upon