Recent advances in total synthesis of illisimonin A

• Juan Huang and
• Ming Yang

Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199

• deprotection of the cyclization precursor was essential, as the TES-protected analogue of 35 failed to deliver the desired spirocycle 38 under the Nazarov cyclization conditions. α-Oxidation of 38 with molecular oxygen afforded 39, which was then converted to 40 via formation of a chloromethyl silyl ether

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• condensing abilities. Specific facial preferences are displayed as cholesterol interacts with different neighboring lipids and transmembrane proteins [33][34]. These biochemical interactions are poorly understood, so the synthesis of a «smoothed» cholesterol analogue provided an opportunity to experimentally

• of cyclopentane derivatives, promising for the synthesis of iridoids and compounds, that stimulate the formation of receptors that prevent platelet aggregation [75]. The derivatives of the Diels–Alder adduct of LG and piperylene, keto epoxide 146 and its analogue 152 lacking the spiro-fused

Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis

• Peng-Xi Luo,
• Jin-Xuan Yang,
• Shao-Min Fu and
• Bo Liu

Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177

• analogue achieved high efficiency: the bulky bromine atom sterically biased the population toward the reactive conformer I, where the benzylic C–H bond is optimally positioned for 1,6-HAT. Therefore, (S)-113 was selected as the precursor for the key photoredox reaction (Scheme 15). To prepare this, a

Halogenated butyrolactones from the biomass-derived synthon levoglucosenone

• Johannes Puschnig,
• Martyn Jevric and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2025, 21, 2297–2301, doi:10.3762/bjoc.21.175

• intermediate in synthesis [1][2]. Several nucleoside analogue drugs are prepared using γ-butyrolactones, that when reduced give pentose sugars that can be used as glycosyl donors [3][4]. A number of these clinically used drugs contain fluorine as a hydroxy bioisostere at C2, most notably gemcitabine (1) and

Discovery of cytotoxic indolo[1,2-c]quinazoline derivatives through scaffold-based design

• Daniil V. Khabarov,
• Valeria A. Litvinova,
• Lyubov G. Dezhenkova,
• Dmitry N. Kaluzhny,
• Alexander S. Tikhomirov and
• Andrey E. Shchekotikhin

Beilstein J. Org. Chem. 2025, 21, 2062–2071, doi:10.3762/bjoc.21.161

• (5) (Scheme 1), a structural analogue of the biologically active alkaloid tryptanthrin (Figure 1). An alternative scheme to indolo[1,2-c]quinazoline-12-carboxylic acid (3) was based on initial acylation followed by a haloform reaction. Refluxing compound 1 with trifluoroacetic anhydride (TFAA) in

• . Comparative analysis of the most active derivative 9c (Table 2) with its structural analogue 10b (Table 3) revealed that replacing the carbonyl group with a methyl moiety appears to increase the non-specific cytotoxicity of this chemotype, thereby reducing its selectivity. We also estimated the potency of the

Preparation of spirocyclic oxindoles by cyclisation of an oxime to a nitrone and dipolar cycloaddition

• Beth L. Ritchie,
• Alexandra Longcake and
• Iain Coldham

Beilstein J. Org. Chem. 2025, 21, 1890–1896, doi:10.3762/bjoc.21.146

• -phenyl cycloadduct 6 (Scheme 4). The yield of cycloadduct 6 was good and there were only two stereoisomers obtained that were inseparable. Based on the result with the N-methyl analogue, we predict that the major isomer has the same stereochemistry as that of compound 5a. The dipolarophile dimethyl

Unique halogen–π association detected in single crystals of C–N atropisomeric N-(2-halophenyl)quinolin-2-one derivatives and the thione analogue

• Mai Uchibori,
• Nanami Murate,
• Kanako Shima,
• Tatsunori Sakagami,
• Ko Kanehisa,
• Gary James Richards,
• Akiko Hori and
• Osamu Kitagawa

Beilstein J. Org. Chem. 2025, 21, 1748–1756, doi:10.3762/bjoc.21.138

• , Shibaura Institute of Technology, 307 Fukasaku, Minuma-ku, Saitama 337-8570, Japan 10.3762/bjoc.21.138 Abstract In single crystals of C–N atropisomeric N-(2-halophenyl)quinolin-2-one and the thione analogue, a unique association based on a halogen–π interaction was detected. In racemic and optically pure

• C–N atropisomers and their structural properties for over 25 years [16][17]. As a part of the C–N atropisomeric chemistry, we succeeded in the asymmetric synthesis of mebroqualone (I) and the thione analogue II [18][19]. In the course of this study, it was found that intermolecular association in

• through a σ-type intermolecular halogen bonding (C–Br···O) between the ortho-bromine atom and the carbonyl oxygen. The formation of similar heterochiral polymers through a σ-type intermolecular halogen bond (C–Br···S) was also found in crystals of the thio-analogue rac-II. On the other hand, in the

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

• them, the phenyl-substituted aza[7]helicene 43f exhibits pronounced chiroptical activity, with |gabs| and |glum| values reaching 3.04 × 10−3 and 1.30 × 10−3, respectively, and a high BCPL of 11.5 M−1 cm−1 in the near-infrared region. In contrast, the corresponding aza[5]helicene analogue shows

• [5]helicene (compound 57b) by coupling two 12H-benzo[b]phenoxazine (BPO) units and systematically compared it to its N,N-analogue (compound 57a) derived from 13H-dibenzo[b,i]phenoxazine (DBPO) scaffolds [72] (Table 19). Compound 57b was obtained in significantly higher yield and, like compound 57a

• sensitivity of chiral excited-state properties to heteroatom substitution within the helicene framework. Extending this design principle, the group reported a double N,S-hetero[5]helicene 58 constructed from two benzo[b]phenothiazine units in 2023 [73]. Compared to the N,O-analogue 57b, this new compound

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

• become quite attractive structural motifs in drug design [13][14]. A few examples are shown in Figure 3: oxetano-thalidomide 1 was designed as an analogue of the infamous thalidomide to block racemisation and hence prevent the severe side-effects caused by the opposite enantiomer [15]. Compound 2 is a

• alkenes and high diastereocontrol (dr ≥ 80:20) was achieved for trisubstituted ones. Switching the bromonium activator to the iodonium analogue only led to a lower yield. This haloetherification method was further expanded by McLaughlin and Roberts in 2022 who reported a convenient two-step sequence

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

• part of this review, see Table 3). Cooling leads to a reduction of the intensity of the central EPR signal, fine structure, and significant diradical anisotropy, indicating that the triplet state becomes less and less populated (see Figure 12b) [95]. By contrast, the TTM-TTM analogue without chlorine

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

• brevicarine (2, isolated as its dihydrochloride salt). Based on the above results, Eschweiler–Clarke methylation of primary amine 25 was applied for the synthesis of N-methylbrevicarine (27) [39], a close structural analogue of alkaloid 2. The NMR data of our synthesized brevicarine (2) base and

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

• -NBD2 (Supporting Information File 1), demonstrating the intermediate availability of O-QC2. In a similar manner, the aza analogue N-NBD2 was investigated. The UV–vis experiments (Figure 4) yielded results comparable to those obtained for N-NBD1. Initially, the conversion to N-QC2 is anticipated at

Origami with small molecules: exploiting the C–F bond as a conformational tool

• Patrick Ryan,
• Ramsha Iftikhar and
• Luke Hunter

Beilstein J. Org. Chem. 2025, 21, 680–716, doi:10.3762/bjoc.21.54

• molecular dipole moment of 1.90 D. In contrast, the monofluorinated analogue 2 can access three different staggered rotamers 2a–c about the C–C(F) bond; all three of these rotamers have similar energies, but their molecular dipole moments vary considerably depending on whether the C–F dipole is aligned with

• or against the dipole of the indole moiety. A similar phenomenon occurs with the difluorinated analogue 3. The fluorinated molecules 2 and 3 can be said to have a “chameleonic” character [9][10][11][12][13][14]: they have the ability to change polarity to suit their environment. This is a potentially

• favourable accommodation of a wider C–C(F2)–C angle within the cyclic product 11. Another illustration of the geometric perturbation caused by the wider C–C(F2)–C angle comes from the stearic acids 12 and 13 (Figure 3); the gem-difluorinated analogue 13 has substantially greater conformational disorder

Binding of tryptophan and tryptophan-containing peptides in water by a glucose naphtho crown ether

• Gianpaolo Gallo and
• Bartosz Lewandowski

Beilstein J. Org. Chem. 2025, 21, 541–546, doi:10.3762/bjoc.21.42

• ). Peptide 7, the acetylated analogue of 4, is bound by 1 with essentially the same affinity as the non-acetylated variant (entry 6, Table 2). Peptide 8, consisting of three alanine residues, is bound by the glucose naphtho crown ether with a significantly lower affinity, 3–4 times weaker than the Trp

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

• , the size and conformational flexibility of the five BnF groups resulted in significant disruption of CORA–CORA π–π interactions due to the greater CORA–CORA bowl-to-bowl distances relative to the less bulky C5-CORA(CF3)5 analogue [18][19]. However, corannulene derivatives are only weakly fluorescent

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

• rotate in this form [41], the structure can be termed rigid. Nonetheless, slight variations in the cavity height can be controlled by engineering the twist along the triptycene axis. For instance, comparing crystal structures of cage 2 and its monoacetylated analogue, 2Ac1 (Figure 9B), a decrease of 0.3

Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• (Figure 6) seems to preserve the punctual group of its linear analogue, especially concerning the outermost NAP moieties. Interestingly, this quasi-D2h symmetry is broken upon oxidation, which is supported by the appearance of the triplet of Raman bands in the 1600–1550 cm−1 region. On the other hand, the

Effect of substitution position of aryl groups on the thermal back reactivity of aza-diarylethene photoswitches and prediction by density functional theory

• Misato Suganuma,
• Daichi Kitagawa,
• Shota Hamatani and
• Seiya Kobatake

Beilstein J. Org. Chem. 2025, 21, 242–252, doi:10.3762/bjoc.21.16

• effective methods for predicting the thermal back reactivity, density functional theory (DFT) calculations can be considered [51][58][59][60][61][62]. For example, in previous studies on the thermal back reactivity of diarylbenzene that is an analogue of diarylethene, we found that the M06-2X level of

Facile one-pot reduction of β-nitrostyrenes to phenethylamines using sodium borohydride and copper(II) chloride

• Laura D’Andrea and
• Simon Jademyr

Beilstein J. Org. Chem. 2025, 21, 39–46, doi:10.3762/bjoc.21.4

• ]. One of the most studied and inexpensive routes to synthesize substituted phenethylamines focuses on the reduction of their α,β-unsaturated nitroalkene analogue (β-nitrostyrene), where both the double bond and the nitro group need to be reduced to deliver the corresponding primary amine. Their

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• from certain plant species (Figure 1) [12]. The acenaphthylene-fused thiophene-based heteroarene 3 is another heterocyclic fluoranthene analogue, which was used as an organic semiconductor in transistors [13]. The synthesis and coordination complexes of the acenaphthylene-fused N-heterocyclic (NHC

• 1,8-diiodonaphthalene (12) and a broad range of arylboronic acids and esters to afford substituted fluoranthenes 13 in good to high yields (Scheme 1d) [43]. In that work, we had only one example of a heterocyclic fluoranthene analogue where the use of 4-pyridylboronic acid provided the corresponding

• the targeted benzo[j]fluoranthene product 32 was isolated in 45% yield. It should be noted that this reaction was not successful when an analogue of compound 31 with -OTIPS instead of the -OMOM group was tested as the boronic ester reaction partner, due to the decomposition of this compound presumably

Discovery of ianthelliformisamines D–G from the sponge Suberea ianthelliformis and the total synthesis of ianthelliformisamine D

• Sasha Hayes,
• Yaoying Lu,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2024, 20, 3205–3214, doi:10.3762/bjoc.20.266

• /CH2Cl2 at room temperature (17% yield). Subjecting the methoxylated benzaldehyde intermediate 9 to a Doebner–Knoevenagel condensation with malonic acid and pyridine afforded the brominated cinnamic acid analogue 10 in 54% yield [19]. Amidation chemistry using carbonyldiimidazole (CDI) [18] and the

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• . The authors proposed a mechanism for the reaction, in which the alkene is activated by PhI(OAc)2, followed by intramolecular nucleophilic attack of nitrogen and displacement of iodobenzene by fluoride. The intramolecular aminofluorination of unsaturated amines using a structural analogue of Togni’s

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

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

• trichloroacetimidate 10e by reaction with hydrazine and subsequent treatment with trichloroacetonitrile. The same synthesis was carried out also with the β-configured analogue of 10a. However, employment of the α-anomer 10a proved to be advantageous in terms of yield. The reaction of 1d with 10e afforded indigo-N

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• addition of 3.0 equivalents of HS−(aq) ions. The calculated theoretical LoD was 0.63 μM (20 ppb), which is comparable to that observed with the europium(III) analogue (1.1 μM, 36 ppb) [16]). The chemosensor exhibited significant reversibility over multiple cycles involving the addition and subsequent

• upon our previously reported findings. Our earlier work demonstrated an increase in europium luminescence with a LoD of 100 ppb and 665 ppb for two Eu analogues [Eu(triazole-DPA)3·3Cu]3+ [16] and [Eu(DO2A)DPA·Cu]+ [17], while the [Tb(DO2A)DPA·Cu]+ analogue [17] exhibited no significant change in

• emission spectrum, unlike that observed with the europium(III) analogue. This result suggests potential variations in the luminescence response among terbium(III) analogues and highlights the complexity of the interaction between lanthanide complexes and gaseous H2S, and understanding the nuances of this