Acyclic cucurbit[n]uril bearing alkyl sulfate ionic groups

• Christian Akakpo,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 717–726, doi:10.3762/bjoc.21.55

• acyclic CB[n] are not macrocycles, they are preorganized into a C-shaped geometry by virtue of their polycyclic chemical structure and display binding affinities approaching those of macrocyclic CB[n]. M1 and analogues display outstanding biocompatibility and have been used for a number of in vivo

• closer to the ureidyl C=O portals [68][69]. However, a close examination of the structures of M0 and M1 show that the ionic group for M1 is a sulfonate and for M0 is a sulfate. Accordingly, M1 and M0 differ in two ways: a) different (CH2)n linker length and b) different ionic group (sulfonate versus

• sulfate) while maintaining the distance of the ionic group from the ureidyl C=O portal we designed acyclic CB[n]-type receptor C1 (Scheme 1). The only structural difference between M1 and C1 is the swapping of one CH2 group for one O atom in each alkyl chain which effectively changes the sulfonate group

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

• Patrick Ryan Ramsha Iftikhar Luke Hunter School of Chemistry, The University of New South Wales (UNSW), Sydney 2052, Australia 10.3762/bjoc.21.54 Abstract When present within an organic molecule, the C–F bond tends to align in predictable ways with neighbouring functional groups, due to

• fluorine atoms into the structure. The C–F bond has certain fundamental characteristics that enable it to serve as an effective conformational tool (Figure 1) [2][3][4]. First, the C–F bond is quite short at only ≈1.35 Å (cf. ≈1.09 Å for C–H, or ≈1.43 Å for C–O). The short length of the C–F bond, and the

• compact size of the fluorine atom itself, means that fluorine can be incorporated into an organic molecule as a replacement for hydrogen without drastically altering the molecular volume. Second, the C–F bond is highly polarised. This means that any molecular conformation in which the C–F dipole is

Photochemically assisted synthesis of phenacenes fluorinated at the terminal benzene rings and their electronic spectra

• Yuuki Ishii,
• Minoru Yamaji,
• Fumito Tani,
• Kenta Goto,
• Yoshihiro Kubozono and
• Hideki Okamoto

Beilstein J. Org. Chem. 2025, 21, 670–679, doi:10.3762/bjoc.21.53

• the manipulation of the solid-state optoelectronic nature of polycyclic aromatic molecules to develop future functional materials in organic electronics. Chemical structures of phenacenes studied in this work. UV–vis and fluorescence spectra of F8PIC (a), F8FUL (b), and F87PHEN (c) (red lines) and the

• corresponding parent phenacenes (black lines) in CHCl3. The broken lines show long-wavelength absorption bands at 10-times magnification of the intensity for clarity. Photoluminescence spectra of F8PIC (a), F8FUL (b), and F87PHEN (c) in toluene at 77 K. Electronic spectra of F8PIC (a), F8FUL (b), and F87PHEN (c

• state. The orange and blue sites, respectively, indicate negative and positive regions (−0.02 ≈ 0.02 hartree). Synthesis of building blocks 10, 13, and 15. Reagents and conditions: a) NaBH4, MeOH, THF, reflux; b) PBr3, reflux; c) N-methylmorpholine-N-oxide, THF, reflux; d) ethylene glycol, p-TsOH

Asymmetric synthesis of fluorinated derivatives of aromatic and γ-branched amino acids via a chiral Ni(II) complex

• Maurizio Iannuzzi,
• Thomas Hohmann,
• Michael Dyrks,
• Kilian Haoues,
• Katarzyna Salamon-Krokosz and
• Beate Koksch

Beilstein J. Org. Chem. 2025, 21, 659–669, doi:10.3762/bjoc.21.52

• identified as optimal delivering a yield of alkylated complex of 60% (Table 1, entry 4). With DBU as base different solvents differing in polarity have been tested. At room temperature, acetonitrile proved best and increased the yield to 88% (Table 1, entry 11). Lowering the temperature to 0 °C led to a

• final yield of 94%. At these conditions (DBU, MeCN and 0 °C) the base and bromide equivalents were further modified but no further increase in yield could be achieved. Thus, 1.5 equiv DBU with 1.05 equiv alkyl bromide in MeCN at 0 °C have been identified as optimal conditions for the Ni complex

• (II) complex of bisTfMePhe have differed significantly. Here, sodium hydride (NaH) was identified as optimal base leading to a yield of 85% when using DMF as solvent at 0 °C to room temperature (Table 2, entry 4). Testing different base equivalents, solvents, solvent mixtures and temperatures didn’t

Recent advances in allylation of chiral secondary alkylcopper species

• Minjae Kim,
• Gwanggyun Kim,
• Doyoon Kim,
• Jun Hee Lee and
• Seung Hwan Cho

Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51

• significance of this transformation lies in its unique ability to efficiently create a stereogenic center while forming new carbon–carbon or carbon–heteroatom bonds (e.g., C–N, C–O, and C–S) with excellent selectivities. The field of metal-catalyzed allylic substitution has evolved significantly since its

• (Scheme 3) [46]. Their methodology involves a stereoretentive I/Li exchange at −100 °C, followed by transmetalation with CuBr·P(OEt)3 to generate the secondary alkylcopper species 14. These organocopper species demonstrated remarkable reactivity in SN2-type additions to allylic bromides with exceptional

• synthesis underscore the robustness and reliability of this copper-mediated transformation in creating stereochemically complex molecules. Mechanistic investigations revealed several key factors controlling the stereochemical outcome of these transformations. The extremely low temperature (−100 °C) during

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

• Olesja Koleda,
• Janis Sadauskis,
• Darja Antonenko,
• Edvards Janis Treijs,
• Raivis Davis Steberis and
• Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

• also suitable as nucleophiles for the cyclization into 2-aminoproline and 2-aminopipecolic acid derivatives 6 (Figure 2, reaction 3). The starting disubstituted malonic esters are readily available by C-alkylation of inexpensive and readily available diethyl acetamidomalonate, followed by

• observed by LC–MS when the electrolysis was performed in 5:1 MeCN/D2O (Scheme 2, reaction 2). The considerably higher O–H bond dissociation energy (119 kcal/mol) [12] as compared to that of the C–H bond in MeCN (86 kcal/mol) [13] renders the hydrogen atom abstraction from water by a carbon-centered radical

• decarboxylation/cyclization conditions, and the respective 2-aminoproline derivatives 6a–c were obtained in 49–75% yield. Redox-sensitive 4-anisoyl and 4-cyanobenzoyl groups-containing monoesters 9d,e are also suitable as substrates as evidenced by the formation of 6d,e in 38–63% yields. Not only N-tosylates

Semisynthetic derivatives of massarilactone D with cytotoxic and nematicidal activities

• Rémy B. Teponno,
• Sara R. Noumeur and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 607–615, doi:10.3762/bjoc.21.48

• curvupallides, and the spirostaphylotrichins [8][9][10]. Massarilactones A and B were isolated for the first time from the freshwater aquatic fungus Massarina tunicata [8], massarilactones C and D from Coniothyrium sp. associated to the succulent plant Carpobrotus edulis [11], massarilactones E, F, and G from

• presence of these groups was evidenced by resonances observed at δC 166.4 (C-1''), 164.8 (C-1'''), 136.4 (C-2'', C-2'''), 128.4 (C-3'''), 128.0 (C-3''), 18.3 (Me-2''), and 18.1 (Me-2'''). The HMBC correlations from H-3 (δH 5.23, t, J = 3.4 Hz) and H-4 (δH 5.75, dd, J = 3.3, 1.3 Hz) to carbons at δC 164.8

• (C-1''') and 166.4 (C-1''), respectively, revealed that the two methacryloyl moieties were linked at C-2 and C-3. The other salient feature of the 13C NMR spectrum was the presence of some signals at δC 171.7 (C-1'), 82.3 (C-2'), 31.4 (C-3'), 26.0 (C-4'), 105.1 (C-5'), 137.0 (C-6'), 25.1 (Me-2'), and

Total synthesis of (±)-simonsol C using dearomatization as key reaction under acidic conditions

• Xiao-Yang Bi,
• Xiao-Shuai Yang,
• Shan-Shan Chen,
• Jia-Jun Sui,
• Zhao-Nan Cai,
• Yong-Ming Chuan and
• Hong-Bo Qin

Beilstein J. Org. Chem. 2025, 21, 601–606, doi:10.3762/bjoc.21.47

• Xiao-Yang Bi Xiao-Shuai Yang Shan-Shan Chen Jia-Jun Sui Zhao-Nan Cai Yong-Ming Chuan Hong-Bo Qin School of Chemistry and Environment, Yunnan Minzu University, Kunming 650000, China 10.3762/bjoc.21.47 Abstract The total synthesis of (±)-simonsol C was accomplished using a dearomatization under

• route. Keywords: acidic dearomazation; benzofuran; (±)-simonsol C; total synthesis; Introduction Star anise, derived from Illicium species cultivated in southeastern China [1] possesses significant economic, culinary, and medicinal value [2]. Particularly noteworthy are its medicinal properties

• , including insecticidal, antibacterial, anti-inflammatory, analgesic, and neurotrophic activities [3]. In 2013, Wang’s group isolated (±)-simonsol C from star anise, which features a unique 6/5/6 tricyclic benzofuran structure [4]. They found that it exhibits biological activity that promotes neuronal

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

• were first verified using different equivalents of KOCN at different temperatures in water under microwave heating conditions (Scheme 1, Table 1), and 5.0 equiv of KOCN and microwave irradiation at 80 °C produced the best yield for H1a (Table 1, entry 2). Inspired by the simplicity of the procedure, a

• second step was attempted as part of a one-pot synthesis of hydantoins by the addition of concentrated hydrochloric acid followed by microwave irradiation of the reaction mixture at 80 °C for 15 min (Scheme 2). Gratifyingly, the acid-induced intra-cyclization of the urea derivative H1a proceeded smoothly

• substrate reactivity, minor side reactions, or minor losses during microwave irradiation. The remaining part may be caused by factors such as slight volatilization or incomplete conversion under specific use conditions. We found the synthetic procedure facile as the less polar hydantoin products (H2a–c, H2e

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

• first reacts with the aniline under cobalt(III) catalysis, and the resulting intermediate C then attacks the thionium ion A. Quinolines of general structure II are formed after the loss of methyl sulfide from intermediate D, followed by final cyclization of intermediate E (Scheme 8, path II

• reacts with the enolate of the ketone, which is stabilized by coordination with Fe(III), resulting in the formation of the C–C bond. A further oxidative aromatization process affords compound I. Compared to the protocol developed by Zhang et al. [24], the reaction is less regioselective, as Troger’s base

• DMSO (Scheme 12) [45]. In this case, the reaction works well under metal-free conditions using iodine as the catalyst. Remarkably, the activation of DMSO was accomplished using Selectfluor, and in this case, DMSO is the source of a C-1 unit. It is important to note that the reaction could be performed

Study of the interaction of 2H-furo[3,2-b]pyran-2-ones with nitrogen-containing nucleophiles

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2025, 21, 556–563, doi:10.3762/bjoc.21.44

• fragment leads to hemiaminal A. Then, enamine 4 is formed via dehydration of intermediate B. In the case of amines 2 the reaction stops at this stage while for other substrates the further recyclization proceeds. So, the additional NH or OH fragment attacks the lactone moiety leading to intermediate C. The

Asymmetric synthesis of β-amino cyanoesters with contiguous tetrasubstituted carbon centers by halogen-bonding catalysis with chiral halonium salt

• Yasushi Yoshida,
• Maho Aono,
• Takashi Mino and
• Masami Sakamoto

Beilstein J. Org. Chem. 2025, 21, 547–555, doi:10.3762/bjoc.21.43

• catalysis (Figure 2c). Results and Discussion Chiral halonium salts 9a–c were prepared according to our previously reported methods [33]. The Mannich reaction of ketimine 7a and cyanoester 16a was selected as a benchmark, and catalyst screening was conducted (Scheme 1). The reaction was carried out with 1.0

• chiral halonium salt. Next, the reaction temperature was optimized, and −40 °C was found to be optimal (Table 1, entries 7–9). Further optimization of the reaction conditions (amounts of potassium carbonate and pre-nucleophile, catalyst loading, and concentration) were conducted, and the reaction with

• 5.0 equivalents of pre-nucleophile and 1.0 equivalent of potassium carbonate in the presence of 1.0 mol % of 9 at 0.025 M of toluene and −40 °C was found to be optimal (Table 1, entries 10–13). Five equivalents of pre-nucleophile are required to obtain higher yields and enantioselectivities. Next, the

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

• aqueous media is limited (Figure 1a–c) [13][14][15][16][17][18]. In particular, receptors which bind tryptophan residues in peptides are rare [19][20]. Recently, we developed a glucose-based naphtho crown ether 1 (Figure 1d) which binds amino acid methyl esters with aromatic side chains chemoselectively

• tripeptides 2–7 consisting of one tryptophan and two alanine residues. We varied the position of the tryptophan in the peptide sequence, N-terminus in 2, middle of the chain in 3, and C-terminus in 4 to check if this affects their binding by 1. To probe the importance of the N-terminal amino group in the

• , they open exciting opportunities for the development of other monosaccharide-based selective receptors of amino acids in aqueous environments. a–c) Examples of synthetic receptors for selective binding of tryptophan in aqueous media, taken from refs. [14][15][16]; d) glucose-based naphtho crown ether 1

Vinylogous functionalization of 4-alkylidene-5-aminopyrazoles with methyl trifluoropyruvates

• Judit Hostalet-Romero,
• Laura Carceller-Ferrer,
• Gonzalo Blay,
• Amparo Sanz-Marco,
• José R. Pedro and
• Carlos Vila

Beilstein J. Org. Chem. 2025, 21, 533–540, doi:10.3762/bjoc.21.41

• properties along a C=C double bond [1]. This effect has been established to be very advantageous to expand the range of reactions of different functional groups that can be coupled efficiently through a conjugated π-system. In this context, the addition reaction of vinylogous nucleophiles to carbonyl

• starting materials to study the vinylogous functionalization with alkyl trifluoropyruvates. The synthesis of compounds 3 was accomplished by the reaction of cyclic ketones 1 and 5-aminopyrazoles 2 in the presence of acetic acid (Scheme 1) [30][31]. Cyclohexenones 1a–c provided the corresponding products

• -butyl group is present in the C-3 position of the pyrazole as in the case of substrate 2e, the reaction did not take place, likely due to a considerable increase in steric hindrance. We also attempted to synthesize 4-(alkenyl)-5-aminopyrazoles using an acyclic ketone, such as acetone, but unfortunately

Cryptophycin unit B analogues

• Thomas Schachtsiek,
• Jona Voss,
• Maren Hamsen,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

• -phenyl position of unit A [9][10][11] or derivatisation of unit A’s epoxide moiety into a halohydrin (-glycinate) [5][12][13][14][15][16][17]. Cryptophycins modified at the α-position of unit C [18] and, most recently, various derivatives with modifications in unit D [19] were established as potent and

• formation and N-Boc-protection [24] provided nitroarene 5 in 40% yield over three steps. Reduction of the nitro group was performed with Pd/C and hydrogen to obtain aniline 6 in 98% yield, which served as a precursor for mono- and dimethylated unit B derivatives 7 and 8, respectively. While dimethylaniline

• control of equivalents and pH, or Leuckart–Wallach-like reaction with ammonium formate and Pd/C [25] provided monomethylaniline 7 in 37% and 35% yield, respectively. The absolute structure of monomethylaniline 7 was confirmed by single-crystal X-ray diffraction measurements (Figure 2). Compound 7

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

• other, yet to be identified, ANTH(BnF)n compounds were also observed. In this reaction, ANTH dissolved in DMSO was heated to between 120 °C and 160 °C in the presence of 2 equiv of BnFI and 3 equiv of Cu powder as promotor for 24 h, resulting in the complete conversion of ANTH to reaction products. When

• higher selectivity with milder reaction temperatures. The weaker C(sp2)–Br bond is easier to cleave than a C(sp2)–H bond, resulting in a higher likelihood of radical substitution at those positions. To the best of our knowledge, there are no previous examples of perfluorobenzyl substitution of any PAH(Br

• used for the perfluorobenzylation of PERY were used [22]. 9,10-ANTH(Br)2 and BnFI were dissolved and heated to 160 °C in PhCN in the presence of either Cu powder (22 h) or Na2S2O3 (4 h). According to the 1H NMR spectra of the filtered product mixtures, the reaction with Cu showed poor conversion, but

Synthesis of the aggregation pheromone of Tribolium castaneum

• Biyu An,
• Xueyang Wang,
• Ao Jiao,
• Qinghua Bian and
• Jiangchun Zhong

Beilstein J. Org. Chem. 2025, 21, 510–514, doi:10.3762/bjoc.21.38

• , Mori and Phillips achieved the complete separation of the derivatives from the four stereoisomers by reversed-phase HPLC at −54 °C, and revealed that the natural pheromone consists of four stereoisomers of 4,8-dimethyldecanal (Figure 1) [16][17]. Previous syntheses mainly focused on chiral sources of

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

• 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

• and is therefore not expected to undergo this topochemical reaction (Figure 6b). Examination of the reported structure of 9,10-dioxa-syn(carboethoxy,methyl)bimane in the CCDC database (BESGAH) [19][21], shows that it crystallizes in the monoclinic (P2(1)/c space group, unlike Me2B which crystallizes

• groups play a role by increasing the number of hydrogen bonds (C–H···O, 3.18(5)–3.62(6) Å) The intermolecular distances between the C–H groups and the chlorine atoms in Cl2B (A) are C13A–H13···Cl1A, 3.69(5), and C18A–H18C···Cl2A, 3.69(3) Å, indicating further molecular attraction [22]. A previously

Synthesis of N-acetyl diazocine derivatives via cross-coupling reaction

• Thomas Brandt,
• Pascal Lentes,
• Jeremy Rudtke,
• Michael Hösgen,
• Christian Näther and
• Rainer Herges

Beilstein J. Org. Chem. 2025, 21, 490–499, doi:10.3762/bjoc.21.36

• biochemical reactions usually take place in aqueous environments [13]. The substitution of one CH2 group in the CH2CH2 bridge by N–C(=O)–CH3 leads to an intrinsic water solubility of the N-acetyl diazocine 1 (Figure 1) [3]. Furthermore the photoconversion of 1 shows no significant drop in pure water in

• amination is a versatile and powerful tool for C–N bond formation and widely applied in the synthesis of new pharmaceutical substances [29][30][31]. Furthermore, azobenzenes [32][33], as well as diazocines [34][35], have been derivatized via Buchwald–Hartwig amination. The Buchwald–Hartwig amination of

• particular to gain insight into the effects of different substituents on UV spectra and switching behavior. For the determination of the n–π*-absorption maxima of the E and Z isomers 250 µM solutions of each compound in acetonitrile were prepared and measured at 25 °C. All compounds (4, 7–14, 17, 19–21, 23

Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• methanol (1.3 mL). Anhydrous magnesium sulfate (340 mg, 2.82 mmol, 10 equiv) and the respective amino alcohol (2.82 mmol, 10 equiv) were added. The mixture was sonicated for 30 minutes and subsequently stirred at room temperature for 16 h. After cooling to 0 °C, sodium borohydride (96.1 mg, 2.54 mmol, 9

Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction

• James Guevara-Pulido,
• Fernando González-Pérez,
• José M. Andrés and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34

• additive (entries 10–13, Table 2), but none of the tests performed led to an improvement in enantioselectivity. We also studied the influence of the reaction temperature by performing two tests at 0 °C (entries 15 and 16, Table 2). We observed that the reaction occurs more slowly, and the enantiomeric

• excess reached is lower than at room temperature. Additionally, when the reaction mixture was stirred at −18 °C, no change was observed after 100 hours (entry 14, Table 2). These results led us to raise the reaction temperature to 31 °C (entries 17–20, Table 2). We observed that the retro-Michael

• reaction occurs more rapidly than at 20 °C (entry 2, Table 2). However, the enantiomeric ratio decreases as the reaction time increases. Based on these results, we considered conducting tests to monitor how the percentage of ReM and enantiomeric ratio change over time (Table 3). With this aim, a 0.028 M

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

• alignment within the crystal drives the reaction. For example, in 2008, Vittal et al. [62] designed a mechanochemical strategy to align the C=C bonds of 4,4'-bipyridylethylene (bpe, 1.1) molecules to drive efficient [2 + 2] cycloaddition and give the corresponding cyclobutanes (1.2). This approach relied on

• spectroscopy (Scheme 1). During the reaction progress, the C=C bonds of bpe ligands undergo pedal-like motion prior to photodimerization [63]. For the single-crystal irradiation, the slow reactivity can be attributed to the hindered pedal motion in the single crystals, likely due to the presence of

• Na2CO3 was ground in a mortar at room temperature for 3–5 min. Second, the reaction mixture was transferred into a quartz tube, heated to 50 °C (heating mantle) for 18 h, while being irradiated with blue LEDs under air-equilibrated conditions. In these conditions, product 3.3 was isolated in excellent

Electrochemical synthesis of cyclic biaryl λ³-bromanes from 2,2’-dibromobiphenyls

• Andrejs Savkins and
• Igors Sokolovs

Beilstein J. Org. Chem. 2025, 21, 451–457, doi:10.3762/bjoc.21.32

• optimized reaction conditions in hand, next, the substrate scope was evaluated (Scheme 2). Symmetrical biaryls with electron-deficient substituents such as Cl (4b) or CF3 (4c) afforded the respective Br(III) products 1b,c in slightly reduced yields as compared to that of 1a. Gratifyingly, electron-rich MeO

• -substituted 1d could be also obtained under the developed conditions. Unsymmetrically substituted 4e and monosubstituted dibromides 4f,g demonstrated reactivity similar to that of their symmetrical analogues 4b,c with exception of the mono-MeO-substituted dibromide 4h. Notably, the presence of two stabilizing

• Br(II) followed by subsequent deprotonation to generate radical B. A following disproportionation of radical B would lead to the formation of Br(III) species C (anodic oxidation cannot be fully excluded), which undergoes intramolecular SNAr-type substitution to form cyclic λ3-bromane 1a and

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

• versions. Recent advances using hexameric resorcin[4]arene-based capsules [122][123][124] (Figure 4B and C), notably by Tiefenbacher [105][125][126][127][128][129][130][131][132][133], have demonstrated substrate-controlled selectivities that vary from the bulk phase due to the stabilization of cations in

• concentration. As for the macrocycles discussed above, dual confinement/encapsulation [36] and the hydrophobic effect dominate the origin of catalytic rate enhancements [158][159]. To avoid product inhibition, model reactions that increase molecularity (A → B + C) or that generate weakly interacting or less

• ]. Lattices can also contain defects, which may affect catalytic activity unpredictably [228]. Nonetheless, macroscale structures, like those that arise from the stacking in 2D COFs, can contribute to catalysis, for instance dense arrays of aligned C–H bonds can provide CH–π interactions in Diels–Alder

Unraveling aromaticity: the dual worlds of pyrazole, pyrazoline, and 3D carborane

• Zahra Noori,
• Miquel Solà,
• Clara Viñas,
• Francesc Teixidor and
• Jordi Poater

Beilstein J. Org. Chem. 2025, 21, 412–420, doi:10.3762/bjoc.21.29

• a π system with 6 π electrons [11]. When fused with a benzene ring, sharing a C–C bond, it remains aromatic, which is the case of indazole. Pyrazoline (C3H6N2), similar to pyrazole, formally has only one double bond and a lone pair on the nitrogen, so it does not satisfy Hückel's rule and it is

• therefore non-aromatic. Even when fused with benzene via a C–C bond, pyrazoline remains non-aromatic, which is the case of indazoline. Icosahedral carboranes are globular molecular clusters made of carbon and boron, displaying 3D aromaticity [12][13][14][15]. Their unique properties – such as aromaticity

• -1,3-dimethylimidazolinium hexafluorophosphate (ADMP) in the presence of DBU in acetonitrile. This one-pot process enables sequential diazotization and cyclization, leading to the formation of two or three C–N bonds under extremely mild conditions, with excellent tolerance for various functional groups