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

• napthalene-1,5-dicarboxaldehyde was protected as an acetal, was prepared through a 5-step reaction sequence. Phosphonium salt 5 [39] and the partly protected o-phthalaldehyde 6 [47] were obtained by previously reported procedures. The reaction of phosphonium salt 5 with aldehyde 6 in the presence of KOH and

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

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

• 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

• undergo the decarboxylative cyclization, but also N-mesyl-protected monoester 9f could be converted into 2-aminoproline derivative 6f in 60% yield using a graphite cathode. However, the N-o-nosyl-protecting group is not compatible with the developed electrolysis conditions, likely because it undergoes an

• of N-o-nosyl-protected monoester 9g was performed in a divided cell in the presence of NaOH as a base (1 equiv). Gratifyingly, by this route N-o-nosyl-protected 6g was obtained in 25% yield. The attempted synthesis of 2-aminopipecolic acid derivative 6h under the developed conditions was unsuccessful

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

• -carbonyl group was linked through an ester bond and the only hydroxy group available for this esterification was the one at C-7. This compound was finally elucidated as massarilactone D 3,4-di-O-methacryloyl-7-O-(6-chloro-3,4-dihydro-2,5-dimethyl-2H-pyran-2-carbonyl). For the formation of compound 2, an

• ]+ corresponding to the molecular formula C29H24O7. The presence of two cinnamoyl moieties was supported by resonances shown at δH 7.77 (d, J = 16.0 Hz, H-3'''), 7.76 (d, 16.0, H-3''), 7.72–7.70 (o, H-5'', H-9'', H-5''', H-9'''), 7.46–7.44 (o, H-6'', H-7'', H-8'', H-6''', H-7''', H-8'''), 6.60 (d, J = 16.0 Hz, H-2

• ''), 129.3 (C-5''', C-9'''), 118.0 (C-2''), and 117.8 (C-2''') [19][20]. The HMBC correlations were observed from H-3 (δH 5.43, t, J = 3.6 Hz) to C-1''' (δC 165.7) and from H-4 (δH 5.90, o) to C-1'' (δC 165.9). The 1H NMR spectrum of compound 3 revealed the presence of two signals at δH 5.28 (d, J = 3.0 Hz

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

• , several efforts have been made to improve the chemoselectivity of the oxidation step. Among the most relevant examples, o-iodoxybenzoic acid (IBX) has been used in Ugi and Passerini reactions to oxidize the suitable alcohol to the desired aldehyde [13]. Alternatively, catalytic amounts of a ternary system

• phosphites can also undergo an addition to the C=O bond of the carbonyl component (Abramov reaction) giving α-hydroxy phosphonates 33 as byproducts (Scheme 26a) [72]. Competition between the two nucleophiles for the electrophilic carbonyl compound depends on their relative reactivity [74][77] and this lack

• of chemoselectivity becomes important when formaldehyde is used. Moreover, primary amines (alkyl- and arylamines) can also react with two equivalents of both the formaldehyde and the P(O)H compound. In this case, a double Kabachnik–Fields condensation gives bis(phosphorylmethyl)amines 34 as possible

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

• (R)-citronellic acid [18], methyl (S)-3-hydroxy-2-methylpropanoate, (S)-2-methyl-1-butanol [19], (R)-2,3-O-isopropylideneglyceraldehyde [20], (R)- and (S)-citronellol [21], (R)-4-methyl-δ-valerolactone [22], porcine pancreatic lipase (PPL)-catalyzed acetylation of racemic citronellol [23], and Evan′s

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

• Metodej Dvoracek Brendan Twamley Mathias O. Senge Mikhail A. Filatov School of Chemical and Biopharmaceutical Sciences, Technological University Dublin, City Campus, Grangegorman, D07 ADY7 Dublin, Ireland School of Chemistry, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

• 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

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

• were required to obtain the corresponding mesylate 3b. Similar to 11, compound 12 was isolated as its trifluoroacetate salt. Selective Boc protection of the aliphatic amine gave 13, which was selectively O-mesylated to give compound 14. Compound 14 was found to slowly undergo intramolecular cyclization

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

• investigated. When o-terphenyl (10.1) was milled (30 Hz, PTFE balls) and irradiated (λ = 270 nm) in the presence of silica gel (bulking agent), I2 (1 equiv) as an oxidant, and K2CO3 (1 equiv) as a base in the presence of toluene, the expected product 10.2 was obtained in 81% yield after isolation upon 181 h of

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

• carbonyl oriented outward (designated by “0” or “O”) and amide carbonyl oriented inward (designated by “1” or “I”). There are 64 (26) permutations of carbonyl orientations in our cages, of which 13 are unique for cage 1 after grouping by symmetry (and ignoring enantiomers), which we have labelled as C1–C13

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

• Barcelona, Spain 10.3762/bjoc.21.29 Abstract A new series of o-carborane-fused pyrazoles has been recently successfully synthesized. This fusion was expected to create a hybrid 3D/2D aromatic system, combining the 3D aromaticity of o-carborane with the 2D aromaticity of pyrazole. However, while the boron

• cage retains its aromatic character, the pyrazole’s aromaticity is lost. As a result, rather than forming o-carborane-fused pyrazoles, the synthesis yielded o-carborane-fused pyrazolines, which are non-aromatic. The limited overlap between the π molecular orbitals (MOs) of the planar heterocycle and

• ], offering enhanced properties and efficacy [28][30][33][34][35]. Therefore, the advancement of simple, efficient methodologies for synthesizing o-carborane-fused heterocycles is critically needed. However, the limited number of synthetic strategies for carborane functionalization [36] continues to constrain

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

• achieve better stereocontrol and to facilitate the formation of synthetically challenging glycosidic linkages. Keywords: chemical O-glycosylation; neighbouring group participation; remote group participation; solvent effect; stereocontrol; Introduction Cell surface glycans in living cells have

• , however, are used synonymously owing to their same participating property and the same Zemplén deprotection strategy [87]. A recent study showed the use of modified Zemplén conditions to synthesise deacetylated methyl β-glycopyranosides directly from per-O-acetylated α-glycosyl halides using a

• neighbouring group participation for the formation of the acetoxonium ion intermediate was more favourable in the locked systems like o-substituted benzoyl groups instead of aliphatic protections. Many protecting groups have been developed for the protection of the amine functionality of nucleosides like 2

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• Yurii A. Sayapin Eugeny A. Gusakov Inna O. Tupaeva Alexander D. Dubonosov Igor V. Dorogan Valery V. Tkachev Anna S. Goncharova Gennady V. Shilov Natalia S. Kuznetsova Svetlana Y. Filippova Tatyana A. Krasnikova Yanis A. Boumber Alexey Y. Maksimov Sergey M. Aldoshin Vladimir I. Minkin Federal

• Comprehensive Cancer Center at University of Alabama at Birmingham, Department of Medicine, Section of Hematology/Oncology, Heersink School of Medicine, Birmingham, AL 35233, USA 10.3762/bjoc.21.26 Abstract The acid-catalyzed reaction of benzo[e(g)] derivatives of 2,3,3-trimethylindolenines with o-chloranil

• -(1,1-Dimethyl-1H-benzo[e]indolin-2-yl)-5,6,7-trichloro-1,3-tropolone exhibited high in vitro cytotoxic activity against A431 skin cancer and H1299 lung cancer cell lines. Keywords: cytotoxic activity; fluorescence; o-chloranil; quantum chemical DFT calculations; 1,3-tropolones; X-ray diffraction

Synthesis, characterization, antimicrobial, cytotoxic and carbonic anhydrase inhibition activities of multifunctional pyrazolo-1,2-benzothiazine acetamides

• Ayesha Saeed,
• Shahana Ehsan,
• Muhammad Zia-ur-Rehman,
• Erin M. Marshall,
• Sandra Loesgen,
• Abdus Saleem,
• Simone Giovannuzzi and
• Claudiu T. Supuran

Beilstein J. Org. Chem. 2025, 21, 348–357, doi:10.3762/bjoc.21.25

• ) products and with alkylating agents 6i–n to give the N- and O-alkylated (dialkylated) products. The alkylation of compound 5 was controlled by the molar quantities of alkylating agents and base present. Thus, compound 5 was N-alkylated using equimolar quantities of the alkylating agents 6a–h to give the

• respective derivatives 7a–h. On the other hand, compound 5 was N-alkylated as well as O-alkylated using 2.0 equivalents of alkylating agents 6i–n to yield the respective derivatives 7i–n. The formation of monoalkylated derivatives is based on the fact that the NH group of the pyrazole ring in 5 is more

• susceptible to alkylation than the OH group. However, under more basic conditions and using the alkylating agent in excess can lead to a dialkylated product. It has already been established that N-alkylation takes place before O-alkylation because the nitrogen atom is a softer nucleophile as compared to the

Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates

• Kirill A. Gomonov,
• Vasilii V. Pelipko,
• Igor A. Litvinov,
• Ilya A. Pilipenko,
• Anna M. Stepanova,
• Nikolai A. Lapatin,
• Ruslan I. Baichurin and
• Sergei V. Makarenko

Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24

• frequency values (1725–1731 cm−1). This observation may be due to the position of the ester fragment relative to the heterocyclic system. The analysis of the results of X-ray diffraction analysis shows that the torsion angle C(10)–C(3)–C(16)–O(17) of methyl esters 5a and 6c is −0.8(2), and 5(2)°, and of

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• thulium nanoparticles [26] and the use of a molybdenum-centered [27] and tungsten-centered complexes have been described in the literature [28]. The work by O. S. Wenger et al. introduces a system that mimics the Z-scheme of photosynthesis, utilizing a copper(I) bis(α-diimine) complex in combination with

• 9,10-dicyanoanthracene radical anion (DCA•−) [29]. This system effectively drives photoredox-mediated reduction and C–C cross-coupling reactions under mild red-light conditions with various aryl halides, an aliphatic iodide, and O- and N-tosylated substrates (Scheme 4a). The authors discuss two

•  4d) [30]. In a continuation of this trend, a recent study by O. S. Wenger et al. further expands the frontiers of red-light photoredox catalysis with first-row transition metals by introducing Cr(0) luminophores that exhibit photophysical properties competitive with Ru(II) and Os(II) complexes [31

Three-component reactions of conjugated dienes, CH acids and formaldehyde under diffusion mixing conditions

• Dmitry E. Shybanov,
• Maxim E. Kukushkin,
• Eugene V. Babaev,
• Nikolai V. Zyk and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 262–269, doi:10.3762/bjoc.21.18

• and 8, the reaction also produced hetero-Diels–Alder reaction adducts 6 and 9. For these, CH–O 1H NMR signals in the region of 4.9–5.4 ppm were characteristic. It is worth noting that the individual isolated compounds 8 and particularly 9 were unstable when stored in solution, and boiling adduct 8 or

• the signal of the CH–O group at 5.03 ppm, as well as by ethyl bromide, which indicated the predominance of isomer 4a in the mixture. For isomers 5, preferential formation of dibromide 23 and products of carbocationic rearrangements containing an ester group, the precursor of which was compound 5b

Synthesis of disulfides and 3-sulfenylchromones from sodium sulfinates catalyzed by TBAI

• Zhenlei Zhang,
• Ying Wang,
• Xingxing Pan,
• Manqi Zhang,
• Wei Zhao,
• Meng Li and
• Hao Zhang

Beilstein J. Org. Chem. 2025, 21, 253–261, doi:10.3762/bjoc.21.17

• , demonstrated that a wide range of disulfides were synthesized efficiently when sodium sulfinates served as substrates. The isolated yields ranged from 49% to 89% for products 2a–o. In the case of sodium arylsulfinates with various substituents on the benzene ring, we observed minimal effects on the reaction

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

• Information File 1. The photochromic properties of N3, N4, and I1–I4 were investigated in n-hexane. Figure 1a,b and Figure S1 in Supporting Information File 1 show the absorption spectral changes of N3, N4, and I1–I4 in n-hexane upon UV light irradiation. Compounds N3(o), N4(o), and I1(o)–I4(o) have

• absorption maxima (λmax) at 299, 307, 291, 301, 307, and 369 nm, respectively. The molar absorption coefficients at λmax of N3(o), N4(o), and I1(o)–I4(o) were determined to be 12200, 12700, 47800, 22700, 12900, and 12700 M−1 cm−1, respectively. Upon irradiation with 365 nm, a new absorption band appeared in

• confirmed that the colorless solution of N4(o) turned yellow upon irradiation with UV light and returned to the initial color upon removal of the irradiation. The photophysical properties of N3, N4, and I1–I4 are summarized in Table 1 together with the data of N1 and N2. Thermal back reactivity in n-hexane

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

• . T. and H. O.), the Japan Agency for Medical Research and Development (AMED) Strategic Center of Biomedical Advanced Vaccine Research and Development for Preparedness and Response (SCARDA) Japan Initiative for World-leading Vaccine Research and Development Centers UTOPIA program (JP223fa627001: R. T

• .), JST ACT-X (JPMJAX211B: R. T.), the Naito Foundation (R. T. and H. O.), the Asahi Glass Foundation (H. O.), JST-Mirai Program Grant Number JPMJMI23G2 (K. Y.), and the Platform Project for Supporting Drug Discovery and Life Science Research (Basis for Supporting Innovative Drug Discovery and Life

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

• Seungmin Lee,
• Minsuk Kim,
• Hyewon Han and
• Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

• conventionally challenging functionalizations, such as N- or O-arylations using aryl halides [29][30][31][32][33][34][35][36][37][38] or arylboronic acids [39][40][41][42], hydrofunctionalizations of unsaturated motifs [25][43][44][45][46][47][48][49][50][51][52][53][54][55][56], the oxidation of alcohols [57

• depicted in Figure 2. The reaction is initiated by formation of the five-membered copper-containing intermediate INT-5 through coordination of Cu(OAc)2 with the N-iminoquinolinium ylide species 5. This process is followed by decarboxylative N–O bond insertion into 4, yielding the N-acyl copper(III

• ) chloride reacts with boronic acids, forming the copper aryl complex INT-16, which then undergoes decarboxylative N–O bond insertion to generate the copper nitrenoid intermediate INT-17. Thereafter, nitrene insertion into the copper–carbon bond occurs, forming a new C(sp2)–N bond (INT-18). Finally, the

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

• . We expect this information to be useful for the rational application of the CF2H group in drug development and molecular design. Previous quantum mechanical calculations revealed that the CF2H···O binding energy (ΔE) ranges from 1.0 kcal/mol to 5.5 kcal/mol [14][15][18][21]. In addition, as measured

• reveal the fundamental differences between the C–H bond and the O–H bond as HB donors and provide important quantitative information for applying the CF2H group as an OH group mimic. We next attempted to establish correlations of experimentally determined HB donation ability, in terms of Kd or ΔGexp

• weak inverse association was observed between ΔGexp and ΔδDMSO–CDCl3 values for neutral hydrogen bond donors (Figure 6D). This result suggests that the CF2H···O interactions are likely to be a predominant contributor to the binding between HB donating and accepting molecules but other weak

Hydrogen-bonded macrocycle-mediated dimerization for orthogonal supramolecular polymerization

• Wentao Yu,
• Zhiyao Yang,
• Chengkan Yu,
• Xiaowei Li and
• Lihua Yuan

Beilstein J. Org. Chem. 2025, 21, 179–188, doi:10.3762/bjoc.21.10

• noncovalent interactions, particularly intermolecular π–π-stacking and C–H···O interactions. Specifically, π–π-stacking interactions were found between two guest molecules with aromatic rings arrayed in an offset fashion with a distance of 3.3 Å (Figure 3a). Interestingly, these interactions also existed

• /or π-stacking interactions, conferring the characteristic 2:2 constitutional stoichiometry onto this host–guest complex. In addition, there were eight C–H···O interactions between the hydrogen atoms of G1 and the nearby pyridinium group of H2, with distances of 2.2–3.5 Å, and two C–H···O interactions

• and G1. The brown dotted lines show the hydrogen bond distance between H2 and the positively charged region of G1 (d[C–H···O] = 2.2–3.5 Å). The red dotted lines show the hydrogen bond distance between H2 and the proton of the phenyl group of G1 (d[C–H···O] = 2.7–2.9 Å). c) Dimeric structure showing

Recent advances in electrochemical copper catalysis for modern organic synthesis

• Yemin Kim and
• Won Jun Jang

Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9

• –heteroatom (C–X, where X = N, O, or halogens) bonds in organic synthesis. Copper was one of the first transition metals employed in cross-coupling to form C–C and C–X bonds [1][2]. In 1901, Ullmann reported the first cross-coupling reaction for the formation of biaryl compounds in the presence of

• stoichiometric quantities of a copper reagent [3]. This pioneering work, known as the “classical Ullmann reaction”, was extended by Ullmann and Goldberg to enable the C–N and C–O bond formation [4][5][6]. Subsequently, key developments in Cu-catalyzed cross-coupling reactions were achieved, including the