A m-quaterphenyl probe for absolute configurational assignments of primary and secondary amines

• Yuka Takeuchi,
• Mutsumi Kobayashi,
• Yuuka Gotoh,
• Mari Ikeda,
• Yoichi Habata,
• Tomohiko Shirai and
• Shunsuke Kuwahara

Beilstein J. Org. Chem. 2025, 21, 2211–2219, doi:10.3762/bjoc.21.168

• secondary amines through the combined use of a m-quaterphenyl probe 1 and theoretical calculations. The probe 1 is covalently attached to chiral amines to form conjugates that exhibit exciton-coupled circular dichroism (ECCD) in the m-quaterphenyl chromophores. The calculated ratios of the P and M

• effect in CD, the direction of twist can be estimated. The absolute configuration of amines can be determined by comparing the direction of the twist determined by CD with that obtained by conformational analysis using theoretical calculations. However, this method has only been applied to simple primary

• conjugates. Since the CD spectra revealed the twist between the two methoxybiphenyl chromophores, we next examined the relationship between the absolute configuration of the amine and the observed twist. Based on the previously reported stable conformations obtained from theoretical calculations of related

Synthesis of N-doped chiral macrocycles by regioselective palladium-catalyzed arylation

• Shuhai Qiu and
• Junzhi Liu

Beilstein J. Org. Chem. 2025, 21, 1917–1923, doi:10.3762/bjoc.21.149

• , theoretical calculations were performed to evaluate the energy barriers of isomerization. As shown in Figure S3 (Supporting Information File 1), the configuration observed in the crystal structure has the lower energy by 24.0 kcal mol−1 than that of the isomeric structure with two pyrene units at the same

• macrocycles, theoretical calculations on the frontier molecular orbitals were carried out based on the optimized structures. As shown in Figure 4, the distributions of the highest occupied molecular orbitals (HOMOs) are disjointed from that of the lowest unoccupied molecular orbitals (LUMOs). Specifically

Thermodynamics and polarity-driven properties of fluorinated cyclopropanes

• Matheus P. Freitas

Beilstein J. Org. Chem. 2025, 21, 1742–1747, doi:10.3762/bjoc.21.137

• advanced materials, particularly those whose properties rely on the polarity and spatial arrangement of C–F bonds within a cyclopropane framework. Keywords: cyclopropane; fluorination; polarity; theoretical calculations; Introduction Cyclopropane, the smallest cycloalkane, has a rigid structure that

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

• to form oxazolo[3,2-c]pyrimidine derivative 7 (Scheme 7). The highly diastereoselective formation of product 7 can be explained based on the theoretical calculations by Elliott et al. of aza-Diels–Alder reaction of vinyloxazoline with TsNCO [19]. According to their investigations, the aza-nucleophile

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

• : Experimental and computational details, synthesis and characterization of compounds, additional spectroscopic results, and theoretical calculations. Acknowledgements The authors acknowledge Dr. Tatsuo Nakagawa, UNISOKU Co., Ltd., for nanosecond transient absorption measurements Funding This work was supported

Tautomerism and switching in 7-hydroxy-8-(azophenyl)quinoline and similar compounds

• Lidia Zaharieva,
• Vera Deneva,
• Fadhil S. Kamounah,
• Nikolay Vassilev,
• Ivan Angelov,
• Michael Pittelkow and
• Liudmil Antonov

Beilstein J. Org. Chem. 2025, 21, 1404–1421, doi:10.3762/bjoc.21.105

• makes possible to analyze the tautomerism in 1 as a function of (E+KE) and KK. The NMR spectra of 1 in acetonitrile-d3 are in agreement with the above analysis of tautomeric equilibration based on theoretical calculations and UV spectra. At room temperature the proton signals are very broad and

• show detectable changes upon irradiation. The twisting barrier (2TS(KE-KK) in Table 1) here is substantially larger comparing to 1, which means that if switching to KK occurs the relaxation process back should be slower. The theoretical calculations give the possible reason for lack of switching – due

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

• revealed that none of the azulene subunits exhibits the characteristic azulene-like aromaticity. Additionally, both 186 and 187 show moderate open-shell biradical character, according to theoretical calculations. A similar strategy, leading to different types of skeletal rearrangements, was reported by Ma

• substituents of precursor 188 after annealing. In contrast, all the other observed PAHs 189–194 result from oxidative ring-closure and skeletal ring-rearrangement reactions. Theoretical calculations revealed that nanographene 188 possesses an antiferromagnetic open-shell singlet ground state, whereas the other

• detected, and instead, products of some additional annulations were observed (200–202). The more planar structure of nanographenes 200–202 likely drives the process toward more annulated configurations. Theoretical calculations of the studied azulene-embedded PAHs indicated a strong antiaromatic character

Selective monoformylation of naphthalene-fused propellanes for methylene-alternating copolymers

• Kenichi Kato,
• Tatsuki Hiroi,
• Seina Okada,
• Shunsuke Ohtani and
• Tomoki Ogoshi

Beilstein J. Org. Chem. 2025, 21, 1183–1191, doi:10.3762/bjoc.21.95

• ], [4.3.3]_Br and [4.3.3]_2Br. To gain insight into the different reactivity between [3.3.3] and [4.3.3], theoretical calculations were performed at the ωB97X-D/6-31G(d,p) level of theory (Figures S901–S903 in Supporting Information File 1). Although distribution of the highest occupied molecular orbitals

• copolymers.a Supporting Information Supporting information includes general information, synthetic procedures and compound data, NMR and MS spectra, HPLC charts, and results of PXRD, DSC, TGA, gas adsorption, and theoretical calculations. Supporting Information File 2: Experimental. Acknowledgements The

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

Dicarboxylate recognition based on ultracycle hosts through cooperative hydrogen bonding and anion–π interactions

• Wen-Hui Mi,
• Teng-Yu Huang,
• Xu-Dong Wang,
• Yu-Fei Ao,
• Qi-Qiang Wang and
• De-Xian Wang

Beilstein J. Org. Chem. 2025, 21, 884–889, doi:10.3762/bjoc.21.72

• . Synthesis of ultracycles. Supporting Information Supporting Information File 4: Experimental details and characterization data (including 1H NMR, 13C NMR, IR, and HRMS of precursor compounds and ultracycles, X-ray data for B4aH, theoretical calculations, and NMR titration data). Funding Financial support

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

• recognized for fluorinated oligoacene systems [30][34][36]. The theoretical calculations suggest that, in the ground state, the polarization of the phenacene molecules inverted upon the introduction of fluorine atoms. As seen from electrostatic potential (ESP) mapping (Figure 5b), the phenacene cores are

• , and their electronic spectral features were investigated. They displayed UV–vis and fluorescence spectra which were seemingly the same as those of the parent phenacene molecules in the solution phase although theoretical calculations predicted the MO energy levels of F8-phenacenes markedly lowered by

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

• of these compounds in the field of photocatalysis [49]. The study has included a detailed mechanistic investigation to differentiate between competing single-electron transfer and energy transfer pathways. Through both experimental measurements and theoretical calculations, the authors have

Synthesis and characterizations of highly luminescent 5-isopropoxybenzo[rst]pentaphene

• Islam S. Marae,
• Jingyun Tan,
• Rengo Yoshioka,
• Zakaria Ziadi,
• Eugene Khaskin,
• Serhii Vasylevskyi,
• Ryota Kabe,
• Xiushang Xu and
• Akimitsu Narita

Beilstein J. Org. Chem. 2025, 21, 270–276, doi:10.3762/bjoc.21.19

• BPP 2 and BPP-OiPr 3. Supporting Information Supporting Information File 114: Experimental and computational details, X-ray crystallography, synthesis and characterization of new compounds, additional PL, mass, and NMR spectra, and theoretical calculations. Acknowledgements We appreciate the help

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

• , CDCl3) δ = 9.3, 12.0, 111.9, 120.6, 122.5, 123.4, 127.1, 129.3, 139.0, 140.0, 143.0, 152.3, 155.6. HRMS–DART+ (m/z): [M + H]+ calcd for C18H12F6NOS+, 404.0544; found, 404.0550. Theoretical calculations DFT calculations were performed in a manner similar to procedures from [58]. Geometry optimizations

• theory in combination with the 6-31G(d) basis set well reproduces the experimental value of the activation energy for the thermal back reaction of various diarylbenzenes, resulting in the accurate prediction of the half-lifte time [58][63]. Thus, the combination of experiments and theoretical

• calculations can be a powerful tool for molecular design. In this work, we newly synthesize various aza-diarylethene derivatives N3, N4, and I1–I4 with different substitution positions of the aryl group, and investigate their photochromic behaviors and thermal back reactivities as the data set for 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

• systems significantly enhances its hydrogen bond donation ability, a result consistent with theoretical calculations. We anticipate that this chemistry will be valuable for designing functional molecules for chemical biology and medicinal chemistry applications. Keywords: bioisostere; difluoromethyl

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

• conditions also supported the generation of the radical anion [67]˙−. Furthermore, the authors used thermodynamic theoretical calculations to investigate catalytic steps, finding that the protonation of [67]˙− to generate [67-H] is thermodynamically favored (free energy of +2.39 kcal mol−1) over its

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• . Moreover, owing to the interaction between the narrower rim side of PMα-CD and the amino groups on the axle ends, the [3]rotaxane- or [4]rotaxane-species-contained PMα-CDs directed their narrower rim sides to the axle ends, as confirmed by theoretical calculations, thus indicating that such relatively weak

gem-Difluorovinyl and trifluorovinyl Michael acceptors in the synthesis of α,β-unsaturated fluorinated and nonfluorinated amides

• Monika Bilska-Markowska,
• Marcin Kaźmierczak,
• Wojciech Jankowski and
• Marcin Hoffmann

Beilstein J. Org. Chem. 2024, 20, 2946–2953, doi:10.3762/bjoc.20.247

• , we observed a striking illustration of this phenomenon. A Michael addition involving gem-difluorovinyl and trifluorovinyl acceptors was successfully achieved, demonstrating high stereoselectivity. This selectivity was further elucidated through theoretical calculations. Using this methodology, a

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• NMR spectra of new ion pairs, details for crystal structures, and theoretical calculations. Acknowledgements Theoretical calculations were partially performed at the Research Center for Computational Science, Okazaki, Japan (Projects: 22-IMS-C077, 23-IMS-C069, and 24-IMS-C067). The synchrotron

Machine learning-guided strategies for reaction conditions design and optimization

• Lung-Yi Chen and
• Yi-Pei Li

Beilstein J. Org. Chem. 2024, 20, 2476–2492, doi:10.3762/bjoc.20.212

• – allowing for the generation of extensive data through large-scale simulations – chemical reactions pose a much greater difficulty for accurate simulation. The development of systematic theoretical calculations to model correlations between reaction yields and various substrates and catalysts requires

• theoretical calculations are typically restricted to gas-phase reactions [31]. Despite these challenges, recent advances in quantum chemical methods have shown that theoretical calculations can provide practical guidance for validating experimental results [32]. Thus, we posit that the role of theoretical

• calculations in generating data for ML applications will grow increasingly critical. At present, employing theoretical calculations systematically to construct accurate, large-scale databases of reaction conditions remains highly challenging for complex reaction systems, leading to a primary reliance on

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• yields (82–85%) (Scheme 28). The authors proposed a free radical mechanism facilitated by hydrogen peroxide, generating a primary radical at the terminal nitrogen atom -CO-HN• which then adds to the carbon atom of the imino group. The reaction mechanism was substantiated by theoretical calculations

Divergent role of PIDA and PIFA in the AlX₃ (X = Cl, Br) halogenation of 2-naphthol: a mechanistic study

• Kevin A. Juárez-Ornelas,
• Manuel Solís-Hernández,
• Pedro Navarro-Santos,
• J. Oscar C. Jiménez-Halla and
• César R. Solorio-Alvarado

Beilstein J. Org. Chem. 2024, 20, 1580–1589, doi:10.3762/bjoc.20.141

• different hypervalent iodine reagents for this reaction. To find the correlations between experiments and theoretical calculations, chlorination and bromination of 2-naphthol using PIFA/AlCl3 and PIDA/AlBr3 were carried out. Consequently, we found an excellent correlation between the yield and the energy

Diameter-selective extraction of single-walled carbon nanotubes by interlocking with Cu-tethered square nanobrackets

• Guoqing Cheng and
• Naoki Komatsu

Beilstein J. Org. Chem. 2024, 20, 1298–1307, doi:10.3762/bjoc.20.113

• diameter range. The diameter selectivity is supported by the theoretical calculations with the GFN2-xTB method, indicating that the most preferred SWNT diameter for the square Cu-nanobrackets is 1.04 nm. Keywords: complexation; diameter; extraction; interlock; nanobracket; single-walled carbon nanotubes

• summarized in a graphene map (Figure 5c). This shows that Cu-nanobrackets 1b preferentially recognize larger diameters with wider range (0.94–1.10 nm) than 1a (0.90–0.92 nm) due to the larger cavity with more flexibility of 1b than 1a. Theoretical calculations To interpret the diameter selectivity, the

• diameters ranging from 0.94 to 1.10 nm among ≈20 kinds of SWNTs from 0.76 to 1.20 nm in their diameters. The most preferable SWNTs for 1b are found to be 1.04 nm in diameter by theoretical calculations, supporting the experimental results. Experimental Materials and instruments Reagents were purchased from

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• -silylene adduct 3 of C60 based on spectroscopic measurements, X-ray crystallography, electrochemical analyses, and theoretical calculations. Results and Discussion Synthesis of bis-silylene adduct 3 The synthesis of the silylene adduct was conducted using a modified literature procedure [15]. A degassed

• . These results confirm that the two addends in 3 are both silirane structures, which represents the first example of a crystallographic analysis of silirane derivatives of fullerenes. Theoretical calculations Hirsch and co-workers reported the bis-functionalization of C60 using the Bingel–Hirsch, the

• . The regioselectivity in the addition reaction of 1 with C70 was explained earlier in terms of the interaction between the HOMO of 1 and the LUMO of C70 [16]. The reaction mechanism of ethylene with a silylene substituted with thiolate ligands has been studied using theoretical calculations, in which