Synthesis of the tetracyclic skeleton of Aspidosperma alkaloids via PET-initiated cationic radical-derived interrupted [2 + 2]/retro-Mannich reaction

• Ru-Dong Liu,
• Jian-Yu Long,
• Zhi-Lin Song,
• Zhen Yang and
• Zhong-Chao Zhang

Beilstein J. Org. Chem. 2025, 21, 2470–2478, doi:10.3762/bjoc.21.189

• synthesis; d) naturally occurring Aspidosperma alkaloids; e) ring strain energy of cyclopentene, bicyclo[3.2.0]heptane, cycloheptane, cyclobutene, bicyclo[2.2.0]hexane and cyclohexane. Computational study. a) Energy profiles from IN1 to IN3 and spin density of TS2 (isovalue = 0.004), solvated (SMD) Gibbs

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

• of practical approaches to the synthesis of known compounds and the synthesis of new biologically active functionalized compounds containing a cyclopentane/enone fragment through transformation of a cyclohexane/ene ring is an urgent task for synthetic chemists. This review summarizes information on

• cyclohexane/ene ring contraction. The structure of the review includes examples of simple transformations (ozonolysis–aldol condensation, ozonolysis–Dieckmann reaction, and Baeyer–Villiger cleavage–Dieckmann reaction) and rearrangements (photochemical, benzil, semi-pinacol, Wolff, Meinwald, Wagner–Meerwein

• obtaining medically interesting dactylicapnosine-like analogues for detailed study of their biological activity. Matoba et al. [45] reported the first enantioselective synthesis of the hasubanane alkaloid (−)-metaphanine (70) and the norhasubanane alkaloid (+)-stephadiamine (71) using a cyclohexane ring

Synthesis of chiral cyclohexane-linked bisimidazolines

• Changmeng Xi,
• Qingshan Sun and
• Jiaxi Xu

Beilstein J. Org. Chem. 2025, 21, 1786–1790, doi:10.3762/bjoc.21.140

• bisimidazolines are efficient chiral ligands in metal-catalyzed asymmetric organic transformations. Chiral cyclohexane-linked bisimidazolines were prepared from optically active cyclohexane-1,2-dicarboxylic acid and 1,2-diphenylethane-1,2-diamines via the monosulfonylation of 1,2-diphenylethane-1,2-diamines

• , condensation of N-sulfonylated 1,2-diphenylethane-1,2-diamines and cyclohexane-1,2-dicarboxylic acid, and the final cyclization with the in situ generated Hendrickson reagent. Keywords: bisimidazoline; cyclohexane; cyclohexane-1,2-dicarboxylic acid; 1,2-diphenylethane-1,2-diamine; Introduction Chiral

• the substrate scope due to their complete rigidity. Cyclohexane-1,2-linked bisoxazolines (cHBOX) are a class of bisoxazoline ligands with the more flexible cyclohexane as linker [21][22]. Chiral cyclohexane-1,2-linked bisoxazolines fix transition states in catalytic asymmetric reactions, in whch the

3,3'-Linked BINOL macrocycles: optimized synthesis of crown ethers featuring one or two BINOL units

• Somayyeh Kheirjou,
• Jan Riebe,
• Maike Thiele,
• Christoph Wölper and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2025, 21, 1719–1729, doi:10.3762/bjoc.21.134

• enantioselective molecular recognition. Different chiral backbones were used for the construction of such chiral crown ethers, especially chiral 1,2-diols such as tartaric acid [5][6][7][8], propane-1,2-diol [9][10][11][12][13], cyclohexane-1,2-diol [14], carbohydrates [15], 1,1'-binapthyl-2,2'-diol (BINOL) [16

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

• number of industrially used azo dyes [1][3] and therefore its tautomerism is studied in details. The existing experimental data for low polar solvents (cyclohexane and tetrachloromethane) indicate a ΔG value of around 0.4 kcal/mol [53] at room temperature, which gives a prevalence of the E-tautomer (a

A versatile route towards 6-arylpipecolic acids

• Erich Gebel,
• Cornelia Göcke,
• Carolin Gruner and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 1104–1115, doi:10.3762/bjoc.21.88

• slightly distorted gauche couplings with torsion angles of approximately 60° and −60°, respectively. By analogy to a cyclohexane ring, the carboxylate of (2R,6R)-9 would be expected to adopt an equatorial position rather than an axial one. However, it is known from N-acyl pipecolic acid derivatives, that

• being intermediate conformations in six-membered rings with dihedral angles ϕ near 90° (a front and side view of cyclohexane is shown in Figure S1, Supporting Information File 1). In case of a twist-boat conformation all dihedral angles for H2 would ultimately result in double-doublets for 3J(H2,H3,pro

Salen–scandium(III) complex-catalyzed asymmetric (3 + 2) annulation of aziridines and aldehydes

• Linqiang Wang and
• Jiaxi Xu

Beilstein J. Org. Chem. 2025, 21, 1087–1094, doi:10.3762/bjoc.21.86

• -dicarboxylates from aldehydes and dialkyl 2-aryl-1-sulfonylaziridine-2,2-dicarboxylates under the catalysis of the readily available salen–Sc(OTf)3 complex (Scheme 1d). The salen ligand can be prepared in one step from enantiopure cyclohexane-1,2-diamines and substituted salicylaldehydes. Results and Discussion

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

• alkaloids, though it features a truncated cyclopentane rather than the characteristic cyclohexane or cyclohexene. In their optimization studies, the authors found the sequential catalysis of a chiral binol–Ti complex and BF3·Et2O to be the most efficient, providing products 39 in high yields with excellent

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

• improved photostability (see Figure 1a). While the triaryl oxyether-TTM does not enhance the ϕ, triaryl thioether-TTM exhibits a ϕ of up to 37.5% (in cyclohexane). Due to the stronger electron donating effect of the chalcogens compared to halogens, the emission is shifted to lower energies with λem = 625

• functionalization with a much broader variety of donors (and even acceptors) than is possible through a radical-mediated nucleophilic aromatic substitution (SRN1, see also below) [3][46][47]. The I-TTM has a maximum emission at λem = 578 nm and a ϕ of 3% (in cyclohexane), indicating that the symmetry does not seem

• bathochromically shifted for mono- and bis-para-nitrile TTM radicals, successive nitrilation increases the ϕ to 4.6% and 7.4% (in cyclohexane) [53]. This improvement is most likely induced by symmetry breaking, resulting in excited states with some charge-transfer character. Moreover, the photostability of such

Synthesis of HBC fluorophores with an electrophilic handle for covalent attachment to Pepper RNA

• Raphael Bereiter and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 727–735, doi:10.3762/bjoc.21.56

• Na2SO4 and concentrated to dryness. Finally, the crude compound was purified via silica gel chromatography using 50–70% ethyl acetate in cyclohexane as gradient. General procedure B. The product obtained in general procedure A was dissolved in ethanol mixed with 4-cyanophenylacetonitrile and 8 drops of

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

• chemical shift (Δδ) for C1·guest. As the central hydrophobic binding domain of the guests we selected alkylene, p-xylylene, cyclohexane, and adamantane moieties that are known to bind well to (acyclic) CB[n] receptors [71][72][73]. The cross-sectional area of this hydrophobic moiety increases as follows

• contributions to binding is likely due to stronger electrostatic interactions between the guest and the sulfate ionic groups. For both C1 and M1, the Me6HDA and Me6PXDA are the strongest binding guests whereas the cyclohexane and adamantane-based guests with a larger cross-sectional area bind 10–100-fold more

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

• , toluene, reflux; e) tert-BuLi, DMF, THF, −78 °C; f) KOH, 18-crown-6, CH2Cl2, reflux (rt for 8); g) hν, I2, cyclohexane (toluene/THF mixture for 11); h) p-TsOH, acetone, reflux. Synthesis of F8PIC, F8FUL, and F87PHEN. Reagents and conditions: a) KOH, 18-crown-6, CH2Cl2, reflux; b) hν, I2, toluene, rt

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

• -emitting device. The photophysical data of ANTH and 9,10-disubstituted anthracene derivatives are summarized in Table 1. The measured photoluminescence quantum yield, PLQY (Φf) of ANTH in cyclohexane is in agreement with the literature values of 0.28–0.36 [32][33][34][35]. An increase in Φf was previously

• . Experimental Solvents and reagents The following reagents and solvents were used as received unless otherwise indicated: anthracene (TCI America, 94%); 9,10-dibromoanthracene (Thermo Scientific Chemicals, 98%); heptafluorobenzyl iodide (C6F5CF2I, SynQuest, 90%); cyclohexane (Mallinckrodt); 1,4‐bis

• = 13.63 Hz, 2F), −140.67 (m, 2F), −151.7 (t, J = 21.8 Hz, 1F), −162.68 (m, 2F); 1H NMR (δ/ppm): 8.23 (m, 4H), 7.45 (m, 4H); EIMS (m/z): [M]+ calcd for 610.0402; found, 610.100. Absorption and emission spectroscopy Absorption spectra were collected under aerobic conditions in cyclohexane. Measurements were

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

• irradiation. The authors claim that toluene acts as a photosensitizer since cyclohexane, which has similar solubilizing power, did not serve well as a LAG agent. The authors demonstrated that nanographenes could be obtained via cyclodehydrochlorination of 10.3 under photomechanochemical conditions as well

Synthesis, structure and π-expansion of tris(4,5-dehydro-2,3:6,7-dibenzotropone)

• Yongming Xiong,
• Xue Lin Ma,
• Shilong Su and
• Qian Miao

Beilstein J. Org. Chem. 2025, 21, 1–7, doi:10.3762/bjoc.21.1

• orange solution in common organic solvents, and its solution in cyclohexane exhibits very weak orange photoluminescence with a quantum yield as low as 3.9 × 10−4 upon excitation at 400 nm. Such a low photoluminescence quantum yield may be attributed to the conformational motions of the helicene moieties

• in 3, which consume the energy of the excited state. Figure 4 shows the UV–vis absorption spectrum of 3 in cyclohexane with the absorption edge at 561 nm and its emission spectrum with a peak at 580 nm. In the test windows of cyclic voltammetry (Supporting Information File 1, Figure S1), 3 exhibits

• nm) of compound 3 in cyclohexane (1 × 10−5 mol/L). a) Synthesis of 1; b) reactions of 1; c) synthesis of 3. Supporting Information Supporting Information File 63: Experimental details, characterization data, and spectra. Supporting Information File 64: CIF-files of compounds 1 and 3

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

• Robin Schulte,
• Dustin Schade,
• Thomas Paululat,
• Till J. B. Zähringer,
• Christoph Kerzig and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

• acetylenes at ca. 85 ppm and 95 ppm were observed. The norbornadienes 1h–l,n exhibit very good solubility in organic solvents, like ethyl acetate, chloroform, or benzene, whereas they have poor solubility in cyclohexane, acetonitrile, or ethanol. In polar protic solvents, like methanol or water, they are

• cyclohexane (20 µM, Figure 2), because the norbornadienes and the corresponding quadricyclanes are sufficiently soluble in this solvent and because it allows direct comparison with literature data [30][34]. As a general trend, the long-wavelength absorption maximum of each substrate decreased for all

• be investigated in the presence of the photosensitizer because these substrates have no sufficient solubility in acetonitrile. To assess the efficiency of the photoreactions, photoisomerization quantum yields were determined in cyclohexane by actinometry (λex = 310 nm or 340 nm) [41][42]. The quantum

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• of allylic peroxidation 2, 4 and 5 were observed (Scheme 4) [24]. Similar transformations were reported later using CuCl as the catalyst [39]. Later, Gade with coauthors demonstrated the allylic peroxidation of cyclohexane with TBHP using the alkylperoxocobalt(III) complexes [Co(BPI)(OAc)(OO-t-Bu

• oxidation of cyclohexane 83 with TBHP using mononuclear [77][78][79] and dinuclear [80] non-porphyrin iron complexes (Scheme 30). Besides the oxygen atom transfer products, cyclohexanol (85) and cyclohexanone (15), the formation of peroxide 84 was observed. Oxidation of cyclohexane (83) was also carried out

• directly by the Co(lll) complexes with TBHP (Scheme 30) [82]. The key step in the Fe-catalyzed peroxidation mechanism is the generation of the set of tert-butoxy and tert-butylperoxy radicals from TBHP via Fe(II)/Fe(III) cycle. HAT from cyclohexane by tert-butoxy radical and the recombination of the

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• -naphthols 21 by using iodonium salts 16 as the source of the aryl group (Scheme 7) [61]. Through optimization, it was determined that the presence of Na2CO3 as base and cyclohexane as solvent facilitated the C–C cross-coupling reaction. The products were obtained in satisfactory yields using various

Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction

• Yuta Kabumoto,
• Eiichiro Yoshimoto,
• Bing Xiaohuan,
• Masato Morita,
• Motohiro Yasui,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2776–2783, doi:10.3762/bjoc.20.233

• diethyl ether, toluene, hexane, and cyclohexane, (S)-20b was obtained in 30% to 40% yield and significant amounts of unreacted substrate were still observed, although formation of the byproduct 22b could be generally suppressed. We also examined the reaction using other bases instead of DBU. As shown in

Synthesis and conformational analysis of pyran inter-halide analogues of ᴅ-talose

• Olivier Lessard,
• Mathilde Grosset-Magagne,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2024, 20, 2442–2454, doi:10.3762/bjoc.20.208

• to the non-halogenated compound. The puckering amplitude for an ideal cyclohexane chair, with C–C bond lengths of 1.54 Å, is 0.63 Å [50]. The azimuthal angle (θ) represents the distortion of the ring. For pyranose rings, an azimuthal angle of θ = 0° represents a perfect 4C1 chair, and an angle of θ

Diastereoselective synthesis of highly substituted cyclohexanones and tetrahydrochromene-4-ones via conjugate addition of curcumins to arylidenemalonates

• Deepa Nair,
• Abhishek Tiwari,
• Banamali Laha and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2024, 20, 2016–2023, doi:10.3762/bjoc.20.177

• compound 4a (Figure 2). These studies confirmed that R and Ar in the cyclohexane ring of compounds 3 and 4 are trans to each other and the Ar in the dihydropyran ring of 4 is trans to R and cis to Ar in the cyclohexane ring. The diastereoselectivity observed in the above cascade double Michael reaction of

Radical reactivity of antiaromatic Ni(II) norcorroles with azo radical initiators

• Siham Asyiqin Shafie,
• Ryo Nozawa,
• Hideaki Takano and
• Hiroshi Shinokubo

Beilstein J. Org. Chem. 2024, 20, 1967–1972, doi:10.3762/bjoc.20.172

• antiaromatic character of the macrocycle changed to nonaromatic upon radical addition (see Supporting Information File 1). 1,1'-Azobis(cyclohexane-1-carbonitrile) (V-40) was also examined as a radical source. The reaction afforded 2b in 87% yield (Scheme 2). Unfortunately, other radical sources, such as

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

• Yu Fan,
• Ahmed El Rhaz,
• Stéphane Maisonneuve,
• Emilie Gillon,
• Maha Fatthalla,
• Franck Le Bideau,
• Guillaume Laurent,
• Samir Messaoudi,
• Anne Imberty and
• Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

• concentrated under reduced pressure and purified by flash chromatography (cyclohexane/EtOAc 7:3) to give the thioglycoside. General procedure IV for the Zemplén deacetylation: To a seal tube containing the galactose derivatives in dry MeOH (0.15 M), NaOMe (30 mol %, 0.5 M sol. in MeOH) was added. The mixture

Novel route to enhance the thermo-optical performance of bicyclic diene photoswitches for solar thermal batteries

• Akanksha Ashok Sangolkar,
• Rama Krishna Kadiyam and
• Ravinder Pawar

Beilstein J. Org. Chem. 2024, 20, 1053–1068, doi:10.3762/bjoc.20.93

• and oscillatory strength for the first fifteen singlet electronic excited states. To assess the influence of solvents, the geometries were optimized and photoswitching properties were determined in different polarity solvents (dielectric constant) including cyclohexane (2.0165), toluene (2.3741

Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793

• Zhen Ying,
• Xiao-Ming Li,
• Sui-Qun Yang,
• Hong-Lei Li,
• Xin Li,
• Bin-Gui Wang and
• Ling-Hong Meng

Beilstein J. Org. Chem. 2024, 20, 470–478, doi:10.3762/bjoc.20.42

• (C-2 to C-5), and a –CH–CH2–CH= moiety (C-8 to C-10) (Figure 2). HMBC correlations from H-4 to C-2 and C-6, from H-5 to C-1 and C-3, from 1-OH to C-2 and C-6, and from 6-OH to C-1, C-5, and C-14, led to the construction of the cyclohexane ring for 1, while HMBC correlations from H-9 to C-11, and from

• H-12 and H-13 to C-10 and C-11 constructed the isopentenyl group. Further HMBC correlations from H-15 to C-1, C-7, and C-8 connected the cyclohexane ring and isopentenyl from C-1 and C-8 via the non-protonated carbon C-7. The assignment of the thio-ether bond between C-8 and C-14 was supported by