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

• previous work [56][57], whereas compounds N4 and I1–I4 were synthesized according to Scheme 2 in the Experimental section. The chemical structures of all compounds were confirmed by 1H NMR and 13C NMR spectroscopy and high-resolution mass spectrometry. 1H NMR and 13C NMR spectra are shown in Supporting

• by distillation before use. 1H NMR (300 MHz) and 13C NMR (75 MHz) spectra were recorded on a Bruker AV-300N spectrometer with tetramethylsilane (TMS) as the internal standard. High-resolution mass spectra (HRMS) were measured on a JEOL AccTOF LC mass spectrometer. UV–vis absorption spectra were

• solution, extracted with ether, washed with brine, dried over MgSO4, filtered, and concentrated in vacuo. The crude product was purified by column chromatography on silica gel using n-hexane and ethyl acetate 95:5 to give 1.4 g of I2(a) in 50% yield. 1H NMR (300 MHz, CDCl3, TMS) δ = 2.55 (d, JHF = 3.2 Hz

Visible-light-promoted radical cyclisation of unactivated alkenes in benzimidazoles: synthesis of difluoromethyl- and aryldifluoromethyl-substituted polycyclic imidazoles

• Yujun Pang,
• Jinglan Yan,
• Nawaf Al-Maharik,
• Qian Zhang,
• Zeguo Fang and
• Dong Li

Beilstein J. Org. Chem. 2025, 21, 234–241, doi:10.3762/bjoc.21.15

• . Optimization of reaction conditions.a Supporting Information Supporting Information File 102: Experimental procedures, product characterization, and copies of NMR spectra. Funding We are grateful to the Scientific Research Project of Hubei Education Department (T2020023 and Q20211402) and the open project of

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

• a fluorescent intermediate 18, and subsequent ring opening allowed a streamlined one-pot access to the substructure of THIQ alkaloids 14 in a good yield of 60% from 11. The structure of the resulting 14 was elucidated through comprehensive two-dimensional NMR spectroscopy, complemented by NOE

• by small crystal analysis using an X-ray free-electron laser (XFEL) [54][55]. aSee Supporting Information File 1 for details. Supporting Information Supporting Information File 100: The experimental procedures and characterization data, including copies of NMR spectra and X-ray crystallographic

Heteroannulations of cyanoacetamide-based MCR scaffolds utilizing formamide

• Marios Zingiridis,
• Danae Papachristodoulou,
• Despoina Menegaki,
• Konstantinos G. Froudas and
• Constantinos G. Neochoritis

Beilstein J. Org. Chem. 2025, 21, 217–225, doi:10.3762/bjoc.21.13

• methods, synthetic procedures, analytical data and exemplary copies of NMR spectra of novel compounds. Supporting Information File 97: CheckCIF report for 7b. Supporting Information File 98: CIF file for 7b. Acknowledgements We acknowledge the mass spectrometry facility of the University of Crete

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

• established methods, including 1H NMR-based hydrogen bond acidity determination, UV–vis spectroscopy titration with Reichardt's dye, and 1H NMR titration using tri-n-butylphosphine oxide as a hydrogen bond acceptor. Our experiments reveal that the direct attachment of the CF2H group to cationic aromatic

• by hydrogen bond acidity [47][48] which is derived from the 1H NMR chemical shift difference of a given proton in DMSO-d6 and CDCl3, the CF2H group is generally a stronger donor than the methyl group but substantially weaker than the OH or amide NH groups [19][20]. These results collectively indicate

• method [19][20][47][48]. This convenient approach relies on comparing the 1H NMR chemical shift of a hydrogen bond donor in DMSO-d6 to that of it in CDCl3. The HB donor presumably interacts strongly with hydrogen-accepting DMSO [51], but barely with CDCl3, which has a weak hydrogen bond acceptance

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

• cooperative intermolecular forces. Zinc ion-induced coordination with the macrocycle and a terpyridinium derivative enabled orthogonal polymerization, as revealed by 1H NMR, DLS, and TEM techniques. In addition, viscosity measurements showed a transition from oligomers to polymers at the critical

• molar ratio observed in ESI experiments. These inspiring results prompted us to further examine the interaction between host H1 and G1 by 1H NMR spectroscopy. Our prior experience with cyclo[6]aramide has confirmed binding to the cationic guest [49]. Indeed, addition of compound H1 to the guest solution

• macrocycle H1 and a metal ion via each of two end groups (pyridinium and terpyridyl). As such, host–guest complexation and zinc coordination of the AB-type monomer were investigated. To begin with, the complex formation between host H1 and G2 was explored by 1H NMR spectroscopic titrations in CDCl3/CD3CN 1:1

Nickel-catalyzed cross-coupling of 2-fluorobenzofurans with arylboronic acids via aromatic C–F bond activation

• Takeshi Fujita,
• Haruna Yabuki,
• Ryutaro Morioka,
• Kohei Fuchibe and
• Junji Ichikawa

Beilstein J. Org. Chem. 2025, 21, 146–154, doi:10.3762/bjoc.21.8

• , excluding boronic acid 2a (Scheme 6). The reaction was monitored using 19F and 31P NMR spectroscopy. The 19F NMR analysis showed that 79% of 1b remained and revealed a new broad double doublet peak at 55.0 ppm (JFP = 53, 42 Hz) relative to internal C6F6 (δ = 0.0 ppm). The 31P NMR spectrum depicted broad

• important in pharmaceuticals and agrochemicals [41][42][43][44][45][46][47], we expect that this method will provide a novel and efficient approach for producing these valuable compounds. Experimental General: 1H NMR, 13C NMR, 19F NMR, and 31P NMR were recorded on a Bruker Avance 500 or a JEOL ECS-400

• spectrometer. Chemical shift values are given in ppm relative to internal Me4Si (for 1H NMR: δ = 0.00 ppm), CDCl3 (for 13C NMR: δ = 77.0 ppm), C6F6 (for 19F NMR: δ = 0.0 ppm), and H3PO4 (for 31P NMR: δ = 0.0 ppm). IR spectra were recorded on a Horiba FT-730 spectrometer. Mass spectra were measured on a JEOL

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

Hot shape transformation: the role of PSar dehydration in stomatocyte morphogenesis

• Remi Peters,
• Levy A. Charleston,
• Karinan van Eck,
• Teun van Berlo and
• Daniela A. Wilson

Beilstein J. Org. Chem. 2025, 21, 47–54, doi:10.3762/bjoc.21.5

• shape transformation experiments are indicative of a clear correlation between the dehydration of the membrane and its susceptibility to change shape through osmotic shock (Figure 3). Besides this, one final evidence for dehydration of the PSar corona was provided by NMR in Supporting Information File 1

• thank Nuwanthika Kumarage for helping with the temperature dependent NMR. We extend our heartfelt gratitude to the late Teun van Berlo for his invaluable contributions to this work. Though his time with us was brief, his significant impact on our research endeavors is deeply appreciated. It was a

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

• aromatic compounds. Experimental NMR spectra were recorded on Bruker Avance 400 MHz or Bruker Avance III HD 600 MHz spectrometers. Residual solvent peaks (CDCl3, D2O, CD3OD, (CD3)2SO) were used as internal standard (7.26, 4.79, 3.31, and 2.50 ppm for 1H, and 77.16, 49, and 39.52 ppm for 13C, respectively

• hydrochloride (1b): The product was isolated by use of (II) as an amorphous white solid (83%). 1H NMR (600 MHz, CD3OD) δ 2.97 (m, J = 5.18 Hz, 2H), 3.18 (m, J = 5.24 Hz, 2H), 7.28 (m, J = 5.0 Hz, 3H), 7.35 (m, J = 7.6 Hz, 2H); 13C NMR (151 MHz, CD3OD) δ 34.55, 41.98, 128.26, 129.77, 129.99, 137.92; ESI-MS m/z

• : [M + 1]+ 121.1; found, 121.0; mp 220–221 °C. 2-(4-Methoxyphenyl)ethan-1-amine hydrochloride (2b): The product was isolated by use of (I) as a white solid (82%). 1H NMR (600 MHz, CD3OD) δ 2.89 (t, J = 7.7 Hz, 2H), 3.13 (t, J = 7.7 Hz, 2H), 3.78 (s, 3H), 6.91 (ddd, J = 8.4, 2.8, 0.2 Hz, 2H), 7.19 (ddd

Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

• four-step process involves allylation, Claisen rearrangement, isomerization, and oxidative dimerization. Each reaction step was optimized independently by using either online HPLC or in-line benchtop NMR spectroscopy to afford an overall yield of 67% in 66 iterative experiments over four linear

• spectroscopic (e.g., NMR, FTIR, UV–vis, Raman) characterization methods are commonly used in real-time reaction monitoring. To quantify the products of a chemical reaction, a calibration curve is required before the optimization campaign. The following sequential steps are typically employed to refine raw data

• . [70] assembled four complementary PATs, including in-line NMR, UV–vis, IR, and online ultra-high-performance liquid chromatography (UHPLC) to meticulously monitor the intricate three-step linear synthesis of the drug mesalazine (18, Figure 7) with a 1.6 g⋅h−1 throughput. In the first step, the

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

• . This corresponds to a molecular formula of C119H122O9, which is in agreement with the fully fused product 11 in its protonated form. Unfortunately, clean 1H and 13C NMR spectra of this product could not be obtained to allow full characterization of this product. Efforts to increase the yield of 11

• dibenzotropone moieties capable of flapping with small energy barriers. This is supported by the 1H NMR spectrum of compound 1 (Supporting Information File 1, Figure S11), which presents only four different signals due to rapid conformational shifts in solution. Additional evidence of the small energy barrier

• for conformational change is provided by the earlier report that the NMR spectrum of 1 at −80 °C did not display significant broadening [1]. To better understand the two conformers of 1 found in the crystals, density functional theory (DFT) calculations were carried out using the molecular geometries

Synthesis, characterization, and photophysical properties of novel 9‑phenyl-9-phosphafluorene oxide derivatives

• Shuxian Qiu,
• Duan Dong,
• Jiahui Li,
• Huiting Wen,
• Jinpeng Li,
• Yu Yang,
• Shengxian Zhai and
• Xingyuan Gao

Beilstein J. Org. Chem. 2024, 20, 3299–3305, doi:10.3762/bjoc.20.274

• available 2-bromo-4-fluoro-1-nitrobenzene, featuring a noble-metal-free system, mild reaction conditions, and a good yield, especially for the final Cs2CO3-facilitated nucleophilic substitution (77–91% yield). The characterization data obtained from IR and NMR spectroscopy (1H, 13C, 19F, and 31P) as well as

• 2–7 was performed by NMR spectroscopy, which confirmed the synthetic outcomes (Figures S1–S11, Supporting Information File 1). The structures of compounds 7 were further confirmed by HRMS and IR analyses (Figures S12–S18, Supporting Information File 1). In addition, the chemical structure of 7-H was

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

• , characterization data, and copies of 1H and 13C{1H} NMR spectra. Acknowledgements The data presented in this article are partially taken from the M.Sc. theses of Merve Yence (Bilkent University, 2019) and Dilgam Ahmadli (Bilkent University, 2021). Funding Financial support for some parts of this work from the

Reactivity of hypervalent iodine(III) reagents bearing a benzylamine with sulfenate salts

• Beatriz Dedeiras,
• Catarina S. Caldeira,
• José C. Cunha,
• Clara S. B. Gomes and
• M. Manuel B. Marques

Beilstein J. Org. Chem. 2024, 20, 3281–3289, doi:10.3762/bjoc.20.272

• the electrophilic amination of tert-butyl 3-(p-tolylsulfinyl)propanoate (4a) with BBX 2a (0.23 mmol of limitant in 2 mL of solvent). Supporting Information Supporting Information File 54: Experimental procedures, characterization data, NMR spectra, and X-ray diffraction data. Funding The authors

• /50006/2020 DOI 10.54499/UIDP/50006/2020, and LA/P/0008/2020 DOI 10.54499/LA/P/0008/2020). FCT/MCTES is also acknowledged for supporting the National NMR Facility (ROTEIRO/0031/2013 − PINFRA/22161/2016, cofinanced by FEDER through COMPETE 2020, POCI, and PORL and FCT through PIDDAC), and RECI/BBB-BEP

Giese-type alkylation of dehydroalanine derivatives via silane-mediated alkyl bromide activation

• Perry van der Heide,
• Michele Retini,
• Fabiola Fanini,
• Giovanni Piersanti,
• Francesco Secci,
• Daniele Mazzarella,
• Timothy Noël and
• Alberto Luridiana

Beilstein J. Org. Chem. 2024, 20, 3274–3280, doi:10.3762/bjoc.20.271

• nm, 25 °C, overnight. The yield of 3 was calculated by 1H NMR with 1,1,2-trichloroethene as external standard. Supporting Information Supporting Information File 52: 1H NMR, 13C NMR, and HRMS spectra of all the synthesized compounds. Acknowledgements We are grateful to University Research Services

Efficient synthesis of fluorinated triphenylenes with enhanced arene–perfluoroarene interactions in columnar mesophases

• Yang Chen,
• Jiao He,
• Hang Lin,
• Hai-Feng Wang,
• Ping Hu,
• Bi-Qin Wang,
• Ke-Qing Zhao and
• Bertrand Donnio

Beilstein J. Org. Chem. 2024, 20, 3263–3273, doi:10.3762/bjoc.20.270

• ) was synthesized via consecutive Suzuki coupling and Scholl reaction in a total yield of 77%. The synthesis, molecular structures, nomenclature, and synthetic yields of all compounds are shown in general Scheme 1. All prepared molecules were fully characterized by NMR (1H, 19F and 13C), HRMS, and CHN

• positions. The similarity of the 19F NMR spectra of F and alkoxy-substituted derivatives, Fn, showing 6 single peaks, corresponding to the 8 different fluorine atoms at almost identical positions (Figures S8–S14 and S21 in Supporting Information File 1), confirms that the pattern of the annulation reaction

• '-hexafluoro-6,6',7,7',10,10',11,11'-octakisalkoxy-2,2'-bitriphenylene dimers (G55, G66 and G48). Mesophases’ parameters. Supporting Information Synthesis (Schemes S1–S3) and characterization, 1H, 13C, and 19F NMR (Figures S1–S21), HRMS (Figures S22–S32), EA, single crystal X-ray structures (Figures S33, S34

Intramolecular C–H arylation of pyridine derivatives with a palladium catalyst for the synthesis of multiply fused heteroaromatic compounds

• Yuki Nakanishi,
• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2024, 20, 3256–3262, doi:10.3762/bjoc.20.269

• /MeOAc 1:1) to give 31.0 mg (87% yield) of 2a as a colorless solid. (NMR yield: 94%); mp 85.1–86.6 °C; 1H NMR (CDCl3) δ 8.98 (s, 1H), 8.43 (d, J = 8.4 Hz, 1H), 8.31 (dd, J = 8.0, 1.2 Hz, 1H), 7.95 (d, J = 8.4 Hz, 1H), 7.76 (ddd, J = 8.0, 7.6, 1.2 Hz, 1H), 7.62 (ddd, J = 7.6, 7.6, 1.2 Hz, 1H), 7.54 (ddd

• , J = 8.4, 8.0, 1.2 Hz, 1H), 7.37 (d, J = 8.4 Hz, 1H), 7.30 (dd, J = 8.0, 7.6 Hz, 1H), 4.40 (dd, J = 8.0, 7.6 Hz, 2H), 1.76–1.88 (m, 2H), 1.44–1.56 (m, 2H), 1.18–1.42 (m, 8H), 0.86 (t, J = 6.8 Hz, 3H); 13C{1H} NMR (CDCl3) δ 160.1, 148.4, 142.0, 136.7, 131.1, 130.5, 130.2, 130.1, 129.1, 128.7, 127.7

• . Supporting Information File 48: Additional experimental details and copies of 1H and 13C{1H} NMR spectra. Acknowledgements We thank Professor Shigeki Mori and Ms. Rimi Konishi (Ehime University) for the X-ray crystallographic analysis.

Ceratinadin G, a new psammaplysin derivative possessing a cyano group from a sponge of the genus Pseudoceratina

• Shin-ichiro Kurimoto,
• Kouta Inoue,
• Taito Ohno and
• Takaaki Kubota

Beilstein J. Org. Chem. 2024, 20, 3215–3220, doi:10.3762/bjoc.20.267

• /bjoc.20.267 Abstract A new psammaplysin derivative, ceratinadin G (1), was obtained from the Okinawan marine sponge Pseudoceratina sp., and the gross structure was clarified through spectroscopic and spectrometric analyses. The absolute configuration of compound 1 was established by comparing its NMR

• , after which the extract was partitioned between EtOAc and H2O. The EtOAc-soluble fraction was subjected to silica gel column chromatography. A detailed analysis of the 1H NMR spectrum of the fraction eluted after the one containing ceratinadins E and F revealed signals corresponding to psammaplysin F (2

• existence of a substituted benzenoid chromophore was suggested by the UV absorption maximum at 258 nm. The presence of hydroxy and/or amino groups and a carbonyl group was indicated by IR absorptions at 3337 cm−1 and 1671 cm−1, respectively. The analysis of the HSQC spectrum, along with the 1H and 13C NMR

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

• aeruginosa biofilm inhibitors and antibiotic enhancers. Large-scale extraction and isolation studies resulted in the discovery of four new and minor natural products, ianthelliformisamines D–G (4–7) and the known steroid, aplysterol (8). Compounds 4–7 were fully characterised following 1D/2D NMR, MS and UV

• brown gum. The LRESIMS of 4 indicated the presence of two bromine atoms due to a 1:2:1 ion cluster at m/z 459/461/463 [M + H]+, whilst the HRESIMS data allowed a molecular formula of C17H20Br2N2O3 to be assigned. The 1H NMR (Table 1) and edited HSQC spectra of 4 in DMSO-d6 indicated the presence of one

• protons indicating the presence of a symmetrical aromatic moiety, were observed. The 13C NMR (Table 1) spectrum of 4 showed two carbonyls (δC 164.4, 173.9), with the carbonyl at δC 164.4 readily assigned to an acrylamide group, which is present in all previously published ianthelliformisamine molecules [7

Germanyl triazoles as a platform for CuAAC diversification and chemoselective orthogonal cross-coupling

• John M. Halford-McGuff,
• Thomas M. Richardson,
• Aidan P. McKay,
• Frederik Peschke,
• Glenn A. Burley and
• Allan J. B. Watson

Beilstein J. Org. Chem. 2024, 20, 3198–3204, doi:10.3762/bjoc.20.265

• ) Functionalisation of germylated triazoles. Isolated yields unless stated. (i) Pd(PPh3)4 (10 mol %), 2-bromothiazole (1.2 equiv), KCl (3.0 equiv), PhMe/EtOH 4:1, N2, 100 °C, 16 h. NMR yield in parentheses. (ii) Pd2(dba)3 (2.5 mol %), iodobenzene (1.5 equiv), AgBF4 (1.5 equiv), DMF, N2, 80 °C, 16 h. (iii) NBS (2.0

• /53959471-068e-483e-bcd4-920e6761926b and CCDC 2355570 contains the supplementary crystallographic data for this study. Supporting Information File 38: Characterization data and copies of NMR spectra. Supporting Information File 39: Crystallographic information file (cif) for compound 13. Supporting

Direct trifluoroethylation of carbonyl sulfoxonium ylides using hypervalent iodine compounds

• Radell Echemendía,
• Carlee A. Montgomery,
• Fabio Cuzzucoli,
• Antonio C. B. Burtoloso and
• Graham K. Murphy

Beilstein J. Org. Chem. 2024, 20, 3182–3190, doi:10.3762/bjoc.20.263

• studies using methyl ester sulfoxonium ylide 1a and 2,2,2-trifuoroethyl(mesityl)iodonium triflate salt (2a), as model substrates (see also Table S1 in Supporting Information File 1). Combining these at room temperature in acetonitrile produced 3a in 8% 1H NMR yield (Table 1, entry 1). Repeating the

• , entry 15). An additional solvent screen under microwave conditions offered no improvement (Table 1, entries 16–18). Finally, multivariate screening ultimately showed that 3a could be obtained in 79% 1H NMR yield (75% isolated yield, Table 1, entry 19) when using 1a (1.0 equiv), 2a (2.0 equiv) in ACN (1

• Information File 32: Experimental part, NMR spectra, computational details and crystallgraphic data. Acknowledgements We would like to acknowledge the Schipper lab at the University of Waterloo for providing access to the microwave reactor used in this study. We would also like to acknowledge Boris Ragula

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• intramolecular Michael addition. Preliminary conformational studies on tripeptides including this scaffold in the central position show an extended conformation in solution (NMR) and in the solid state (X-ray). Keywords: fluoroalkyl groups; heterocycles; hydrazino acids; peptides; tetrahydropyridazines

• analysis (Figure 5). Consequently, it was possible to assess the stereochemistry of the other diastereoisomer 8f’ and their precursors 7f and 7f’. On the other hand, considering the similarities of the 1H NMR spectra of the CF2H and CF3 analogs, by comparison, we could hypothesize the absolute

• phenylalanine) indicate that they are not involved in hydrogen bonds. Furthermore, the 2D 1H-1H NOE NMR spectra and the chemical shifts of the NH protons of compounds 8f’, 8e, and 8e’ did not show any significant differences compared to 8f. Overall, the ability of the new fluorinated β-analogs of

Controlled oligomerization of [1.1.1]propellane through radical polarity matching: selective synthesis of SF₅- and CF₃SF₄-containing [2]staffanes

• Jón Atiba Buldt,
• Wang-Yeuk Kong,
• Yannick Kraemer,
• Masiel M. Belsuzarri,
• Ansh Hiten Patel,
• James C. Fettinger,
• Dean J. Tantillo and
• Cody Ross Pitts

Beilstein J. Org. Chem. 2024, 20, 3134–3143, doi:10.3762/bjoc.20.259

• the equivalents of [1.1.1]propellane (1) relative to SF5Cl and evaluating the impact on selectivity (Table 1). A 0.1 M solution of SF5Cl in n-pentane was added to a 0.8 M solution of 1 in Et2O at room temperature, and the mixture was stirred for 3 hours prior to 19F NMR analysis. Upon increasing from

• be accounted for in the formation of these two products alone by 19F NMR. To the best of our knowledge, this is an exceptionally rare instance whereby oligomerization of 1 appears to be stunted beyond formation of the [2]staffane; only trace yields of putative higher-order staffanes (n > 2) were

• detected in the crude reaction mixture. Remarkably, using 20 equiv of 1, the observed 4:2 product ratio improved to 1:3, with 2 formed in 72% yield. In an even more extreme case, the [2]staffane still remained the major product formed in 66% yield when using 50 equiv of 1 (19F NMR signals of presumed

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 level of this chemoselectivity was dependent on the iodane ligand: OPiv was more selective for aminofluorination than OAc, which was proposed to be due to differences in basicity and nucleophilicity (Scheme 10). Detailed mechanistic studies were carried out using multinuclear NMR spectroscopy

• , deuterium labelling, rearrangements on stereodefined substrates, and structural analyses (NMR and X-ray) of the reaction products. RT-NMR-derived data strongly supported a pathway of alkene activation by the iodane, as opposed to the formation of an N-I(III) adduct. The presence of 5-exo-products, with

• activated after coordination to PhI(OAc)2, then intramolecular nucleophilic attack from oxygen and nucleophilic attack by bromide forms the final product. NMR studies of PIDA and the substrate indicated that there was no interaction between them, thereby discounting this second pathway and thereby providing