Kinetic resolution of racemic planar-chiral vinylcymantrenes by molybdenum-catalyzed asymmetric metathesis dimerization

• Haruna Imazu,
• Hitoshi Izu,
• Yasuhiro Ohki and
• Masamichi Ogasawara

Beilstein J. Org. Chem. 2026, 22, 568–574, doi:10.3762/bjoc.22.42

• Science Institute, Tokushima University, Tokushima 770-8501, Japan 10.3762/bjoc.22.42 Abstract Highly diastereo- and enantioselective kinetic resolution (KR) of a series of racemic planar-chiral 1-R-2-vinylcymantrenes (rac-1; R = Br, Me, I) was realized by an asymmetric metathesis dimerization (AMD

• resolution; molybdenum; olefin metathesis; planar chirality; Introduction The development of the well-defined molybdenum- [1][2] or ruthenium-alkylidene [3][4][5] catalysts has proven the olefin metathesis reaction to be a powerful tool in organic synthesis. Asymmetric extension is a recent trend in

• the excellent tolerance of the Mo-/Ru-metathesis catalysts toward the organometallic substrates. The olefin metathesis protocols could be extended to the asymmetric synthesis of diverse planar-chiral transition metal complexes either by the kinetic resolution of the racemic substrates [14][15][16] or

Molecular tweezer–peptide conjugates disrupt the protein–protein interaction between survivin and histone H3 essential in mitosis

• Catherine Gsell,
• Philipp Rebmann,
• Karina Opara,
• Christine Beuck,
• Peter Bayer,
• David Bier,
• Ingrid R. Vetter and
• Thomas Schrader

Beilstein J. Org. Chem. 2026, 22, 557–567, doi:10.3762/bjoc.22.41

• . Crystallizations with this compound and the truncated survivin constructs 1–122 and 1–127 were finally successful and yielded high-resolution X-ray structures (Figure 4) [15]. The structures of both survivin truncation mutants look very similar, both have a survivin dimer in the asymmetric unit, and the H3 peptide

Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B

• Horst Weber,
• Kim-Thao Tran-Cong,
• Bernhard Mayer,
• Guido J. Reiss,
• Iryna S. Konovalova,
• Marc S. Appelhans,
• Kenneth R. Wood and
• Claus M. Passreiter

Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39

• resolution electrospray ionization mass spectrometry (HRESIMS) and NMR spectra. However, the isomeric compound 3 could not be detected in the extract (Figure 1). Since 4 could be an artefact, built by oxidation of 2 during working up of the extract, and to finally confirm the structure, the isomeric

• colorless and amorphous substance. The molecular formula was determined as C18H22O5 by high resolution electrospray ionization mass spectrometry (HRESIMS), thus containing one more oxygen atom than the melifoliones. The UV spectrum showed a maximum at 250 nm, typical for an α,β-unsaturated carbonyl

• crystals. The high-resolution mass spectrum gave a protonated mol peak at 279.1226 indicating the formula C15H19O5. Compared to melifoliones this means a loss of 3 C-atoms. Based on the NMR spectra (1H, 2D-COSY, 13C, HSQC, HMBC) the structure of the oxidation product was determined as the spirofuranone 11

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

• 119. The addition of propargyl bromide led to racemic 120. By the use of a flow setup involving a column packed with Amano lipase, an enzyme from the bacterium Pseudomonas fluorescens, a kinetic resolution of 120 was performed leading to the continuous production of acetate 121 and free alcohol 122

• ketophosphonate 169 using MePO(OMe)2 and n-BuLi. Notably, building block 171 used herein can be synthesized from 170 within 6 steps including a kinetic resolution with Amano lipase PS-800. [94] Another fragment, 181, was synthesized from alcohols 173 and 174, which were perpared from tri-O-acetyl-ᴅ-glucal and (S

• . Hydrolytic kinetic resolution of 209 afforded enantioenriched epoxide (S)-209, which was opened regioselectively with lithium acetylide. The allylation and [3 + 2]-cycloaddition with tosyl azide led to 212. Treatment with Rh2(OAc)4 induced a [2,3]-Wittig rearrangement and subsequent hydrolysis afforded 213

Synthesis of a HDAC inhibitor–nanogold probe for cryo-EM visualization in class I HDAC co-repressor complexes

• Wiktoria A. Pytel,
• John W. R. Schwabe and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2026, 22, 480–485, doi:10.3762/bjoc.22.35

• nucleosomal substrate specificity [5][6], and each complex has distinct cellular functions [7]. Cryo-electron microscopy (cryo-EM) has revolutionized structural biology by enabling high-resolution, three-dimensional visualization of macromolecular multiprotein complexes in differing functional states

• . Examples of structure elucidation utilizing cryo-EM for class I HDAC complexes include the MiDAC and SIN3 complexes [8][9]. However, despite these advances, obtaining high-resolution structures of flexible multiprotein complexes can still prove challenging. One such example of this includes the tripartite

• , the intrinsic flexibility of the CoREST complex has limited the achievable resolution in cryo-EM reconstructions, making it difficult to confidently assign the orientation of the HDAC catalytic domain relative to LSD1 [10]. Understanding the spatial positioning of the HDAC active site within the

Recent advances in the stereoselective synthesis of distal biaxially chiral molecules

• Fanxing Zhou,
• Chen Zhang,
• Lingyu Sun,
• Yiyun Fang,
• Siming Zheng,
• Lina Hu,
• Mengyang Shen,
• Zhen Zhao,
• Wei Xu,
• Yunqiang Sun and
• Zi-Qiang Rong

Beilstein J. Org. Chem. 2026, 22, 461–479, doi:10.3762/bjoc.22.34

• alkylation for dynamic kinetic resolution. Moreover, additional alkylation at a sterically congested second rotational axis enabled the construction of remote, double axially chiral molecules 26. Further advances have come from transition-metal catalysis. Li’s group established a rhodium-catalyzed protocol

• organocatalytic approach. The mechanistic study revealed that the reaction proceeds through a stepwise double cyclization process: The first cyclization generates an intermediate bearing a stereogenic axis, while the second cyclization involves dynamic kinetic resolution of the spiral reaction intermediate under

• biaxial terphenyl atropisomers with chlorinated and brominated variants to achieve high diastereo- and enantioselectivity. The process takes place via a two-step kinetic resolution. In 2021, Shi and co-workers reported a highly trans-selective synthesis of axially chiral styrenes 76 containing a

Synthesis and anti-cancer activity of naphthalimide–organylselanyl conjugates

• Rajkumar Ravi and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2026, 22, 416–435, doi:10.3762/bjoc.22.29

• conserved 3-(4-(tert-butyl)phenoxy)propyl function at the imide nitrogen. The resultant naphthalimide–organylselanyl conjugates, NAP-SePh and NAP-Se(n-Oct), were characterised using various spectroscopic techniques, including FTIR, ¹H, ¹³C, ⁷⁷Se NMR and high-resolution mass spectrometry (HRMS). NAP-SePh was

• single-crystal X-ray diffraction data. To perform high-resolution electrospray ionisation mass spectrometry (HRESIMS), a Waters Xevo G2-XS QT spectrometer was used. Fourier transform infrared (FTIR) spectra were recorded on an Agilent Cary 630 spectrometer using a KBr module. Naphthalimide derivatives 10

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• unstable emulsions obtained by shaking solutions of calixarenes 47–51 in CDCl3 with water were rapidly collected. Although lowered-resolution NMR spectra were obtained, in all cases only resonances of the respective homodimers were detected, despite the presence in the spectra of a large signal from the

Synthesis of tricyclic fused pyrrolidine nitroxides from 2-alkynylpyrrolidine-1-oxyls

• Mark M. Gulman,
• Yuliya F. Polienko,
• Sofia Yu. Trakhininа,
• Yuri V. Gatilov,
• Tatyana V. Rybalova,
• Sergey A. Dobrynin and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2026, 22, 344–351, doi:10.3762/bjoc.22.22

• group, respectively. The elemental analyses data and high-resolution mass spectra (HRMS) of 6a,b were in agreement with the assigned structure. Oxidation of propargyl alcohols is another way to α,β-acetylenic carbonyl compounds [31]. Mild oxidation of propargyl alcohol 2c with activated manganese

Arene activation via π-bond localization: concepts and opportunities

• Paul Meiners,
• Julian J. Melder and
• Tobias Morack

Beilstein J. Org. Chem. 2026, 22, 257–273, doi:10.3762/bjoc.22.19

• ) systems [56][57][58]. Beyond the conceptual advance, the Mo(0) manifold offers practical benefits in terms of scalability and recyclability [59]. However, the preparation of enantioenriched η2-arene complexes presented unique challenges. In contrast to the Re(I) and W(0) analogues, where resolution of the

Configuration–packing synergy enabling integrated crystalline-state RTP and amorphous-state TADF

• Ruiyan Wang and
• Yunan Wu

Beilstein J. Org. Chem. 2026, 22, 224–236, doi:10.3762/bjoc.22.16

• without further purification. Instruments and measurements Low-resolution mass spectra were recorded on a DSQ electron-impact (EI) mass spectrometer. High-resolution mass spectra (HRMS) were acquired on a Thermo MAT95XP instrument using fast atom bombardment (FAB) ionization. 1H and 13C NMR spectra were

Synthesis of diaryl phosphates using phytic acid as a phosphorus source

• Kazuya Asao,
• Seika Matsumoto,
• Haruka Mori,
• Riku Yoshimura,
• Takeshi Sasaki,
• Naoya Hirata,
• Yasuyuki Hayakawa and
• Shin-ichi Kawaguchi

Beilstein J. Org. Chem. 2026, 22, 213–223, doi:10.3762/bjoc.22.15

• File 1. The isolated compounds were characterized via NMR (1H, 13C, 19F, and 31P) and low-resolution mass spectrometry measurements. The NMR measurements were conducted using a Varian NMR 400 MHz system (400 MHz) and a Bruker AVANCE NEO console (400 MHz). Mass spectrometry was performed using LCMS-2020

Screwing the helical chirality through terminal peri-functionalization

• Devesh Chandra,
• Sachin and
• Upendra Sharma

Beilstein J. Org. Chem. 2026, 22, 205–212, doi:10.3762/bjoc.22.14

• through a catalytic kinetic resolution (KR) process was developed by Liu and co-workers [32]. The authors screened a range of organocatalysts, i.e., Takemoto’s thiourea catalyst, (S,S)-1,2-cyclohexanediamine-derived thioureas, cinchona alkaloid-derived thiourea, and squaramides to achieve the desired

• enantioselectivity. Notably, [6]helicene 3k was also readily produced, via kinetic resolution (Scheme 1). Computational studies suggested that hydrogen bonding and π interactions between the reactants and catalyst L1 controlled the stereochemical output of the products 3. The catalyst proximate both reactants to

• helical chiral entities was reported by Wang and co-workers. They reported an organocatalyzed asymmetric synthesis of phosphorus-containing chiral helicenes enabled by dynamic kinetic resolution using copper and peptide-mimetic phosphonium salts, i.e. amino acid-derived phosphonium iodide and bromide as

A new synthesis of Tyrian purple (6,6’-dibromoindigo) and its corresponding sulfonate salts

• Holly Helmers,
• Mark Horton,
• Julie Concepcion,
• Jeffrey Bjorklund and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2026, 22, 167–174, doi:10.3762/bjoc.22.10

• authors wish to thank the University of Notre Dame and Dr. William Bogges for his assistance in obtaining high-resolution mass spectra of synthesized compounds. Moreover, the authors want to thank the 2024 and 2025 Organic Chemistry II classes at North Central College, whose preliminary work served as

Circumventing Mukaiyama oxidation: selective S–O bond formation via sulfenamide–alcohol coupling

• Guoling Huang,
• Huarui Zhu,
• Shuting Zhou,
• Wanlin Zheng,
• Fangpeng Liang,
• Zhibo Zhao,
• Yifei Chen and
• Xunbo Lu

Beilstein J. Org. Chem. 2026, 22, 158–166, doi:10.3762/bjoc.22.9

• previously disclosed a PIDA-mediated oxidative strategy for alcohol incorporation via activation of the S–NH bond (Scheme 1a) [14]. More recently, Wu and co-workers advanced the field by developing a dynamic kinetic resolution protocol for the enantioselective synthesis of sulfinimidate esters from racemic

• exceeds the theoretical maximum of 23% expected from the starting diastereomeric ratio, suggesting that the two diastereomers of 5 did not react at identical rates. These results are consistent with a partial kinetic resolution, wherein the major diastereomer of 5 reacts preferentially, leading to the

• reactivities of the two diastereomers. Although these findings strongly support the occurrence of a partial kinetic resolution, further kinetic measurements would be required for definitive confirmation. A plausible mechanism is outlined as follows. First, the sulfenamide 1 is oxidatively brominated by N

Design and synthesis of an axially chiral platinum(II) complex and its CPL properties in PMMA matrix

• Daiki Tauchi,
• Sota Ogura,
• Misa Sakura,
• Kazunori Tsubaki and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2026, 22, 143–150, doi:10.3762/bjoc.22.7

• spectroscopy, as well as high-resolution mass spectrometry (HRMS). Due to its low solubility, single crystals suitable for X-ray crystallographic analysis could not be obtained. Spectroscopic analysis and DFT calculations To elucidate the electronic structure of the platinum(II) complex, UV–vis absorption

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• (1H), 100.53 MHz (13C) in CDCl3 using residual signals of the nondeuterated solvent (δH 7.26, δC 77.16) as the references. The vibrational spectra were measured on a Shimadzu IR-Prestige-21 Fourier-transform IR spectrometer in KBr pellets over 400–4000 cm−1 range (resolution was 2 cm−1). Mass spectra

Total synthesis of natural products based on hydrogenation of aromatic rings

• Haoxiang Wu and
• Xiangbing Qi

Beilstein J. Org. Chem. 2026, 22, 88–122, doi:10.3762/bjoc.22.4

• hydrogenation reaction (Scheme 7) [60]. Using an acid-assisted dynamic kinetic resolution method, they obtained a series of chiral indolines 56 containing exocyclic stereocenters in high yields and excellent enantioselectivity. Mechanistic studies of the reaction revealed that the dynamic kinetic resolution

• the reaction include high functional group tolerance and excellent stereocontrol. In the same year, Zhou and co-workers reported a rhodium/bisphosphine-catalyzed asymmetric hydrogenation reaction of all-carbon aromatic rings 69 (Scheme 8) [64]. Through desymmetrization or kinetic resolution, a series

• the cyano group to an amide (162) under acidic conditions, which then allowed successful Pd/C-mediated hydrogenation to 163. Subsequent dehydration with POCl3 and chiral resolution using ᴅ-DBTA provided the optically enriched compound 165 (Scheme 22). While this approach rendered catalytic

Reactivity umpolung of the cycloheptatriene core in hexa(methoxycarbonyl)cycloheptatriene

• Dmitry N. Platonov,
• Alexander Yu. Belyy,
• Rinat F. Salikov,
• Kirill S. Erokhin and
• Yury V. Tomilov

Beilstein J. Org. Chem. 2026, 22, 64–70, doi:10.3762/bjoc.22.2

• negative free energy changes for all the stages of this reaction. A chlorination experiment with 2,2,6,6-tetramethylpiperidinyloxyl revealed a trace amount of a trap product detected by high-resolution mass spectrometry to support the radical mechanism. However, this does not exclude the possibility of a

Sustainable electrochemical synthesis of aliphatic nitro-NNO-azoxy compounds employing ammonium dinitramide and their in vitro evaluation as potential nitric oxide donors and fungicides

• Alexander S. Budnikov,
• Nikita E. Leonov,
• Michael S. Klenov,
• Andrey A. Kulikov,
• Igor B. Krylov,
• Timofey A. Kudryashev,
• Aleksandr M. Churakov,
• Alexander O. Terent’ev and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2025, 21, 2739–2754, doi:10.3762/bjoc.21.211

• delta (δ) units, parts per million (ppm) downfield from internal TMS (1H, 13C) or external CH3NO2 (14N negative values of δN correspond to upfield shifts). The IR spectra were recorded with a Bruker ALPHA-T spectrometer in the range of 400–4000 cm−1 (resolution 2 cm−1) as pellets with KBr or as a thin

• layer. High-resolution ESI mass spectra (HRMS) were recorded with a Bruker micrOTOF II instrument. Silica gel 60 Merck (15–40 μm) was used for preparative column and thin-layer chromatography. Silica gel “Silpearl UV 254” was used for preparative column and thin-layer chromatography. Analytical thin

Synthesis of new tetra- and pentacyclic, methylenedioxy- and ethylenedioxy-substituted derivatives of the dibenzo[c,f][1,2]thiazepine ring system

• Gábor Berecz,
• András Dancsó,
• Mária Tóthné Lauritz,
• Loránd Kiss,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2645–2656, doi:10.3762/bjoc.21.205

• . High-resolution mass spectra (HRMS) were recorded on a Bruker Q-TOF MAXIS Impact mass spectrometer coupled with a Waters I-Class UPLC system with a diode array detector. HRMS (TOF MS EI) measurements were performed on an Agilent 2750 GC/Q-TOF mass spectrometer with MSD direct inlet probe. Single

Efficient solid-phase synthesis and structural characterization of segetalins A–H, J and K

• Liangyu Liu,
• Wanqiu Lu,
• Quanping Guo and
• Zhaoqing Xu

Beilstein J. Org. Chem. 2025, 21, 2612–2617, doi:10.3762/bjoc.21.202

• RP-HPLC. This optimized protocol afforded segetalins A–H, J and K (1–10) with 45% to 70% isolated yields (Figure 1). Structural characterization The synthetic compounds 1–10 were rigorously characterized to confirm their identity and purity (see Supporting Information File 1). High-resolution

Rotaxanes with integrated photoswitches: design principles, functional behavior, and emerging applications

• Jullyane Emi Matsushima,
• Khushbu,
• Zuliah Abdulsalam,
• Udyogi Navodya Kulathilaka Conthagamage and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2345–2366, doi:10.3762/bjoc.21.179

• for precise control over their structural, dynamic, and functional properties. By harnessing light as a non-invasive stimulus with high spatial and temporal resolution, these photoswitches allow for the modulation of the rotaxanes’ intra- and intermolecular interactions, optoelectronic properties, and

Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis

• Peng-Xi Luo,
• Jin-Xuan Yang,
• Shao-Min Fu and
• Bo Liu

Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177

• -diketones, the rigid lattice structure locks molecules into a specific conformation, limiting access to certain γ-hydrogens for abstraction and thus enhancing regioselectivity [42]. Enantiopure 87 was obtained by preparative chiral supercritical fluid chromatography (SFC) resolution of the racemate, while

A chiral LC–MS strategy for stereochemical assignment of natural products sharing a 3-methylpent-4-en-2-ol moiety in their terminal structures

• Rei Suo,
• Raku Irie,
• Hinako Nakayama,
• Yuta Ishimaru,
• Yuya Akama,
• Masato Oikawa and
• Shiro Itoi

Beilstein J. Org. Chem. 2025, 21, 2243–2249, doi:10.3762/bjoc.21.171

• the MPO moiety by LC–MS and demonstrate its application to the stereochemical assignment of capsulactone (1) at the microgram scale. The strategy involves the optical resolution of MPO derivatives, chemical degradation of 1, and the stereoselective synthesis of four diastereomers. Results and

• complete separation of the stereoisomers was not achieved, the corresponding peaks exhibited improved resolution compared to those of 4 (Figure S2, Supporting Information File 1). To further enhance separation, the p-nitrobenzoyl (PNB) ester 6 was prepared (Scheme 1B). After repeated trials with several