Synthesis of depressin, cryptomeridiol and 4-epi-cryptomeridiol enabled by a terpenoid chiral pool-producing platform

• Yao Kong,
• Tao Wang,
• Chen Wang,
• Pengcheng Zhang,
• Yuanning Liu,
• Kaibiao Wang,
• Fen Liu,
• Hongli Jia and
• Zhengren Xu

Beilstein J. Org. Chem. 2026, 22, 683–690, doi:10.3762/bjoc.22.53

• ketone in a later step for the synthesis of 1. The 5-hydroxy group in 11 was then protected as a TBS ether to give 12 in 96% yield. However, direct deoxygenation of the 13-ketone of 12 was not fruitful in our hands [58][59][60]. We then converted enone 12 to the allylic alcohols 13a/b as two

• the benzoate ester for reductive deoxygenation were not successful [63], and 13a/b decomposed in the esterification step. We have finally found that the 13-hydroxy group could be smoothly removed by the methyl oxalyl ester deoxygenation method [64][65]. Thus, 13a/b were esterified with methyl

• chlorooxoacetate to give 14a/b in 84% yield, which were subjected to the radical deoxygenation conditions (AIBN, n-Bu3SnH) for 13-hydroxy removal, affording two deoxygenated products that were difficult to be separated from each other. Without further purification, the obtained mixture was treated with tetra-n

Using generative AI to transform peptide hits into small molecule leads

• Joshua Mills and
• Yu Heng Lau

Beilstein J. Org. Chem. 2026, 22, 672–679, doi:10.3762/bjoc.22.51

• , based on training with a supplied dataset. B) Models can use different chemical representations as inputs, such as SMILES strings, point clouds, or molecular graphs. Selected examples of structure-based AI/ML tools for potential end-to-end coverage of the peptide to small molecule pipeline. Tools are

Photoorganocatalytic trifluoromethylation of (het)arenes in green conditions

• Egor N. Boronin,
• Svetlana E. Kaurkina,
• Milena M. Svetlakova,
• Anton S. Bolshakov,
• Maxim V. Arsenyev,
• Vasilii F. Otvagin,
• Alexey Yu. Fedorov,
• Timothy Noël and
• Alexander V. Nyuchev

Beilstein J. Org. Chem. 2026, 22, 662–671, doi:10.3762/bjoc.22.50

• , including rhodamine B, rhodamine 6G, eosin Y, riboflavin, methylene blue, THPP (tetrahydroxyphenylporphyrin), Birch O-PC™ C0103 (benzo[ghi]perylene monoimide) [28], 4CzTPN (tetracarbozalylterephthalonitrile), and 4CzIPN (tetracarbozalylisophthalonitrile), did not afford the desired product (Table 2, entry 1

Advantages of PROTACs in achieving selective degradation of homologous protein families

• Luxi Yang,
• Xinfei Mao,
• Jingyi Zhang,
• Jing Shu,
• Wenhai Huang,
• Xiaowu Dong,
• Yinqiao Chen and
• Mingfei Wu

Beilstein J. Org. Chem. 2026, 22, 628–661, doi:10.3762/bjoc.22.49

• the VH032 ligand. Through systematic optimization of linker lengths, it was found that the molecule achieved optimal activity when the linker a consisted of six methylene groups and linker b consisted of three methylene groups. The resulting products 37 exhibited DC50 values of 7.7 nM and 5.0 nM for

• structure revealed that linker b forms hydrophobic interactions with the ZA loop of BRD4BD2 and stabilizes the PPI interface via a conserved salt-bridge network, while linker a acts as a "hinge" to bring the two proteins into proximity. This study systematically elucidated how macrocyclic linker length and

Hydrogen production from formic acid catalyzed by NHC–Cu complexes

• Orlando Santoro and
• Catherine S. J. Cazin

Beilstein J. Org. Chem. 2026, 22, 620–627, doi:10.3762/bjoc.22.48

• reached a plateau within minutes (Figure 2a and b). Such a value corresponded to the production of ca. 1.5 equivalents of gas (see Supporting Information File 1, section 4). Notably, when [Cu(Ot-Bu)(IMes)] (2a) was employed, the reaction proceeded slowly (Figure 2c). This can be due to the faster

• : formic acid (0.5 mmol, 1 equiv), toluene 2 mL, 3 h. 1a 10 mol %, PhSiH3 (1 equiv), 25 °C (a); 1c 10 mol %, PhSiH3 (1 equiv), 25 °C (b); 2a 10 mol %, PhSiH3 (1 equiv), 25 °C (c); 1a 1 mol %, PhSiH3 (1 equiv), 25 °C (d); 1a 0.1 mol %, PhSiH3 (1 equiv), 40 °C (e). Decomposition of FA catalyzed by NHC–Cu

• complexes in the presence of different silanes. Reaction conditions: formic acid (0.5 mmol, 1 equiv), silane (1 equiv), toluene 2 mL, 1a (10 mol %), 25 °C, 1 h. PhSiH3 (a); Me(EtO)2SiH (b); (EtO)3SiH (c). Hypothetical mechanism for FA decomposition via decarboxylation of NHC–Cu–formato species. Isotopic

Towards the targeted protein degradation of CK2: design and synthesis of CAM4066-based PROTACs

• Sophie Day-Riley,
• Sona Krajcovicova,
• Aryaman Raj Sokhal,
• Jan L. Venne,
• Paul Brear,
• Marko Hyvönen,
• Benjamin C. Whitehurst,
• Jason S. Carroll and
• David R. Spring

Beilstein J. Org. Chem. 2026, 22, 611–619, doi:10.3762/bjoc.22.47

• on 1 (PDB: 5CU4) and S13 (PDB: 9TTA; please see Supporting Information File 1, section 1.4.18 for the full structure). B) Crystal structure of S13. The map is Fo-Fc contoured at 1.5 σ. C) Isothermal titration calorimetry (ITC) reveals the suitable position for linker vector to attach the E3 ligases

• -diisopropylethylamine; DME = 1,2-dimethoxyethane; DMF = dimethylformamide; HOBt = 1-hydroxybenzotriazole; TFA = trifluoroacetic acid. (A) Synthesis of final VHL PROTACs; (B) Synthesis of final CRBN PROTACs. Abbreviations: Boc = tert-butoxycarbonyl; CRBN = cereblon; DIPEA = N,N-diisopropylethylamine; DMF

• grateful to the Czech Science Foundation (GA CR 22-07138O) for their financial support. A. R. Sokhal is grateful to the Gates Cambridge Trust for their financial support (https://www.gatescambridge.org). The Spring lab acknowledges support from the EPSRC, BBSRC, MRC, and Cystic Fibrosis Trust UK. B. C

Computational prediction of C–H hydricities and their use in predicting the regioselectivity of electron-rich C–H functionalisation reactions

• Rasmus M. Borup,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2026, 22, 603–610, doi:10.3762/bjoc.22.46

• hydride transfer reaction, ; see Equation 1. For each set of C–H sites in a molecule, we determine the minimum hydricity (). Hereafter, we assume a linear relationship between the experimental hydricity and as this assumption allows us to derive the empirical constants a and b and correct any systematic

• errors, such as the hydride (H−) ion; see Equation 2, where ΔG° is replaced by . After retrieving the empirical constants a and b, we can determine the QM-computed hydricities for all C–H sites using Equation 2: Because G°(H−)solv is constant across substrates, it is absorbed into the fitted intercept b

• on the entire training set and evaluate it on the test set, selecting the best-performing model. Results and Discussion Computing C–H hydricities In section “Quantum chemistry-based workflow”, we determine the empirical values a and b in Equation 2. For each set of C–H sites in a molecule, we extract

Regioselective approach to 5-arylsulfonylisoxazoles and their antimicrobial activity

• Artem S. Sazonov,
• Dmitry A. Vasilenko,
• Denis V. Porfiriev,
• Yuri K. Grishin,
• Rimma A. Gazzaeva,
• Alisa P. Chernyshova,
• Maxim A. Kryakvin,
• Anna A. Baranova,
• Vera A. Alferova and
• Elena B. Averina

Beilstein J. Org. Chem. 2026, 22, 592–602, doi:10.3762/bjoc.22.45

• Artem S. Sazonov Dmitry A. Vasilenko Denis V. Porfiriev Yuri K. Grishin Rimma A. Gazzaeva Alisa P. Chernyshova Maxim A. Kryakvin Anna A. Baranova Vera A. Alferova Elena B. Averina Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory, 1-3, Moscow 119991, Russian Federation

• 5-sulfonylisoxazoles (Scheme 1, approaches A, B, C). As shown in Scheme 1, nitrile oxides are generated in situ by oxidation of aldoximes with chloramine T (approach A) or by dehydrohalogenation of the corresponding oxime halide under basic conditions (approaches B and C). Subsequently, the nitrile

• 4-unsubstituted isoxazoles with various aryl substituents in position 3 [24][25] (approach B). One example describes the Ru-catalyzed reaction of nitrile oxide with alkynyl sulfone providing 5-sulfonylisoxazole with high regioselectivity [26] (approach C). Despite the widespread application of

Design and synthesis of an erdafitinib-based selective FGFR2 degrader

• Yumeng Jin,
• Shidong Wang,
• Sihan Pan,
• Shuqi Huang,
• Weichen Zhou,
• Xiaohao Huang,
• Lei Zheng and
• Lingfeng Chen

Beilstein J. Org. Chem. 2026, 22, 583–591, doi:10.3762/bjoc.22.44

• ]. b) The FGFR2 design strategy. a) Representative western blots evaluating the total FGFR2 levels in KATO III cells following treatment using the indicated PROTAC. b) Time-course of FGFR2 degradation. c) Chemical structure of LC-JD-6. d,) Dose-course of FGFR2 degradation. e) Cell viability in KATO III

• and HEK293T cells. a) FGFR1, FGFR2, FGFR3, and FGFR4 levels in cells after treatment. b) The mechanism of PROTAC. It was created in BioRender (Chen, Lingfeng https://BioRender.com/7td2yot). This content is not subject to CC BY 4.0. c) Cellular localization of FGFR2 after treatment with LC-JD-6

• . Synthesis of PROTACs towards FGFR2. Reagents and conditions: (a) K2CO3, Pd (dppf)Cl2, 1,4-dioxane/H2O 4:1, 100 °C, 5 h; (b) 3,5-dimethoxyaniline, Pd2(dba)3, BINAP, Cs2CO3, toluene, 100 °C, 12 h; (c) (2-bromoethoxy)-tert-butyldimethylsilane, NaH, DMF, rt, 12 h; (d) tetrabutylammonium fluoride, THF rt, 12 h

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

• centromere protein), and the kinase Aurora B. During mitosis, Aurora B phosphorylates important components of the kinetochore and thus exerts control over key events of the whole process. The other three proteins localize the CPC during the different mitotic phases [4]. Survivin, borealin and INCENP are

• free NH3+ of the first alanine residue contribute directly to the binding of survivin. P-T120 recruits shugoshin 1 and shugoshin 2, which in turn interact with borealin and with survivin itself, probably involving a region that is distinct from the one that interacts with P-T3-H3. B) Crystal structure

• complex. A) Lewis structure of the truncated tweezer peptide monophosphate 2b. B) Close-up of the binding motif formed by 2b (tweezer: green, butynyl ester: red) on the survivin surface encapsulating Lys-121 after MD simulation (Desmond, 100 ns, 300 K, 0.15 mM NaCl) using explicit water solvent. A

Experimental and DFT studies on the regioselective methanolysis of 5-azido-9-oxabicyclo[6.1.0]nonan-4-yl 4-nitrobenzoate isomers

• İlknur Polat,
• Selçuk Eşsiz and
• Emine Salamci

Beilstein J. Org. Chem. 2026, 22, 547–556, doi:10.3762/bjoc.22.40

• formed in both pathways. Free energy computations indicate that the intermediate 12 is thermodynamically more stable by 4.9 kcal mol−1 compared to intermediate 15. The nucleophilic attack by chloride ion bifurcates into two paths, namely C1- (route a) and C2-attacks (route b) for intermediates 12 and 15

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

• to new acetophenones and 2H-chromenes, the dichlormethane extract from leaves of Melicope barbigera A. Gray (Rutaceae) afforded a mixture of the isomeric melifoliones A (1) and B (2) as well as an oxidation product of 2, whose structure was elucidated as the para-quinol 4. For an independent

• been described in the literature. Keywords: Melicope barbigera; Melifoliones A and B; new heterocyclic ring systems; new natural compounds; para-quinols; phenol oxidation; Introduction The genus Melicope is a member of the Rutaceae (Citrus family) and contains more than 200 species distributed in the

• isolated from a dichloromethane extract of leaves of Melicope barbigera A. Gray, a species endemic to the island of Kaua’i, Hawaiian Islands [2][3]. In addition, small amounts of two tetracyclic citrans were identified as a 30:70%-mixture of isomeric melifoliones A (1), and melifolione B (2) [1], both

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

• Sebastian Dominik Graf Gertraud-Kaltenecker Straße 24, D-93049 Regensburg, Germany 10.3762/bjoc.22.37 Abstract Eribulin is a synthetic analog of halichondrin B, a natural product derived from marine sponges, and has gained significant importance in oncology (as its commercial mesylate salt

• eribulin are summarized. Keywords: breast cancer; drug manufacturing; eribulin; Halaven; total synthesis; Introduction Eribulin (1) is a truncated derivative of halichondrin B (2), a complex natural product originally isolated from the marine sponge Halichondria okadai (Figure 1) [1][2][3][4][5]. Already

• within their isolation study on halichondrin B, in 1986, Hirata and Uemura showed its promising activity against murine cancer cells [6], which led to a great interest in the pharmaceutical society [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Only 6 years later, Kishi and co-workers first

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

• complex. The probe was absent in side-view classes. Synthesis of CI-994 and the Au–(CI-994) conjugate. Conditions: a) Boc2O, NEt3, THF, 0 °C to rt, 19 h, 70%; b) 4-nitrobenzoyl chloride, DIPEA, DCM, 0 °C to rt, 16 h, 74%; (c) H2, 10% Pd/C, MeOH/THF 1:1, rt, 17 h, 95%; d) AcCl, NEt3, THF, 0 °C to rt, 21 h

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

• catalysis [26]. These molecules are widely found in natural products [27] and drugs, such as michellamines A and B [28], korupensamines A and B [29], diazonamide A [30], mastigophorene A [31], and the recently developed drug candidate BMS-986142 [32] (Figure 1). When a molecule contains two or more chiral

• systems will be developed with the progress of research in the future, thereby facilitating further breakthroughs in this area. Natural products with various stereogenic axes. Iridium complex-catalyzed asymmetrical synthesis of axially chiral (a) teraryl compounds 3 [40] and (b) pentaaryl derivatives 6

Structural reassignment of compound 968, an allosteric glutaminase inhibitor

• Lindsey A. Albertelli,
• Sainabou Jallow,
• Chun Li and
• Scott M. Ulrich

Beilstein J. Org. Chem. 2026, 22, 455–460, doi:10.3762/bjoc.22.33

• 0.5 mM and the cultures were shaken at 17 °C for 18 hours. The cells were harvested by centrifugation and stored at −80 °C. The cell pellets were lysed in 20 mL B-PER complete (ThermoFisher) supplemented with an EDTA-free protease inhibitor tablet (Roche) according to the manufacturer’s instructions

• synthesized using the published cyclocondensation reaction (middle), and the isomeric benzo[c]acridine compound purchased from ChemDiv. B) Dose–response curves of the three compounds against the glutaminase isoform GAC. C) ORTEP diagram of the X-ray crystal structure of the material synthesized according to

Concept-driven strategies in target-oriented synthesis

• David Yu-Kai Chen,
• Chao Li and
• Yefeng Tang

Beilstein J. Org. Chem. 2026, 22, 451–454, doi:10.3762/bjoc.22.32

• radical cyclization (prostaglandin D2 metabolite, Jun Huang et al.), reductive cyclization cascade (aglacin B, Jina Xiao, Yu Peng et al.), electrochemical cyclization (review, Bin Li, H. N. C. Wong, Xiao-Shui Peng et al.), photochemical reactions (review, Shao-Min Fu, Bo Liu et al.), carbene insertion

A facile and practical method for the synthesis of trans-(±)-taxifolin and its derivatives via Darzens reaction

• Bo Peng,
• Panpan Yang,
• Maaz Khan,
• Xiaotong Lin,
• Jiang Wu,
• Peng Fu and
• Qingqing Wu

Beilstein J. Org. Chem. 2026, 22, 443–450, doi:10.3762/bjoc.22.31

• bioactive trans-(+)-taxifolin. The currently most widely applied synthetic method for trans-(±)-taxifolin and its derivatives (a) and the new method via Darzens reaction reported in this work (b). Darzens reaction of 2 with various arylaldehydes under the optimized conditions. Reaction conditions: 2 (0.81

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

• +/HER2−, Ki-67 low), luminal B (ER+/PR+/HER2+ or HER2−, Ki-67 high), HER2-positive, triple-negative (lacking ER, PR, and HER2 expression), and triple-positive (ER+/PR+/HER2+) subtypes [7]. Among these, breast cancer accounts for 10–20% of triple-negative breast cancer (TNBC) cases [8]. Notably, TNBC

• % probability, b) and c) show Se···Se and Se···C intermolecular interaction in compound. DFT optimised structure of compounds a) 7 and b) 8. HOMO, LUMO, and the energy gap of the compounds: a) 7 and b) 8. Mulliken atomic charge of the compounds: a) 7 and b) 8. MEP analysis of the compounds: a) 7 and b) 8. log

• concentration (µM) vs cell viability (%) of compounds of a) 7 and b) 8. Significant difference of control vs concentration: a) compound 7, b) compound 8. 2D and 3D binding interaction of active (1M17) EGFR tyrosine kinase and synthesised compounds: a) 7 and b) 8, c) 2D interaction of crystal structure 1M17 and

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

• ]arenes by joining propargyl/2-azidoethyl and p-amino groups on a common platform. Parts of 1H,13C HMBC spectra of calixarenes 12 (a) and 13 (b) recorded in CDCl3 solutions at 600 MHz. Red lines show the key correlations between signals from the calixarene narrow-rim substituents and aromatic units

• . Molecular structures of partially nitrated calixarene 16 (a) and exhaustively nitrated calixarene 15 (b). Two projections shown in each case and thermal ellipsoids are drawn at a 50% probability level. Planar and energy-minimized structures (with CHCl3 molecule included and triazole groups highlighted) of

• isomeric homodimers of tetraurea 49 (a); structure of tetratosylureacalix[4]arene 52 (b); planar structure of heterodimer 49·52 (c); fragment of the 1H NMR spectrum of calixarene 49 in CDCl3 (d); fragment of the 1H NMR spectrum of an equimolar mixture of calixarenes 49 and 52 in CDCl3 (e). All spectra were

Design, synthesis and biological evaluation of 2,5-diaryloxazolo[4,5-d]pyrimidin-7-ylamines as selective cytotoxic agents against HeLa cells

• Maryna V. Kachaeva,
• Agnieszka B. Olejniczak,
• Marta Denel-Bobrowska,
• Victor V. Zhirnov,
• Yevheniia S. Velihina,
• Stepan G. Pilyo and
• Volodymyr S. Brovarets

Beilstein J. Org. Chem. 2026, 22, 390–398, doi:10.3762/bjoc.22.27

• Maryna V. Kachaeva Agnieszka B. Olejniczak Marta Denel-Bobrowska Victor V. Zhirnov Yevheniia S. Velihina Stepan G. Pilyo Volodymyr S. Brovarets Department of Chemistry of Bioactive Nitrogen-Containing Heterocyclic Bases, V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry, National

• antiproliferative and cytotoxic activity against the tested NCI60 cancer cell lines. Also, several other 7-(1,4-diazepan)- and 7-piperazine-substituted [1,3]oxazolo[4,5-d]pyrimidines (structures A and B in Scheme 1) showed cytotoxic activity in the micromolar concentration range against most breast cancer cell

• combination of the [1,3]oxazolo[4,5-d]pyrimidin-7-amine fragment (structures A and B) with cytisine, glucamine, and aminoethylamine represents a promising strategy for the rational design of multifunctional hybrids with improved biological activity, water solubility, lower toxicity and target engagement

Dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines

• Evgeny M. Buev,
• Alexander V. Pavlushin,
• Vladimir S. Moshkin and
• Vyacheslav Y. Sosnovskikh

Beilstein J. Org. Chem. 2026, 22, 383–389, doi:10.3762/bjoc.22.26

• consists in the simultaneous generation of two reactive intermediates: terminal alkene A and N-methylazomethine ylide B, and final [3 + 2] cycloaddition. It was found that the latter approach depends on CH-acidity of the active methylene compounds and performs well with the acidic substrates in the range

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• ]helicenes 6a,b hinders their practical applications. The CD spectra of optically pure 5a,b and 6a,b were recorded (Figure 5A), and compared with reported analogous oxaza[7]helicenes [49], and spectra obtained from TD-DFT to assign their absolute configurations [27]. The absolute configurations in the first

• and second fractions of the chiral HPLC analysis were assigned as the (P)- and (M)-enantiomers, respectively, for all 5a,b and 6a,b. As expected, the increase in helical length (n) from 7 to 8, 5a and 5b exhibited more red-shifted maximum |gabs| values at around 350 nm, whereas 6a and 6b showed values

• around 290–300 nm for both enantiomers (Figure 5A). High |gabs| values have also been reported for π-extended helical nanographenes featuring aza[7]helicene subunits [65]. Subsequently, CPL spectra of (P/M)-5a,b and (P/M)-6a,b were measured to evaluate the potential of these oxaza[n]helicenes as chiral

Recent advances in the cleavage of non-activated amides

• Eun-Sol Choi and
• Hyo-Jun Lee

Beilstein J. Org. Chem. 2026, 22, 352–369, doi:10.3762/bjoc.22.23

• of CeO2 to attack the carbonyl carbon, leading to cleavage of the C–N bond (B). Subsequent nucleophilic attack of the octoxide anion on the activated carbonyl center (C) then furnishes the ester product. Later, the same group found that niobium could also serve as a heterogeneous Lewis acid catalyst

• understanding of amide reactivity but also inspire the future development of broadly applicable, efficient, and environmentally sustainable strategies for amide transformation. a) Resonance structure of amide. b) Concept of twisted amides. c) Transition-metal-catalyzed activation of twisted amides. d) Concept

• . Esterification of N,N-dimethyl amides via electrophilic generation of acyl iodide intermediates. Transamidation of DMAc promoted by KOt-Bu. a) LiHMDS-mediated transamidation of tertiary amides. b) Computed reactivities of selected amides. c) Rate-determining step of the LiHMDS-mediated transamidation. d) LiHMDS

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

• framework is impossible is one of the ways to improve properties of ORCA. Feasibility of the synthesis of rigid 3b,4,5,6,6a,7-hexahydropyrrolo[2',3':3,4]pyrrolo[1,2-c][1,2,3]triazole and 3b,4,5,6,6a,7-hexahydropyrrolo[2',3':3,4]pyrrolo[1,2-b]pyrazole ring systems with incorporated nitroxide moiety from 2

• sulfonate group, respectively [24]. The 1H NMR spectra of 3a,b,d–f (Zn/CF3COOH system in CD3OD) showed appearance of a singlet of methanesulfonate hydrogens in the region from 2.78 to 3.17 ppm. The NMR spectra were not recorded for 3c because of heavy resinification upon the sample preparation. The

• catalytic system comprising PPh3, CuI, and Pd(PPh3)2Cl2. This procedure afforded alkynones 6a,b in the yields of 75% and 44%, respectively (Scheme 3). In the IR spectra of 6a,b intense bands were observed at 2212–2214 and 1645–1647 cm−1, assigned to vibrations of the triple bond, and the conjugated carbonyl