Synthetic approach to borrelidin fragments: focus on key intermediates

• Yudhi Dwi Kurniawan,
• Zetryana Puteri Tachrim,
• Teni Ernawati,
• Faris Hermawan,
• Ima Nurasiyah and
• Muhammad Alfin Sulmantara

Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91

• epoxidation and regioselective reduction to install the hydroxy group at the C3 position [39]. In their retrosynthetic analysis, the target molecule 61 was envisioned to be obtained from epoxide 63 through regioselective opening of the epoxide ring, oxidation of the resulting primary alcohol to a carboxylic

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

• the reduction of amide-generated ketone 12 after a subsequent Dess–Martin oxidation. Upon treatment of 12 with Co(acac)2 and PhSiH3 in iPrOH at 80 °C, the Mukaiyama hydration of enamide delivered hemiaminal 13. Despite the incorrect configuration of the newly formed hydroxy group, it is considered

• a fragmentation process for the total synthesis of (−)-phlegmariurine B. A one-pot epoxidation/nucleophilic epoxide opening introduced both a hydroxy group and a chloride across the cyclopentene, producing 14 in 57% yield. After oxidation of alcohol 14 to ketone 15, the Mukaiyama hydration then

• photocyclization. This transformation was carried out using a high-pressure mercury vapor lamp to afford benzazepine 22, completing the construction of the pentacyclic framework of the natural product. Subsequent functional group manipulations, including the Chugaev elimination of the hydroxy group on the

A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids

• Zhiyang Zhang,
• Jialei Hu,
• Hanfeng Ding,
• Li Zhang and
• Peirong Rao

Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75

• simultaneously installing the hydroxy group at C30. The latter intermediate could in turn be derived from dienone 11 by an AcOH-interrupted Nazarov cyclization [32][33][34], thereby establishing the B ring with the desired all-cis stereochemical configuration, including the quaternary carbon at C10 and the

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• the hydroxy group to form complex Int-17 and the amino group undergoes nucleophilic attack to generate Int-18. After CO insertion complex Int-19 is produced and reductive elimination ultimately affords the indolo[3,2-c]coumarin product 10. In 2023, the Garg group achieved the first example of

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

• fluorophore derivatives bind the Pepper aptamer with affinities in the low nanomolar range [12]. Crystal structure analyses revealed that in the ligand binding pocket, a characteristic hydrogen bond is formed between the hydroxy group of the N-hydroxyethyl substituent of HBC and the N7 of G41 [12][13]. We

• monitored by the inherent fluorescent signal of the target RNA [11]. The synthetic route to such an HBC fluorophore is shown in Scheme 6. Piperidine-induced condensation of compound 2 with 4-iodophenylacetonitrile afforded the HBC-like ligand, whose hydroxy group was immediately protected with TBS-Cl to

• -dimensional structure of the Pepper binding site with a bound HBC derivative (pdb code 7EOM). The hydrogen bond between N7 of guanine in position 41 (G41) and the hydroxy group of HBC is highlighted as gray dashed line [12]; d) concept for covalent attachment of HBC fluorophores to the N7 atom of G41 of the

Origami with small molecules: exploiting the C–F bond as a conformational tool

• Patrick Ryan,
• Ramsha Iftikhar and
• Luke Hunter

Beilstein J. Org. Chem. 2025, 21, 680–716, doi:10.3762/bjoc.21.54

• when a fluorine atom is introduced vicinal to the hydroxy group (Figure 8). As was seen with ethers (I, Figure 7), there is again a subtle preference for the O–C–C–F motif to adopt a gauche conformation [44]. This is attributable in part to the hyperconjugation phenomenon (I, Figure 8). In several

• molecules’ intermolecular interactions too. The intramolecular H-bond makes the hydroxy group a weaker intermolecular H-bond donor [104] (e.g., 55 vs 54, Figure 8). This runs counter to a longstanding assumption [105] that the inductive effect of fluorine should always make the hydroxy group a stronger H

• -bond donor. For non-rigid molecules, the greater the population of intramolecularly H-bonded conformers, the worse the hydroxy group will be as an intermolecular H-bond donor [106]. To be clear, fluorine can make the hydroxy group a stronger intermolecular H-bond donor in certain circumstances, for

Semisynthetic derivatives of massarilactone D with cytotoxic and nematicidal activities

• Rémy B. Teponno,
• Sara R. Noumeur and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 607–615, doi:10.3762/bjoc.21.48

• -carbonyl group was linked through an ester bond and the only hydroxy group available for this esterification was the one at C-7. This compound was finally elucidated as massarilactone D 3,4-di-O-methacryloyl-7-O-(6-chloro-3,4-dihydro-2,5-dimethyl-2H-pyran-2-carbonyl). For the formation of compound 2, an

• oxa-Diels–Alder reaction between two methacryloyl chloride molecules could have taken place to yield 6-chloro-3,4-dihydro-2,5-dimethyl-2H-pyran-2-carbonyl chloride as previously described [18] before esterification of the hydroxy group at C-7. Compounds 3 (6% yield) and 4 (90% yield) were obtained

• , Ha-11) and 5.23 (d, J = 3.0 Hz, Hb-11) characteristic of exo-methylene protons as in massarilactone H [13][21], suggesting an exo-dehydration of the C-7 hydroxy group. This was further supported by resonances depicted at δC 148.8 (C-7) and 94.3 (C-11). Since compound 3 is massarilactone H 3,4-di-O

Total synthesis of (±)-simonsol C using dearomatization as key reaction under acidic conditions

• Xiao-Yang Bi,
• Xiao-Shuai Yang,
• Shan-Shan Chen,
• Jia-Jun Sui,
• Zhao-Nan Cai,
• Yong-Ming Chuan and
• Hong-Bo Qin

Beilstein J. Org. Chem. 2025, 21, 601–606, doi:10.3762/bjoc.21.47

• DIPEA, affording compound 17 with an 89% yield [11]. For the following alkylation step with tert-butyl bromoacetate, three bases were tested: potassium carbonate, cesium carbonate, and sodium hydride. Considering the targeted alkylation of a phenolic hydroxy group and the pKa requirements of this

• alcohol 19 was isolated in 89% yield. The copper-catalyzed replacement of the bromine substituent in 19 with a hydroxy group was achieved in the presence of a catalytic amount of oxalamide ligand I [13]. This transformation is critical for enabling further functionalization and the reaction conditions

Cryptophycin unit B analogues

• Thomas Schachtsiek,
• Jona Voss,
• Maren Hamsen,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

• conjugable payloads by our group. Modifications of unit B with conjugation handles are scarcely explored and mainly include the exchange of the para-methoxy group (Figure 1B). The sole exchange of the para-methoxy group of cryptophycin-52 (IC50 = 22 pM) by a hydroxy group reduces the cytotoxicity by

• approximately only one order of magnitude (IC50 = 0.52 nM) when tested on CCRF-CEM T lymphoblasts [20]. Loss of the meta-chloro substituent shows a similar trend. Functionalisation of the hydroxy group with ethylene glycol residues further decreases cytotoxicity, whereby this effect increases with increasing

Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• . First, the alkyl handles bearing a primary hydroxy group were introduced and then converted into the electrophile of choice. More specifically, to furnish compounds 4b–d, precursor 9 was treated with the corresponding amino alcohols in the presence of a desiccant. The imines formed were subjected to

Identification and removal of a cryptic impurity in pomalidomide-PEG based PROTAC

• Bingnan Wang,
• Yong Lu and
• Chuo Chen

Beilstein J. Org. Chem. 2025, 21, 407–411, doi:10.3762/bjoc.21.28

• product on HPLC even for the reaction of diethylene glycolamine and 1. Capping the free hydroxy group with a methyl group improved the separation on HPLC marginally. However, incorporating a clickable propargyl group greatly benefited separation. Similar to the alcohol, amino-PEG5-acid also reacted with 1

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• room temperature was the only difference with the pivaloyl group. Protecting the C-2 hydroxy group as ADMB ester yielded 1,2-trans glycosides in high yields. However, its participating mechanism is still unclear. So, we reserve our views on placing the use of ADMB as potential neighbouring group

• ether-type chiral auxiliary group for protection of the hydroxy group in the C-2 position was devised by Boons et al. in 2005 which opened a new avenue in oligosaccharide synthesis. Auxiliary group indicates a substituted ethyl protection which has a nucleophilic centre that can donate electrons in the

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• tropolone ring proton, which appears at 6.9 ppm. A characteristic specificity of the 1H NMR spectra of compounds 7 and 8 is the presence of signals of hydroxy group protons forming a strong hydrogen bond with the indoline nitrogen atom, which closes the six-membered chelate cycle. These signals are observed

• in the weak field at 15.2–15.8 ppm for 7a,b and 14.3–14.8 ppm for 8a,b, respectively, as a broadened singlet peak. A dynamic equilibrium of tautomeric forms 7, 8 (OH)–7, 8 (NH) exists in solution, which can be detected by the broadening of the hydroxy group proton signal in the 1H NMR spectrum

Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia

• Rita Toshe,
• Syeda J. Khalid,
• Blondelle Matio Kemkuignou,
• Esteban Charria-Girón,
• Paul Eckhardt,
• Birthe Sandargo,
• Kunlapat Nuchthien,
• J. Jennifer Luangsa-ard,
• Till Opatz,
• Hedda Schrey,
• Sherif S. Ebada and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23

• ketocarbonyl carbon at δC 192.9 (C-1') confirming the presence of a hydroxy group at C-3' and to be as depicted in Figure 1. Further key HMBC correlations were recognized including those from an olefinic proton at δH 5.51 (d, J = 9.6 Hz, H-11) to one allylic methyl group at δH 1.77 (d, J = 1.2 Hz, H3-16) and

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

• antitumor activity, triggered by DNA alkylation [6][7][8]. The aminonitrile/hemiaminal at C21 generates an iminium cation while releasing a cyanide or a hydroxy group under physiological conditions. This iminium cation facilitates nucleophilic attack by guanine residues in the minor groove of the GC-rich

• three base pairs, predominantly 5’-GGC-3’ and 5’-GGG-3’ [12][13]. Notably, a bis-phenol type unnatural analog 3, composed of the C5 deoxy A-ring bearing a phenolic hydroxy group at C8, presumably as a HB donor upon interaction with nucleic acids, exhibits superior DNA alkylation capability compared to

• thermodynamically more stable than its 5-exo counterpart 13. Thirdly, the 2,3-diaminobenzofuran would be utilized as a temporary protecting group for both the phenolic hydroxy group and the nitrile moiety. These functional groups are necessary for the aromatic A-ring to interact with DNA and for synthetic

Cu(OTf)₂-catalyzed multicomponent reactions

• Sara Colombo,
• Camilla Loro,
• Egle M. Beccalli,
• Gianluigi Broggini and
• Marta Papis

Beilstein J. Org. Chem. 2025, 21, 122–145, doi:10.3762/bjoc.21.7

• derivative, yielding a 3-alkylidene-substituted oxindole XXXIX that, after coordination with Cu(OTf)2, is able to react with the enolic form of kojic acid to generate the C-alkylated intermediate XL. Subsequent intramolecular nucleophilic attack of the enolic hydroxy group to the copper-activated cyano group

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

• , adding a hydroxy group to the benzene ring of indoles 111 and reacting them with tosyl-protected iminoquinone 109 with the help of CPA C30 led to the shift in regioselectivity providing different axially chiral products 113. All products were obtained with high degree of enantiomeric purity as well as

• significantly high yields. The CPA organocatalyst activates quinones with an acceptor hydrogen bond while indole acts as hydrogen-bond donor. On the other hand, a hydroxy group of hydroxyindole becomes a hydrogen donor and the iminoquinone nitrogen represents an acceptor to the hydrogen from the CPA, resulting

• purities, solid yields and very good diastereomeric ratios. The hydroxy group present in products 156 and 158 could be transformed to provide axially chiral phosphines that could be utilized as chiral ligands in transition-metal-catalyzed reactions. Testing both substrates 156 and 158 for conformational

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• quinuclidine moiety can act as a base activating a nucleophile, secondly the secondary hydroxy group can participate in hydrogen bonding or can behave as a Brønsted acid (Figure 5). Additionally, the quinoline moiety can interact through π–π stacking with the reactants. On the other hand, the (DHQD)2-based

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• -galactose and subsequent perbenzoylation afforded an anomeric mixture (α:β = 87:13) of tribenzoyl-4,6-benzylidene-ᴅ-galactose from which the pure α-anomer 10a was separated (Scheme 6) [20]. Cleavage of the acetal and subsequent regioselective replacement of the hydroxy group OH-6 with an iodide by

Synthesis of fluoroalkenes and fluoroenynes via cross-coupling reactions using novel multihalogenated vinyl ethers

• Yukiko Karuo,
• Keita Hirata,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 2691–2703, doi:10.3762/bjoc.20.226

• 5l) could be introduced into 1a in 76% or 52% yields, respectively (Table 4, entries 10 and 11). Reactions using acetylenes possessing a hydroxy group, amino group and thiophene proceeded well (3m–o) (Table 4, entries 12–14). Hexa-1-yne 5p and cyclopropylacetylene (5q) afforded 3p and 3q

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

• 1,6-anhydro-2,3-dideoxy-2,3-difluoro-β-ᴅ-mannopyranose (5) readily accessible form levoglucosan (1, Scheme 1) [24]. Activation of the C4 hydroxy group as triflate and direct treatment with a nucleophilic halogen furnished intermediates 8–11. The latter compounds proved to be difficult to purify

Efficient one-step synthesis of diarylacetic acids by electrochemical direct carboxylation of diarylmethanol compounds in DMSO

• Hisanori Senboku and
• Mizuki Hayama

Beilstein J. Org. Chem. 2024, 20, 2392–2400, doi:10.3762/bjoc.20.203

• diarylacetic acids from diarylmethanol species and carbon dioxide without transformation of the hydroxy group into appropriate leaving groups, such as halides and esters including carbonates. Keywords: C(sp3)–O bond cleavage; diarylacetic acid; diarylmethanol; electrochemical reduction; fixation of carbon

• , respectively. In the electrocarboxylation of 1f and 1g, having a methyl or methoxy group on both phenyl rings, the yield of 2f and 2g was comparably lower, namely 32% and 21%, respectively, probably due to the electron-donating groups. When diphenylmethanol 1h, having a hydroxy group on the phenyl ring, was

• [13], plausible reaction pathways are proposed as seen in Scheme 6. At the cathode, one-electron reduction of the hydroxy group in diarylmethanol 1 generates H2 and the corresponding alkoxide ion A, which captures carbon dioxide to form carbonate ion B. Although it is currently unclear whether this

Synthesis, electrochemical properties, and antioxidant activity of sterically hindered catechols with 1,3,4-oxadiazole, 1,2,4-triazole, thiazole or pyridine fragments

• Daria A. Burmistrova,
• Andrey Galustyan,
• Nadezhda P. Pomortseva,
• Kristina D. Pashaeva,
• Maxim V. Arsenyev,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2024, 20, 2378–2391, doi:10.3762/bjoc.20.202

• groups (O1–H1···O2: the H1···O2 distance is 1.98(1) Å, the O1···O2 distance is 2.581(3) Å, angle O1–H1–O2 is 117°) and between hydroxy group O2–H2 and nitrogen atom N1 of the pyridine cycle (O2–H2···N1A/B: the H2···N1 distance is 1.75(1)/2.08(1) Å, the O2···N1 distance is 2.560(3)/2.893(3) Å, angle O2–H2

• contacts O1–H1···N3 (the H1···N3 distance is 1.84(1) Å, the O1···N3 distance is 2.73(1) Å, the angle O1–H1–N3 is 168.3°) with the pyridine group of the catechol moiety of the neighbouring pair lead to the formation of chains. As a result of such interaction, the hydroxy group O1–H1 is turned away from the

• oxidation peak of the catechol fragment to the cathode region (Figure 7). This is due to the less acceptor nature of the thiazole ring compared to the more electron-deficient oxadiazole cycle, which contains three heteroatoms. In addition, according to NMR spectral data, one proton of the hydroxy group of

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• synthesis, the deprotected derivatives such as 69 are desired for the synthesis of natural products. Therefore, an easy-to-perform two-step deprotection procedure was developed that is based on methylation of the phenolic hydroxy group with an excess of MeI in acetone at rt (68), followed by oxidative

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

• glycosylation: i) N-glycosylation, where a N-acetylglucosamine (GlcNAc) is linked to the nitrogen atom of an asparagine side chain [28]; ii) O-glycosylation, where a GlcNAc or N-acetylgalactosamine (GalNAc) is linked to the hydroxy group of a serine or threonine residue [29]; iii) C-glycosylation, where a