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

• pyridine sulfur trioxide (1.1838 g, 7.437 mmol) was dissolved in dry pyridine (57 mL). The resulting mixture was heated at 90 °C under N2 for 18 h and then cooled to rt. The precipitate was collected by first decanting some of the solvent and then the remaining mixture was transferred to a 50 mL centrifuge

• %; c) dry pyridine, pyridine sulfur trioxide complex (20 equiv), 90 °C, 18 h, 68%. Thermodynamic parameters (Ka (M−1), ∆H° (kcal/mol) determined for the C1·guest, M1·guest and M0·guest complexes by ITC. Conditions: 298.0 K, phosphate-buffered saline, pH 7.4. Supporting Information The X-ray crystal

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

• scaffolds – alkanes – then we will progress to ethers, alcohols, sugars, amines (and their derivatives), carbonyl compounds, peptides, and finally sulfur-containing compounds. By arranging the material in this way, we hope that newcomers to the field might be able to readily envisage ways to apply these

Formaldehyde surrogates in multicomponent reactions

• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

• only when aliphatic disulfides are used because of the higher Lewis basicity of the alkylated sulfur atom, which poisons the copper catalyst. When the reaction was carried out with paraformaldehyde and other solvents (such as DMF, 1,4- dioxane, toluene, and DCE) the yield was very low (between 0–34

• %), but when DMSO is used as solvent and reagent, the yield was greatly improved. The proposed mechanism involves the activation of the disulfide component by CuBr2 as the Lewis acid (Scheme 14). The copper(II) center coordinates the sulfur atom of the disulfide allowing for the electrophilic addition to

• " of the methyl sulfur group in intermediate 22 for the cleavage of the C–S bond. In the end, the C–C bond is formed between intermediate 23 and the enol form from the methyl ketone 18. Sodium carbonate is added to prevent too much acidification of the reaction medium and to deprotonate the NH that

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• such as zinc as proposed by Furuyama et al. [35]. In this way, the authors have developed a series of phthalocyanin zinc complexes with electron-rich sulfur atoms at the non-peripheral positions of the phthalocyanin ring. This functionalization allows the destabilization of the highest occupied

Synthesis of disulfides and 3-sulfenylchromones from sodium sulfinates catalyzed by TBAI

• Zhenlei Zhang,
• Ying Wang,
• Xingxing Pan,
• Manqi Zhang,
• Wei Zhao,
• Meng Li and
• Hao Zhang

Beilstein J. Org. Chem. 2025, 21, 253–261, doi:10.3762/bjoc.21.17

• this study, we report the synthesis of corresponding disulfides under the catalysis of TBAI (tetrabutylammonium iodide) using sodium alkyl or aromatic sulfinates as sulfur sources. Sodium sulfinates are more stable than sulfonyl hydrazides, sulfonyl chlorides, and thiols, and there is no need to add

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

• Seungmin Lee,
• Minsuk Kim,
• Hyewon Han and
• Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

• modular copper-catalyzed method for the synthesis of N-acyl sulfenamides 20 from dioxazolones 18 using thiols 19 via nitrogen–sulfur bond formation (Scheme 7) [92]. Secondary and tertiary thiols were highly effective in affording the corresponding N-acyl sulfenamides 20a–d. Moreover, the bioactive motifs

• slightly diminished reactivity (23c and 23d). In addition, poor reactivity was observed with dioxazolones bearing thiophene, implying that the undesired coordination of sulfur to copper reduces the reactivity (23e). Despite the reduced reactivity, excellent enantioselectivity was still maintained. Moreover

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

• oxygen, nitrogen, or sulfur, and a positively charged hydrogen atom, which interacts with a lone pair on the acceptor. Apart from these common heteroatom-containing hydrogen bond donors, certain carbon–hydrogen moieties can also act in this way, although in a substantially weaker capacity [5][6][7][8][9

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

• and sulfur dioxide afforded vinyl sulfones with excellent regio- and stereoselectivity (Scheme 9) [22]. The authors used DABCO(SO2)2 to generate sulfur dioxide, and visible light irradiation and the mandatory presence of a photocatalyst for this transformation suggested a radical mechanism. The

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

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

• oxidative chlorination with aqueous chlorine [30], or treatment with toxic sulfur dioxide. Thus, we envisaged to further investigate BBX reactivity to address the S–N-bond formation, as an alternative method towards sulfur-containing compounds [22]. Results and Discussion We initiated our study by extending

• Supporting Information File 1). We propose a mechanism pathway involving the retro-Michael addition of 4, releasing acrylate and hydrogen (H2). The charge of the sulfenate anion may shift between sulfur and oxygen atoms, possibly leading to an O-Michael addition (pathway B) [35]. The intermediate of these

• reactions could undergo disproportionation, a radical process resulting in the homolytic cleavage of the S–O bond [35]. The formation of disulfide 7 isolated in the experiments can be explained by combining two radical sulfur species. Furthermore, the oxygen species generated in this radical reaction may

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

• phenomenon is quite sensitive to changes in the fluorinated sulfur reagent scaffold (see Supporting Information File 1 for more details). This second instance of controlled oligomerization of 1 using CF3SF4Cl was also studied at the PWPB95-D4/def2-QZVPP//PCM(Et2O)-ωB97X-D/def2-TZVP level of theory (Figure 3

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 intramolecular HVI-mediated halocyclisation of alkenes using carbon, oxygen, nitrogen or sulfur nucleophiles. Herein, we describe the examples reported in the literature, which are organised by the different halogens involved and the internal nucleophiles. Keywords: cyclisation; halogenation

• excellent yields. The structures were also assigned by X-ray crystallography. Sulfur nucleophiles In 2015, Li and co-workers reported the synthesis of 5-bromomethyl-2-phenylthiazoline (79, Scheme 41) [48]. Sulfur was used as the internal nucleophile instead of nitrogen, as previously reported by the authors

• -phenylthiazoline (87) in 2015 in addition to the synthesis of 5-bromomethtyl-2-thiazoline (Scheme 41), using sulfur as an internal nucleophile (Scheme 48) [48]. Using PhI(OAc)2 with TMSI, N-allylbenzothioamide (78) was cyclised to form 87 in excellent yield. Conclusion The HVI-mediated halocyclization of alkenes

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

• and diphenyliodonium triflates 16 using an optimal sulfur dioxide surrogate, 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) (DABSO, Scheme 13). The Z-isomer of the desired products was obtained by optimizing the reaction conditions. The involvement of radicals in both the arylation and aryl

• strong C–N bond. The ring opening incorporated nitrogen, oxygen, sulfur, carbon, and halogen-containing nucleophiles and their derivatives. The substrate scope was examined with numerous aryl groups on iodonium salts 40 and the progress of aryl migration happens fruitfully by considering electronic

• compound 57 was obtained by treating hypervalent iodine salt 56 with NaNO2 in the presence of DBU as the base (Scheme 23). This salt was also studied for the arylation of sulfur, oxygen, and carbon giving good yields of corresponding products [74]. O-Arylation Arylation of oxygen is a significant chemical

C–H Trifluoromethylthiolation of aldehyde hydrazones

• Victor Levet,
• Balu Ramesh,
• Congyang Wang and
• Tatiana Besset

Beilstein J. Org. Chem. 2024, 20, 2883–2890, doi:10.3762/bjoc.20.242

• corresponding sulfur-containing heteroarenes, only a few methods have been developed (Scheme 1). In 1988, Lee and co-workers reported the synthesis of SR-containing hydrazones in a two-step process (chlorination [65] then reaction with thiols) from readily available aldehyde-derived hydrazones [66]. Wang et al

• cyclization of aryl hydrazones with aryl isothiocyanates promoted by elemental sulfur [70]. In the course of their studies for the thiocyanation of ketene dithioacetals, Yang, Wang and co-workers developed an electrochemical oxidization-based synthetic strategy to circumvent the need for external oxidants. In

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

• in collaboration with Jürgen Eberle (Charité Berlin) [27]. In fact, melanoma is a dangerous type of skin cancer which can be life threatening. Excellent IC50 values were observed for β-33d and other thioindirubin-N-glycosides. In contrast, indirubin-N-rhamnoside β-17a, lacking the sulfur atom, proved

• represents a π-donor. Although nitrogen, as present in indirubins 17, is an even better donor than oxygen, the stability of the intramolecular hydrogen bond overrules this effect. Sulfur and selenium are very weak π-donors. It was not studied so far whether the E/Z ratio of indirubin derivatives can be

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• at low concentrations through enzymatic conversions of sulfur-containing substrates, and it exerts diverse biological roles across nearly all organ systems. Within the central nervous system, H2S functions as a neuromodulator, influencing pain perception and neuronal potentiation [2]. H2S is

• removal of Na2S followed by the precipitation and re-addition of Cu2+ ions (Figure 5). Comprehensive selectivity studies were conducted with various anions/sulfur compounds (SO42−, SO32−, S2O52−, S2O42−, S2O32−, ClO−, OAc−, NO3−, I−, HCO3−, CO32−, Cl−, lipoic acid, and glutathione, as depicted in Figure 6

• ). It was interesting to note that neither of the sulfur-containing compounds caused a remarkable increase in luminescence, especially lipoic acid and glutathione which contain an –S–S (pKa = 4.7) and –SH (pKa = 9.65) group respectively similar to HS−(aq) (pKa = 6.9). This demonstrates that the sensors

Mechanochemical difluoromethylations of ketones

• Jinbo Ke,
• Pit van Bonn and
• Carsten Bolm

Beilstein J. Org. Chem. 2024, 20, 2799–2805, doi:10.3762/bjoc.20.235

• -depleting sulfur dioxide as side products [46][47]. Later, Ichikawa and co-workers established the release of difluorocarbene from TFDA with catalytic amounts of an N-heterocyclic carbene and a base (Scheme 1C) [29][48][49]. In these reactions, difluoromethyl enol ethers were obtained, which were

C–C Coupling in sterically demanding porphyrin environments

• Liam Cribbin,
• Brendan Twamley,
• Nicolae Buga,
• John E. O’ Brien,
• Raphael Bühler,
• Roland A. Fischer and
• Mathias O. Senge

Beilstein J. Org. Chem. 2024, 20, 2784–2798, doi:10.3762/bjoc.20.234

• porphyrins, achieved porphyrins 32 and 33 in a 47% and 56% yield, respectively (Table 1, entries 13 and 21), using Cs2CO3 as the base. Electron-withdrawing sulfur-containing heterocyclic substrates 21 and 23 do not readily undergo protodeboronation even at high pH [44][47] making the yields of porphyrins 31

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• . Subsequently, the generated intermediate 29 is oxidized at the anode, then attacked by the acid to obtain the final product (Scheme 10). C–H bond sulfur functionalization: The direct formation of the CS bond is an attractive way to prepare aryl sulfides. From this perspective, Wu and coworkers developed a

• further emphasized its utility. Mechanistic studies have demonstrated that the key to this selective chemical conversion lies in the dual oxidation process at the anode. The authors suggest that anodic oxidation of the sulfide generates a sulfur radical cation intermediate, which reacts with water at the

• aliphatic alcohols, benzyl alcohols are also suitable reagents. Numerous LSF examples and upscaling were demonstrated. The mechanism involves two anodic oxidations: first, the thiophenol is oxidized at the anode, forming a sulfur radical that attacks the isocyanide. The newly formed carbon radical is then

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

• corresponding thiols. The starting reagents such as substituted 1,3,4-oxadiazole-2-thiols and 4H-triazole-3-thiols are characterized by thiol–thione tautomerism, therefore their reactions with 3,5-di-tert-butyl-6-methoxymethylcatechol can proceed at the sulfur or nitrogen atom. In the case of mercapto

• established for these compounds. The electrochemical behavior of the studied compounds is influenced by several factors: the nature of the heterocycle and its substituents, the presence of a sulfur atom in the catechol ring, or a thione group in the heterocyclic core. The radical scavenging activity and

• heteroatoms (nitrogen, sulfur, selenium, tellurium, etc.) as well as redox-active functional groups allows one to vary significantly the biological activity of such compounds. Heterocyclic molecular blocks are widely used in medicinal chemistry [12]. Thiazole, oxadiazole, triazole, imidazole, and other

Hydrogen-bond activation enables aziridination of unactivated olefins with simple iminoiodinanes

• Phong Thai,
• Lauv Patel,
• Diyasha Manna and
• David C. Powers

Beilstein J. Org. Chem. 2024, 20, 2305–2312, doi:10.3762/bjoc.20.197

• center [26][27]. Despite the prevalence of acid-activation in promoting carbon [28], oxygen [29][30], sulfur [31], chlorine [32], and fluorine [33] transfer reactions of hypervalent iodine compounds, these strategies have not been applied to activation of iminoiodinanes for nitrene transfer chemistry. We

Efficacy of radical reactions of isocyanides with heteroatom radicals in organic synthesis

• Akiya Ogawa and
• Yuki Yamamoto

Beilstein J. Org. Chem. 2024, 20, 2114–2128, doi:10.3762/bjoc.20.182

• photoredox system. Phenanthridine synthesis induced by phosphorus-centered radicals. Phenanthridine synthesis induced by sulfur-centered radicals. Phenanthridine synthesis induced by boron-centered radicals. Phenanthridine synthesis by oxidative cyclization of 2-aminobiaryls. Acknowledgements The authors

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• the aromatic product 85, thereby regenerating the catalyst (Scheme 16) [61]. Given its abundance, stability, and low price, elemental sufur (S8) is an ideal source of sulfur atom to produce thiacycles [62]. In 2019, H.-T. Tang utilized this reagent in combination with (hetero)aromatic ketone-derived

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• underrepresented in the peer-reviewed literature in comparison to phenyl groups or their six-membered counterparts (e.g., pyridines, pyrimidines) [42]. Furthermore, the increasing importance of small heteroaromatic rings containing nitrogen, sulfur and/or oxygen in medicinal chemistry is well depicted by the list

2-Heteroarylethylamines in medicinal chemistry: a review of 2-phenethylamine satellite chemical space

• Carlos Nieto,
• Alejandro Manchado,
• Ángel García-González,
• David Díez and
• Narciso M. Garrido

Beilstein J. Org. Chem. 2024, 20, 1880–1893, doi:10.3762/bjoc.20.163

• envisaged by Heffernan et al. [40], including human TAAR1 agonist activity and structural evaluation via homology model development followed by molecular docking and molecular dynamics studies (Scheme 6). Structural features like sulfur location and ring opening of the aminoethyl section were investigated

• data showed good agreement, suggesting two different binding topologies. Patil et al. [63] synthesized compound 88, an oxidized version at position 1 of the propyl chain, and observed H-type agonism in guinea pig ileum assays (Scheme 11). The sulfur-containing histidine compounds ovothiol (90) and