Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• high selectivity. The present review is centered on the use of cyclodextrins, natural and biocompatible oligosaccharides that form upon microbial fermentation of starch. The method is environmentally safe because it resorts to natural compounds, posing as a promising alternative to the use of cyanides

• such as sodium sulfite. As a disadvantage, the step of gold reduction causes co-precipitation of all other metals that are present in solution, which has raised the need for the use of selective precipitation methods. One of the strategies to address this selectivity precipitation issue is the use of β

A versatile route towards 6-arylpipecolic acids

• Erich Gebel,
• Cornelia Göcke,
• Carolin Gruner and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 1104–1115, doi:10.3762/bjoc.21.88

• kinetically controlled diastereofacial selectivity. The resulting diastereomers are separable by chromatography. 1H NMR was used to assign the configuration of the 2 diastereomers [53][54][55]. Carbon C2 is R-configured, as ᴅ-2-aminoadipic acid (1) was employed as the starting material. The minor diastereomer

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

• -branched (L/B) selectivity of >20:1. The reaction involves the formation of palladium hydride (Pd–H) 270 as the key species followed by alkyne and CO insertion reactions via 271 and 272 (Scheme 68A) [116]. On the one hand, Jia and co-workers (2021) utilized environmentally benign water as the hydrogen

• -Markovnikov selectivity catalyzed by Au(III) in the presence of dimethylaminopyridine N-oxide (DMAPO) as oxidant. The reaction proceeds via Au–allenylidene species 307 (Scheme 73) [124]. Various cinnamic esters and amides with natural product-based alkoxy groups 301–304 and sulfoximines 305 and 306, a

• cinnamamides 13, 77, 99, and 371 in good yields via the active palladium–hydride species 372 (Scheme 81A) [137]. The Z-to-E-selectivity could be effectively tuned by changing the solvent and temperature from CH3CN to DMF and rt to 80 °C, respectively. Similarly, Wang and co-workers (2023) employed Pd to

Harnessing tethered nitreniums for diastereoselective amino-sulfonoxylation of alkenes

• Shyam Sathyamoorthi,
• Appasaheb K. Nirpal,
• Dnyaneshwar A. Gorve and
• Steven P. Kelley

Beilstein J. Org. Chem. 2025, 21, 947–954, doi:10.3762/bjoc.21.78

• , which attacks the pendant olefin to form an aziridinium cation (Scheme 2). A sulfonate counter-anion then opens this aziridinium ring in an exo-selective, SN2 reaction. We were successful in scaling the reaction from 0.3 mmol to 11.5 mmol (38-fold increase) without any erosion in yield or selectivity

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

• literatures focusing on key regulatory factors for product divergent formation, in which controlling chemical selectivity primarily relies on ligands, metal catalysts, solvents, time, temperature, acids/bases, and subtle modifications of substrates. To gain a deeper understanding of the mechanisms underlying

• reaction activity and selectivity differentiation, the review provides a systematic analysis of the mechanisms of critical steps through specific case studies. It is hoped that the controllable/divergent synthesis concept will spark the interest of practitioners and aficionados to delve deeper into the

• control The precise regulation of product selectivity represents a fundamental challenge in transition-metal-catalyzed organic transformations, with significant implications for complex molecule synthesis. In this context, ligand-modulated divergent catalysis has emerged as a paradigm-shifting strategy

Dicarboxylate recognition based on ultracycle hosts through cooperative hydrogen bonding and anion–π interactions

• Wen-Hui Mi,
• Teng-Yu Huang,
• Xu-Dong Wang,
• Yu-Fei Ao,
• Qi-Qiang Wang and
• De-Xian Wang

Beilstein J. Org. Chem. 2025, 21, 884–889, doi:10.3762/bjoc.21.72

• selectivity for heptanedioate (C72−) was attributed to cooperative hydrogen bonding, anion–π interactions, and a size-matching effect, as supported by DFT optimizations. Keywords: anion–π interactions; anion recognition; hydrogen bonding; dicarboxylates; ultracycles; Introduction Macrocycles containing more

• anticipated to exhibit high association efficiency and selectivity for large guests, driven by cooperative effects of their convergent macrocyclic elements. Dicarboxylates are crucial species in biological system and chemistry [20]. Examples such as malonate, succinate, and glutarate play key roles in

• interactions, the host undergoes conformational adjustments: the distance between the two submacrocycles increases, and the glycol chains adopt extended conformations compared to the structure shown in Figure 1. These results suggest that the experimentally observed strong binding capability and selectivity of

Unraveling cooperative interactions between complexed ions in dual-host strategy for cesium salt separation

• Zhihua Liu,
• Ya-Zhi Chen,
• Ji Wang,
• Qingling Nie,
• Wei Zhao and
• Biao Wu

Beilstein J. Org. Chem. 2025, 21, 845–853, doi:10.3762/bjoc.21.68

• and making new receptors, thereby saving considerable time. However, the selectivity of ion separation achieved through the dual-host strategy may not match that of ion-pair receptors, possibly due to less defined interactions between the receptor-complexed anions and cations. Early studies employing

• , the extraction efficiency follows the order of PO43− > CO32− > SO42− > NO3−, consistent with the order of negative charges as well as the anions’ hydration energies (Table 1) [49][50]. This anti-Hofmeister selectivity of phosphate over other studied oxyanions is normally seen in liquid–liquid and

Regioselective formal hydrocyanation of allenes: synthesis of β,γ-unsaturated nitriles with α-all-carbon quaternary centers

• Seeun Lim,
• Teresa Kim and
• Yunmi Lee

Beilstein J. Org. Chem. 2025, 21, 800–806, doi:10.3762/bjoc.21.63

• by the regio- and stereoselective allylation with p-toluenesulfonyl cyanide. The proposed methodology is efficient for accessing acyclic β,γ-unsaturated nitriles with α-all-carbon quaternary centers and achieves yields up to 99% and excellent regio- and E-selectivity. The reaction proceeds under mild

• , we synthesized new and versatile functionalized acyclic nitriles that include all-carbon quaternary centers with high selectivity (Scheme 1c). Compared to previous methodologies, our approach enables the efficient generation of tertiary nitrile products with a broader substrate scope, highlighting

• efficiently constructed α-all-carbon quaternary centers on β,γ-unsaturated nitriles with excellent >98% regioselectivity and >98% (E)-selectivity. 1,1-Disubstituted allenes bearing silyl ether- and benzyl ether-tethered propyl groups were successfully converted into the desired nitriles 3a–c in yields ranging

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• that controls reaction selectivity by adjusting voltage or current [13]. Simple synthetic systems in electrochemical methods are limited to electrodes, cells, electrolytes, and power supplies. Today, in addition to the above, light, metallic, and organic catalysts are also used to increase the

• resistance, and maintain ion balance (e.g., LiClO4, n-Bu4NBF4), and active electrolytes, which participate directly in redox reactions, acting as oxidizing or reducing agents (e.g., H2SO4, Et4NOH). Choosing the proper electrolyte affects reaction efficiency, selectivity, and overall performance. Electrodes

• -phosphorylated indole was obtained with high selectivity when n-Bu4NClO4 was used as the electrolyte. Additionally, under certain conditions that reduced the reaction yield, the C3-phosphorylated product was also observed. Similar to previous heteroaromatic coupling reactions with phosphine oxides [53][54], this

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

• used, although often with limited success. We believe that the electrophilic warheads presented here offer an excellent balance between reactivity and selectivity for labeling of nucleic acids, and therefore, may also stimulate new designs for RNA targeting and RNA drugging. Experimental General

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

• target binding will incur little entropic cost) and high selectivity (since off-target interactions will be minimised) [1]. There are several methods by which the conformations of small molecules can be controlled, but in this review we will focus upon one particular method, which is the installation of

• motif has been exploited in the design of bioactive molecules [22][23] such as the histone deacetylase (HDAC) inhibitors 6 and 7 (Figure 2). The presence of the 1,2-difluoro moiety in 6 leads to greater potency and selectivity for certain HDAC isoforms, attributable to the higher polarity of the

• including protein kinase A (PKA). Fluorination was investigated as a strategy for altering the conformation of the central seven-membered nitrogen heterocycle, and hence possibly improving the selectivity for PKCε. A variety of fluorination patterns were investigated (100–103, Figure 11), which were found

Recent advances in allylation of chiral secondary alkylcopper species

• Minjae Kim,
• Gwanggyun Kim,
• Doyoon Kim,
• Jun Hee Lee and
• Seung Hwan Cho

Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51

• their exploration of phosphoramidite ligands with various organometallic nucleophiles [24][25]. The field was further advanced by the research group of Hoveyda, who made substantial contributions by introducing bidentate N-heterocyclic carbene (NHC)-based chiral ligands, achieving high selectivity with

• into a powerful and versatile tool in asymmetric synthesis, capable of employing a wide array of organometallic reagents that furnish the desired compounds with high efficiency and selectivity. The regioselective asymmetric construction of stereogenic carbon centers from prochiral allylic substrates

• regioselectivity (SN2/SN2' = >99:1). The reaction with 3-methylbut-2-en-1-yl bromide (15) was particularly noteworthy, as it exhibited superior selectivity compared to the corresponding phosphates. The high efficiency of this protocol was demonstrated through the synthesis of various functionalized alkenes with

Photocatalyzed elaboration of antibody-based bioconjugates

• Marine Le Stum,
• Eugénie Romero and
• Gary A. Molander

Beilstein J. Org. Chem. 2025, 21, 616–629, doi:10.3762/bjoc.21.49

• conjugation methods often face challenges related to site-selectivity and heterogeneous product mixtures, highlighting the need to develop new, innovative chemical strategies. Photoredox chemistry emerges as a powerful tool in this context, enabling precise, mild, and selective modifications of peptides and

• ], therapeutic index, selectivity, and overall success of the ADC. The linker will ideally be stable in plasma for an extended period before the intended target can be reached, and after internalization, linkers play a key role in the drug-releasing event. Importantly, some exceptions exist. For example, in

• functionalized nature of polypeptides/proteins demands exquisite selectivity to target specific sites on the macromolecule of interest. In addition to the requisite features of the chemical methods outlined above, there are key requirements for synthetic methods used in ADCs, which include high site-selectivity

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

• preserved, with chemical modifications focusing on massarilactone H rather than massarilactone D. These modifications should target other regions of the molecule, such as the number and position of acyl substituents. Future research should investigate the stability and selectivity of these compounds, as

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

• (75 °C) are needed. The selectivity of the reaction shown in Scheme 27 could be explained according to the proposed mechanism (Scheme 28a). The first step is the generation of the trialkyl(chloromethyl)ammonium chloride species 36 from the amine compound and CH2Cl2. Then, 36 decomposes by a cleavage

• product 35b was obtained, confirming that the dihaloalkane compound is the source of the methylene unit (Scheme 28c). Depending on the stability of the leaving carbocation, the selectivity of the R–N cleavage follows the decreasing order for the R groups: H, t-Bu, allyl, benzyl > methyl > primary

• amine with two methyl groups and a benzyl or allyl group, the cleavage of the N–CH2Ph and N–allyl bond takes place more selective (by 85% and 67%, respectively), instead of the cleavage of an N–Me bond. This explains the high selectivity observed for some examples in Scheme 27. Finally, this methodology

Binding of tryptophan and tryptophan-containing peptides in water by a glucose naphtho crown ether

• Gianpaolo Gallo and
• Bartosz Lewandowski

Beilstein J. Org. Chem. 2025, 21, 541–546, doi:10.3762/bjoc.21.42

• chain is the second highest among the tested amino acids and approximately 30% lower than towards Trp (entry 5, Table 1). Thus, the glucose-derived naphtho crown ether 1 displays selectivity towards the binding of tryptophan over other amino acids in water. Additionally, 1 displays a slight preference

Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• higher selectivity with milder reaction temperatures. The weaker C(sp2)–Br bond is easier to cleave than a C(sp2)–H bond, resulting in a higher likelihood of radical substitution at those positions. To the best of our knowledge, there are no previous examples of perfluorobenzyl substitution of any PAH(Br

• , and poor selectivity. The latter approach was shown to be more promising due to a faster rate, use of an inexpensive, low-boiling solvent, and easier work-up. This method will continue to be investigated in our laboratory. The emission spectrum of 9,10-ANTH(BnF)2 revealed its deeper blue fluorescence

Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction

• James Guevara-Pulido,
• Fernando González-Pérez,
• José M. Andrés and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34

• promotes the Michael reaction, leading to the formation of the enantiomer (3R,4S) and consequently returning to the racemate. Then, we decided to investigate how concentration affects the rate and selectivity of the reaction at room temperature (Table 4). The retro-Michael reaction mainly occurs at a

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• adhesion on the vial walls. Thus, the reactor was operated at 17.7 Hz for 20 h and the dimerization to 9.2 occurred in 96% 1H NMR yield with a 6:94 anti/syn selectivity. A different selectivity was observed when crystals were first ground, and then irradiated under argon without applying forces (65% yield

• , 70:30 anti/syn). This indicates a unique divergent photomechanochemical reaction pathway with respect to the simple irradiation in solid state. Remarkably, no selectivity was observed in solution state (DMSO as solvent), while a completely reversed selectivity (99%, anti/syn 91:9) was obtained when

• insoluble reagents and/or photocatalysts. Additionally, as discussed, the use of impact forces can lead to unique selectivity profiles compared to solution-based methods, further enhancing its utility. Thirdly, dissolved oxygen must be often meticulously removed in solution-based methods via tedious

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• -accelerations (1019) [1], tolerance of contaminants, and selectivity associated with the power of enzymes. It is for this reason that I have sought to introduce supramolecular approaches into my organocatalysis [2]. From thermodynamics, there are two components to catalysis: organization (entropic) and

• hydrophobic [160] products have been popular, including hydrolyses, ring openings, and rearrangements [22]. These reaction classes have been discussed [24][25][140]. Cavity-directed changes in ion-localization [161][162] and pKa are effective [37][107][163][164], and size-selectivity [36][165][166][167] and

• conspicuously rare [340]. One reason is the requirement for structural directional bonding in self-assembly strategies, which limits available bonding vectors for precise internally directed functionality [340]. Indeed, a recent perspective [21] identified two approaches to site-selectivity in supramolecular

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

• phenol 16 and acceptor 19 to the anomeric position, thereby, making it suitable for glycoconjugate formation. They also reported the glycosylations leading to disaccharide 20 formation in solvent free conditions in significant 1,2-trans selectivity. This study holds the potential in improving the various

• acetoxonium ion, facilitating the 1,2-trans glycoside formation in high selectivity. The special feature of this protecting group lies in its orthogonal deprotection in the presence of acetyl or benzoyl protecting groups. The chloroacetyl group was found to be particularly labile on the application of

• ] or hydrazine dithiocarbonate [116][117]. Owing to its versatile selectivity, it has been widely used in oligosaccharide synthesis [118][119][120][121][122] to implement the neighbouring group participation protocol, thereby producing 1,2-trans glycosides in high yield and selectivity without

Synthesis, characterization, antimicrobial, cytotoxic and carbonic anhydrase inhibition activities of multifunctional pyrazolo-1,2-benzothiazine acetamides

• Ayesha Saeed,
• Shahana Ehsan,
• Muhammad Zia-ur-Rehman,
• Erin M. Marshall,
• Sandra Loesgen,
• Abdus Saleem,
• Simone Giovannuzzi and
• Claudiu T. Supuran

Beilstein J. Org. Chem. 2025, 21, 348–357, doi:10.3762/bjoc.21.25

• evolves [3]. Complex chemical scaffolds with more than one protein-engaging functionality in a single molecule are advantageous for selectivity. This concept of synergistic compounds and complex chemical interactions helps to boost biological activity and prolongs the emergence of resistance in pathogens

• for four types of human CA isoforms: CA I, CA II, CA IX, and XII. The first two are cytosolic forms while the other two are transmembrane forms. Reason for the selection of these CA isoforms was to develop a comparative relationship for inhibition selectivity between CAs (IX, XII) attributed to tumour

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

• become a powerful approach for achieving sustainable chemical transformations, combining high efficiency with energy-saving, mild conditions. By harnessing the deeper penetration and selectivity of red and near-infrared light, this method minimizes the side reactions typical of higher-energy sources

• for red-light-mediated reactions. In particular, the versatility of these catalysts offers new avenues for facilitating red-light-driven chemical transformations with greater selectivity and efficiency. Recently, the squaraine family, a class of organic compounds characterized by a four-membered

Molecular diversity of the reactions of MBH carbonates of isatins and various nucleophiles

• Zi-Ying Xiao,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2025, 21, 286–295, doi:10.3762/bjoc.21.21

• biologically important 3-substituted and spirooxindole derivatives [5][6][7]. The unique molecular architecture and remarkable pharmacological activities have made spirooxindole one of the hottest synthetic targets with fruitful chemical and steric selectivity [8][9][10][11][12][13][14][15]. In recent years

• triene derivatives can be prepared under relative mild reaction conditions with good steric selectivity. The single crystal structures of compounds 7a and 8a were successfully determined by X-ray diffraction method (Figure 4 and Figure 5). From the crystal structures, it can be found that the compound 7a

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

• difluoromethylene (PhCF2) group, stand out as particularly valuable in drug design. The CF2H group can serve as a lipophilic isostere for hydroxy (OH), amino (NH2), and thiol (SH) groups, thereby enhancing the efficacy and selectivity of therapeutic agents [4][5][6]. Similarly, the PhCF2 group offers unique