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

• strain-driven examples, Vollhardt’s studies on phenylenes show that enhanced reactivity can also derive from a combination of structural and electronic effects. Fusing cyclobutadiene motifs to benzene perturbs its π-system by introducing local antiaromatic character that, together with ring strain

A mild and atom-efficient four-component cascade strategy for the construction of biologically relevant 4-hydroxyquinolin-2(1H)-one derivatives

• Dmitrii A. Grishin,
• Kseniia I. Sharkovskaia,
• Ilya G. Kolmakov,
• Daria A. Ipatova,
• Rostislav A. Petrov,
• Nikolai D. Dagaev,
• Dmitry A. Skvortsov,
• Maria G. Khrenova,
• Valeriy V. Andreychev,
• Sergei A. Evteev,
• Yan A. Ivanenkov,
• Roman L. Antipin,
• Olga А. Dontsova and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2026, 22, 244–256, doi:10.3762/bjoc.22.18

• activity [33]. Halogen substituents in this position have been shown to modulate antibacterial, antiviral, and antiproliferative activities, likely through electronic effects and improved target binding. The C3 position was functionalized with a propanoic acid moiety, explored in both its open-chain (acid

• , is likely due to the electronic effects within pyranoquinoline. As an enol ester conjugated with an amide and an aromatic ring, electron-withdrawing groups decrease electron density on the enol OH, while aliphatic substituents (methyl, ethyl) increase electron density on the alcohol oxygen. This

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

• excellent yields (77–92%). Notably, ortho-substituted sulfenamides gave consistently high yields (3l–o, 87–92%), indicating excellent tolerance toward steric hindrance. These results suggest that the reaction is largely insensitive to both steric and electronic effects, underscoring its broad functional

Pathway economy in cyclization of 1,n-enynes

• Hezhen Han,
• Wenjie Mao,
• Bin Lin,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173

• assembled the pentacyclic spiroindole framework 61 (Scheme 13, path b). The controllability of this cyclization process arose from the steric and electronic effects of the aryl group, where the π–π interactions and rigid structure of the aryl group facilitated the stabilization of the five-membered spiro

• . In contrast, when the alkyne was substituted with a phenyl group, the reaction shifted toward a 6-endo-dig cyclization pathway due to steric and electronic effects (Scheme 14, path b). When HEH was employed as the nucleophile, a spiro[indoline-3,3'-piperidine] framework 66 was formed. When indole

• modulating reaction parameters – including solvent polarity, catalyst architecture, ligand electronic effects, and substrate strain effects – chemists can achieve unprecedented control over reaction pathways. This approach enables divergent access to complex molecular architectures from a unified substrate

Chiral phosphoric acid-catalyzed asymmetric synthesis of helically chiral, planarly chiral and inherently chiral molecules

• Wei Liu and
• Xiaoyu Yang

Beilstein J. Org. Chem. 2025, 21, 1864–1889, doi:10.3762/bjoc.21.145

• framework of the diol precursors, predominantly axially chiral structures such as BINOL, H8-BINOL, SPINOL and VAPOL scaffolds, which are widely used in the development of CPA catalysts. Furthermore, the ortho-aryl substitutions of the CPA catalyst can efficiently modulate the stereochemical and electronic

• effects of the CPAs, which establish a chiral microenvironment within the chiral scaffold that governs the stereoselectivity of asymmetric reactions. Chiral molecules, characterized as three-dimensional structures that are nonsuperimposable with their mirror image, have significant applications in

Synthesis of chiral cyclohexane-linked bisimidazolines

• Changmeng Xi,
• Qingshan Sun and
• Jiaxi Xu

Beilstein J. Org. Chem. 2025, 21, 1786–1790, doi:10.3762/bjoc.21.140

• vicinal amino alcohols as starting materials in their synthesis. However, it is difficult to tune the electronic effects of cHBOX ligands. Chiral cyclohexane-1,2-linked bisimidazolines possess similar structural features as cHBOX ligands and their electronic effect can be tuned by the introduction of

Approaches to stereoselective 1,1'-glycosylation

• Daniele Zucchetta and
• Alla Zamyatina

Beilstein J. Org. Chem. 2025, 21, 1700–1718, doi:10.3762/bjoc.21.133

• -configured lactols, rendering it the most appropriate choice for 2N-protection in GlcN-derived lactol acceptors. The electronic effects of remote protecting groups in the 2-N3-protected GlcN lactols were deliberately tuned to shift the anomeric ratio in favor of the β-anomer, although the inherent anomeric

3-Aryl-2H-azirines as annulation reagents in the Ni(II)-catalyzed synthesis of 1H-benzo[4,5]thieno[3,2-b]pyrroles

• Julia I. Pavlenko,
• Pavel A. Sakharov,
• Anastasiya V. Agafonova,
• Derenik A. Isadzhanyan,
• Alexander F. Khlebnikov and
• Mikhail S. Novikov

Beilstein J. Org. Chem. 2025, 21, 1595–1602, doi:10.3762/bjoc.21.123

• 3-aryl-2H-azirines with different substitution patterns of the aryl group (Scheme 2). As the presented data show, the reaction is insensitive to the electronic effects of substituents in the aryl group and, in the majority of cases, gives very high yields of annulation products. The introduction of

pH-Controlled isomerization kinetics of ortho-disubstituted benzamidines: E/Z isomerism and axial chirality

• Ryota Kimura,
• Satoshi Ichikawa and
• Akira Katsuyama

Beilstein J. Org. Chem. 2025, 21, 1568–1576, doi:10.3762/bjoc.21.120

• isomerization rate constant and pH. The result indicates that C–N rotation from the molecular form of amidine was dominant in the observed isomerization. a) Correlation between isomerization rate constant and electronic effects of the substituents. b) Possible protonated states of compound 7. Analysis of the

Photoredox-catalyzed arylation of isonitriles by diaryliodonium salts towards benzamides

• Nadezhda M. Metalnikova,
• Nikita S. Antonkin,
• Tuan K. Nguyen,
• Natalia S. Soldatova,
• Alexander V. Nyuchev,
• Mikhail A. Kinzhalov and
• Pavel S. Postnikov

Beilstein J. Org. Chem. 2025, 21, 1480–1488, doi:10.3762/bjoc.21.110

• reaction yields allowed us to establish the dependency from the electronic effects of substituents in the diaryliodonium salts. Diaryliodonium salts containing electron-deficient aryls afforded products 2 in higher yields compared to those bearing electron-donating groups (EDG). Specifically, the reaction

• , which provided the best yields in the scope. Moreover, the strong correlation of the yield with the electronic effects in aryl rings was clearly shown in the experiment with iodonium salt 1q (Scheme 3). We believe that the reason for the predominant transfer of the electron-poor ligands under the given

Advances in nitrogen-containing helicenes: synthesis, chiroptical properties, and optoelectronic applications

• Meng Qiu,
• Jing Du,
• Nai-Te Yao,
• Xin-Yue Wang and
• Han-Yuan Gong

Beilstein J. Org. Chem. 2025, 21, 1422–1453, doi:10.3762/bjoc.21.106

• , indicating a strong dependence of photophysical behavior on boryl-substituent identity. Compared to their parent azahelicenes, these compounds displayed significantly larger Stokes shifts, highlighting the pronounced electronic effects of boryl incorporation. Notably, when a CF3 group was introduced as a

Recent advances in amidyl radical-mediated photocatalytic direct intermolecular hydrogen atom transfer

• Hao-Sen Wang,
• Lin Li,
• Xin Chen,
• Jian-Li Wu,
• Kai Sun,
• Xiao-Lan Chen,
• Ling-Bo Qu and
• Bing Yu

Beilstein J. Org. Chem. 2025, 21, 1306–1323, doi:10.3762/bjoc.21.100

• /mol (Figure 2a) [28][29][30]. Almost 5 kcal/mol difference between two species could spontaneously undergo a HAT process. That also justifies the selectivity and efficiency of amidyl radical serving as HAT reagent. 2) Recent research indicated a critical correlation between electronic effects and

• positive and negative charges of two species can be stabilized by the electronic effects, these species are considered to be polarity matched during the HAT process. Conversely, when there is a polarity mismatch, the HAT process is likely to be impeded (Figure 2a). C–H bonds predominantly prefer to be

• modifications of amidyl radicals aimed at optimizing their polarity via electronic effects, which may enhance their effectiveness in hydrogen abstraction from electron-deficient substrates. Additionally, strategies to optimize steric effects could improve their regioselectivity in hydrogen abstraction from

Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

• Jiangfei Chen,
• Yi-Lin Qu,
• Ming Yuan,
• Xiang-Mei Wu,
• Heng-Pei Jiang,
• Ying Fu and
• Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

• –c) and electron-withdrawing (e.g., fluorine, chlorine, ester groups) (78d–f) substituents on bromodifluoroacetamides were well tolerated, yielding high reaction efficiency. Interestingly, the reaction was less sensitive to electronic effects on the aromatic ring, as yields remained high regardless

On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

• Daniel Straub,
• Markus Gross,
• Mona E. Arnold,
• Julia Zolg and
• Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

• electronic effects will cause the Cz-unit to twist out of conjugation almost completely with the TTM radical core plane, leading to marginal orbital overlap between the D0 and D1 states. The reason for this increase in fluorescence lifetime τ is not completely understood; however, if the emission involves a

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

• preferentially occupied the palladium coordination site. Sequential insertion of CO and aryne, followed by reductive elimination, culminated in acridone formation. This ligand-dependent mechanistic dichotomy underscores the critical interplay between aryne availability, steric modulation, and electronic effects

• influence of steric and electronic effects during the hydrometallation process, simultaneously achieving the synthesis of chiral α-quaternary carbon amino acid derivatives 26 and α-chiral β-amino acid derivatives 27. Using a copper catalyst, the chiral α-quaternary carbon amino acid derivatives 26 were

Substituent effects in N-acetylated phenylazopyrazole photoswitches

• Radek Tovtik,
• Dennis Marzin,
• Pia Weigel,
• Stefano Crespi and
• Nadja A. Simeth

Beilstein J. Org. Chem. 2025, 21, 830–838, doi:10.3762/bjoc.21.66

• medicine. Despite their potential, their structural diversity is still limited and a larger pool of substitution patterns remains to be systematically investigated. This is paramount as electronic effects play a crucial role in the behavior of photoswitches and a deeper understanding enables their

• straightforward development for specific applications. In this work, we synthesized novel N-acylpyrazole-based photoswitches and conducted a comparative study with 33 phenylazopyrazoles, comparing their photoswitching properties and the impact of electronic effects. Using UV–vis and NMR spectroscopy, we

• investigated in detail and allowed to correlate thermal relaxation rates and steric or electronic effects as well as mechanistic peculiarities, which has been in the spotlight recently for different classes of azobenzenes [34]. Despite these studies, the variety of substitution patterns in PAPs is limited

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

• meta or ortho positions, which may be due to steric and electronic effects. The reaction proceeded via a radical process by forming Ph2P(O)H (Scheme 16). The reaction failed to give the corresponding product when using TEMPO in the reaction mixture. Zhang and co-workers [61] reported an electrochemical

Asymmetric synthesis of β-amino cyanoesters with contiguous tetrasubstituted carbon centers by halogen-bonding catalysis with chiral halonium salt

• Yasushi Yoshida,
• Maho Aono,
• Takashi Mino and
• Masami Sakamoto

Beilstein J. Org. Chem. 2025, 21, 547–555, doi:10.3762/bjoc.21.43

• formed 17g in good yield and diastereoselectivity with decreased enantioselectivity, likely due to electronic effects. 6-Bromo- and 7-chloro-substituted substrates also provided 17h and 17i in good yields with moderate to good stereoselectivities. Next, Cbz-protected imine 7j was employed in the present

Vinylogous functionalization of 4-alkylidene-5-aminopyrazoles with methyl trifluoropyruvates

• Judit Hostalet-Romero,
• Laura Carceller-Ferrer,
• Gonzalo Blay,
• Amparo Sanz-Marco,
• José R. Pedro and
• Carlos Vila

Beilstein J. Org. Chem. 2025, 21, 533–540, doi:10.3762/bjoc.21.41

• diastereoselectivity (up to 7:1). Keywords: alcohols; diastereoselectivity; nitrogen heterocycles; pyrazoles; vinylogous reaction; Introduction Vinylogy refers to the transmission of electronic effects through a conjugated π-system, enabling the extension of a functional group's nucleophilic or electrophilic

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

Phenylseleno trifluoromethoxylation of alkenes

• Clément Delobel,
• Armen Panossian,
• Gilles Hanquet,
• Frédéric R. Leroux,
• Fabien Toulgoat and
• Thierry Billard

Beilstein J. Org. Chem. 2024, 20, 2434–2441, doi:10.3762/bjoc.20.207

• ], electronic effects [17][18], and conformation [19][20][21]. Some trifluoromethoxylated molecules can be used as drugs in the treatment of various pathologies (Figure 1) [22][23][24][25][26][27][28][29]. On the other hand, despite its toxicity at higher doses, selenium is also an essential trace element in

Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis

• Stefan P. Schmid,
• Leon Schlosser,
• Frank Glorius and
• Kjell Jorner

Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196

• effects, the representation of electronic effects has also been further developed. Milo et al. [58] introduced the intensity and frequency of manually selected molecular vibrations as descriptors (Figure 5). For the selection of relevant vibrations, a mechanistic proposal is required a priori, commonly

Selective hydrolysis of α-oxo ketene N,S-acetals in water: switchable aqueous synthesis of β-keto thioesters and β-keto amides

• Haifeng Yu,
• Wanting Zhang,
• Xuejing Cui,
• Zida Liu,
• Xifu Zhang and
• Xiaobo Zhao

Beilstein J. Org. Chem. 2024, 20, 2225–2233, doi:10.3762/bjoc.20.190

• -en-1-ones 1a–l were smoothly hydrolyzed to produce a series of S-ethyl 3-oxo-3-arylpropanethioates 2a–l in excellent yield, wherein the electronic effects of electron-donating and electron-withdrawing groups on the aromatic ring adjacent to the carbonyl group did not impact the formation of the

• well as electron-withdrawing substituents on the two phenyl rings in compounds 1, such as methyl, methoxy, halogen atoms (F, Cl, Br, I), CF3 and SO2CH3, were well tolerated, and their electronic effects insignificantly impacted the formation of 3. Similarly, N-benzyl-3-oxo-3-phenylpropanamide (3w

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

• Zsuzsanna Fehér,
• Dóra Richter,
• Gyula Dargó and
• József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

• more precise stereocontrol of the reaction [128][129][130][131][132]. Therefore, the difference in enantioselectivity values may be attributed to these electronic effects. Ultimately, the most favourable outcomes were achieved with catalyst C30 at 0 °C, with yields reaching up to 84% and enantiomeric

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• HOMO (diazo compound)–LUMO (alkyne) interaction during the 1,3-dipolar cycloaddition [163], Wu et al. showed that electronic effects in this strategy do not influence the yield. In addition, sterically demanding reactants could be used in the method. Enhanced yields were achieved by using NaOEt and