Palladium-catalyzed benzocyclization reactions of quinoline-2-carboxamides via sequential C–H/N–H functionalization

• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2026, 22, 905–914, doi:10.3762/bjoc.22.71

• carbon–heteroatom bonds. The classical coupling reactions, such as Kumada–Tamao–Corriu coupling [11][12][13], Sonogashira coupling [14][15], Negishi coupling [16][17], Migita–Kosugi–Stille coupling [18][19][20], Suzuki–Miyaura coupling [21][22], and Hiyama coupling [23][24] involve carbon–halogen and

Preparation of 3-(alkylamino)imidazo[1,2-a]pyridine-2-carbaldehydes via Kornblum oxidation and unexpected ring-opening reactions of the corresponding alcohols under oxidative conditions

• Sandile J. Mkhize,
• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2026, 22, 763–770, doi:10.3762/bjoc.22.58

• compounds displayed reduced activity against mutant viral strains, possibly because of a lack of torsional flexibility which could potentially be increased by introduction of a heteroatom between the two aromatic moieties. Thus, we embarked upon this current study to prepare derivatives possessing increased

• is based on Sandile J. Mkhize’s MSc dissertation (“Exploration of the synthesis of imidazo[1,2-a]pyridin-3-amine derivatives with heteroatom linkers as potential HIV-1 reverse transcriptase inhibitors”, University of the Witwatersrand, 2022). Funding The authors would like to acknowledge the

Harnessing light energy with molecules

• Grace G. D. Han,
• Mogens Brøndsted Nielsen and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2026, 22, 680–682, doi:10.3762/bjoc.22.52

• structure by a heteroatom (oxygen or nitrogen) in donor–acceptor, push–pull NBD derivatives are reported. In a computational study, Pawar and co-workers [7] further expanded the NBD structure by elongating the unsaturated bridge with different heteroatoms or functional groups. Azobenzenes, interconverting

Synthesis and stereochemical analysis of dynamic planar chiral oxa[7]orthocyclophene

• Yukiho Hashimoto,
• Yuuya Kawasaki,
• Kazunobu Igawa and
• Katsuhiko Tomooka

Beilstein J. Org. Chem. 2026, 22, 436–442, doi:10.3762/bjoc.22.30

• ][3][4][5][6][7][8][9][10], we previously synthesized hetera[7]orthocyclophenes 1 having a heteroatom-embedded ansa-chain (X = O or NR) and an (E)-alkene moiety (Figure 1) [6][9], and found that the orthocyclophenes exhibit dynamic planar chirality in a wide range of stereochemical stability depending

• on the differences of the heteroatom and substituents on the (E)-alkene moiety [11][12]. The half-lives of the optical activity optt1/2 of 1aa (X = O, Y = H) and 1ba (X = NTs, Y = H) were 380 h and 56.7 h at 25 °C, respectively, indicating that the stereochemical stability of the oxygen-containing

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

• along the helical rim – are far rarer. Their scarcity primarily reflects the formidable challenge of controlling chemo- and regioselectivity during ring annulation and heteroatom introduction, which often necessitates multistep synthetic strategies [36][37][38]. To the best of our knowledge, only four

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

• emphasized heteroatom-driven reactions in which metal coordination enhances the natural polarization of the molecule, primarily by disrupting its aromaticity. For example, a π-base preferentially binds to the C(2) and C(3) positions of monosubstituted arenes, maintaining linear conjugation between the

• benzylic vs. dearomative functionalization. Strategies for para- and ortho-selective arene functionalization/dearomatization via η3-benzyl complexes. η4-Arene coordination as an underexplored but promising pathway for arene activation [96][98][99][100]. Heteroatom-directed reactions of η2-arene complexes

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

• versatile intermediates for enantioselective S–C bond formation under mild and metal-free conditions. Keywords: asymmetric synthesis; late-stage functionalization; selective oxidation; sulfenamides; sulfinimidate esters; Introduction Sulfur is a privileged heteroatom in organic chemistry, celebrated for

Reactivity umpolung of the cycloheptatriene core in hexa(methoxycarbonyl)cycloheptatriene

• Dmitry N. Platonov,
• Alexander Yu. Belyy,
• Rinat F. Salikov,
• Kirill S. Erokhin and
• Yury V. Tomilov

Beilstein J. Org. Chem. 2026, 22, 64–70, doi:10.3762/bjoc.22.2

• -group elimination but through intermolecular hydride-transfer reactions as well. Therefore, the expected strategy to establish a chemical bond with a cycloheptatriene core is a reaction of a tropylium ion derivative with a nucleophile. Such reactions may involve either carbon [9][10][11] or heteroatom

Recent advancements in the synthesis of Veratrum alkaloids

• Morwenna Mögel,
• David Berger and
• Philipp Heretsch

Beilstein J. Org. Chem. 2025, 21, 2657–2693, doi:10.3762/bjoc.21.206

• the semisynthesis of Liu/Qin [26] 15 years later. The only non-green transformations displayed at the start were a protecting group installation (red) and a condensation (yellow), which was needed for the C–H activation (light green). All other transformations connect either C–C or C–heteroatom bonds

Visible-light-driven NHC and organophotoredox dual catalysis for the synthesis of carbonyl compounds

• Vasudevan Dhayalan

Beilstein J. Org. Chem. 2025, 21, 2584–2603, doi:10.3762/bjoc.21.200

• cross-coupling between the C-centered and N-centered radicals. These methods are expected to open new avenues for visible-light- and NHC/4CzIPN-catalyzed carbon–heteroatom bond-forming processes (Scheme 1) [51]. In 2021, Studer et al. developed a novel method for the 1,3-difunctionalization of

Enantioselective radical chemistry: a bright future ahead

• Anna C. Renner,
• Sagar S. Thorat,
• Hariharaputhiran Subramanian and
• Mukund P. Sibi

Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174

• for the construction of carbon–carbon and carbon–heteroatom bonds. Unlike many ionic reactions, radical reactions are often functional group tolerant and carried out under mild, neutral conditions, avoiding harsh acidic or basic conditions that can promote epimerization or decomposition of the product

• transferred to the radical. Important processes of this kind are hydrogen atom transfer (HAT) and halogen atom abstraction. An intramolecular group transfer reaction can result in the net migration of a functional group. Addition of a radical to a π-bond (carbon–carbon or carbon–heteroatom) is another common

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

• under gold(I) catalysis through a substituent-controlled strategy (Scheme 8) [15]. Substrates with heteroaryl substituents underwent 6-endo-dig cyclization via gold-heteroatom coordination, furnishing the lactone-fused pyran scaffold 34 (Scheme 8, path a). Substrates with aryl substituents at the

Photochemical reduction of acylimidazolium salts

• Michael Jakob,
• Nick Bechler,
• Hassan Abdelwahab,
• Fabian Weber,
• Janos Wasternack,
• Leonardo Kleebauer,
• Jan P. Götze and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153

• employed including carboxylic acids [37], xanthates [38], electron-rich toluene or heteroatom-substituted species [39][40][41][42], organoboron compounds [43][44] and organosilanes [43][45]. Moreover, three-component radical relay processes employing styrene derivatives have also been widely studied. In

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

• ]arenes displayed a distinctive 1,3-alternate conformation, notably differing from the typical cone conformation of the conventional calix[4]arenes. Moreover, unlike previously documented examples, the inherent chirality of these products arises from the difference of just one heteroatom (O and NH) in the

Transition-state aromaticity and its relationship with reactivity in pericyclic reactions

• Israel Fernández

Beilstein J. Org. Chem. 2025, 21, 1613–1626, doi:10.3762/bjoc.21.125

• the lower barriers computed for the Hopf cyclizations of ene–ene–ynes E=CH–CH=CH–C≡CH where the terminal CH2 group was replaced by a heteroatom (E = NH or O). Figure 8 shows the corresponding ASDs for the parent cyclization (E = CH2) and the analogous process involving the imine system (E = NH). In

Facile synthesis of hydantoin/1,2,4-oxadiazoline spiro-compounds via 1,3-dipolar cycloaddition of nitrile oxides to 5-iminohydantoins

• Juliana V. Petrova,
• Varvara T. Tkachenko,
• Victor A. Tafeenko,
• Anna S. Pestretsova,
• Vadim S. Pokrovsky,
• Maxim E. Kukushkin and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 1552–1560, doi:10.3762/bjoc.21.118

• form two new carbon–heteroatom bonds in a 1,2,4-oxadiazoline ring through both variants of orbital overlap. It should be noted that, in this case, NMR spectroscopy is not applicable to assign the product structure due to the presence of only quaternary carbon atoms in the tetrasubstituted 1,2,4

• known that nitrile oxides are capable of reacting with various multiple carbon–heteroatom bonds [28]. In contrast to the products of nitrile oxide cycloaddition to imino groups, 1,4,2-oxathiazoles, formed by addition to C=S bonds, are unstable and undergo decomposition into isothiocyanate and a carbonyl

• in the formation of two new carbon–heteroatom bonds and the formation of a five-membered ring. Thus, the aryl attached to the nitrogen atom from the dipolarophile fragment is brought closer to the substituent from the C-end of the dipole. This proximity in the presence of ortho-substituents in the

Azide–alkyne cycloaddition (click) reaction in biomass-derived solvent Cyrene^TM under one-pot conditions

• Zoltán Medgyesi and
• László T. Mika

Beilstein J. Org. Chem. 2025, 21, 1544–1551, doi:10.3762/bjoc.21.117

• and atom-economical strategies for efficiently assembling new carbon–carbon [1][2][3] and carbon–heteroatom [4][5][6] bonds. Thus, it has become the most attractive and facile methodology for creating various complex organic molecular structures from the laboratory to the industrial scale. Among these

• successfully introduced into homogeneous [26][27][28][29] and heterogeneous [30][31] carbon–carbon and carbon–heteroatom bond-forming protocols. Although its reactive carbonyl group could limit its application when a strong base (aldol condensation [29]) or amines (potential Schiff-base formation) are present

Copper catalysis: a constantly evolving field

• Elena Fernández and
• Jaesook Yun

Beilstein J. Org. Chem. 2025, 21, 1477–1479, doi:10.3762/bjoc.21.109

• , decarboxylative functionalizations, and Chan–Lam coupling reactions. In doing so, the authors point out the combination of transition-metal catalysis and electrochemistry as an efficient, sustainable method for the oftentimes challenging formation of C–C and C–heteroatom bonds in complex molecules. Another Review

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

• helical architectures, have attracted considerable attention due to their intrinsic chirality and tunable optoelectronic properties. Among them, nitrogen-doped helicenes (azahelicenes) and their heteroatom-co-doped counterparts – such as B/N-, O/N-, S/N-, and Se/N-doped helicenes – have emerged as highly

• emitters. Boron–nitrogen co-doping strategies, in particular, have facilitated the development of materials with ultra-narrowband emissions, near-unity photoluminescence quantum yields, and electroluminescence dissymmetry factors (|gEL|) exceeding 10−3. Likewise, heteroatom co-doping with oxygen, sulfur

• systems – has granted access to increasingly complex helicene frameworks with well-defined chirality. This review systematically summarizes recent advancements in the synthesis, structural engineering, and chiroptical performance of nitrogen-doped helicenes and their heteroatom-doped derivatives

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

• epoxides and heteroatom-stabilised carbocations generated from alkenes (Scheme 10). In 1992, Arjona and co-workers examined the synthesis of 4,7-dioxatricyclo[3.2.1.03,6]octane derivatives 45 via intramolecular cyclisation of the corresponding hydroxyalkene precursors 44 using arylsulphenyl and arylselenyl

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

• C–C or C–heteroatom bonds. The incorporation of HAT strategies into the functionalization of C–H bonds represents a significant advancement in synthetic organic chemistry for their high atom economy and step economy. HAT reagents (HR), including alkoxyl, acyloxyl, halogen radicals, and amidyl

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

• Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

• scaffolds of this type. Given the rapid progress in this field, with nearly half of the cited works published since 2020, this review focuses primarily on purely hydrocarbon structures, with less emphasis on heteroatom-containing molecules. Typically, only the final synthetic steps leading to the fused

• gap 1.07 eV) which is impressive for such small π-scaffold. Formation of carbon–heteroatom bonds: Although the primary focus of this review is the synthesis of all-carbon azulene-embedded nanographenes, some carbon–heteroatom fusion reactions are also worth mentioning. In general, azulene-fused

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

• heteroatom for the synthesis of functionalized oxindoles was also reported in 2013 [3]. In this study, DBU was employed as a ligand and TBHP as an oxidant. A series of ethers, including 1,2-dimethoxyethane, THF, 1,4-dioxane, tetrahydro-2H-pyran, 2,3-dihydrobenzofuran, tetrahydro-2H-thiopyran, and N

Enhancing chemical synthesis planning: automated quantum mechanics-based regioselectivity prediction for C–H activation with directing groups

• Julius Seumer,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2025, 21, 1171–1182, doi:10.3762/bjoc.21.94

• activation, transforming these inert bonds into reactive carbon–transition metal (C–M) bonds. Subsequent transformations of these complexes enable the formation of an array of new functional groups, such as carbon–carbon and carbon–heteroatom bonds, underpinning a plethora of synthetic applications

• in Figure 1. Using this approximation the generation and optimization of structures simplifies greatly. In an automatized workflow, all unique and possible combinations of C–H bonds and ortho-directing groups (heteroatom with lone pair) in the substrate are found following this procedure: 1. All

• combinations of C–H bonds from sp2-hybridized C atoms and directing groups (heteroatom with lone pair) in the substrate, which are between two and five bonds apart from each other, are detected with SMART patterns. These patterns are general enough to cover all directing groups that were encountered in the

Supramolecular assembly of hypervalent iodine macrocycles and alkali metals

• Krishna Pandey,
• Lucas X. Orton,
• Grayson Venus,
• Waseem A. Hussain,
• Toby Woods,
• Lichang Wang and
• Kyle N. Plunkett

Beilstein J. Org. Chem. 2025, 21, 1095–1103, doi:10.3762/bjoc.21.87

• heteroatoms at axial positions resulting in a three-center four-electron bond [13][14]. In this unique “T” configuration, the bond length between iodine and one of the heteroatoms is influenced by the bond distance of the other heteroatom and is responsible for the stabilization of the hypervalent iodine