Melifoliox B, a novel phloroglucin derivative isolated from Melicope barbigera (Rutaceae) and synthesis of new oxidation products from melifoliones A and B

• Horst Weber,
• Kim-Thao Tran-Cong,
• Bernhard Mayer,
• Guido J. Reiss,
• Iryna S. Konovalova,
• Marc S. Appelhans,
• Kenneth R. Wood and
• Claus M. Passreiter

Beilstein J. Org. Chem. 2026, 22, 535–546, doi:10.3762/bjoc.22.39

• , a cross peak was found for the interaction of C-3’ with the protons of the 6-CH3 group. These observations suggest unusual (4J)-long-range C/H-couplings in the rigid spirocyclic 4-ring system. The formation of 11 can be suggested by the following hypothetical pathway (Scheme 3): In a first step, the

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

• , pyridine, DMAP, DCM, rt; iii. allyl-TMS, BF3·Et2O, DCM, −78 °C; (h) 9-BBN, THF, H2O2, 0 °C to rt; (i) i. AD-mix β, MsNH2, t-BuOH, H2O, rt; ii. 2,2-dimethoxypropane, (±)-CSA, DCM, rt; (j) i. DMP, DCM, rt; ii. Ph3PCH2COOEt, toluene, rt; (k) p-TsOH, EtOH, reflux; (l) i. DBU, toluene, reflux; ii. TBAF, THF, rt

Recent advances in the stereoselective synthesis of distal biaxially chiral molecules

• Fanxing Zhou,
• Chen Zhang,
• Lingyu Sun,
• Yiyun Fang,
• Siming Zheng,
• Lina Hu,
• Mengyang Shen,
• Zhen Zhao,
• Wei Xu,
• Yunqiang Sun and
• Zi-Qiang Rong

Beilstein J. Org. Chem. 2026, 22, 461–479, doi:10.3762/bjoc.22.34

• atropisomeric (hetero)biaryls (Scheme 17) [56]. This highly enantioselective C–H arylation of heteroarenes employs a Pd(0) complex with H8-BINAPO L8 as the chiral ligand, enabling the arylation of 1,2,3-triazoles and pyrazoles in excellent yields with great selectivity. This method also facilitates

• first enantioselective C–H amination of arenes catalyzed by a chiral phosphoric acid. Thus, this nucleophilic aromatic substitution reaction not only enables the synthesis of compounds bearing two chiral N-aryl axes but also provides a viable alternative to metal-catalyzed C–N cross-coupling reactions

• conjugated 1,3-diene scaffold though a Pd(II)-catalyzed strategy involving a thioether-directed alkenyl C–H olefination (Scheme 21) [60]. Pleasingly, the strategy also enabled the synthesis of stereoisomers having two stereogenic axes with high enantioselectivity. The axially chiral styrenes produced in this

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

• : 254 nm): a1), a2) chromatograms monitored at 254 nm; b1), b2) CD spectrum of the first eluates in a flow cell; c1), c2) calculated CD spectra using TD-DFT calculations at the B3LYP level using the 6-311G(2d,2p) basis set for C, H, and O atoms and the SDD basis set with the corresponding effective core

Synthesis and anti-cancer activity of naphthalimide–organylselanyl conjugates

• Rajkumar Ravi and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2026, 22, 416–435, doi:10.3762/bjoc.22.29

• ···C distance of 3.588 Å. Third and fourth, as shown in Supporting Information File 1, Figure S20, the intermolecular interaction of C–H···O, having an H···O distance of 2.544 Å and the (π···π) interaction having a C···C distance of 3.376 Å, stabilise and glue the self-assembled architecture in the

Recent advances in the cleavage of non-activated amides

• Eun-Sol Choi and
• Hyo-Jun Lee

Beilstein J. Org. Chem. 2026, 22, 352–369, doi:10.3762/bjoc.22.23

• transition-metal-catalyzed asymmetric C–H activation reactions as a directing group, thus necessitating an efficient method for the cleavage of 8-aminoquinoline-derived amides. The role of Me2SO4 in this transformation was elucidated through DFT calculations. Methylation of the carbonyl oxygen by Me2SO4

Ring contraction and ring expansion reactions in terpenoid biosynthesis and their application to total synthesis

• Nicolas Kratena,
• Nicolas Heinzig and
• Peter Gärtner

Beilstein J. Org. Chem. 2026, 22, 289–343, doi:10.3762/bjoc.22.21

• biosynthesis, when the oxidation state of the terpenoids is being adjusted [28][29][30][31][32][33][34][35][36]. Starting with an already substantial number of these common polycyclic frameworks and adding the almost unlimited variability for oxidative enzymatic C–H functionalisation, it is not surprising that

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

• disrupting the aromatic core, such as electrophilic and nucleophilic aromatic substitutions, transition metal-catalyzed cross-couplings [11], and C–H functionalizations [12]. Taken together with their natural abundance, these transformations have established arenes and heteroarenes as versatile synthetic

• introduced by Cheong and Altman in 2020 (Figure 10A) [83]. In this study, the authors explored an intramolecular, decarboxylative C–H functionalization of benzylic electrophiles, uncovering a decisive role of the base in governing site selectivity. Computational and mechanistic analyses revealed that only

• enriching the repertoire of arene functionalization beyond the established cross-coupling and C–H activation canon. Alternatively, merging arene activation with additional concepts, such as photoredox catalysis offers an exciting opportunity to address thermodynamic constraints and to harness light-driven

Conformational analysis of difluoromethylornithine: factors influencing its gas-phase and bioactive conformations

• Matheus P. Freitas

Beilstein J. Org. Chem. 2026, 22, 237–243, doi:10.3762/bjoc.22.17

• part because its C–N bond is not flanked by two C–F bonds. At the other extreme, structure 13 is highly destabilized sterically due to folding of the N-alkyl chain, which brings N–H and C–N bonds into close contact with C–H, C–C, and C=O bonds. This geometry generates several n/σ and σ/σ interactions

Screwing the helical chirality through terminal peri-functionalization

• Devesh Chandra,
• Sachin and
• Upendra Sharma

Beilstein J. Org. Chem. 2026, 22, 205–212, doi:10.3762/bjoc.22.14

• , the peri-functionalization approach paved a new pathway for the generation of chiral helical molecules. In this article, we highlight the key advancements in these parallel approaches for the generation of helical chiral architectures. Keywords: catalysis; C–H functionalization; helical chirality

• approaches have been developed for the synthesis of chiral helical molecules and the most prevalent approaches include cycloaddition reactions [24], ring extensions [25], and related approaches [26][27]. However, some parallel and more sustainable approaches have emerged in recent years and C–H

• functionalizations are one of these approaches. In the following section, we discuss the parallel approaches, i.e., peri-C–H functionalization, over the prevalent approach for the generation of helical chirality, which generally considers π extension. The peri-C–H functionalization approach provides direct access to

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• (electron) pair – the π-system of the nitro group, and bonds of the Cl···O, Cl···N, C–H···X (X = Cl, O, N) are realized, which are shown in Figures S47–S57 in Supporting Information File 1. The energy of such interactions can be comparable with the energy of “classical” hydrogen bonds [47]. Conclusion In

Total synthesis of natural products based on hydrogenation of aromatic rings

• Haoxiang Wu and
• Xiangbing Qi

Beilstein J. Org. Chem. 2026, 22, 88–122, doi:10.3762/bjoc.22.4

• stereoselective synthesis of 157, which strategically combined a Pd-catalyzed pyridine C–H acylation and an Ir-catalyzed asymmetric hydrogenation of the aromatic core [92]. The synthesis began with the coupling of trisubstituted benzene 158 and 2-substituted pyridine 159, furnishing the bicyclic intermediate 160

Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review

• Daniel S. Müller

Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1

Total synthesis of asperdinones B, C, D, E and terezine D

• Ravi Devarajappa and
• Stephen Hanessian

Beilstein J. Org. Chem. 2025, 21, 2730–2738, doi:10.3762/bjoc.21.210

• gene clusters that code for a (3R) configuration. Keywords: C–H activation; indole alkaloid; Negishi reaction; prenylation; Introduction Alkaloids constitute an important family of naturally occurring compounds with a rich history in the annals of bioactive compounds [1]. Among these, the family of

• , the Pirrung group reported two practical syntheses of 7-prenylindole [48][49]. The regioselective C-7 prenylation of indole has been achieved by directing-group C–H activation as reported by Snieckus [50]. However, the deprotection of the preferred N-bis-tert-butylphosphinoyl directing group required

• ), members of a new class of prenylated 3-indolyl-2,5-benzodiazepine-1,4-diones and diketopiperazine alkaloids, respectively, through Negishi cross-coupling and related C–H functionalization strategies. Importantly, no epimerization was observed during the Negishi coupling or throughout the subsequent steps

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

• 3-position, a copper-mediated C–H activation of position 12 and subsequent protection of the introduced hydroxy moiety to give compound 25 (Scheme 6). Installation of the lactone moiety in 22 was carried out in a three-step sequence via a 1,2-addition of organocerium reagent 26 to the ketone

• , with the hydroxy group at C17 playing a crucial role trapping a cationic intermediate from this rearrangement. Starting point in this synthesis is again dehydroepiandrosterone (24), which was protected in 3-position with an acetyl group (Scheme 12). A copper-mediated C–H activation procedure to obtain

• 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

Chemoenzymatic synthesis of the cardenolide rhodexin A and its aglycone sarmentogenin

• Fuzhen Song,
• Mengmeng Zheng,
• Dongkai Wang,
• Xudong Qu and
• Qianghui Zhou

Beilstein J. Org. Chem. 2025, 21, 2637–2644, doi:10.3762/bjoc.21.204

• ; C–H hydroxylation; chemoenzymatic synthesis; Mukaiyama hydration; protecting-group-free synthesis; Introduction Cardiac glycosides (CGs) are widely distributed natural products, generated by plants and amphibians [1]. Structurally, they are composed of an aglycone-steroidal moiety, an unsaturated

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

• –H bond functionalization of important structural motifs with good to excellent diastereoselectivities, high yields, and late-stage functionalization of drugs and complex natural products. The visible-light-promoted dual catalytic method opens new avenues in direct C–H bond acylation and complements

• existing metal-catalyzed C–H bond functionalization methods (Scheme 3) [53]. Recently, Scheidt et al. discovered an NHC/organic photoredox-catalyzed three-component coupling reaction for the efficient and novel preparation of γ-aryloxy ketone scaffolds 12. This transformation builds on the emerging field

• amide via dual catalysis. Visible-light promoted cooperative NHC/photoredox catalyzed ring-opening of aryl cyclopropanes. NHC-catalyzed benzylic C–H acylation by dual catalysis. NHC/photoredox-catalyzed three-component coupling reaction for the preparation of γ-aryloxy ketones. NHC-catalyzed silyl

Recent advances in total synthesis of illisimonin A

• Juan Huang and
• Ming Yang

Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199

• rearrangement. Finally, a White–Chen C–H oxidation [33][34][35] was employed to install the lactone ring, thereby completing the synthesis. The synthesis began with commercially available compound 19 and known compound 20 (Scheme 2). These were joined via an intermolecular aldol reaction to give adduct 21

• −Chen C–H oxidation [33][34][35] of 30 installed the lactone, completing the synthesis of racemic illisimonin A (1). Noting that the C1 configuration of illisimonin A was opposite to that of other Illicium sesquiterpenes, Rychnovsky’s group sought to confirm the absolute configuration of the natural

Palladium-catalyzed regioselective C1-selective nitration of carbazoles

• Vikash Kumar,
• Jyothis Dharaniyedath,
• Aiswarya T P,
• Sk Ariyan,
• Chitrothu Venkatesh and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2025, 21, 2479–2488, doi:10.3762/bjoc.21.190

• valuable platform for the selective functionalization of carbazoles, offering potential applications in optoelectronics, functional organic materials, and related areas while contributing to the advancement of C–H activation methodologies. Keywords: C–H activation; carbazole; catalysis; nitration

• addition to cross-coupling reactions, transition metal-catalyzed cyclization involving C–H activation approaches have also been reported [29][30][31][32][33][34][35][36]. Despite the significant advances in carbazole core constructions, the established protocols significantly lack access to selectively C1

• -decorated carbazoles. Consequently, functionalizing carbazoles via transition metal-catalyzed directed C–H activation becomes more attractive to introduce the desired functionality in a regioselective fashion. The C–H activation strategy is elegant in many ways since it utilizes nonfunctionalized or lesser

Catalytic enantioselective synthesis of selenium-containing atropisomers via C–Se bond formations

• Qi-Sen Gao,
• Zheng-Wei Wei and
• Zhi-Min Chen

Beilstein J. Org. Chem. 2025, 21, 2447–2455, doi:10.3762/bjoc.21.186

• synthetic approaches for constructing selenium-containing atropisomers have been reported, such as C–H selenylation of arenes, selenosulfonylation of vinylidene o-quinone methides (VQM), and hydroselenation of alkynes. Nevertheless, a comprehensive review that systematically summarizes these advances is

• axially chiral selenium-containing compounds by the formation of C–Se bonds is reviewed from three aspects. Review 1. Catalytic atroposelective synthesis of selenium-containing atropisomers by transition-metal-catalyzed C–H selenylation reactions Transition-metal-catalyzed enantioselective C–H activation

• has emerged as a powerful strategy for the rapid synthesis of functionally enriched axially chiral diaryl compounds. However, due to the potential strong coordination between organoselenium compounds and transition metals, the direct construction of C–Se bonds via metal-catalyzed C–H bond

Synthetic study toward vibralactone

• Liang Shi,
• Jiayi Song,
• Yiqing Li,
• Jia-Chen Li,
• Shuqi Li,
• Li Ren,
• Zhi-Yun Liu and
• Hong-Dong Hao

Beilstein J. Org. Chem. 2025, 21, 2376–2382, doi:10.3762/bjoc.21.182

• vibralactone, a potent inhibitor of pancreatic lipase, is reported. The synthesis of the challenging all-carbon quaternary center within the cyclopentene ring was achieved through intramolecular alkylidene carbene C–H insertion. Keywords: alkylidene carbene; C–H insertion; total synthesis; vibralactone

• lactone 13 through allylic oxidation and cross metathesis. For the construction of the cyclopentene ring, an alkylidene carbene-mediated C–H insertion would be applied [35]. The synthetic route could be traced back to β-lactone 14, which contains two continuous stereogenic centers with trans configuration

• deprotection followed by C–H insertion. However, when attempting to remove the ketal protecting group, only decomposition of the starting material was observed. A plausible explanation for this outcome is that the β-lactone ring, located at the β-position of the methyl ketone, may undergo facile β-elimination

Comparative analysis of complanadine A total syntheses

• Reem Al-Ahmad and
• Mingji Dai

Beilstein J. Org. Chem. 2025, 21, 2334–2344, doi:10.3762/bjoc.21.178

• strategies and creative tactics, reflecting how emerging synthetic capabilities and concepts can positively impact natural product total synthesis. Keywords: biomimetic synthesis; C–H functionalization; complanadine; lycopodium alkaloid; skeletal editing; total synthesis; transition metal catalysis

• reaction to rapidly establish the tetracyclic skeleton of complanadine A and an iridium-catalyzed site-selective pyridine C–H borylation followed by a Suzuki–Miyaura cross coupling to forge the C2–C3’ linkage. Their synthesis achieves a high degree of synergy between classic transformations and modern

• with an Ir-catalyzed regioselective C–H borylation developed simultaneously by Ishiyama, Miyaura, Hartwig, and co-workers and Smith and co-workers [26][27]. First, the triflate group of 33 was removed by a Pd-catalyzed reduction with ammonium formate as the reducing reagent. The resulting Boc-protected

Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis

• Peng-Xi Luo,
• Jin-Xuan Yang,
• Shao-Min Fu and
• Bo Liu

Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177

• -hydroxy-β-lactams or 2-hydroxycyclobutanones can function either as inherent structural motifs in target natural products or as strained reactive intermediates, facilitating C–H functionalization via four-membered ring opening [6][7][8][9][10][11]. Quinones display distinct photochemical reactivities

• proximal phenol, yielding the cyclization product H (Scheme 1b). Notably, the quinone is reduced, while the proximal C–H bond is subject to oxidation. Building on these mechanistic insights and the synthetic merits of dicarbonyls, Norrish–Yang cyclization and related photoredox reactions have been serving

• key late-stage step in this total synthesis, the Norrish–Yang photocyclization exhibits high chemoselectivity and efficiency. It regulates selectivity through C–H bond dissociation energy and restricted bond rotation, constructing a 6/6/4 fused ring system with three contiguous quaternary carbons

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

• as reductive elimination [62]. G. Liu and Stahl disclosed an elegant methodology to functionalize benzylic C–H bonds via copper catalysis [30]. Under the catalytic conditions, alkylarenes were converted to benzylic nitriles in good yields and excellent enantioselectivities. In the proposed mechanism

• enantioselectivities. A radical chaperone methodology is based on a multicatalytic system in which a chiral Cu(I) catalyst, Brønsted acid (camphoric acid) and Ir photocatalyst work synergistically. An asymmetric synthetic method based on radical C–H functionalization was reported by Nagib and co-workers for the

• aldolase, a photoredox catalyst, and an oxidizing agent. With this catalytic system, they were able to accomplish the C–H functionalization of glycine and α-branched amino acids, obtaining α-tri- and tetrasubstituted amino acids with moderate to good yields, good diastereoselectivity, and high

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

• distinct from those generated through thermal Diels–Alder cycloaddition of (Z)-100. However, when [ReCl(CO)5] was used as the catalyst, a regioselective C–H bond insertion pathway was observed for substrate (E)-100, leading to the formation of tricyclic products 104 and 105 (Scheme 21, path b). This

• pathway changed significantly. The (E)-benzofulvene product 110 was exclusively generated through palladium-catalyzed C–H activation followed by a 5-exo-dig cyclization (Scheme 22, path b). This study established a general method for the divergent syntheses of phenylnaphthalenes and benzofulvenes from