Rhodopyran, a carboxylated hexahydrocyclopenta[b]pyran from Rhodococcus

• Enjuro Harunari,
• Sara Fushimi and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2026, 22, 1107–1113, doi:10.3762/bjoc.22.89

• metabolism, followed by partial reduction, dehydration, intramolecular aldol- or Michael-type C–C cyclization, intramolecular O-cyclization, and tailoring oxidations. Considering the oxidative and catabolic capacity of Rhodococcus, possible entry from endogenous fatty-acid β-/ω-oxidation intermediates cannot

Synthesis of novel 1,2,4-oxadiazole-isoxazoline hybrids and their in silico potential with adenosine receptors

• Pshtiwan S. Mohammed,
• Mohammed K. S. Dalo,
• Onur C. Yazıcı,
• Muhammet Yildirim and
• Akın Sağırlı

Beilstein J. Org. Chem. 2026, 22, 1033–1047, doi:10.3762/bjoc.22.82

• , palladium-catalyzed reactions, anodic oxidations, transformations from other heterocycles or 1,3-dipolar cycloaddition [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. For isoxazoline derivatives, the 1,3-dipolar cycloaddition (1,3-DC) of nitrile oxides serves as a fundamental synthetic

Synthesis of depressin, cryptomeridiol and 4-epi-cryptomeridiol enabled by a terpenoid chiral pool-producing platform

• Yao Kong,
• Tao Wang,
• Chen Wang,
• Pengcheng Zhang,
• Yuanning Liu,
• Kaibiao Wang,
• Fen Liu,
• Hongli Jia and
• Zhengren Xu

Beilstein J. Org. Chem. 2026, 22, 683–690, doi:10.3762/bjoc.22.53

• skeletons including casbene (4) and germacrene A (5) were produced by an Escherichia coli-based heterologous host harboring the isopentenol utilization pathway and corresponding terpene cyclases. Two allylic oxidations of both C13 and C5 positions of the casbene skeleton followed by deoxygenation of C13

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

• framework and ring contraction (10b). From here, follow up oxidations and olefin isomerisation afford β-vetivone B (11), a constituent of aromatic vetiver oil. Finally, in the biosynthesis of the antibiotic pleuromutilin (13) [61][62][63] a similar ring contraction takes place (see Scheme 2C). Cyclisation

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

• conditions, exhibits a broad substrate scope and high chemoselectivity, and clearly distinguishes itself from classical Mukaiyama-type oxidations. The reaction is readily scalable to gram quantities and is applicable to late-stage functionalization of complex alcohols, including bioactive molecules such as

• , such transformations remain synthetically challenging. This is primarily due to the well-known Mukaiyama-type oxidation, wherein sulfenamides serve as redox catalysts for NBS- or NCS-mediated oxidations of alcohols to aldehydes or ketones (Scheme 1b, top) [38][39][40][41][42]. Under such oxidative

Total syntheses of highly oxidative Ryania diterpenoids facilitated by innovations in synthetic strategies

• Zhi-Qi Cao,
• Jin-Bao Qiao and
• Yu-Ming Zhao

Beilstein J. Org. Chem. 2025, 21, 2553–2570, doi:10.3762/bjoc.21.198

• successfully accomplished via an epoxide ring-opening/tandem lactonization/olefin hydration sequence. In total, 12 consecutive redox manipulations (7 oxidations and 5 reductions) established all stereocenters, with subsequent functional group transformations completing the total synthesis of garajonone (8

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• ring contraction of (S,S)-carveol-derived TBS ether 163b with triethylborane (Scheme 31). This reaction proceeded with isomerization and formation of the intermediate carbocation 181, which underwent 1,2-carbon migration to form the cyclopentane product 182. A sequence of oxidations of borane 182 with

Halogenated butyrolactones from the biomass-derived synthon levoglucosenone

• Johannes Puschnig,
• Martyn Jevric and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2025, 21, 2297–2301, doi:10.3762/bjoc.21.175

• the Baeyer–Villiger reaction without epoxidation may be challenging. Conclusion In conclusion, we have successfully established halogenation strategies of the biomass derivates 5 and 6, including fluorinations and trifluoromethylation. Baeyer–Villiger oxidations of these materials provide access to

Bioinspired total syntheses of natural products: a personal adventure

• Zhengyi Qin,
• Yuting Yang,
• Nuran Yan,
• Xinyu Liang,
• Zhiyu Zhang,
• Yaxuan Duan,
• Huilin Li and
• Xuegong She

Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160

• as a single isomer, which further underwent a migratory rearrangement and afforded iboluteine. On the other hand, oxidation of ibogaine with molecular iodine achieved both indole and amine oxidations, delivering lactam 35. Intermediate 35 could be oxidized with H2O2 through C–C bond cleavage to give

• might undergo benzylic oxidations and intramolecular dehydration to access a diaryltetrahydrofuran (THF) skeleton. Then, oxidation of one aryl group through phenol oxidation would generate a putative cyclohexadienone intermediate to be further captured by the other phenol to access eupodienone through a

Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics

• Leticia A. Gomes and
• Steven A. Lopez

Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156

• starting materials for different types of reactions including thermal isomerization to cyclopentenes [36][37][38] and 1,4-pentadienes [37][38], chemical electron-transfer oxidations to cyclopentene [39] and cycloaddition reactions with electron-deficient alkenes and alkynes [38][40][41] (Scheme 1b

Heterologous biosynthesis of cotylenol and concise synthesis of fusicoccane diterpenoids

• Ye Yuan,
• Zhenhua Guan,
• Xue-Jie Zhang,
• Nanyu Yao,
• Wenling Yuan,
• Yonghui Zhang,
• Ying Ye and
• Zheng Xiang

Beilstein J. Org. Chem. 2025, 21, 1489–1495, doi:10.3762/bjoc.21.111

• activity than cotylenin A in cell growth inhibition assays and less toxicity in single-agent treatments [27][28]. Recently, Jiang and Renata described a chemoenzymatic approach that combines the skeletal construction by chemical methods and enzymatic C–H oxidations [29]. The synthesis employs a catalytic

• Nozaki–Hiyama–Kishi reaction and a one-pot Prins cyclization/transannular hydride transfer to construct the 5-8-5 tricyclic scaffold. Enzymatic oxidations were used to install the hydroxy group at the C-3 position. Ten fusicoccanes were synthesized in 8–13 steps each. Despite these efforts, a strategy

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

• comprehensive work by Volochnyuk and Ryabukhin et al. who analysed the oxetane core tolerance towards various reaction conditions such as oxidations, reductions, alkylations or C–C bond formations [83]. Since the general recognition of 3-oxetanone as the principal building block, a large number of new

• oxidation state ruthenium, allowing for a facile purification (simple acidic/basic workup) and is very mild, scalable and high-yielding. However, the yield tends to get rather low (below 25%), if the oxetane bears a heterocycle (e.g., indole or thiophene), most likely due to competing oxidations of the

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

• , making it particularly suited for large-scale applications. Recent advances highlight the unique advantages of both metal-based and metal-free catalysts under red-light irradiation, broadening the range of possible reactions, from selective oxidations to complex polymerizations. In biological contexts

Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• 1600–1550 cm−1 triplet. This result is fully compatible with the presence of the two rather overlapped (i.e., with similar energies) one-electron oxidations in the cyclic voltammetry of 2. The spectral resemblances for 2•+ and 22+ might also indicate that the positive charge is mainly gathered by the

• theoretical Raman band at 1730 cm−1. FT-Raman spectra in CH2Cl2 (approx. 10−2 to 10−3 M) of: top) 1 (black), 1•+ (blue), and 12+ (red). Bottom) 2 (black), 2•+ (blue), and 22+ (red). Oxidations are carried out by stepwise addition of NOBF4 in CH2Cl2. Force constants for the CC stretching vibrational

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

• . Review 1 LSF via anodic oxidation To date, the majority of electrosynthetic methods in organic chemistry consists of anodic oxidations. These techniques are generally more robust and can often be performed outside of a glovebox, making them particularly attractive for larger scale applications in

• . However, it should be noted that anodic oxidations often require electrodes with high resistance to oxidation, such as platinum electrodes, or inert electrodes with a highly developed surface, like reticulated vitreous carbon (RVC). Anodic oxidations generally involve the evolution of hydrogen (indicated

• 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

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

O,S,Se-containing Biginelli products based on cyclic β-ketosulfone and their postfunctionalization

• Kateryna V. Dil and
• Vitalii A. Palchykov

Beilstein J. Org. Chem. 2024, 20, 2143–2151, doi:10.3762/bjoc.20.184

• oxidations of rare Biginelli products are discussed in Supporting Information File 1 using compound 2a as an example. In silico evaluation of ADMET parameters and biological profile We performed in silico screening of the biological properties of Biginelli products 2a–r and their postfunctionalized

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

• electrolyte with potassium carbonate as a base and two platinum electrodes. Mechanistically, condensation of the two reactants formed isatin-derived acylhydrazone 37. Hydrolysis of the latter in the presence of the inorganic base gave rise to potassium carboxylate 39. Meanwhile, two consecutive SET oxidations

Synthesis of polycyclic aromatic quinones by continuous flow electrochemical oxidation: anodic methoxylation of polycyclic aromatic phenols (PAPs)

• Hiwot M. Tiruye,
• Solon Economopoulos and
• Kåre B. Jørgensen

Beilstein J. Org. Chem. 2024, 20, 1746–1757, doi:10.3762/bjoc.20.153

• alternative to classical synthesis [25][26][27][28]. Electrochemical oxidation reactions are further used to emulate enzymatic oxidations of drugs and explore potential metabolites [29][30][31]. Electrochemical flow systems provide fast electrosynthesis with low cell resistance, large electrode area, and good

• (1a) into o-quinone 5 revealed that the oxidation comprises two separate 1-electron oxidations [38]. Electrooxidative dearomatization has proven to be an effective synthetic tool [39]. However, we have not found examples of electrochemical oxidation of PAPs applied in synthesis. Here, we report the

• to be overoxidized and provided only traces of multiple products. Some overoxidation of 4d was observed as 12-methoxychrysene-5,6-dione (10), but the alternative product chrysene-6,12-dione was not formed. In contrast to the ortho-selective oxidations of PAPs with SIBX [18], the electrochemical

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• I (9). As a pioneering investigation to elucidate the mechanism of this essentially identical allylic oxidations by Fe(II)/2OG-dependent dioxygenase, Dairi and co-workers conducted in vitro enzymatic conversions with the homologous enzyme Bsc9, derived from Alternaria brassicicola ATCC96836 [24

Oxidation of benzylic alcohols to carbonyls using N-heterocyclic stabilized λ³-iodanes

• Thomas J. Kuczmera,
• Pim Puylaert and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 1677–1683, doi:10.3762/bjoc.20.149

• -iodanes have drawbacks, in particular low solubility and moisture sensitivity [11]. Hypervalent iodine compounds in a lower oxidation state (λ3-iodanes), such as iodosobenzene (PhIO)n or phenyliodine(III) diacetate (PIDA) have been reported in alcohol oxidations but they often result in overoxidation to

• to undesired oxidations of the triple bond. The behavior of secondary benzylic alcohols was tested next, giving 4-methylacetophenone (4t) in an excellent yield of 97% and 1-indanone (4u) in 46%. It is worth noting that for some derivatives oxidized by method A, an acylation of the alcohol was

Recent developments in the engineered biosynthesis of fungal meroterpenoids

• Zhiyang Quan and
• Takayoshi Awakawa

Beilstein J. Org. Chem. 2024, 20, 578–588, doi:10.3762/bjoc.20.50

• residues, the catalytic activities of these enzymes were exchanged [34]. From 24, PrhA V150L/A232S produced 27, and AusE L150V/S232A produced 28. Surprisingly, PrhA V150L/A232S/M241V catalyzed additional oxidations of 27 to produce compounds 29 and 30, as unnatural products. As demonstrated in these

• reactions, the terpenoid skeleton undergoes significant structural changes due to radical formation through oxidase-induced hydrogen atom abstraction. Close examinations of the substrate complex structures of these αKG-dependent dioxygenases involved in these meroterpenoid oxidations revealed that the

• common intermediate 21 to ascochlorin (22) and ascofuranone (23), respectively. The multistep oxidations catalyzed by AusE and PrhA from the common intermediate 24. Reactions of SptF with native substrates 31 and 32. A) Reactions of SptF with unnatural substrates. B) Reactions of SptF variants with 31

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• reactive intermediate 1O2 is known to induce DNA damage [78][88]. Nevertheless, these lesions, namely DNA base oxidations, often require alkaline treatment to lead to a strand cleavage, so that the DNA damage remained mainly unnoticed in the employed assay. At the same time, it has been reported that 1O2

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• Tetrathiafulvalene (TTF, Figure 1) is a redox-active molecule that has been widely explored in materials chemistry and supramolecular chemistry [1][2][3][4][5][6][7][8]. TTF reversibly undergoes two sequential one-electron oxidations, generating first a radical cation (TTF+•) and subsequently a dication (TTF2

• in Figure 6, and potentials against ferrocene (Fc/Fc+) (obtained from differential pulse voltammetry, see Supporting Information File 1) are summarized in Table 2. Compounds 11 and 15 showed two irreversible first oxidations at +0.34 V and +0.38 V vs Fc/Fc+, showing that replacing the ketone with the

• with 0.1 M Bu4NPF6 as supporting electrolyte) are shown in Figure 8. Quasi-reversible one-electron oxidations of the two DTF-functionalized compounds 22 and 23 are observed at +0.41 V followed by irreversible oxidations at +0.76 V (22) and +0.81 V (23), respectively. One reversible oxidation at +0.84 V

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• , resulting in 1g• and 1h• being more reducing monomers than their non-methoxylated analogues 1b• and 1e•, respectively. Cyclic voltammograms of both 1H and 12 both reveal irreversible oxidations (with the corresponding 1+ reductions seen in subsequent reductive cycles, see Figure 6 for examples). These 1H