Design and synthesis of an axially chiral platinum(II) complex and its CPL properties in PMMA matrix

• Daiki Tauchi,
• Sota Ogura,
• Misa Sakura,
• Kazunori Tsubaki and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2026, 22, 143–150, doi:10.3762/bjoc.22.7

• chiral platinum(II) complex was synthesized via Sonogashira coupling and subsequent coordination of a pincer ligand to a precursor. The complex exhibited a broad absorption band ranging from 250 to 550 nm in the UV–vis spectrum, with TD-DFT calculations indicating mixed ligand-to-ligand charge transfer

• two platinum(II) chromophore units, leading to the chiroptical properties in the MLCT region through exciton coupling under restricted molecular motion. Keywords: axial chirality; chiral chemistry; circularly polarized luminescence (CPL); phosphorescence; platinum(II) complex; Introduction

• exciton coupling in both the ground and excited states. While no CPL was observed in solution, distinct CPL properties observed in the PMMA matrices. This behavior is attributed to the effect of the axial chirality, which becomes more effective upon suppression of molecular motion within the polymer

Symmetrical D–π–A–π–D indanone dyes: a new design for nonlinear optics and cyanide detection

• Ergin Keleş,
• Alberto Barsella,
• Nurgül Seferoğlu,
• Zeynel Seferoğlu and
• Burcu Aydıner

Beilstein J. Org. Chem. 2026, 22, 131–142, doi:10.3762/bjoc.22.6

• /acetic acid buffers with a good yield (84%). Target compounds were synthesized by a coupling reaction between 2-(1,3-dihydro-2H-inden-2-ylidene)malononitrile (1) and appropriate alkylaminobenzaldehyde derivatives in acetic anhydride. Compounds were obtained with low to good yields (25–75%, conventional

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

• )/CH3 (pyrazolone) (δH = 2.15 ppm) in the minor isomer 9b (Scheme 5). Thus, the relative configurations of the stereocenters in these molecules can be defined as 1SR,2RS,3SR (9a) and 1SR,2RS,3RS (9b). Cyclopropanes 2–8 are formed as single diastereomers. The vicinal spin–spin coupling constants of C1H

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

• ][19][20]. In recent years, promoted by the rapid development of asymmetric catalysis, a wealth of reactions applicable to aromatic systems – including substitution reactions, transition-metal-coupling reactions, and even dearomatization [21][22][23] – have been reported, further extending their

• ]. Starting from pyridine derivatives 129, they obtained the key intermediate 131 via a Simmon–Smith reaction and a bimetallic-mediated photocatalytic radical coupling reaction. Intermediate 132 was then constructed by Friedel–Crafts alkylation using diethylaluminum chloride as a Lewis acid. The pyridine ring

• , which perfomed as a key substrate for the aerobic oxidation. The formation of the tetracyclic 3-spirooxindole structure 137 was achieved through a transition-metal-free intramolecular cross-dehydrogenative coupling. With 137 in hand, a sequence of transformations including ketone reduction with NaBH4

Advances in Zr-mediated radical transformations and applications to total synthesis

• Hiroshige Ogawa and
• Hugh Nakamura

Beilstein J. Org. Chem. 2026, 22, 71–87, doi:10.3762/bjoc.22.3

• alkyl iodide 10 were subjected to nickel catalysis in the presence of zirconocene dichloride and zinc dust, intermolecular coupling occurred to afford ketone 12 in good yields. This reaction was applicable to substrates bearing β-alkoxy substituents, which are typically problematic under anionic

• suggested that the developed reaction would be applicable to halichondrin synthesis. The Zr/Ni-mediated ketone synthesis was then applied to the total synthesis of homohalichondrin B (58, Scheme 11B). Using a fragment corresponding to homohalichondrin B, the coupling reaction furnished ketone 57 in 82

• ). The developed dimerization protocol proved scalable to 100 g scale, affording 40 g of the desired dimer 61b in 47% yield. Subsequent removal of the two Boc groups with TMSI, followed by HATU-mediated amide coupling with various amino acids 65–67, furnished the diketopiperazine precursors 68–70

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

• alkenyl chlorides. The discussion begins with reductive metalation, reactions with organolithium reagents, and eliminations to terminal alkynes – some of which are also exemplified in chapter 1. This is followed by palladium- and nickel-catalyzed cross-coupling reactions. The chapter concludes with a

• previous studies, aliphatic alkynes were found to be inefficient coupling partners under these conditions (compound 238). Sasaki observed that hydrated zinc dichloride enabled the formation of alkenyl chloride 242 upon reaction of silylated alkyne 241 with 1-adamantyl chloride (240) (Scheme 46A) [152

• construction of structurally complex motifs in a concise number of steps. A recent account by Frontier and Hernandez provides a comprehensive and mechanistically summary of halo-Nazarov electrocyclizations [173]. 1.7 Coupling reactions As already mentioned in the introduction, the coupling reaction of 1,1

Sustainable electrochemical synthesis of aliphatic nitro-NNO-azoxy compounds employing ammonium dinitramide and their in vitro evaluation as potential nitric oxide donors and fungicides

• Alexander S. Budnikov,
• Nikita E. Leonov,
• Michael S. Klenov,
• Andrey A. Kulikov,
• Igor B. Krylov,
• Timofey A. Kudryashev,
• Aleksandr M. Churakov,
• Alexander O. Terent’ev and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2025, 21, 2739–2754, doi:10.3762/bjoc.21.211

• ][31][32][33][34][35] coupling is very limited. In most existing approaches, the N–N and N–O moieties are derived from hydrazine or hydroxylamine synthons, respectively. The development of novel synthetic methodologies based on non-traditional retrosynthetic disconnections offers a potential pathway to

• and N–O bond formation. However, it also represents a highly efficient and valuable strategy due to the synthetic availability of starting materials. Therefore, the development of new methods for direct selective N–N and N–O coupling remains an important goal in synthetic chemistry. To date

• approaches focus mainly on intramolecular radical cyclizations [42][54][55][56][57][58][59][60][61][62][63], while intermolecular [1][64][65][66][67][68] N–N coupling remains a poorly studied area. In addition to the preparation of azo compounds [69][70], intermolecular N–N coupling reactions are of

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

• tryptophan were explored. Different approaches were adopted for the functionalization of C4–C7 prenylindoles at C-3 using Negishi cross-coupling methods. The asperdinones are among the rare tryptophan-derived indole alkaloids which appear to have undergone epimerization due to genetic alteration of specific

• transferase AnaPT. A second, less evident approach, starts with a prenylindole, followed by introducing an (R)- or (S)-2-aminopropionate (alanine) unit at C-3 by a Negishi cross-coupling reaction (Figure 2, approach B, D–F). Although each approach has precedents in different contexts, achieving regioselective

• amorphous powder. Viswanathan [25] and Chen [28] reported a C-2 prenylation of tryptophan methyl ester mediated by acid salts and Lewis acids, respectively. A prenylation at C-4 in bis-N-Boc-tryptophan methyl ester has been achieved by Chein utilizing optimized Suzuki coupling conditions [29]. Results and

Competitive cyclization of ethyl trifluoroacetoacetate and methyl ketones with 1,3-diamino-2-propanol into hydrogenated oxazolo- and pyrimido-condensed pyridones

• Svetlana O. Kushch,
• Marina V. Goryaeva,
• Yanina V. Burgart,
• Marina A. Ezhikova,
• Mikhail I. Kodess,
• Pavel A. Slepukhin,
• Alexandrina S. Volobueva,
• Vladimir V. Zarubaev and
• Victor I. Saloutin

Beilstein J. Org. Chem. 2025, 21, 2716–2729, doi:10.3762/bjoc.21.209

• , HMBC experiments. The relative configuration was established based on the analysis of spin–spin coupling constants 3JH,H and 4JH,H as well as on a set of NOE-correlations. Equatorial or pseudo-equatorial protons of the methylene groups in compounds 4 and 5 were identified by the long-range coupling

Mechanistic insights into hydroxy(tosyloxy)iodobenzene-mediated ditosyloxylation of chalcones: a DFT study

• Jai Parkash,
• Sangeeta Saini,
• Vaishali Saini,
• Omkar Bains and
• Raj Kamal

Beilstein J. Org. Chem. 2025, 21, 2703–2715, doi:10.3762/bjoc.21.208

• dearomatization [7], amination [8], oxidative coupling [9], ring contraction [10][11][12], oxidative rearrangement [13][14][15], dihydroxylation of alkenes, arylation [16], oxidation of sulfides [17] and many more. These hypervalent compounds contain iodine in higher oxidation state than its usual −(I) valence

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

• group disclosed a total synthesis in 2023 [23]. Their synthesis relies on a retrosynthetic cut through the D-ring, enabling a convergent coupling of two similarly complex fragments between C15–C16. Key disconnection steps include a Tsuji–Trost reaction to form the spirocyclic E-ring, and a ring-closing

• alkylation was diasteroselective. In the next steps, addition of isopropenyllithium to the lactone moiety led to a hemiketal, which was then opened and a protecting group on the hydroxy group was installed, furnishing fragment 42. Key convergent coupling of this total synthesis was performed by lithium

• spirocyclic moiety. Another disconnection was provided by the group of Zhu/Gao in 2023 (Scheme 9) [25]. The major retrosynthetic cut proceeds through the C-ring, while also including a late-stage spirocyclization. The convergent coupling occurs between C11 and C12, while a ketone moiety is present at C11

Synthesis of new tetra- and pentacyclic, methylenedioxy- and ethylenedioxy-substituted derivatives of the dibenzo[c,f][1,2]thiazepine ring system

• Gábor Berecz,
• András Dancsó,
• Mária Tóthné Lauritz,
• Loránd Kiss,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2645–2656, doi:10.3762/bjoc.21.205

• . The pulse programs were taken from the Bruker software library (TopSpin 3.5) and full 1H and 13C assignments were achieved with widely accepted strategies. 1H assignments were accomplished using general knowledge of chemical shift dispersion with the aid of the 1H–1H coupling pattern. CDCl3 or DMSO-d6

• was used as the solvent and tetramethylsilane (TMS) as the internal standard. Chemical shifts (δ) and coupling constants (J) are given in ppm and in Hz, respectively. Coupling constants reported in the 1H NMR spectra are H–H couplings unless otherwise stated (J ≡ JH–H). Three-bond H–H couplings (3J

Efficient solid-phase synthesis and structural characterization of segetalins A–H, J and K

• Liangyu Liu,
• Wanqiu Lu,
• Quanping Guo and
• Zhaoqing Xu

Beilstein J. Org. Chem. 2025, 21, 2612–2617, doi:10.3762/bjoc.21.202

• from the high cost of the specialized resin and large solvent volumes required for dilution, coupled with DPPA's poor efficiency in forming sterically hindered peptide bonds involving residues like Val or Ile. Dahiya and Kaur synthesized segetalin C (3) via a solution-phase fragment coupling strategy

• (Scheme 1). Building upon previous work [17][18][19], we focused on optimizing key parameters: resin selection, Fmoc deprotection conditions, coupling reagents for linear assembly, and crucially, the cyclization step. Cost-effectiveness and commercial availability led us to select 2-chlorotrityl chloride

• sequences, coupling efficiency was significantly enhanced using a 1:1 mixture of 1-hydroxybenzotriazole (HOBt) and 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) in DMF [23]. Finally, we obtained crude linear peptides with 75% to 95% yields (Table 1). The critical head-to

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

• -coupling processes. This cooperative organic dual catalysis has great potential in medicinal, pharmaceutical, and materials science applications, including the development of organic semiconductors and polymers. In recent years, NHC-involved photocatalysis has attracted considerable attention in synthetic

• carbenes (NHCs) with photocatalysts. The review encompasses transition-metal-based photocatalytic reactions for C–C and C–HA cross-coupling reactions involving various acyl fluorides, amides, aldehydes, carboxylic acids, and esters, highlighting their broad applications in organic synthesis and medicinal

• , generating an N-centered radical species C. This species subsequently undergoes a rapid C–N cross-coupling with ketyl radical B. This cross-coupling method offers a transition-metal free route to highly substituted amides 3 from aldehydes 1 and imines 2, without the need for any external reductants or

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

• substructure hidden inside the natural product’s cage-like ring system, Kalesse’s group chose to construct this architecture first using a tandem Nazarov/ene cyclization [36]. The cis-pentalene was subsequently assembled via a Ti(III)-mediated epoxide–ketone coupling reaction. Starting from the known

• triflate formation followed by a palladium-catalyzed coupling reaction with AlMe3. The carbonyl group at C8, required for the subsequent aldol reaction, was introduced by enolate oxidation followed by Jones oxidation. Hydrolysis of the ketal at C11 afforded ketoester 64. A TBD (1,5,7-triazabicyclo[4.4.0

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

• -ryanodol, cinnzeylanol, and cinncassiols A,B In 2014, the Inoue group at the University of Tokyo reported a synthetic strategy for ryanodol (4) that leveraged substrate symmetry design, employing intramolecular radical coupling and olefin metathesis as key steps [46] (Scheme 4). Recognizing an embedded

• , achieved the total synthesis of anhydroryanodol (10) and a formal synthesis of ryanodol (4) through a key low-valent titanium-mediated intramolecular stereoselective coupling of alkynes with 1,3-dicarbonyl compounds [52] (Scheme 9). To construct the oxygenated fused-ring system with contiguous

• . This work not only demonstrates the efficacy of the titanium-mediated intramolecular alkyne-1,3-diketone coupling but also provides a novel strategic approach for synthesizing natural products within this structural class. The synthesis commenced from commercially available compound 83. Sequential

Ni-promoted reductive cyclization cascade enables a total synthesis of (+)-aglacin B

• Si-Chen Yao,
• Jing-Si Cao,
• Jian Xiao,
• Ya-Wen Wang and
• Yu Peng

Beilstein J. Org. Chem. 2025, 21, 2548–2552, doi:10.3762/bjoc.21.197

• aryltetralin[2,3-c]furan skeleton embedded in this natural product. Keywords: aryltetralin; conjugate addition; cyclolignan; nickel; reductive coupling; Introduction Proksch and co-workers isolated aglacins A, B, C, and E (1–4, Figure 1) from the methanolic extract of stem bark of Aglaia cordata Hiern from

• synthesis of both enantiomers of aglacins A (1), B (2), and E (4) by asymmetric photoenolization/Diels–Alder reactions as the key steps for the construction of the C7–C8 and C7′–C8′ bonds [8]. During the past decade, we had developed nickel-catalyzed or -promoted reductive coupling/cyclization reactions for

Pentacyclic aromatic heterocycles from Pd-catalyzed annulation of 1,5-diaryl-1,2,3-triazoles

• Kaylen D. Lathrum,
• Emily M. Hanneken,
• Katelyn R. Grzelak and
• James T. Fletcher

Beilstein J. Org. Chem. 2025, 21, 2524–2534, doi:10.3762/bjoc.21.194

• tandem deprotection/click chemistry followed by Pd-catalyzed annulation is summarized in Table 1. The alkyne-substituted analogs 1–6 [48][49][50][51][52] used in this study were prepared from commercially available aryl halides using microwave-promoted Sonogashira coupling (Table S1, Supporting

Isoorotamide-based peptide nucleic acid nucleobases with extended linkers aimed at distal base recognition of adenosine in double helical RNA

• Grant D. Walby,
• Brandon R. Tessier,
• Tristan L. Mabee,
• Jennah M. Hoke,
• Hallie M. Bleam,
• Angelina Giglio-Tos,
• Emily E. Harding,
• Vladislavs Baskevics,
• Martins Katkevics,
• Eriks Rozners and
• James A. MacKay

Beilstein J. Org. Chem. 2025, 21, 2513–2523, doi:10.3762/bjoc.21.193

• incomplete conversion resulted in Boc protected beta-alanine that was challenging to separate from the desired product (3). Carboxylic acid 3 then underwent a peptide coupling reaction with allyl-protected PNA backbone 4 to afford nitrobenzene 5 in 69% yield. Nitrobenzene 5 was then reduced to the

• % of the final desired monomer 8 was also isolated in the coupling step, presumably due to hydrolysis of the allyl ester in the iron reduction step. The remaining allyl ester 7 was deallylated via Pd(PPh3)4 to afford the monomer 8 in 51% yield. Db2 Synthesis Db2 was prepared through a convergent

• perform equally well using conventional heating methods. Aniline 10 and carboxylic acid 13 were combined under standard (HBTU) amide coupling conditions to afford benzyl ester 14 in 52% yield. Compound 14 was subsequently debenzylated via hydrogenolysis to afford the target Db2 monomer 15 in 77% yield

Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions

• Udyogi N. K. Conthagamage,
• Lilia Lopez,
• Zuliah A. Abdulsalam and
• Víctor García-López

Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192

• -deuterated solvent signals (acetonitrile-d3: δH = 1.94 ppm, δC = 1.32 ppm). Coupling constant (J) values are in hertz (Hz). Resonance multiplicities are described as s (singlet), app s (apparent singlet), d (doublet), t (triplet), q (quartet), m (multiplet), and br (br). Mass spectrometry (MS) was conducted

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

• methodologies are greatly limited due to harsh reaction conditions that impact the scope of the reaction, poor yield, and regioselectivity issues. In sharp contrast, transition metal-catalyzed cross-coupling reactions promisingly improve the regioselectivity issues and substrate scope [25][26][27][28]. In

• 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

The intramolecular stabilizing effects of O-benzoyl substituents as a driving force of the acid-promoted pyranoside-into-furanoside rearrangement

• Alexey G. Gerbst,
• Sofya P. Nikogosova,
• Darya A. Rastrepaeva,
• Dmitry A. Argunov,
• Vadim B. Krylov and
• Nikolay E. Nifantiev

Beilstein J. Org. Chem. 2025, 21, 2456–2464, doi:10.3762/bjoc.21.187

• -Sundralingam parameters for C1-endo and C1-exo conformations of compound 2 are given in Table 1. The resulting most stable C1-endo conformer of furanoside 2 is in agreement with the 1H,1H coupling constants that were observed for it previously [26]: 3J1,2 < 1 Hz, 3J2,3 = 1.6 Hz and 3J3,4 = 5.0 Hz. The

The high potential of methyl laurate as a recyclable competitor to conventional toxic solvents in [3 + 2] cycloaddition reactions

• Ayhan Yıldırım and
• Mustafa Göker

Beilstein J. Org. Chem. 2025, 21, 2389–2415, doi:10.3762/bjoc.21.184

• aromatic aldehydes exhibit a Z-configuration [112][113] and it appears that endo-coupling of the Z-configured C,N-diphenylnitrone with maleimide is more favorable. Indeed, the distribution of the cis/trans product is also found to be significantly influenced by the nature of the substituents present in the

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

• 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

• in 55% from 25 and 26 in three steps. Triflation of the pyridone gave 33 with a triflate at the C2 position for cross coupling to form the C2–C3’ linkage. At this stage, the Sarpong group needed to install a functional group at the C3 position of the pyridine. They creatively solved this challenge

• lycodine 34 underwent Ir-catalyzed C3–H borylation mainly guided by steric factors to provide boronic ester 35 in 75% yield. With the boronic ester handle at the C3 position, the subsequent Suzuki–Miyaura cross coupling between 35 and 33 occurred smoothly to deliver pseudo-dimer 36, which upon acidic

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

• intermediate is also capable of cyclization through radical coupling to form cyclobutanol D, a process systematically expanded upon by Yang's group at the University of Chicago [4], which later became known as the Norrish–Yang cyclization. In recent years, dicarbonyls, specifically 1,2-diketones, α-keto esters

• ]. In contrast to the direct radical coupling in Norrish–Yang cyclization, the distal biradical F, formed from quinone E through a pathway analogous to that of C in the photoredox process, subsequently undergoes intramolecular SET to generate a zwitterion G. This intermediate is then trapped by the

• conformational preference at C8 that favors 1,5-HAT occurring at C9. (2) In terms of stereoselectivity, the steric hindrance between the spin center at C14 and the axial methyl group at C10 restricts the rotation around the C13–C14 bond, thereby enabling the diradical to undergo coupling stereoselectively. As a