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

• cancer cell line. Molecular docking simulation revealed strong binding interaction and affinities towards the tyrosine kinase domain of epidermal growth factor receptor (EGFR), and the protein–ligand interaction resembles the interaction found in the co-crystallised protein–erlotinib complex. Result and

• conformation (4HJO). The docking results revealed that both ligands fit well within the binding pocket of the EGFR tyrosine kinase domain. The binding interactions were further validated by comparison with the crystal structures of the active (1M17) and inactive (4HJO) forms of EGFR complexed with the co

• carbonyl oxygen surface promotes hydrogen-bond formation. The binding site interactions of compounds 7 and 8 with the tyrosine kinase were further validated by comparison with the crystal structure of 1M17 with co-crystallised ligand erlotinib (Figure 9c), showing that both compounds form similar active

Dialkylaminoalkylation of β-ketosulfones via ring-opening of 3-sulfonylpyrrolidines

• Evgeny M. Buev,
• Alexander V. Pavlushin,
• Vladimir S. Moshkin and
• Vyacheslav Y. Sosnovskikh

Beilstein J. Org. Chem. 2026, 22, 383–389, doi:10.3762/bjoc.22.26

• , sarcosine, and paraformaldehyde in PhMe/MTBE, followed by treatment of the reaction mixture with an alkyl halide, and subsequent heating of the precipitated quaternary ammonium salt in the presence of Cs₂CO₃ and a nucleophile – we proceeded to apply this methodology to other β-ketosulfones. Next, we

• -amine (5) in 77% yield (Scheme 4). This observation prompted us to examine methoxy and morpholine adducts 4a and 4o in the same process that resulted in the isolation of sulfonylamine 5 in 69 and 48%, respectively. The literature search revealed that previously Langler and co-authors observed the

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

• comparatively underdeveloped [30], despite the appealing prospect of higher barriers to enantiomerization and richer optoelectronic behavior [31]. In 2021, Yorimitsu and co-workers disclosed a series of symmetric dihetero[8]helicenes I–IV that exhibited intriguing chiroptical properties utilizing the

• characteristic transformations of the organosulfur functionality [32][33]. In 2024, Badani, Karnik, and co-workers accessed one member of this class, 7,12-dioxa[8]helicene I, through a sequence featuring photochemical E–Z isomerization, electrocyclization, and oxidative aromatization [34]. In parallel, Liu and

• co-workers introduced the π-extended azabora[8]helicene V with exceptional chiroptical signals and high brightness, emphasizing the promise of this class of chiral molecules (Scheme 1A) [35]. Despite these advances, unsymmetrical hetero[8]helicenes – where heteroatoms occupy non-equivalent positions

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

• , thousands of closely related compounds could be identified. Among these, the more structurally interesting, rearranged or highly oxidised members can often only be vaguely traced back to their biogenetic origin based on co-isolation and biochemical intuition. Synthetic approaches can sometimes help to solve

• elucidated by Dickschat and co-workers in 2023, describing the biosynthesis of the spirocyclic diterpene spiroluchuene A (20, see Scheme 5), catalysed by the synthase AlTS (Aspergillus luchuensis terpene synthase) [70]. Geranylgeranyl diphosphate (GGPP, 12) is initially cyclised through the well-known 1,10

• carbocation 29d, according to the mechanistic proposal by Coates [81]. By interception of the cation with water we arrive at presilphiperfolan-8β-ol (31) Dickschat and co-workers reported an example for a ring contraction during the biosynthesis of sodorifen (32) [82]. The cyclisation is triggered by the C

Spirobarbiturates with a pyrrolizidine moiety: synthesis, structure and biological evaluation

• Arthur A. Puzyrkov,
• Andrew S. Drachuk,
• Ekaterina A. Popova,
• Alexander V. Stepakov and
• Vitali M. Boitsov

Beilstein J. Org. Chem. 2026, 22, 274–288, doi:10.3762/bjoc.22.20

• ]. In 2018, Kota and Sreevani prepared spirobarbiturates via a Mo(CO)6-catalyzed intermolecular [2 + 2 + 2] cycloaddition of propargyl halides with dipropargylbarbituric acid [24]. Almeida and colleagues described the formation of spiroindoline barbiturates via thermal rearrangement of 2,1-benzisoxazole

• determines cell motility, and its structural organization can serve as an indicator of the metastatic potential of tumor cells [63][64][65]. The presence of stress fibers and filopodia-like protrusions were used to evaluate the Sk-mel-2 cells' actin cytoskeleton structure after their co-incubation with spiro

• -fused adducts 4f, 4g, 4i, 4k, and 4l. Confocal microscopy showed that co-incubation of Sk-mel-2 cells with adducts 4f, 4g, 4i, 4k, and 4l led to significant changes in the structure of their actin cytoskeleton resulting in stress fibers disappearance (granular actin was found in the cytoplasm of up to

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

• –Alder reactions with several electron-deficient dienes, furnishing distinctive methano-bridged structures (Figure 3C) [32][33][34][35]. Similarly, small cyclophanes are known to act as reactive dienes in Diels–Alder chemistry [36][37]. More recently, Lu and co-workers reported the unusually facile

• chemical literature, underscoring the potential of this strategy as a powerful platform for molecular discovery and medicinal chemistry. A similar strategic approach was utilized by Harman and co-workers to transform η2-coordinated anisole into a library of 3,6-substituted cyclohexenes with distinct

• early example was reported by Stille and co-worker in 1978, who elegantly demonstrated the formation of an η3-benzyl–palladium complex via oxidative addition of Pd(0) to a benzyl halide (Scheme 5C) [73]. Detailed stereochemical and NMR analyses revealed a temperature- and solvent-dependent equilibrium

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

• reactions catalyzed by diverse agents (Scheme 1). For instance, in 2013, Shi et al. described a three-component reaction involving 4-hydroxyquinolin-2(1H)-one, an aromatic aldehyde, and Meldrum’s acid, catalyzed by ʟ-proline under heating [37]. In the same year, Kurosh Rad-Moghadam and co-workers developed

Configuration–packing synergy enabling integrated crystalline-state RTP and amorphous-state TADF

• Ruiyan Wang and
• Yunan Wu

Beilstein J. Org. Chem. 2026, 22, 224–236, doi:10.3762/bjoc.22.16

• Ruiyan Wang Yunan Wu Sendelta International School, Shenzhen 518038, China Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400014, China New Materials Research Institute of CASCHEM (Chongqing) Co., Ltd, Chongqing 400714, China 10.3762/bjoc.22.16

• Technology Co., Ltd.; 3-(9H-carbazol-9-yl)phenylboronic acid (5) was obtained from Sukailu Co., Ltd.; glacial acetic acid, anhydrous sodium sulfate, dichloromethane, n-hexane, ethanol, chloroform, and tetrahydrofuran were supplied by Guangzhou Chemical Reagents Co., Ltd. All reagents were used as received

Synthesis of diaryl phosphates using phytic acid as a phosphorus source

• Kazuya Asao,
• Seika Matsumoto,
• Haruka Mori,
• Riku Yoshimura,
• Takeshi Sasaki,
• Naoya Hirata,
• Yasuyuki Hayakawa and
• Shin-ichi Kawaguchi

Beilstein J. Org. Chem. 2026, 22, 213–223, doi:10.3762/bjoc.22.15

• Research, Saga University, 152-1 Shonan-cho, Karatsu, Saga 847-0021, Japan Nippon Concrete Industries Co., Ltd., 4-6-14 Shibaura, Minato-ku, Tokyo 108-8560, Japan 10.3762/bjoc.22.15 Abstract Phytic acid is a phosphorus-rich molecule, which is produced by plants using water-soluble phosphates absorbed from

• overnight. The next day, the suspension was centrifuged (2000g, 10 min), and the supernatant was removed. The remaining pellets were resuspended in an appropriate amount of methanol, and the suspension was filtered via vacuum filtration using ADVANTEC No. 2 filter paper (ADVANTEC TOYO Co. Ltd., Tokyo, Japan

• ). The residue was washed with methanol and dried under vacuum overnight. Finally, 2.52 g of the crude sodium phytate was obtained as a white solid. Purification of extracted phytic acid Well-conditioned DOWEX 50W × 2 100–200 mesh (H) cation exchange resin (Dow Chemical Co., Midland, MI, USA) (60 mL) was

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

• through a catalytic kinetic resolution (KR) process was developed by Liu and co-workers [32]. The authors screened a range of organocatalysts, i.e., Takemoto’s thiourea catalyst, (S,S)-1,2-cyclohexanediamine-derived thioureas, cinchona alkaloid-derived thiourea, and squaramides to achieve the desired

• helical chiral entities was reported by Wang and co-workers. They reported an organocatalyzed asymmetric synthesis of phosphorus-containing chiral helicenes enabled by dynamic kinetic resolution using copper and peptide-mimetic phosphonium salts, i.e. amino acid-derived phosphonium iodide and bromide as

Streptoquinolines A and B, new antibacterial meroterpenoids produced by Streptomyces sp. TMPU-A0679

• Akiho Yagi,
• Hitomi Tomura,
• Ami Konno and
• Ryuji Uchida

Beilstein J. Org. Chem. 2026, 22, 185–191, doi:10.3762/bjoc.22.12

• Kyokuto Pharmaceutical Co. (Tokyo, Japan). All other chemicals used in this study were of special grade. General experimental procedures HRESIMS spectra were recorded using a mass spectrometer (Xevo G2-XS QTof, Waters Co., Milford, MA, USA). NMR spectra were acquired on a spectrometer (JNM-AL-400; JEOL

• crude materials containing 1 and 2 (23.5 mg). These materials were finally purified by preparative HPLC: column, Develosil C30-UG (Nomura Chemical Co., Ltd., Aichi, Japan), i.d. 10 × 250 mm; mobile phase, 55% MeCN aq. isocratic; detection, UV at 210 nm; flow rate, 3.0 mL /min. Under these conditions

Improved synthesis and physicochemical characterization of the selective serotonin 2A receptor agonist 25CN-NBOH

• Adrian G. Rossebø,
• Hannah G. Kolberg,
• Anders E. Tønder,
• Louise Kjaerulff,
• Poul Erik Hansen,
• Karla A. Frydenvang,
• Jesper Østergaard and
• Jesper L. Kristensen

Beilstein J. Org. Chem. 2026, 22, 175–184, doi:10.3762/bjoc.22.11

• through a 0.45 µm PVDF filter (Ø = 4 mm, Phenomenex) with the first 400 µL being discarded. Samples were diluted with ultrapure water before measurement by a UV spectrophotometry at 241 nm using 10 mm micro quartz cuvettes (Hellma GmbH & Co. KG, Müllheim, Germany) and a Cary 60 UV–vis spectrophotometer

A new synthesis of Tyrian purple (6,6’-dibromoindigo) and its corresponding sulfonate salts

• Holly Helmers,
• Mark Horton,
• Julie Concepcion,
• Jeffrey Bjorklund and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2026, 22, 167–174, doi:10.3762/bjoc.22.10

• ) and concentrated sulfuric acid (Scheme 7A). The trisulfonated 6,6’-dibromo-5,5’,7-indigotrisulfonic acid trisodium salt (10) was produced by heating 1 in oleum (20% free SO3), as shown in Scheme 7B. Although monosulfonation of indigo was reported by Sullivan and co-workers, an analogous reaction was

• and co-workers reported a 10% yield over 5 steps from p-toluidine, Wolk and Frimer reported a 25% yield over 5 steps from p-dibromobenzene, while Voß and Gerlach reported a yield of 61% over 3 steps from 1,4-dibromo-2-nitrobenzene, although specialized techniques were required [8][33][34]. We believe

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

• preparation of sulfinimidate esters remain scarce. For instance, Degennaro and Luisi reported a direct amination strategy using N,N’-disubstituted sulfenamides in alcoholic solvents; however, this method suffered from limited substrate scope [13]. Subsequently, Malacria and co-workers reported an oxidative

• previously disclosed a PIDA-mediated oxidative strategy for alcohol incorporation via activation of the S–NH bond (Scheme 1a) [14]. More recently, Wu and co-workers advanced the field by developing a dynamic kinetic resolution protocol for the enantioselective synthesis of sulfinimidate esters from racemic

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

• aim to explore the development of materials exhibiting circularly polarized luminescence (CPL). However, most reported chiral pincer-type platinum(II) complexes utilize point chirality as the chiral element. For instance, Zhong and co-workers reported a chiral platinum(II) complex bearing a leucine

• -derived pendant group, which exhibited aggregation-enhanced red phosphorescence and CPL properties in the solid states [20], while Yam and co-workers also reported pincer-type platinum(II) complexes containing chiral amine moieties, and investigated their aggregation behavior and chiroptical properties

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

• proposed mechanism was investigated in more detail by DFT studies. It is given in the next section. In order to examine the sensitivity of the dyes to anions in aqueous media, firstly, the best ratio with DMSO as a co-solvent for aqueous medium was determined. For this purpose, absorption spectra were

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

• in the presence of metal catalysts including Pd or Ir and different ligands. In 2021 and 2022, Wang and co-workers reported two impressive hydroboration–hydrogenation reactions catalyzed by FLP (triarylphenylborane) that reduced pyridine compounds 11 or 15 to dihydropyridine compounds 12 or chiral

• piperidine 17 (Scheme 3) [43][44]. Mechanistic studies demonstrated that the nitrogen atoms present in both pyridine and piperidine complexed with the triarylborane, cleaving the H–H bond and reducing the pyridine. In 2022, Xiao and co-workers reported a study on the conversion of isolated pyridinium salts

• be noted that in the presence of water, the reaction would undergo transamination with the pyridinium nitrogen moiety while inducing chirality on the ring. Hydrogenation of carbocyclic aromatic rings: In 2021, Andersson and co-workers reported a rhodium-catalyst precursor capable of operating in both

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

• photoredox catalyst, homolytic C–O bond cleavage occurred, generating alkyl radicals 50. These radicals abstracted a hydrogen atom from γ-terpinene, affording the corresponding alkanes. In this reaction, oxo-bridged dimeric zirconocene was employed. This catalytic system was first reported by Romero and co

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

• Synthesis of Acetylenes” [29] which discusses the preparation of alkenyl chlorides via ketone chlorination using PCl5 (Figure 3A). The synthesis of β-chlorovinyl ketones was later reviewed by Poland and Benson in 1966 (Figure 3B) [30]. More recently, Morandi and co-workers summarized transition-metal

• -catalyzed C–halogen bond formation (Figure 3E) [36]. Exchange reactions were reviewed by Evano and Nitelet in 2018 (Figure 3F) [37]. In 2020, Gandelman and co-workers provided an overview of decarboxylative chlorination reactions of carboxylic acids (Figure 3G) [38]. Hoveyda’s 2023 review highlights

• co-workers published a mini-review in 2013, written in Chinese, summarizing advances in the synthesis of vinyl chlorides [43]. As illustrated by the summary of existing reviews (Figure 3), the synthesis of alkenyl chlorides encompasses a wide range of mechanistically distinct strategies. An overview

Tandem hydrothiocyanation/cyclization of CF₃-iminopropargyl alcohols with NaSCN in the presence of AcOH

• Ruslan S. Shulgin,
• Ol’ga G. Volostnykh,
• Anton V. Stepanov,
• Igor’ A. Ushakov,
• Alexander V. Vashchenko and
• Olesya A. Shemyakina

Beilstein J. Org. Chem. 2025, 21, 2694–2702, doi:10.3762/bjoc.21.207

• ionic liquid- [16] or lactic acid-catalyzed [17] reactions of alkynoates, KSCN and water under ultrasound conditions as well as by the reactions of alkynoates, KSCN and water using deep eutectic solvents [18]. Reddy and co-workers [19] proposed an approach to thiocyano enones through the

• ). Increasing the quantity of acetic acid in the reaction mixture improved the product yields, especially for 2,5-dihydrofuran 3a (Table 1, entries 10 and 11). The best yield (76%) of 2a was obtained using acetic acid as co-solvent in a 3:1 (v/v) mixture of MeCN and AcOH (Table 1, entry 12); in this way a total

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

• cevanine-type Veratrum alkaloid to be successfully synthesized in the laboratory is (−)-verticine (15) (sometimes also called peimine). In 1977, Kutney and co-workers reported its semisynthesis from hecogenin acetate (91) in 30 steps [20][46]. It was only until four decades later that chemical methods

• -Methylenegermine The total synthesis of (±)-4-methylenegermine (17) was reported by Stork and co-workers in 2017 [22]. It represents an unnatural derivative of germine (20) with an additional methylene unit at C4 that was introduced to increase the stability of synthetic intermediates by avoiding the base

• overall yield of 2.0% from 100 [22]. A plan for the conversion of 105 to (±)-(20) was to follow Barton’s conditions for decarboxylative hydroxylation [48]. However, due to lack of material at the late stage, these steps could not be realized. The total synthesis of 20 was later disclosed by Luo and co

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

• -catalyzed anaerobic conditions [30], 11 was transformed into the C14 hydroxylated intermediate 12 as epimeric mixture in 42% yield and dr = 1:5, among which the undesired 14α-hydroxy epimer was the major component. Interestingly, the use of Co(acac)2 or Mn(acac)2 as the catalyst [31][32] instead of Fe(acac

• -carbonyl reduction by dissolved lithium metal in liquid NH3 solution, and the C11 α-hydroxylated intermediate 13 was obtained as a single diastereoisomer in 54% yield. Lastly, as expected, a Co(acac)2-catalyzed Mukaiyama hydration of 13 afforded the desired natural product sarmentogenin (2) in 69% yield

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

• chemistry and active pharmaceutical ingredients [38][39][40]. Over the years, the groups of Hopkinson, Wang, Dong, Marzo, and co-workers published a comprehensive review detailing the synthetic approaches and mechanistic insights of visible light-promoted dual photocatalysis that combined N-heterocyclic

• , and advanced optical and energy materials. Review Visible-light-driven NHC/4CzIPN-catalyzed reactions Recently, Shu and co-workers developed a direct and innovative preparation of highly functionalized aryl amide derivatives 3 from aryl aldehydes 1 and substituted imines 2 under mild conditions in the

• by the removal of the PMP protecting group using 2 equivalents of CAN and pyridine, affording 2,3-dihydrofurans 12a in 58% (Scheme 4) [54]. In 2022, Sumida, Ohmiya, and co-workers developed a dual NHC/4CzIPN-organocatalyzed, versatile, light-driven silyl radical generation strategy from substituted

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

• ][23][24][25]. In 2017, Yu and co-workers isolated a new Illicium sesquiterpene, namely illisimonin A, from the fruits of Illicium simonsii [26]. Unlike other Illicium sesquiterpenes, illisimonin A features an unprecedented bridged tricyclo[5.2.1.01,5]decane carbon framework that incorporates a highly

• neuroprotective effects against oxygen-glucose deprivation-induced cell injury in SH-SY5Y cells, suggesting its potential as a lead compound for the treatment of neurodegenerative diseases. The possible biosynthetic pathway of illisimonin A was also proposed by Yu and co-workers, as illustrated in Scheme 1. The

• Rychnovsky [28], Kalesse [29], Yang [30], Dai [31] and Lu [32] have achieved the total synthesis of this molecule. Notable, Rychnovsky and co-workers revised the absolute configuration of (−)-illisimonin A to 1S,4S,5S,6S,7R,9R,10R. This review summarizes the reported synthetic routes toward illisimonin A

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

• were ultimately elucidated in 1968 by Wiesner and co-workers using a combination of chemical degradation and X-ray crystallography [14]. Notably, in 2016, Inoue’s group at the University of Tokyo reconciled discrepancies through comparative analysis of experimental and natural product data, confirming

• adduct was subjected to AgOTf-catalyzed lactonization to successfully construct the D ring of target molecular framework. Next, a 1,4-addition reaction introduced a vinyl group to compound 68, affording compound 70. A Pauson–Khand cyclization of 70 under [RhCl(CO)2]2/CO conditions smoothly furnished the

• ). The synthesis commenced with the preparation of key cyclization precursor 98 via Barbier coupling and Babler–Dauben oxidative rearrangement. A pivotal palladium-catalyzed Heck/carbonylative cyclization then efficiently furnished the ABC tricyclic core 99. Notably, adding N-formylsaccharin under a CO