Kinetic resolution of racemic planar-chiral vinylcymantrenes by molybdenum-catalyzed asymmetric metathesis dimerization

• Haruna Imazu,
• Hitoshi Izu,
• Yasuhiro Ohki and
• Masamichi Ogasawara

Beilstein J. Org. Chem. 2026, 22, 568–574, doi:10.3762/bjoc.22.42

• by the desymmetrization of the Cs-symmetric substrates [17][18][19] by the use of an appropriate chiral catalyst (see the drawing in Table 1 for the structures of the representative chiral molybdenum precatalysts used in this study) [20][21][22][23]. Planar-chiral transition-metal complexes have been

• of rac-1a giving (R,R)-2a of 99% ee and (S)-1a of 45% ee with 37% conversion (krel = 754; Table 1, entry 4). The lower catalyst loading (5 mol %) led to an unsatisfactory conversion (18%) probably due to the decomposition of the molybdenum catalyst prior to the completion of the reaction (Table 1

• in Figure 2) likely inhibits the effective interaction of the substrate with the chiral catalyst, resulting in highly enantioselective kinetic resolution. Cymantrene is far less electron-poor than ferrocene due to the presence of the three carbonyl ligands, which are strong π-acids, on the manganese

Get a better glimpse on sequential photoreactions of trisnorbornadienes with ¹⁹F NMR spectroscopy

• Julian Felix Maria Hebborn,
• Ben Eric Merten,
• Thomas Paululat and
• Heiko Ihmels

Beilstein J. Org. Chem. 2026, 22, 527–534, doi:10.3762/bjoc.22.38

• (see Supporting Information File 1, Figure S10). The photosensitized reaction in the presence of Ir(ppy)3 or 1-butyl-7,8-dimethoxy-3-methylalloxazin (4) as an alternative catalyst [44][45] with λex = 405 nm (LED) was investigated by in situ 1H NMR spectroscopy. In both cases, the photoreaction was

• mass, indicating decomposition above this temperature (see Supporting Information File 1, Figure S3). The cycloreversion of trisquadricyclane 2f0,3 was also initiated in a ground-state reaction with magic blue (5), which has already been shown to be an effective catalyst for this reaction [46][47][48

• ]. Upon addition of magic blue (5, 7.5 mol %) to a solution of quadricyclane 2f0,3 in CDCl3, the norbornadiene 1f was formed almost quantitatively in addition to very small traces of tri(4-bromophenyl)amine, i.e., the reduced catalyst (see Supporting Information File 1, Figure S12). Discussion A

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

• and further treated with Lindlar catalyst and DIBAL-H to afford the alkene and aldehyde motifs of 195, respectively. Oxime formation and oxidation yielded an intermediate nitrile oxide, which underwent an intramolecular [3 + 2]-cycloaddition with the adjacent ethene substituent towards isoxazoline 196

• -Tol2IOTf led to the formation of salt 239. Additionally, building block 247 was synthesized from commercial 240 (Scheme 27). Again, stereoselective chlorination using NCS and MacMillan catalyst 248 was perfomed to yield 241 [101]. Subsequently, ketone 249 was added to aldehyde 241 within a stereoselective

• macrocycle. Hence, this pathway enables the quick assembly of multiple derivatives. The late-stage allene-Prins reaction also facilitates the application of other substituents on the central 3-methylenetetrahydropyran unit. On top of that, the commonly used NHK reaction involving a Cr(II)-catalyst is

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

• potential applications in ligand and catalyst development. In a complementary direction, Smith’s group achieved the highly enantioselective synthesis of axially chiral naphthamides (Scheme 6) [47]. Their strategy employed transition-state hydrogen bonding to induce substrate deracemization, followed by

• biaxially chiral compounds. In 1989, Ito and co-workers reported the synthesis of the first distally biaxially chiral compound (Scheme 12) [35]. This reaction employed nickel as transition-metal catalyst, for the cross-coupling of 2-methyl-1-naphthylmagnesium bromide (43) with 1,5- (44) and 1,4

• (Scheme 13) [29]. The reactions were carried out under mild conditions and required only low catalyst loading. The key to achieving high enantioselectivity lies in the stereoselective synthesis of the starting compounds which relies on polar–π interactions between an aryl component containing a highly

A facile and practical method for the synthesis of trans-(±)-taxifolin and its derivatives via Darzens reaction

• Bo Peng,
• Panpan Yang,
• Maaz Khan,
• Xiaotong Lin,
• Jiang Wu,
• Peng Fu and
• Qingqing Wu

Beilstein J. Org. Chem. 2026, 22, 443–450, doi:10.3762/bjoc.22.31

• all the Lewis acids screened, ZnCl2 was associated with best yield of 90%. Overall, the optimal conditions for the Darzens reaction involved treatment of 2 (1.0 equiv) with 3a (1.2 equiv) in MeCN at room temperature, using t-BuOLi (1.2 equiv) as the base and ZnCl2 (0.1 equiv) as Lewis acid catalyst

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

• synthetic route for the C6-iodo-substituted 1ad is shown in Scheme 2. The Heck reaction of O-TIPS-protected 5a with allyl alcohol in the presence of a palladium catalyst provided the aldehyde 4a in 78% yield [9]. The reaction of 4a with CBr4 and PPh3, followed by treatment with n-BuLi, afforded the terminal

Cone p-aminocalix[4]arenes enriched with ‘clickable’ alkyne or azide functionalities

• Ilia Korniltsev,
• Vasily Bazhenov,
• Alexander Gorbunov,
• Dmitry Cheshkov,
• Stanislav Bezzubov,
• Vladimir Kovalev and
• Ivan Vatsouro

Beilstein J. Org. Chem. 2026, 22, 399–415, doi:10.3762/bjoc.22.28

• next the TBS-protecting groups were removed from the acetylene units in the Boc-protected tetraamines 21–23 (Scheme 4). For the removal of the TBS groups, instead of using an equivalent amount of n-Bu4NF, it was used as a catalyst in a water/THF mixture, which showed excellent efficiency for the room

• conditions, and the wide-rim pernitrated tetra- and ditosylates 29 and 30 were obtained in good yield. However, the subsequent reduction step was expectedly complicated. On the one hand, even partial reduction of the tosyl groups in calixarenes 29 and 30 might result in poisoning of a metal catalyst, thus

• copper complex (although an extraction procedure for complex destruction using Na2S2O3 was applied), which was difficult to separate from the relatively polar free calixarene 37 using column chromatography. In line with this, when toluene-soluble CuI·P(OEt)3 was used as a catalyst (in this case heating

Non-central chirality in organic chemistry

• Ken Tanaka and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2026, 22, 370–371, doi:10.3762/bjoc.22.24

• remote from the reaction site. Second, non-central chiral frameworks remain fertile ground for catalyst design, not only as derivatives of established motifs but also as newly conceived architectures that redefine how chirality can be embedded into catalytic systems. Third, the pronounced chiroptical and

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

• , respectively. N-Phenylbenzamide (5) also afforded 1 in 86% yield. Secondary and tertiary acetamides 6–8 were also successfully cleaved, affording the product 2 in high yields. The CeO2 catalyst was recyclable, although a slight decrease in yield was observed upon reuse. Notably, catalytic activity was fully

• of CeO2 to attack the carbonyl carbon, leading to cleavage of the C–N bond (B). Subsequent nucleophilic attack of the octoxide anion on the activated carbonyl center (C) then furnishes the ester product. Later, the same group found that niobium could also serve as a heterogeneous Lewis acid catalyst

• for the hydrolysis of amides (Scheme 3) [47]. In the presence of a catalytic amount of Nb2O5, N,N-dialkylamides 3 and 4 and anilides 5 and 10 were efficiently converted into the corresponding carboxylic acids 9 in high yields, and the Nb2O5 catalyst could be successfully recycled. The authors proposed

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

• catalyst yields desirable cycloalkenes after oxidative decomplexation in excellent yield. The same reaction with D2 produces a single isomer in which all the deuterium atoms are anti to osmium. Earlier authoritative reviews by Harman provide comprehensive accounts of the rich chemistry accessible through

• this review, η3-benzyl complexes stand out as catalytically competent intermediates in redox-catalytic transformations. Future advances in this arena will depend on broadening the nucleophile portfolio, exerting precise catalyst control over site-selectivity (spanning benzylic, ortho, and para

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

• a related protocol operating at room temperature using the ionic liquid [Bmim]HSO4 as a catalyst, expanding the scope to include aliphatic aldehydes [38]. Later, in 2017, Esmayeel Abbaspour-Gilandeh et al. reported a modified variant of this transformation under solvent-free heating, catalyzed by

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

• [22] and as insecticides [23]. Particularly, phosphate diesters are among the most important synthetic catalysts, such as the Akiyama–Terada catalyst that serves as a chiral Brønsted acid catalyst [24][25] and promotes a variety of stereoselective reactions. Phosphate diesters also catalyze the ring

• esters could be slightly improved by using a catalytic amount of 1-butylimidazole; however, in the present work, a catalyst was not employed to simplify the purification step. The reaction temperature in this process should have been set to 230 °C. However, at this temperature, a burnt black material 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

• outcome of the reaction. After rigorous testing, (S,S)-1,2-cyclohexanediamine-derived catalyst L1 was found to be the most effective organocatalyst to induce both the helical chirality and remote axial chirality during the functionalization of the [4]- and [5]helicenes 3a–k with good yield and excellent

• enantioselectivity. Notably, [6]helicene 3k was also readily produced, via kinetic resolution (Scheme 1). Computational studies suggested that hydrogen bonding and π interactions between the reactants and catalyst L1 controlled the stereochemical output of the products 3. The catalyst proximate both reactants to

Base-promoted deacylation of 2-acetyl-2,5-dihydrothiophenes and their oxygen-mediated hydroxylation

• Vladimir G. Ilkin,
• Margarita Likhacheva,
• Igor V. Trushkov,
• Tetyana V. Beryozkina,
• Vera S. Berseneva,
• Vladimir T. Abaev,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2026, 22, 192–204, doi:10.3762/bjoc.22.13

• S3 of Supporting Information File 1) we have studied their transformations in ethanolic or methanolic solutions in the presence of sodium ethoxide or methoxide, accordingly. As a result, catalyst-free oxidation under mild conditions of 2-acetyl-2,5-dihydrothiophenes into 2-hydroxy-substituted

Asymmetric Mannich reaction of aromatic imines with malonates in the presence of multifunctional catalysts

• Kadri Kriis,
• Harry Martõnov,
• Annette Miller,
• Mia Peterson,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2026, 22, 151–157, doi:10.3762/bjoc.22.8

• with the steric effect of the tert-butyl group of the catalyst, is responsible for the high stereoselectivity of the reaction. Keywords: aromatic imine; asymmetric catalysis; Mannich reaction; noncovalent interactions; organocatalysis; Introduction The Mannich reaction, i.e., the addition of an

• led to the use of multifunctional catalysts of “homocooperativity,” where multiple units of the same catalyst perform different but complementary roles [17]. These catalysts employing noncovalent interactions via hydrogen bonds and also possess Lewis basic and π–π-interaction sites have been highly

• ], halogen bonding is more frequently employed as a component of multifunctional catalytic systems [23][24][25]. Multifunctionality of the catalyst is essential to intensify weak noncovalent interactions. Results and Discussion As a continuation of our previous studies [18][24], we now report an asymmetric

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

• saturation the aromatic ring facilitates synthetic chemists to efficiently synthesize natural products with complex three-dimensional structures. Recent advances in catalyst and ligand design have enabled unprecedented progress in the catalytic hydrogenation of (hetero)aromatic systems. Quinoline

• limitation requires the design of catalysts that achieve precise electronic complementarity, enabling selective activation across a broad spectrum of aromatic compounds (Scheme 2) [32]. From the standpoint of scalable synthesis, catalyst cost is a major bottleneck in aromatic hydrogenation. Most state-of-the

• transformation into a broadly enabling strategy in complex molecule synthesis, yet a unified perspective connecting recent methodological advances with their strategic applications in the total synthesis of natural products remains lacking. Although several reviews discuss catalyst development for (hetero)arene

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

• Schwartz’s reagent to furnish product 4d. In 2017, Kishi et al. reported a radical-based ketone synthesis employing zirconocene and a nickel catalyst (Scheme 2A) [9]. Traditional anion-based ketone syntheses (e.g., Grignard or RLi reagents) are often unsuitable for complex molecules due to the strongly basic

• a photosensitizer, together with compound 22 as a sacrificial reductant, in the dimerization of benzyl bromide (19). The desired dimerized product 20 was obtained in 40% yield. This study highlights the potential of zirconium complexes as a photoredox catalyst, pointing to promising opportunities

• experiments, coordination of thiourea 26 to the Zr center was suggested. This effect is considered to have tuned the reactivity of the Zr-catalyst, thereby having a positive effect on the reaction process. Finally, the regioselectivity of epoxide ring opening was compared between low-valent titanocene and

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

• ). In 2006, Apotex reported the synthesis of alkenyl chlorides using POCl3 in the presence of triethylamine and a copper catalyst (Scheme 16) [69]. The preparation of compound 84 is of industrial significance due to its application in the synthesis of terbinafine (86), an antifungal agent. The reaction

• that were irreversibly adhered (Figure 6, oval stirring bar left a mark in the solid polymer). Various catalyst loadings of CuCl (5–20 mol %) were evaluated, with 15–20 mol % required to achieve useful yields of 9 within several hours (Figure 7). Mechanistic analysis proved challenging, as the catalyst

• described a ruthenium-catalyzed conversion of alkenyl triflates to alkenyl chlorides (Scheme 22C) [80]. A subsequent study from the same group demonstrated that [Cp*Ru(MeCN)3]OTf could serve as an alternative catalyst, thereby avoiding the need for in situ reduction of Ru(III) to Ru(II) by organometallic

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

• 94% yield using CPhos-Pd-G3 as the palladium pre-catalyst (Scheme 1) [31]. However, under the same reported conditions only the unreacted starting material was recovered. In an isolated example, C-7 allylation of 7 was reported via a Stille coupling protocol to give 8 (Scheme 1) [32]. As an

• alternative approach to C-7 functionalization of Nα-Boc-tryptophan methyl ester, we chose a CH activation protocol [33]. Treatment of N1-Piv-Nα-Boc-tryptophan methyl ester (10) with but-3-en-2-one (MVK) in the presence of [RhCp*Cl2]2 catalyst according to Ma et al. [34] led to the 7-(3-keto-1-butyl)-alkylated

• in the presence of the Pd catalyst. It follows that elimination and reduction must occur after Pd insertion and formation of a pallado–zinc intermediate which undergoes β-elimination and proton transfer. Seminal studies by Jackson [61] have reported related results with iodozinc N-Boc-ʟ-alanine

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

• without catalysis or using triethylamine–acetic acid as a bifunctional catalyst (Scheme 2). The reactions with alkyl methyl ketones 2b,c in 1,4-dioxane without catalysis led to the formation of a mixture of octahydropyrido[1,2-a]pyrimidinones 4b,c and hexahydrooxazolo[3,2-a]pyridones 5b,c, but with a

• catalyst, the cis,trans-isomer is preferentially formed, whereas dual acid-base catalysis favors the formation of the other cis,cis-diastereomer. The obtained hydrogenated oxazolo- and pyrimido-condensed pyridones are of interest for biological testing, which is confirmed by the discovery of an antiviral

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

• installed another exo-methylene (in the future F-ring), which would later be reduced to the methyl group at C25. Staudinger reduction and two protecting group manipulations set the stage for the formation of the piperidine (F-ring) through a Mitsunobu reaction. Hydrogenation employing Wilkinson’s catalyst

• enantiomeric excess of 92%. This asymmetric hydrogenation included a novel iridium catalyst featuring a chiral SpiroBAP (spiro bidentate aminophosphorane) ligand, which has been developed previously by this group and was now successfully applied in this synthesis [36]. A silver-catalyzed, enantioselective

• to abstract the chloride of the [Rh(cod)Cl]2 catalyst, forming a cationic rhodium complex in situ, while diethyl fumarate acted as a hydrogen acceptor. Double bond isomerization, ketone reduction and deprotection of 73 furnished veratramine (13). This Diels–Alder strategy concluded the synthesis of

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

• typical Mukaiyama hydration conditions [30][31][32] to install the C14 β-hydroxy group. However, only a trace amount of the undesired C14α-hydroxylated product 10 was obtained. Additional optimizations regarding the transition-metal catalyst, hydrogen source and solvent all failed to improve the results

• -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

Thiazolidinones: novel insights from microwave synthesis, computational studies, and potentially bioactive hybrids

• Luan A. Martinho,
• Victor H. J. G. Praciano,
• Guilherme D. R. Matos,
• Claudia C. Gatto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2025, 21, 2618–2636, doi:10.3762/bjoc.21.203

• different products were obtained), delivers excellent yields (up to 99%), and requires low catalyst loading (10 mol %). This new approach was successfully applied to the synthesis of eight novel imidazo[1,2-a]pyridine–thiazolidinone hybrids in good to excellent yields (66–99%). A spectroscopic study of

• condensation-type reaction between aromatic aldehydes with rhodanine or thiazolidine-2,4-dione [39]. Various protocols have been reported employing diverse catalyst systems and reaction conditions. Common catalysts include inorganic bases such as sodium acetate (NaOAc) [40], urea/thiourea [41], NaOH [42

• drawbacks, including long reaction times, harsh conditions, low to moderate yields, tedious work-up procedures, use of environmentally hazardous solvents, high catalyst loadings, toxic residues, and the need for specialized apparatus. To address these limitations, alternative methodologies have been

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

• positive to enable SET oxidation by photoexcited 4CzIPN. The authors described that the reduction potential of the photoredox catalyst (PC = 4CzIPN) was moderately low [Ered(IrIII*/IrII) = +0.66 V vs SCE in MeCN], and the silylboronate 13 permitted the formation of the silyl radical C under mild oxidation

• catalyst. The anticipated meta-acylation product 32 was achieved through highly selective C(sp3)–C(sp3)-radical–radical cross-coupling between the cyclohexadienyl radical C and the benzyl radical species F, formed via single-electron reduction. This photochemical method overturns the traditional ortho and

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

• the same pot to give 72. Isomerization of the allylic methyl ether to an enol methyl ether was achieved using Crabtree’s catalyst in refluxing THF. Subsequent ketalization with the primary alcohol yielded the bridged ketal 73. A Schenck ene reaction on 73 induced the second olefin isomerization