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

• . Protection of the free alcohol unit enabled the transformation towards 55, which involved the reduction of lactone to lactole, protection of the alcohol as acetate, BF3·Et2O-mediated C-allylation of the aldehyde (via oxocarbenium intermediate) and cyclization (oxy-Michael reaction). Hydroboration–oxidation

• towards 113 upon acidic treatment and TBDMS-protection. Reduction, cleavage of the silyl-protecting groups and acetylation led to tetrahydropyran 114. Lewis acid-catalyzed C-allylation, cross metathesis, basic cleavage of the acetate motifs and transesterification enabled the DBU-induced isomerization of

• to afford 154. Allylation and acidic deprotection led to diol 156 in excellent yields. Next, Au(I)-catalyzed cyclization and reduction led to tetrahydropyran 157, which was TBDMS-protected subsequently. The cross metathesis of 158 and 162 (obtained from ʟ-glutamic acid) yielded 159 in 81%. After

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

• reactions of η2-arene complexes with alkenes and alkynes; NMM: N-methylmaleimide [64][65]. Binding characteristics and pioneering examples of isolable η3-benzyl complexes. p-Selective allylation of benzyl chlorides with allylstannanes and subsequent synthetic expansion of dearomative cross-coupling

Reactivity umpolung of the cycloheptatriene core in hexa(methoxycarbonyl)cycloheptatriene

• Dmitry N. Platonov,
• Alexander Yu. Belyy,
• Rinat F. Salikov,
• Kirill S. Erokhin and
• Yury V. Tomilov

Beilstein J. Org. Chem. 2026, 22, 64–70, doi:10.3762/bjoc.22.2

• norcaradiene product in the case of benzylation, unlike in the close analogues, is due to a steric repulsion. The structure of norcaradiene 6f was confirmed through single crystal X-ray analysis (CCDC 2495985). Allylation of anion 2 was followed by intramolecular [4 + 2]-cycloaddition in norcaradiene 6g to

• further transformation in the case of allylation. Reactions with diazonium salts mainly involve a vicinal addition of the reagent to the anion and subsequent 1,5-sigmatropic shift, 6π-electrocyclization, and azocyclopropane rearrangement into dihydroindazole derivatives. Analysis of the reaction

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

• acetic acid [59] afforded asperdinones 1–4 in an average overall yield of 14% via the allylation/cross metathesis route and 7% via the direct prenylation route. In all cases, spectroscopic and analytical data were in accordance with the literature. The moderate yield in the Negishi cross-coupling

• . Asperidinones 1–4 were obtained in 7% average yields via the direct prenylation route, and 14% from the allylation/cross-metathesis route, whereas terezine D (6) was isolated in 44% overall yield. Insights into the reactivity and stability of the iodozinc N-Fmoc-ᴅ-alanyl anthranilamide reagent derived from 29

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

• identified as the key steps enabling the transformation from the allo-cedrane skeleton to the illisimonane framework. Inspired by the proposed biosynthetic pathway, Yang et al. designed a synthetic route as shown in Scheme 6. Starting from the known compound 53, a Tsuji–Trost allylation was employed to

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

• . This intermediate was intended to be prepared through allylation [36] with its precursor 15 accessible from aldehyde 16 and acetyl chloride through ketene–aldehyde [2 + 2] cycloaddition [37]. Results and Discussion Our synthetic route commenced from the known aldehyde 16 which is readily accessed in a

The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products

• Dong-Xing Tan and
• Fu-She Han

Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164

• -cyclopentanedione derivative was adopted as one of the key reactions, which facilitated the construction of the five-membered ring bearing an all-carbon quaternary center as the key chiral building block. Their synthesis began with 1,3-dione 40 (Scheme 2) [31][32], allylation of this substrate with allylic bromide

Asymmetric total synthesis of tricyclic prostaglandin D2 metabolite methyl ester via oxidative radical cyclization

• Miao Xiao,
• Liuyang Pu,
• Qiaoli Shang,
• Lei Zhu and
• Jun Huang

Beilstein J. Org. Chem. 2025, 21, 1964–1972, doi:10.3762/bjoc.21.152

• were developed. A straightforward transformation was designed involving a cross-metathesis of the C13–C14 double bond and a palladium-catalyzed decarboxylative allylation [32] as the key steps. With 14 in hand, we investigated the feasibility of cross-metathesis of the C13–C14 double bond. Initially

• of 21 with allyl alcohol and triphenylphosphine afforded transesterification product 22 in 21% yield [33], accompanied by unidentified decarboxylation by-products. A variety of standard conditions failed to promote the palladium-catalyzed decarboxylative allylation of allylic β-ketocarboxylate

• was treated with p-toluenesulfonic acid (p-TSA) in EtOH at room temperature to afford ketal 24 in 83% yield as a single diastereomer. Subsequently, palladium-catalyzed decarboxylative allylation delivered compound 25 in 89% yield. The efficiency of our first-generation strategy for asymmetric

Chiral phosphoric acid-catalyzed asymmetric synthesis of helically chiral, planarly chiral and inherently chiral molecules

• Wei Liu and
• Xiaoyu Yang

Beilstein J. Org. Chem. 2025, 21, 1864–1889, doi:10.3762/bjoc.21.145

• % ee). In 2025, Li and co-workers utilized analogous racemic benzaldehyde-containing paracyclophanes as substrates and accomplished their efficient kinetic resolution through catalytic asymmetric allylation [41]. Employing CPA/Bi(OAc)3 as a combined catalyst, the asymmetric allylation of racemic 40

• with allylboronic acid pinacol ester (41) led to efficient kinetic resolution, yielding the recovery of (Sp)-40 with high enantiopurity (Scheme 12). Notably, the allylation products 42, possessing both planar chirality and central chirality, were produced with high enantioselectivity and

• synthesis of planarly chiral macrocycles via CPA-catalyzed macrocyclization. (Dynamic) kinetic resolution of planarly chiral paracyclophanes via CPA-catalyzed asymmetric reductive amination. Kinetic resolution of macrocyclic paracyclophanes through CPA/Bi-catalyzed asymmetric allylation. Enantioselective

Copper catalysis: a constantly evolving field

• Elena Fernández and
• Jaesook Yun

Beilstein J. Org. Chem. 2025, 21, 1477–1479, doi:10.3762/bjoc.21.109

• community in that it elegantly reviews recent advances in allylation reactions of copper-catalyzed asymmetric allylic substitution reactions of chiral secondary alkylcopper species [5]. In summary, the contribution includes stereospecific transmetalations of organolithium and -boron compounds, copper

• allenes with diisobutylaluminum hydride, which is followed by the allylation with p-toluenesulfonyl cyanide in a regio- and stereoselective manner. They propose a new way to access accessing acyclic β,γ-unsaturated nitriles with α-all-carbon quaternary centers. In the process, they managed to achieve a

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

• simple heating in aqueous dioxane and the lactone products were obtained in moderate to excellent yields. In 2023, Han and Huang et al. developed a two-step protocol for the synthesis of tetrahydro-2H-1,4-oxazocines 226 and 1,4-oxazepanes 227 by a Tsuji–Trost allylation of 3-(arylamino)oxetanes 225

Synthetic approach to borrelidin fragments: focus on key intermediates

• Yudhi Dwi Kurniawan,
• Zetryana Puteri Tachrim,
• Teni Ernawati,
• Faris Hermawan,
• Ima Nurasiyah and
• Muhammad Alfin Sulmantara

Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91

• and deprotection steps, functional group transformations, stereocontrolled allylation, cross-metathesis, and Horner–Wadsworth–Emmons (HWE) olefination. This method highlights the power of catalytic stereocontrol, achieving the complex architecture of borrelidin fragments with efficiency and precision

• DIBAL-H to aldehyde 110 also resulted in stereochemical inversion (85%, anti/syn >15:1). Subsequent chelation-controlled allylation of aldehyde 110, following Ōmura’s method [27][29], employed allyltrimethylsilane and MgBr2·OEt2, yielding allyl alcohol 111 in 86% yield with exclusive

• ]. Synthesis of Ōmura’s C1–C11 fragment 61 by Minnaard and Madduri [37]. Synthesis of fragment 62b of borrelidin as proposed by Minnaard and Madduri [37]. Iterative directed allylation for the synthesis of deoxypropionates by Herber and Breit [33]. Iterative copper-mediated directed allyl substitution for the

Regioselective formal hydrocyanation of allenes: synthesis of β,γ-unsaturated nitriles with α-all-carbon quaternary centers

• Seeun Lim,
• Teresa Kim and
• Yunmi Lee

Beilstein J. Org. Chem. 2025, 21, 800–806, doi:10.3762/bjoc.21.63

• by the regio- and stereoselective allylation with p-toluenesulfonyl cyanide. The proposed methodology is efficient for accessing acyclic β,γ-unsaturated nitriles with α-all-carbon quaternary centers and achieves yields up to 99% and excellent regio- and E-selectivity. The reaction proceeds under mild

New advances in asymmetric organocatalysis II

• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 766–769, doi:10.3762/bjoc.21.60

• Malkov reviewed the recent progress in the organocatalytic synthesis of chiral homoallylic amines. This important structural motif is typically made by asymmetric allylation of imines, and the authors describe various catalytic approaches as well as applications of these strategies in total synthesis [25

Recent advances in allylation of chiral secondary alkylcopper species

• Minjae Kim,
• Gwanggyun Kim,
• Doyoon Kim,
• Jun Hee Lee and
• Seung Hwan Cho

Beilstein J. Org. Chem. 2025, 21, 639–658, doi:10.3762/bjoc.21.51

• construct non-benzylic and non-allylic CF3-substituted C(sp3) stereogenic centers. The synthetic utility of this allylation process was demonstrated through the facile functionalization of the allylic moiety in the enantioenriched product 41, providing access to optically active CF3-containing compounds

• asymmetric regiodivergent hydroallylation cycle. Copper-catalyzed enantiotopic-group-selective allylation of 1,1-diborylalkanes The generation of chiral non-racemic organocopper species through enantiotopic-group-selective transmetalation of 1,1-diborylalkanes 47 has recently garnered significant interest

• stereoselectivity. Importantly, this orthogonal reactivity complements established CuH-catalyzed procedures, significantly expanding the scope of copper-catalyzed asymmetric allylic substitution reactions. In 2021, Cho, Baik, and co-workers reported the first enantioselective copper-catalyzed allylation of 1,1

Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

• four-step process involves allylation, Claisen rearrangement, isomerization, and oxidative dimerization. Each reaction step was optimized independently by using either online HPLC or in-line benchtop NMR spectroscopy to afford an overall yield of 67% in 66 iterative experiments over four linear

Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• . Allylation of fluorinated hydrazones 3a–f to obtain 5a–f. Oxidation of hydrazines 5a–f to obtain hydrazones 6a–f. Intramolecular cyclization of compounds 6a–f to obtain tetrahydropyridazines 7a–f. Preparation of tripeptides 8e, 8e’, 8f, and 8f’. Yields refer to the yield over 2 steps. Supporting Information

Enantioselective regiospecific addition of propargyltrichlorosilane to aldehydes catalyzed by biisoquinoline N,N’-dioxide

• Noble Brako,
• Sreerag Moorkkannur Narayanan,
• Amber Burns,
• Layla Auter,
• Valentino Cesiliano,
• Rajeev Prabhakar and
• Norito Takenaka

Beilstein J. Org. Chem. 2024, 20, 3069–3076, doi:10.3762/bjoc.20.255

• systematic catalyst structure–reactivity and selectivity relationship study. The observed catalyst structure–enantioselectivity relationship of the present allenylation reaction was found exactly opposite to that of the analogous allylation reaction. The method provided eleven α-allenic alcohols in 22–99

• aldehyde allylation reaction with allyltrichlorosilane [47], it has been routinely employed in analogous chlorosilane reactions [48][49][50][51][52][53][54][55]. However, a mechanistic basis of its role on the observed rate acceleration remains elusive while it certainly functions as a scavenger of HCl

• structure–enantioselectivity relationship is exactly opposite to that for the analogous allylation reaction reported by Nakajima [47], thus it raises a possibility that the asymmetric induction mechanism could be fundamentally different between the present allenylation with propargyltrichlorosilane and the

Copper-catalyzed yne-allylic substitutions: concept and recent developments

• Shuang Yang and
• Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

• 350100, China 10.3762/bjoc.20.232 Abstract The catalytic (asymmetric) allylation and propargylation have been established as powerful strategies allowing access to enantioenriched α-chiral alkenes and alkynes. In this context, combining allylic and propargylic substitutions offers new opportunities to

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

• electrolyte, and carbon felt and platinum plate as electrodes, the intramolecular hydroamination proceeded smoothly, yielding azetidines in moderate to good yields. This method was applied to the LSF of celecoxib, zonisamide, and dansyl amide (Scheme 33a). Additionally, the allylation of aldehydes also

Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• Nikolay S. Kondratyev Andrei V. Malkov Department of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, WV1 1LY, UK 10.3762/bjoc.20.201 Abstract In recent decades, the chiral allylation of imines emerged

• equimolar chiral controller. However, recent years have witnessed the rise of asymmetric transition-metal catalysts and, importantly, organocatalytic allylation, reshaping the landscape of modern synthetic chemistry. This review explores the latest developments in the asymmetric allylation of imines

• essential to provide a comprehensive overview of this significant topic. Review Asymmetric allylation with boron-based reagents The research on the metal-free, asymmetric organocatalytic allylation of acylimines was pioneered in 2007 by Schaus and co-workers [24]. In their elegant approach, high

Electrochemical allylations in a deep eutectic solvent

• Sophia Taylor and
• Scott T. Handy

Beilstein J. Org. Chem. 2024, 20, 2217–2224, doi:10.3762/bjoc.20.189

• application of simple, inexpensive, and recyclable deep eutectic solvents to the allylation of carbonyls. While several sets of conditions were developed, the goal of avoiding stoichiometric amounts of metal has proven elusive. Still, a deep eutectic solvent can be used to plate out and thus recover the metal

• used, offering an interesting new option for electrochemical allylations. Keywords: allylation; electrosynthesis; eutectic solvent; recycling; tin; Introduction The last several years have witnessed a tremendous resurgence of interest in electrochemistry in the area of organic synthesis [1]. While

• , very little has been reported in terms of their use in electrosynthesis [20][21][22][23][24]. Given our interest in both electrosynthesis and DES, we opted to explore this combination in the area of electrochemical allylation. The allylation of carbonyls is a valuable reaction that has been explored

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• , oxidative allylation of 1,3-dicarbonyl compounds using allyltrimethylsilane (31) in the presence of ammonium cerium(IV) nitrate (CAN) provides access to allylated 1,3-dicarbonyl compounds 33 that are transformed with hydrazines to the corresponding pyrazoles 32 in a one-pot process (Scheme 9) [59]. CAN

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• reported a novel and straightforward method for synthesizing spiro 2,5-dihydrofuran derivatives starting from 17-ethynyl-17-hydroxysteroids such as lynestrenol (38) (Scheme 12) [25]. The 17-hydroxy group of steroids underwent allylation using allyl bromide and sodium hydride. After formation of the alkenyl

• -II) afforded the corresponding 17-spirolactams 123a,b in 71–73% yield (Scheme 34). Notably, when (S)-(+)-tert-butylsulfinamide was used in the initial step of the reaction sequence, the allylation of the resulting imine proceeded diastereoselectively, yielding the 17-allyl-17-sulfinamido compound as

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• synthesis has been reported for several transformations, such as epoxide opening [56], ketal formation and deprotection [57][58], Mannich reaction [59], intramolecular Sakurai cyclization [60], alcohol oxidation [61], aromatic hydrocarbon nitration [62], imine allylation [63], Knoevenagel condensation [64