Z-Selective semihydrogenation of alkynes via Ni/Lewis acid synergistic catalyzed system using DMF as hydrogen source and solvent

• Lei Kang,
• Haifeng Gao and
• Luo Yang

Beilstein J. Org. Chem. 2026, 22, 1004–1012, doi:10.3762/bjoc.22.79

• hydrogenation systems. HCOOH then reacts with the Ni species to form a formate nickel hydride intermediate B (HCOONi(II)H), a key species documented in nickel-catalyzed hydrogen-transfer reactions. Subsequent selective insertion of the internal alkyne into the Ni–H bond of B affords the vinyl-nickel

• intermediate C. Following decarboxylation, the resulting dihydrido vinyl-nickel species D undergoes reductive elimination to release the (Z)-alkene product and regenerates the Ni(0) catalyst A, thereby closing the catalytic cycle. Conclusion In summary, we have developed a highly Z-selective semihydrogenation

Electrochemical reduction of unsaturated carbon–carbon bonds via 3d transition-metal catalysis

• Geon Kang,
• Minki Jeon,
• Pooja Kumari Jat,
• Cheoljae Kim and
• Isaac Choi

Beilstein J. Org. Chem. 2026, 22, 955–981, doi:10.3762/bjoc.22.75

• (37.8 kcal mol−1) bonds in the Co–salen complex disfavor the formation of a persistent vinyl–cobalt σ-bond intermediate. Consequently, the resulting vinyl radical is more appropriately described as undergoing cage escape, thereby favoring a radical-type pathway rather than an organometallic sequence

• of alkynes (Scheme 6C, i). An intramolecular radical trapping experiment employing enynes further corroborated the involvement of a vinyl radical intermediate, as evidenced by the formation of cyclized products via C–C bond formation followed by hydrogen abstraction (Scheme 6C, ii). Mechanistic

• revealed the emergence of new absorption features upon alkyne addition, consistent with the formation of a vinyl–Co(III) intermediate. DFT calculations further demonstrated that variation of the salen ligand framework modulates the Co–C bond-dissociation energy (BDE) of the vinyl–cobalt intermediate

Synthesis of sterically shielded piperidine nitroxides via acid-catalyzed heterocyclization of β-aminoketone derivatives with ketones

• Mark M. Gulman,
• Yurii I. Glazachev and
• Sergey A. Dobrynin

Beilstein J. Org. Chem. 2026, 22, 948–954, doi:10.3762/bjoc.22.74

• (MRI) [4][5] and as spin probes for Overhauser MRI in vivo [6]. Piperidin-1-oxyls played a key role in the development and industrial implementation of controlled polymerization of vinyl monomers (nitroxide-mediated polymerization, NMP) [7]. The unique redox properties of these radicals underpin their

• allyl derivative 7d, extensive signal overlap prevented rigorous simulation, but characteristic terminal vinyl protons at 5.83, 5.28, 5.27 ppm were clearly observed. Elemental analysis and HRMS data were in agreement with the proposed structures. Subsequent hydrogenation of the unsaturated carbon–carbon

Recent advances in copper-catalyzed direct hydroamination of alkenes with (hetero)aromatic amines

• Hyejeong Lee and
• Yunmi Lee

Beilstein J. Org. Chem. 2026, 22, 925–947, doi:10.3762/bjoc.22.73

• ]. Hydroamination simultaneously forms C–N and C–H bonds from simple and readily available starting materials without prefunctionalization. When applied to electron-deficient alkenes such as α,β-unsaturated carbonyl compounds, nitroalkenes, or vinyl sulfones, this transformation is often categorized as an aza

• ) were subsequently evaluated by adding aniline to activated olefins (Scheme 3) [35][36]. Using 5 mol % of the copper–amido catalyst at room temperature, the α,β-unsaturated substrates including acrylonitrile, methyl vinyl ketone, methyl acrylate, and cyclic enones were converted to the corresponding β

• -amino products 1a–d with excellent regioselectivity. These reactions proceeded exclusively in an anti-Markovnikov manner with high efficiency. For example, the addition of aniline to acrylonitrile afforded 1a with >95% conversion after 12 h using IPrCu–NHPh (II), whereas methyl vinyl ketone was rapidly

Diastereodivergent electrophilic trapping of α-boryl lithium derivatives

• Tereza Pavlíčková,
• Noam Orbach and
• Ilan Marek

Beilstein J. Org. Chem. 2026, 22, 882–887, doi:10.3762/bjoc.22.68

• revealed that the electrophile preferentially approaches from the face opposite the coordinating lithium cation, with the lowest-energy transition state stabilized by a lithium cation–vinyl interaction (see A in Scheme 1) [34]. Results and Discussion The intricate interplay of the coordination and steric

• calculations, this model assumes initial coordination of both the vinyl group and the Bpin moiety to the lithium counterion. Within this constrained geometry, when R2 = H, R3 = alkyl, the diastereocontrol is then governed by the relative steric interactions present in these two possible conformers B and C

The trans-influence in gold chemistry from a catalytic perspective

• Manfred Bochmann

Beilstein J. Org. Chem. 2026, 22, 838–856, doi:10.3762/bjoc.22.66

• reported NHC-decorated diphosphene complex (NHC)P(R)–P(R)AuH similarly forms the Z-vinyl product with DMAD (R = 2,6-Mes2C6H3) [64]. Consistent with this, while (C^N^C)AuH inserts neither O2 nor DMAD (nor indeed ethylene, CO2 or benzaldehyde) [31][49], heating (C^C^N)Au–O2CH with RC≡CR (R = t-BuOOC–) gives

• complexes of type 8 can react with acetylenes slowly, in a possibly light-induced radical reaction [49]. The addition of radical initiators such as azobis(isobutyronitrile) (AIBN) reduced the reaction times from days to minutes, with quantitative and completely stereoselective formation of Z-vinyl gold

• ^C)AuH(C6F5)]− 21 react slowly at room temperature with DMAD to give the corresponding Z-vinyl products 24 and 25, respectively. On treatment with acid 24 decomposes with reductive C–C coupling but without Au–vinyl protolysis, while irradiation of THF solutions of 24 or 25 at room temperature leads

Synthesis of heterocycles based on azomethine ylides from α-amino acids (or amines) and carbonyl compounds

• Ekaterina V. Berezhnaya,
• Alexander I. Ponyaev,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2026, 22, 705–741, doi:10.3762/bjoc.22.55

• electron-withdrawing substituents have been widely studied; acrylates, vinyl sulfones, maleimides, β-nitrostyrenes, fumarates, and maleates have been used most frequently [28][29]. Reactions of aromatic and heteroaromatic olefins containing both electron-donating and electron-withdrawing groups in the

• cycloaddition of azomethine ylides based on glycine or alanine methyl ester imines 12 with vinyl phenyl sulfone 13 catalyzed by a chiral silver complex (Scheme 3) [44]. It was found that iminoethers 12 are capable of reacting smoothly with vinylphenylsulfone 13, forming the corresponding endo-cycloadducts 14 in

• group and, thus, somewhat simplifies the cycloaddition reaction. The introduction of aryl and alkynyl substituents at the C4 position of the dipolarophile increases the reactivity of the multiple bond due to double activation by conjugated groups. In 2016, a study was published [56] in which vinyl

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

• and 3 was reported in 1988 starting from 3-vinyl-2-cyclohexen-1-one featuring a key intramolecular aldol condensation reaction [33]. On the other hand, semisyntheses of 2 were achieved starting from related terpene products, including elemol (featuring a Hg(OAc)2-mediated oxymetallation) [34], β

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

• ) presence of a substituent (Br or Me) at the position adjacent to the vinyl group in the clockwise direction, (2) absence of a substituent other than hydrogen at the position adjacent to the vinyl group in the counterclockwise direction (CH or P). The substituent adjacent to the vinyl group (marked in red

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

• protected with TESCl, then regioselective oxidation of the primary TES ether and addition of vinyl grignard led to 87. Another oxidation afforded α,β-unsaturated carbonyl 88 and acidic treatment with BnOH triggered the oxa-Michael reaction and transketalization towards tetracyclic 90. Following Kishi

• )/Cr(II)-mediated coupling of 1-bromo-2-trimethylsilylethene, acidic cleavage of the remaining cyclohexylidene ring, TBDMS-protection of the three alcohol units and electrophilic substitution of the silyl moiety to afford vinyl iodide 103 was applied. Eventually, ester 103 was reduced to target

• 166 via radical cyclization, then the TBDPS-protecting group was cleaved and the obtained alcohol oxidized to aldehyde 167. The Cr(II)/Co(II)-induced asymmetric NHK coupling mediated by 172 with vinyl iodide 171 led to tetrahydrofuran 168. Protection of the secondary alcohol enabled the conversion to

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

• alkyne 6. Subsequent preparation of the lithium acetylide using n-BuLi, followed by treatment with formaldehyde, afforded propargyl alcohol 3a in 70% yield over three steps. The reaction of 3a with Red-Al generated a vinyl aluminum species, which was then treated with iodine to provide the iodinated Z

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

• ] cycloaddition of azomethine ylides at various vinyl sulfones were well studied [38][39][40][41], a method for the preparation of 3-sulfonylpyrrolidines from β-ketosulfones was previously unknown. We synthesized a number of pyrrolidines 2a–f in 83–97% yield, which were purified by an acid-base extraction (Scheme

• . Second is a step-wise route through retro-Claisen reaction, formation of the carbanion at the α-position to sulfonyl group, and Hofmann elimination of the quaternary nitrogen at the β-position. Both routes lead to the formation of terminal vinyl sulfone C, which reacts with the nucleophile present in the

Synthesis of tricyclic fused pyrrolidine nitroxides from 2-alkynylpyrrolidine-1-oxyls

• Mark M. Gulman,
• Yuliya F. Polienko,
• Sofia Yu. Trakhininа,
• Yuri V. Gatilov,
• Tatyana V. Rybalova,
• Sergey A. Dobrynin and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2026, 22, 344–351, doi:10.3762/bjoc.22.22

• dioxide in tetrahydrofuran gave vinyl ether 8, which was isolated with 50% yield (Scheme 4). The structure of the product 8 was confirmed by X-ray crystallographic analysis (Figure 3, CCDC 2512653). Formation of 8 apparently occurs via cyclization of alkynal 7. The formation of vinyl ethers has been

• . Synthesis of mesyl 3a–f and triazole 4a–f derivatives. Synthesis of alkynones 6a,b. Synthesis of vinyl ether 8. Synthesis of pyrazole derivatives 9a–c. Reduction rate constants k2 and EPR spectral parameters of nitroxides 2a–f, 4a–f, 9c. Supporting Information Supporting Information File 3: Experimental

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

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

• electrophilic addition. Comparable effects are observed for furans and pyridines, where η2-coordination accentuates their vinyl ether and imine character, respectively. As an illustrative example, treatment of the phenol complex 5 with methyl vinyl ketone and pyridine affords 4-alkylated 4H-phenol complex 6 as

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

• feature symmetrical alkylaminophenyl donor groups and a strong electron-withdrawing dicyanovinylene as an acceptor connected through vinyl groups as a π-bridge. These strongly π-conjugated organic dyes can absorb in the NIR region, and they showed sensitivity towards the polarity of solvents with

• ). The vinyl bridges were added to the design, which have the potential to open nucleophilic addition reactions (Michael type) due to their electron deficiencies, in addition to acting as π-bridges for the D–A conjugation. Furthermore, a symmetric design with increased π-conjugation was planned to shift

• detect cyanide anions due to the presence of vinyl groups, where cyanide can be attacked via nucleophilic addition reaction. Therefore, the sensitivity and selectivity of dyes towards cyanide were investigated by the addition of cyanide (CN−) and competing anions (F−, Cl−, Br−, I−, AcO−, ClO4−, H2PO4

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

• homogeneous and heterogeneous phases to achieve asymmetric complete hydrogenation of vinyl aromatics – a long-standing challenge in arene reduction (Scheme 4) [46]. By tuning the ratio of phosphine ligand to rhodium precursor, they controlled the formation of distinct catalytic species, which remained

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

• important and versatile functional group. Keywords: alkenyl chloride; chloroalkenes; chloro olefins; vinyl chlorides; Introduction Alkenyl chlorides, while less extensively investigated than their brominated analogues, constitute a synthetically valuable class of organohalides with distinct reactivity

• ], and pesticides [7] (Figure 2). Throughout this review, the term “alkenyl chloride” refers broadly to chloroalkenes beyond vinyl chloride (CH2=CHCl), the monomer used in polyvinyl chloride (PVC) production. Before detailing the synthesis and applications of alkenyl chlorides, we wish to acknowledge

• 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

• acid at the triple bond – vinyl thiocyanates. This protocol features simple operating, readily prepared starting materials and occurs under relatively mild conditions. Keywords: CF3-alkynyl imines; hydrothiocyanation; isothiazolium thiocyanates; propargyl alcohols; sodium thiocyanate; Introduction

• The hydrofunctionalization of alkynes is one of the most effective and convenient ways of synthesizing polysubstituted alkenes [1][2][3][4][5]. Such reactions can also afford more complex products, provided that the vinyl intermediates formed during the reaction undergo further transformations [6][7

• cyclization to isothiazolones (Scheme 1). Silver- [20] and gold-catalyzed [21] hydrothiocyanations of haloalkynes with thiocyanate salts in acetic acid to give Z-vinyl thiocyanates were reported. The reaction between alkynic hydrazones and KSCN in AcOH/MeCN delivered N-iminoisothiazolium ylides [22] (Scheme 1

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

• the hydroxy moiety in C12 was performed, followed by Grignard addition of ethynylmagnesium bromide and then hydrocyanation to result in vinyl nitrile 57 over five steps. The key Wagner–Meerwein-type rearrangement occurred in 68% yield furnishing epoxide 58. Hydrogenation of the alkene moiety as well

• alkyne fragment 116 (see Scheme 33). The synthesis of diyne fragment 112 commenced with an organocatalytic, enantioselective Diels–Alder reaction between siloxydiene 108 (synthesized in one step from ethyl vinyl ketone) and commercially available dienophile 109 using the proline-derived Hayashi ligand

• moiety and protection of the primary alcohol was followed by a Robinson annulation with methyl vinyl ketone to construct bicyclic fragment 111. The enone moiety was protected as an acetal, followed by alkylation of the primary alcohol with a propargyllithium species. Further functional group

Silica gel with covalently attached bambusuril macrocycle for dicyanoaurate sorption from water

• Michaela Šusterová and
• Vladimír Šindelář

Beilstein J. Org. Chem. 2025, 21, 2604–2611, doi:10.3762/bjoc.21.201

• example, an amphiphilic poly(methyl methacrylate)-based polymer modified with calix[4]pyrrole was found to form micelles in water that capture anions from caesium salts and can be precipitated from solution upon heating [11]. Similarly, a hydrogel composed of poly(vinyl alcohol) cross-linked by a “Texas

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

• available starting materials, good functional group tolerance, and mild, transition-metal-free conditions. NHC-catalyzed radical approach furnishes access to substituted 3,4-dihydro-2H-pyrroles 18, in good yields (Scheme 7) [57]. A novel strategy was discovered for 1,2-dicarbonylation of vinyl arenes 11

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

• then converted to vinyl iodide 26 via hydrazine formation followed by iodination using Barton’s method. Subsequent Bouvealt aldehyde synthesis and in situ reduction delivered allylic alcohol 27. Epoxidation of 27 with m-CPBA afforded the rearrangement precursor 28. Protonic acid-promoted semipinacol

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

• 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

Catalytic enantioselective synthesis of selenium-containing atropisomers via C–Se bond formations

• Qi-Sen Gao,
• Zheng-Wei Wei and
• Zhi-Min Chen

Beilstein J. Org. Chem. 2025, 21, 2447–2455, doi:10.3762/bjoc.21.186

• pathway. In both pathways, the active chiral rhodium catalyst is regenerated through a silver salt-mediated recycling, with Ag–SePh being formed as a byproduct (Scheme 2). 2. Catalytic atroposelective synthesis of selenium-containing atropisomers by spontaneous selenosulfonylation of alkynes Vinyl

• selenides, recognized as valuable synthetic intermediates and biologically active compounds, have been demonstrated to exhibit a broad spectrum of biological activities. Among them, the synthesis of β-(selenium)vinyl sulfones can be accomplished via selenosulfonylation reactions initiated by free radicals

• hydroselenation of alkynes can provide an efficient and direct method for the synthesis of chiral vinyl selenides. However, to date, the enantioselective hydroselenation of alkynes remains underexplored. Building upon recent advances in rhodium-catalyzed asymmetric hydroselenation of olefins, in 2024, Li and co