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

• the stereoselective semihydrogenation of alkynes a fundamental transformation in synthesis [1][2][3][4][5]. Among available methods, transition-metal catalysis has played a dominant role. The classical Lindlar catalyst remains the most widely applied heterogeneous system [6], yet it suffers from

• . outlined the state-of-the-art progress on stereoselective semihydrogenation of alkynes catalyzed by first-row (3d) transition metals, which attract substantial attention owing to their natural abundance and low toxicity [5]. In recent years, homogeneous catalysts based on Ni, Cu, Rh, and Co have shown

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

• stereoselective hydrogenation of alkynes under electrochemical and transition-metal-catalyzed conditions. The alkyne semihydrogenation generally benefits from the stronger coordination ability of the C–C triple bonds and the greater accessibility of metal-bound intermediates, thereby often enabling stereocontrol

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

• under the optimized conditions, yielding the desired products in up to 96% yield. A plausible mechanism involves the in situ generation of an NHC-ligated copper–amido species via ligand exchange between the NHC–CuOt-Bu complex and pyrazole substrate (Scheme 15). Subsequent stereoselective aminocupration

• the regio- and stereoselective synthesis of (E)-allylamines 46 from terminal allenes 45 and aniline derivatives (Scheme 17) [58][59][60]. In the presence of Cu(OTf)2 or Cu(CH3CN)4PF6, various monosubstituted allenes bearing aryl, aminocarboxylate, aminophosphonate, and sulfonamide groups smoothly

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

• their stereoselective reactions remains challenging. Here, we examine the diastereoselective generation and trapping of α-boryl lithium species formed by ring opening of substituted iodomethylcyclopropanes. After lithium–iodine exchange and selective C–C bond cleavage, these intermediates react with a

• diverse catalytic and stereoselective transformations [28][29][30][31][32][33]. In this context, we have recently demonstrated that a broad range of arylated (iodomethyl)cyclopropylboronic ester 2 [34] undergo ring-opening reactions, followed by electrophilic trapping of the resulting α-boryl carbanion

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

• 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

Unsymmetrical sulfoxides with sterically hindered catechol fragment: synthesis, structure, electrochemical properties, and antiradical activity

• Daria A. Burmistrova,
• Vasiliy A. Fokin,
• Oleg P. Demidov,
• Mikhail A. Kiskin,
• Maxim V. Arsenyev,
• Andrey I. Poddel’sky,
• Nadezhda T. Berberova and
• Ivan V. Smolyaninov

Beilstein J. Org. Chem. 2026, 22, 828–837, doi:10.3762/bjoc.22.65

• component of Oxone®) [37] – are commonly employed for this purpose. One of the most accessible approaches uses hydrogen peroxide along with catalytic systems based on transition metals [38]. Notably, this process is not stereoselective and affords chiral sulfoxides as a mixture of enantiomers. Besides

Total synthesis of the capsular polysaccharide repeating unit towards the development of a glycoconjugate vaccine against Klebsiella pneumoniae ST512

• Shuo Zhang,
• Ondřej Daněk and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2026, 22, 821–827, doi:10.3762/bjoc.22.64

• . Key synthetic challenges including the stereoselective construction of the 1,2-cis glycosidic linkage on the galacturonic acid core and the inherently low reactivity of elongated oligosaccharide intermediates were addressed employing orthogonally protected building blocks. The resulting library of

• repeating unit {3)-[α-ʟ-Rhap-(1→4)]-α-ᴅ-GalpA-(1→2)-α-ʟ-Rhap-(1→2)-α-ʟ-Rhap-(1→2)-α-ʟ-Rhap-(1→3)-β-ᴅ-Galp-(1→}n (Figure 1) [13]. The chemical synthesis of this molecule is challenging due to the stereoselective formation of the 1,2-cis glycosidic linkage on the galacturonic acid core. In addition, the

• furnished tetrasaccharide 15. Subsequently, donor 3 was coupled with compound 15 under NIS/TfOH promotion to yield pentasaccharide 16 in 89% yield. The stereoselective construction of the 1,2-cis linkage was directed by the bulky 4,6-O-silylidene protecting group of 3. Treatment with HF·pyridine

Synthetic study of vic-bromination of diarylacetylenes, easy purification and separation

• Akane Togo,
• Hiyono Suzuki,
• Yuto Akai,
• Makoto Matsumoto,
• Yoshinori Suzuma,
• Hidehiko Kodama and
• Kouichi Matsumoto

Beilstein J. Org. Chem. 2026, 22, 795–802, doi:10.3762/bjoc.22.61

• , the E isomer could be recovered as a solid material by utilizing the difference in solubility. On the other hand, the Z isomer could be removed by filtration while remaining in solution. Keywords: bromination; diarylacetylenes; green chemistry; purification and separation; stereoselective reaction

• the combination of NBS (N-bromosuccinimide) and FeBr3 in CH2Cl2 was good for the reaction with diphenylacetylene [16][17][18][19] to give 1,2-dibromo-1,2-diphenylethylene with high E-selectivity. The present method has some advantages. First, is mild reaction conditions, and second is stereoselective

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

• shielding of the Si-side of the chiral iminium intermediate by bulky aryl groups leads to a stereoselective endo approach of the 1,3-dipole to the sterically less hindered Re-side of the intermediate iminium cation (Scheme 26). In this context, it is worth noting a work published in 2011, in which the

• and effective for the preparation of racemic cycloadducts [69][70][71]. Of interest are also non-catalytic reactions of 1,3-dipolar cycloaddition of azomethine ylides, which are formed in situ from the corresponding aldehydes and amino acid esters. In 2011, Shi and Gan proposed a stereoselective

• reacts with the nucleophile RXH to form the corresponding 3-substituted cyclopropenes. The latter reacts with azomethine ylide 67 to form cycloadducts in moderate yields. Density functional theory (DFT) calculations revealed that the regio- and endo-stereoselective formation of products in the observed

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

• received, 1.45 g of 27 were obtainable during the second one from one batch (Scheme 3, step e) showing the scalability of this path. Moreover, besides 22 and 27, Konda and co-workers also accomplished the stereoselective syntheses of other diastereomers of the target tetrahydrofuran unit starting from 13

• reactions [76][77] for the assembly of fragment 45 (Scheme 6) [78]. Here, 40 and 42 served as the substrates for the allene-Prins reaction towards 43. Notably, the Bz-derivative of 40, 41, served as a starting point for a corresponding halichondrin B analog. The stereoselective course of this cyclization is

• , stereoselective dihydroxylation with AD-mix β and diol-protection yielded acetonide 57. Another DMP-oxidation, followed by HWE reaction, and deprotection of the diol motifs enabled the cyclization towards 60. After TBDMS-protection and reduction to the respective aldehyde (62), an alkylation with the α-sulfonyl

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

• biaxial chirality, multistep sequential generation, and conversion from central to biaxial chirality, with the aim of providing new perspectives and methodologies for further development in this area. Keywords: axially chiral compounds; stereoselective synthesis; Introduction In recent years, axially

• , Hayashizaki, and Ito reported a highly stereoselective asymmetric cross-coupling reaction of 2-methylnaphthylmagnesium bromide with bromonaphthalene, catalyzed by a nickel complex with ferrocenylphosphine as the ligand, successfully synthesizing biaxially chiral molecules, namely 1,1':5',1"- and 1,1':4',1

• (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

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

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

• substitution pattern along the plane of symmetry, is known as planar chirality, as seen in metallocene and cyclophanes. Molecules containing planar chirality have greater relevance in materials science and stereoselective transformations [12][13]. The fourth branch of the chiral tree is helical chirality. A

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

• both homogeneous and heterogeneous systems, the hydrogenation of (hetero)arenes has become a cornerstone of modern synthesis for constructing saturated carbocycles and heterocycles [37]. When an appropriate ligand is paired with a transition-metal catalyst, stereoselective hydrogenation of aromatic

• catalyst in the presence of perchloric acid to obtain (−)-decahydrotabersonine, a product with a completely reduced aromatic ring (Scheme 13) [79]. Through the structural characterization of the product, the authors found that the hydrogenation was highly stereoselective, yielding only cis-hydrogenated

• products. This suggests that substrate induction during hydrogenation could effectively direct the process, enabling stereoselective product formation. Total synthesis of (±)-nominine by Natsume, 2004 Natural products with complex ring systems, such as bridged rings, spirocycles or highly rigid ring

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

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

• aglycone sarmentogenin in 7 steps from 17-deoxycortisone. The synthesis features a scalable enzymatic C14–H α-hydroxylation, a Bestmann ylide-enabled one-step construction of the butenolide motif, a late stage Mukaiyama hydration, and a stereoselective C11 carbonyl reduction. Keywords: cardiac glycosides

• . Therefore, we decided to perform the Mukaiyama hydration on advanced intermediates. Next, a K-selectride-promoted chemo- and stereoselective reduction of the C3 carbonyl of 9 was realized to solely deliver 11 in 85% yield [33]. Then, 11 was subjected to Mukaiyama hydration conditions. Under the Fe(acac)3

• Bestmann ylide-enabled one-step construction of the butenolide motif, a late-stage Mukaiyama hydration, and a stereoselective C11 carbonyl reduction. We believe this chemoenzymatic synthetic strategy will inspire future endeavors towards the practical synthesis of complex steroids and other bioactive

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

• ) [63]. Chauhan et al. developed a photocatalytic dual catalysis for an efficient stereoselective method that affords direct access to the pyrrolo[1,2-d][1,4]-oxazepin-3(2H)-ones 35 by merging organic eosin Y photoredox with carbene catalysis. Previous reports have shown eosin Y (Ered* in T1 [EY−•/EY

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

• , 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

• . Treatment of 89 with Ti(OiPr)4/iPrMgCl promoted the intramolecular stereoselective alkyne–1,3-dicarbonyl coupling, resulting in the construction of the AB ring system. This transformation afforded tricyclic compound 91 as the major product, accompanied by minor amounts of by-product 90. Subjecting 91 to

• material. Key transformations included regioselective and stereoselective alkene epoxidation, organoselenium-mediated reductive cleavage of the α,β-epoxy ketone, and a hydroxy-directed stereospecific Mukaiyama hydration. These operations successfully introduced the C6 and C10 oxidation states, enabling the

Synthesis of the tetracyclic skeleton of Aspidosperma alkaloids via PET-initiated cationic radical-derived interrupted [2 + 2]/retro-Mannich reaction

• Ru-Dong Liu,
• Jian-Yu Long,
• Zhi-Lin Song,
• Zhen Yang and
• Zhong-Chao Zhang

Beilstein J. Org. Chem. 2025, 21, 2470–2478, doi:10.3762/bjoc.21.189

• formation of intermediate L is challenging because its ring-strain energy (Figure 1e, 52.1 kcal/mol) is higher than that of its counterpart, i.e. the bicyclo[3.2.0]heptane motif (28.3 kcal/mol) in H [24]. Herein, we report our recent results on the development of a novel strategy for the stereoselective

• construction of the tetracyclic core of Aspidosperma alkaloids. Our method involves an Ir-catalyzed PET reaction of K for the stereoselective formation of the cis-configured BC bicyclic core with an all-carbon quaternary center [25][26]. Computational studies suggest that the observed tandem PET reaction of K

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

• ] and vaccines [15][16][17][18]. That is why new efficient and stereoselective methods for the synthesis of both Galf-containing mono- and oligosaccharide derivatives are highly demanded. It is a well-known fact that galactofuranose form constitutes only 5% in water solution of unprotected ᴅ-galactose

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• 111 led to (±)-preterrenoid (107) with 68% yield, which was subjected to stereoselective oxidation with magnesium monoperoxyphthalate (MMPP) to give (±)-terrenoid (108) as a single diastereomer. Subsequent treatment of the key precursor 108 with catalytic amounts of NaOMe in MeOH resulted in

• -dihydronaphthalenes. Silva et al. have also developed an effective method for the stereoselective oxidation of tetralone derivatives using chiral hypervalent iodine reagents [61][62]. Hypervalent iodine compounds are widely used in organic synthesis as selective oxidants and enantiomerically pure reagents. In terms

• % yield. Jin et al. [85] reported an efficient photoinduced carboborative ring contraction of monounsaturated six-membered carbo- and heterocycles, allowing the regio- and stereoselective synthesis of functionalized cyclopentanes at gram scales. This method leads to the formation of compounds with

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

• sugars (Figure 1) [42][43][44][45][46][47][48]. More specifically cycloaddition reactions of nitrones (1,3-dipoles) with N-aryl-substituted maleimides (electron-poor dipolarophiles) are a highly popular and versatile method for the formation of regio- and stereoselective pyrrolo-isoxazolidine-fused ring

• is fully consumed by the end of the five-minute reaction period. In academic and industrial communities alike, there is a high level of interest in catalytic methods of Green Chemistry that allow stereoselective transformations [125][126][127][128]. It is imperative to develop stereoselective

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

• can further undergo ring-opening or rearrangement reaction to assemble complex molecular frameworks. Additionally, quinone photoredox reactions involving single-electron transfer (SET) processes provide novel strategies for the stereoselective synthesis of useful structures such as spiroketals. This

• . This transformation proceeded via sequential regio- and stereoselective Norrish−Yang annulation, followed by intramolecular lactonization mediated by 12a. Notably, when the ethyl ester in 12 was replaced with a methyl group to form 14 with R = Et (Scheme 3), photoreaction of 14 led to 15 in 95% yield

• unprecedented 4,5-spirocyclic B/C ring system and a [4,3,1]propellane F/G/H ring fragment. In 2024, Yang's group achieved the construction of the ABCDE pentacyclic skeleton of phainanoids, leveraging Norrish–Yang cyclization to accomplish the regio- and stereoselective assembly of the rigid, sterically

Halogenated butyrolactones from the biomass-derived synthon levoglucosenone

• Johannes Puschnig,
• Martyn Jevric and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2025, 21, 2297–2301, doi:10.3762/bjoc.21.175

• . Short procedures for their synthesis have been developed starting with levoglucosenone, which can be obtained in a single step from the pyrolysis of acid-treated cellulose. The processes use inexpensive reagents for the stereoselective C3 functionalization of the bicyclic ring system, with a subsequent

• influenza [7], while chlorinated analogues such as 3 have demonstrated activity against hepatitis C (Figure 1) [8]. Stereoselective methods to access halogenated γ-butyrolactones are therefore valuable, as they enable access to nucleoside analogues which have applications in treating cancer and certain

• epoxidations of 5 are highly stereoselective [44]. Unambiguous assignment of configuration for the diastereomers was not possible on the basis of the selective 1D NOE spectra due to the lack of informative crosspeaks. Limiting the amount of oxidant (H2O2 or peracetic acid) resulted in mixtures, suggesting that

Enantioselective radical chemistry: a bright future ahead

• Anna C. Renner,
• Sagar S. Thorat,
• Hariharaputhiran Subramanian and
• Mukund P. Sibi

Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174

• provides a way to avoid the use of stoichiometric chemical oxidants or reductants and to achieve new transformations that are highly regio- and stereoselective. Though not covered in this perspective, flow chemistry and mechanochemistry are also increasingly popular areas that hold significant potential