A cascade synthesis of 2-aminothiochromones from 2-fluorophenyl ketone and thiocarbonyldiimidazole

• Kai Zhang,
• Haofan Shao,
• Kangjun Liao,
• Ying Xu,
• Shimei Du,
• Yanfang Zhao,
• Gang Li,
• Wenzhen Xu,
• Haihong Huang and
• Peng Li

Beilstein J. Org. Chem. 2026, 22, 1151–1159, doi:10.3762/bjoc.22.92

• attenuates its inherent reactivity [1]. These electronic factors, combined with the limited availability of suitable substrates, present significant synthetic obstacles. Current synthetic approaches to thiochromones primarily involve two strategies: transition-metal-catalyzed reaction of aryl halides and

• cyclization of thiophenol derivatives. The transition-metal-catalyzed carbonylation reaction of aryl halides represents an attractive strategy for thiochromone synthesis due to its atom economy and straightforward construction of the essential carbonyl-containing framework [15][16][17][18]. Among these

• methods, the palladium-catalyzed multicomponent synthesis has been extensively studied. This reaction typically employs aryl halides and various alkynes as substrates, with sodium sulfide serving as the sulfur source (Scheme 1a) [19][20][21]. Another well-established method is the cyclization of

Amino acid-based surfactants: sustainable synthesis and antimicrobial mechanisms

• Rafaela Gomes Bezerra,
• Lourdes Pérez and
• Francisco Fábio Oliveira de Sousa

Beilstein J. Org. Chem. 2026, 22, 1067–1085, doi:10.3762/bjoc.22.85

• reactions. N-Alkylation is mainly achieved either by reductive amination with long-chain aldehydes followed by chemical reduction, or by direct nucleophilic substitution using activated alkyl halides or sulfonates [6][10][13]. Reductive amination generally affords improved control over mono-N-alkylation and

One-pot four-component sequential synthesis of S-alkyl dithiocarbamates using lipase as a biocatalyst

• Mansour Shahedi,
• Pargol Tahmasebi pour and
• Zohreh Habibi

Beilstein J. Org. Chem. 2026, 22, 1048–1056, doi:10.3762/bjoc.22.83

• alkyl precursors, such as alkyl halides [16], sulfonium salts [19], diazo compounds [20], methylarenes [21], or α,β-unsaturated compounds [8][22]. While three-component reactions are predominant in the synthesis of S-alkyl dithiocarbamates [23][24], the exploration of four-component, one-pot reactions

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

• tolerance. Ethers, halides (C–Cl, C–Br, C–F), and amides remained intact under the reaction conditions. Notably, substrates with strong electron-withdrawing substituents (e.g., –CF3 in 2f) or multiple halogen atoms (2i, 2o) were also well tolerated, affording the products in good yields and highlighting the

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

• uncontrolled overreduction in iron electrocatalysis. The reaction proceeds efficiently with internal diarylalkynes bearing both electron-donating and electron-withdrawing substituents, while functional groups typically sensitive to reductive conditions, such as aryl halides and arylboronic esters, are well

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

• subsequent reaction with moderately basic organometallic reagents, such as 2-alkynyl- and 2-allylmagnesium halides, enables the facile introduction of diverse substituents, including those with functional groups. If necessary, the multiple carbon–carbon bonds in the side chain can be subjected to

• alkynyl- or allylmagnesium halides gave 2-alkynyl or 2-allyl-substituted nitroxides. Finally, carbon–carbon multiple bonds were removed via Pd-catalyzed hydrogenation and the nitroxide group was recovered by mild oxidation. This approach was used to prepare both symmetric 2,2,6,6-tetraethyl- and 2,2,6,6

A practical CO₂-mediated synthesis of 5,6-carboxylated silicon-rhodamines for targeted probe development

• Dongjie Hou,
• Shaowei Wu,
• Ning Xu,
• Pengjun Bao,
• Wenhao Jia,
• Qinglong Qiao and
• Zhaochao Xu

Beilstein J. Org. Chem. 2026, 22, 915–924, doi:10.3762/bjoc.22.72

• carboxylation of metallated aryl halides with CO2 into SiR chemistry, this method enables the efficient conversion of brominated SiRs into the corresponding carboxylated products using n-BuLi and readily available CO2 under standard Schlenk conditions. The target products are obtained in 60–93% yields under

Palladium-catalyzed benzocyclization reactions of quinoline-2-carboxamides via sequential C–H/N–H functionalization

• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2026, 22, 905–914, doi:10.3762/bjoc.22.71

• -catalyzed coupling reactions involving aryl halides. Synthetic strategy for preparing fused lactams. Detection of the intermediate Int-1ad in the annulation reaction of 1a with 1-bromo-5-tert-butyl-2-iodobenzene (2d). Stepwise formation of C–C and C–N bonds during the annulation reaction. Plausible reaction

Preparation of 3-(alkylamino)imidazo[1,2-a]pyridine-2-carbaldehydes via Kornblum oxidation and unexpected ring-opening reactions of the corresponding alcohols under oxidative conditions

• Sandile J. Mkhize,
• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2026, 22, 763–770, doi:10.3762/bjoc.22.58

• -(Alkylamino)imidazo[1,2-a]pyridine-2-carbaldehydes have not been previously reported, but there is a single report of the N-unsubstituted 2-formyl-3-aminoimidazo[1,2-a]pyridine, prepared from the corresponding nitro-derivative [32]. The conversion of tosylates (or halides) into their corresponding aldehydes

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

• and heteromethylation of active methylene β-ketosulfones, promoted by a leaving benzoyl group, is proposed. The primary domino reaction of sarcosine, paraformaldehyde, and β-ketosulfones affords 3-sulfonyl-3-benzoylpyrrolidines in good to high yields. Further treatment with alkyl halides and heating

• promote Hofmann elimination. To enhance the leaving ability of the nitrogen atom we prepared ammonium salts 3 of the obtained pyrrolidines via treatment with alkyl halides. Since the preparation of quaternary ammonium salts of pyrrolidines is straightforward, we employed a one-pot method for its synthesis

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

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

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

• palladium to aryl halides serving as a prominent example [41]. In addition to such fleeting intermediates, recent decades have seen the emergence of numerous well-defined metal–arene complexes, sufficiently stable to enable systematic exploration of their rich and versatile organic chemistry. η2

• η3-benzyl intermediates from aryl halides in combination with diazo compounds (Scheme 7B) [89][90]. Oxidative addition of the halide to palladium is followed by carbene formation, and facile migratory insertion to generate the η3-benzyl complex. In analogy to Bao’s protocol, this intermediate then

• deuteration, η4-arene complexes exhibit a compelling repertoire of C–C bond-forming reactions [101][102][103]. Notably, reactions with benzyl halides [99], iminium salts [104], nitrones [105], and ketenes [98] reveal rich synthetic potential. In a striking example, the [Mn(CO)3(η4-C6H6)]− complex acts as a

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

• its subsequent radical addition to 2-methylene-1,3-dithiane (14) proceeded, affording radical intermediate 15. This radical intermediate rapidly underwent homodimerization to give vic-bis(dithiane) 16. The reaction could be applied to both tertiary and secondary alkyl halides, providing the

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

• reported [31] halogenations of anion 1 only afforded the corresponding octasubstituted cycloheptatriene derivatives. The reactions of 2 with alkyl halides were selective in terms of the initial reaction – the i-substitution was never observed. However, the alkylation reactions were even more intricate than

• obtained at the revDSD-PBEP86(D4)/aug-ccpVTZ/CPCM(acetonitrile)//r2SCAN-3c/CPCM(acetonitrile) level of theory. Reactions of anion 2 generated from cycloheptatriene 3 with halogens and alkyl halides. Reactions of anion 2 generated from cycloheptatriene 3 with diazonium salts. Radical mechanism for reactions

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

• (chapter 1.11). For areas already covered by prior reviews, repetition has been avoided unless inclusion of key historical reports, overlooked publications, or representative examples was deemed necessary to highlight fundamental concepts. Given the extensive literature on the synthesis of alkenyl halides

• reported the use of (PhO)3P–halogen-based reagents for the synthesis of alkenyl halides (Scheme 12) [64]. A variety of alkenyl chlorides was obtained in good yields, with functional groups such as esters and boronates well tolerated. When camphor was treated with (PhO)3P·Cl2 (TPPCl2), the two

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

• applied to a variety of aromatic aldehydes (Scheme 2). Aldehydes containing halides (–F, –Cl, –Br) or strong electron-withdrawing groups at the ortho-position provided excellent yields (87–99%) for the 5-benzylidene-2-thioxothiazolidin-4-one derivatives 3b–e. The presence of an electron-donating group in

Pentacyclic aromatic heterocycles from Pd-catalyzed annulation of 1,5-diaryl-1,2,3-triazoles

• Kaylen D. Lathrum,
• Emily M. Hanneken,
• Katelyn R. Grzelak and
• James T. Fletcher

Beilstein J. Org. Chem. 2025, 21, 2524–2534, doi:10.3762/bjoc.21.194

• tandem deprotection/click chemistry followed by Pd-catalyzed annulation is summarized in Table 1. The alkyne-substituted analogs 1–6 [48][49][50][51][52] used in this study were prepared from commercially available aryl halides using microwave-promoted Sonogashira coupling (Table S1, Supporting

Assembly strategy for thieno[3,2-b]thiophenes via a disulfide intermediate derived from 3-nitrothiophene-2,5-dicarboxylate

• Roman A. Irgashev

Beilstein J. Org. Chem. 2025, 21, 2489–2497, doi:10.3762/bjoc.21.191

• benzyl halides and other electrophiles were used under optimal reaction conditions to obtain various 3-(alkylthio)thiophene-2,5-dicarboxylates. Among them, compounds 4b–g, bearing benzylthio substituents, were prepared using different benzyl-type alkylating agents. It was found that the reaction

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

• ring, constructing 86 – setting the stage for the group’s key reaction, in which α-hydroxy-β-lactams (e.g., 87) serve as surrogates for α-metalated N-heterocycles in Pd-catalyzed coupling with aryl halides. Both enantiomers of 87 (only one shown in Scheme 10) participated in a Pd-catalyzed

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

• of alkenyl halides 7a and 7b with the green oxidant H2O2 gave trace conversion after 3 days; however, the reaction using m-CPBA catalyzed with p-TSA was complete in 24 hours and afforded the halogenated lactones 8a and 8b in 33% and 34% yield, respectively (Scheme 1). We have recently reported the C3

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

• cross-electrophile coupling of alkyl halides and nitroalkanes [76]. Yang and co-workers reported photoenzymatic asymmetric C(sp3)–C(sp3) oxidative cross-couplings between organoboron reagents and amino acids (Scheme 9) [37]. The authors used a synergistic system consisting of an engineered threonine

• generation and C–H functionalization of aliphatic substrates via HAT and thereby avoiding the use of more highly functionalized radical precursors such as organic halides. The application of electrochemistry for enantioselective radical transformations is a highly promising approach. Electrochemistry

Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings

• Lifen Peng,
• Ting Wang,
• Zhiwen Yuan,
• Bin Li,
• Zilong Tang,
• Xirong Liu,
• Hui Li,
• Guofang Jiang,
• Chunling Zeng,
• Henry N. C. Wong and
• Xiao-Shui Peng

Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166

• skeletally diverse indoles were obtained successfully via electrochemical annulations of o-arylalkynylanilines (Scheme 3) [187]. In an undivided cell (Pt anode, Pt cathode, 10 mA), treatment of o-arylalkynylanilines 6 with ammonium halides (NH4X, X = I, Br, Cl) gave the C3-halogenated indoles 7 in moderate

Photochemical reduction of acylimidazolium salts

• Michael Jakob,
• Nick Bechler,
• Hassan Abdelwahab,
• Fabian Weber,
• Janos Wasternack,
• Leonardo Kleebauer,
• Jan P. Götze and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153

• recently proposed by Marzo and co-workers in an NHC-mediated coupling reaction with alkyl halides mediated by (TMS)3SiH [55]. The O-silylated product 5 could result from a subsequent radical C-silylation followed by a Brook-type rearrangement process [56]. Interestingly, performing the TESH-mediated

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

• reductive cross-coupling of benzyl halides when substituents prone to reduction (CN, esters) are present (Scheme 12C). The Ullman–Goldberg coupling of 41b with Boc-hydrazine followed by deprotection and oxidation then affords 35 [55]. Asymmetric diazocines can be synthesised by Sonogashira cross-coupling

• indigo is a well-known commercial product, we will not focus on other synthetic pathways, which can be found in a review by Hecht and co-workers [65], and instead discuss the N-functionalisation (Scheme 24, bottom). N-Alkylation in 76 can be achieved with alkyl halides and base. There are different