Rh(III)-catalyzed chelation-assisted C–H activation/annulation of 2-arylimidazolines with cyclic diazo-1,3-dicarbonyl compounds: a novel approach to tetracyclic annulated derivatives of 2,3-dihydroimidazo[2,1-a]isoquinoline

• Ivan Lyutin,
• Grigory Kantin,
• Olga Bakulina and
• Dmitry Dar'in

Beilstein J. Org. Chem. 2026, 22, 997–1003, doi:10.3762/bjoc.22.78

• immunosuppressive activity. The latter was used to develop antiasthmatic, pulmonary, and anti-allergy agents acting as platelet-activating factor receptor (PAF-R) antagonists [12][13]. Derivatives with X = H were accessed only via lithiation of 2-(o-tolyl)imidazolines followed by condensation with aromatic esters

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

• previously established in Baran’s study (Scheme 6A) [103]. Redox-sensitive functionalities such as esters, ketones, epoxides, nitriles, and arylboronic esters remained intact, and both electron-rich and electron-poor arenes were fully compatible with the reaction conditions (Scheme 6B). Importantly, this

• authors selected fumarate esters as model substrates, as these species typically undergo oligomerization and competitive hydrogen evolution under conventional electrode-mediated reduction conditions (Scheme 7B). In subsequent controlled-potential coulometry (CPC) experiments conducted at −1.30 V vs Fc+/0

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

• Scheme 7, the use of an air- and moisture-stable (CAAC)Cu–Cl catalyst in the presence of KOt-Bu enabled the efficient hydroamination of activated olefins 12 bearing electron-withdrawing groups such as esters, nitriles, and sulfone substituents. Under these conditions, various anilines reacted efficiently

• -supported copper nanocomplex, Cu(0)NC@PHA, derived from cellulose-based poly(hydroxamic acid) ligands [50]. The supported Cu(0) NPs catalyzed aza-Michael addition reactions of aromatic amines with various α,β-unsaturated esters 33 in ethanol at room temperature. The heterogeneous catalyst exhibited high

Chiral cyclopropenimine-catalyzed enantioselective Michael reactions of phenol and benzofuran-derived α,β-unsaturated pyrazolamides with benzophenone-imine of glycine esters

• Ya Bai,
• Xue-Ying Wang,
• Si-Kai Zhu,
• Yan-Ting Shen,
• Sheng-Yong Zhang and
• Ping-An Wang

Beilstein J. Org. Chem. 2026, 22, 888–896, doi:10.3762/bjoc.22.69

• , 710032, China School of Pharmacy, Lanzhou University, Lanzhou, 730000, China 10.3762/bjoc.22.69 Abstract The enantioselective Michael reactions of benzophenone-imine of glycine esters with phenol- and benzofuran-derived α,β-unsaturated pyrazolamides have been realized by using a chiral cyclopropenimine

• series of 3-substitued glutamic acid esters in high yields and diastereoselectivities through DBU-catalyzed Michael additions of benzophenone-imine of glycine ester and α,β-unsaturated esters which derived from phenols and benzofurans under mild conditions [5][6]. The chiral 3-aryl-substituted glutamic

• and pyroglutamic acid esters were also produced by enantioselective Michael additions of β-aryl-substituted α,β-unsaturated pyrazolamides with benzophenone-imine of glycine ester in excellent ee and de values by using a chiral cyclopropenimine (Lambert catalyst, Figure 2b) as an organosuperbase

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

• range of electrophiles to give boronic esters bearing vicinal tri- and tetrasubstituted stereocenters in good yields and high diastereoselectivities. Notably, substrates bearing alkyl substituents display the opposite sense of diastereoselectivity to previously studied aryl-substituted analogues. The

• facial selectivity during electrophilic trapping. These findings expand the synthetic utility of α-boryl lithium intermediates and provide insight into the origins of their diastereoselectivity. Keywords: α-boryl lithium; diastereoselectivity; (iodomethyl)cyclopropylboronic esters; ring-opening

• regioselectivity. The use of various electrophiles enabled the synthesis of acyclic boronic esters featuring vicinal tri- and tetrasubstituted stereocenters. Cyclopropylmethyl iodide starting materials. Synthesis and reactivity of α-boryl lithium species. Diastereodivergent electrophilic trapping of α-boryl

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

• . for the catalytic formation of trans-vinyl triflate esters (Scheme 20) [93]. The above discussion has highlighted how important the ligand trans-influence is in determining gold-catalysed reaction paths. Nickel or palladium-like reactivity, such as migratory alkene, alkyne or CO insertions into metal

• bonds [20][84]. Catalytic acetylene functionalisation [86][87]. Examples of alkene insertions into Au–C bonds [88][89]. Examples of β-H elimination and chain walking processes in (C^P)-ligated gold alkyls [90]. Mechanism of alkyne hydroarylation with (C^P) gold catalysts [92]. Vinylic triflate esters by

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

• esters, had been obtained from 2-aminopyridines 9a–d while no reaction was observed for 2-aminopyridine 9e (Scheme 1). We reasoned that at the relatively small scale of the reaction (≈350 mg aminopyridine) and because a period of 30 min stirring of all reactants had been allowed prior to addition of the

• . Compound 9f was also successfully converted into 13f under the conditions shown in Table 1. Nenajdenko et al. reported a few examples of the preparation of imidazo[1,2-a]pyridin-3-amine ethyl esters starting from ethyl glyoxylate in toluene and using ammonium chloride as a catalyst in yields of 30–35% [26

• ]. With the relatively facile preparation of esters 13a–d and 13f now demonstrated, we shifted our focus to investigate possible routes to compounds such as 8, that have not been reported previously. There were three immediate possibilities to consider: i) reaction of the ester directly with 2

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

• derivatives with multiple chiral centers under high regio- and stereocontrol. Currently, strategies using azomethine ylides based on imino esters or α-amino acids with a variety of cyclic and acyclic carbonyl compounds dominate. Enantioselective (3 + 2) cycloaddition reactions of azomethine ylides obtained

• from imino esters, catalyzed by chiral Cu(I,II) and Ag(I) complexes, are widely used. Reactions using α-amino acids proceed, in most cases, without the use of catalysts, with high yields and high stereoselectivity. Electrophilic alkenes of various structures, (hetero)aromatic olefins and benzofulvenes

• , the importance of the formation of azomethine ylides from amino esters, amino acids, imine derivatives, aziridines or other substrates was emphasized. A review [26] demonstrates metal-catalyzed as well as metal-free asymmetric and racemic transformations of imino ethers upon interaction with various

Computational prediction of C–H hydricities and their use in predicting the regioselectivity of electron-rich C–H functionalisation reactions

• Rasmus M. Borup,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2026, 22, 603–610, doi:10.3762/bjoc.22.46

• photoredox activation, followed by anion-binding-catalysed functionalisation to form β-amino esters. Here, the reacting atom is the one with the lowest hydricity and BDE. Compounds 8–10 Schmidt et al. [44] reported the visible light-catalysed bromination of compound 8, Kamon et al. [45] reported the light

Synthesis and uranyl(VI) extraction performance of a calix[4]pyrrole–tetrahydroxamic acid receptor

• Sara Karnib,
• Rana Baydoun,
• Wissam Zaidan,
• Nancy AlHaddad,
• Omar El Samad,
• Bilal Nsouli,
• Francine Cazier-Dennin and
• Pierre-Edouard Danjou

Beilstein J. Org. Chem. 2026, 22, 486–494, doi:10.3762/bjoc.22.36

• carboxylic acid derivatives such as esters, acyl chlorides and anhydrides with hydroxylamine salts [41]. A variety of coupling or activating agents were also employed in case of simple addition of hydroxylamine to carboxylic acid compounds [42][43][44]. In addition, alternative methods starting from

• amount of solid KCN in aqueous hydroxylamine has been reported for the solution-phase hydroxylamination of esters previously described by Ho et al. [52]. This study demonstrated that the extent of ester conversion and the formation of carboxylic acid by-products vary markedly with the structure of the

• outcome is strongly influenced by the nature of the ester substrate. As a result, this synthetic route was discontinued. Another straightforward method for the synthesis of hydroxamic acids from esters was reported in 1994 by Hutchinson et al., for the synthesis of calixarene tetrahydroxamates from

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

• yields, indicating potential utility in chiral fluorescent materials. In addition, Du’s group reported an N-heterocyclic carbene (NHC)-catalyzed (3 + 3) cycloaddition of 2,6-disubstituted alkyne esters 38 with 6-aminouracils 39, affording distal biaxial uracil frameworks with both C–C and C–N chiral axes

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

• macrocyclic core through simple acylation of p-aminocalix[4]arenes with the respective phosphorous-containing activated esters. Such grafting of well-known receptor units onto a common platform has led to substantial amplification of the efficiency of lanthanide and actinide extraction from acidic media by

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

• undergoes hydrolysis to afford the benzyl ester 30. Under the optimized conditions, primary, secondary, and tertiary amides 12, 31–33 were successfully converted to benzyl esters in high yields. Notably, loss of enantiopurity of chiral amide 33 was not observed during esterification. Sulfuryl fluoride

• (SO2F2) was demonstrated to be a powerful electrophilic reagent for amide-bond cleavage by Qin et al. (Scheme 8) [56]. Under an atmosphere of SO2F2, esterification of tertiary amides 28, 35–37 smoothly afforded esters 34 in high yields, although the efficiency was reduced when a bulky substituent was

• 2.2 equivalents of 2-bromopyridine as a base, pyrrolidine-derived amides 38 were effectively activated. Subsequent addition of NFSI as the electrophilic fluorinating reagent, along with alcohols as the nucleophile, afforded the corresponding esters 39–43 in moderate yields. Mechanistically, the

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

• acids followed by sequential Michael-type addition and subsequent cascade transformations. This versatile one-pot protocol delivers structurally diverse open-chain 3-arylpropanoate esters in moderate to good yields (46–69%), while cyclic pyranoquinolinones are formed under kinetically controlled

• direct access to scarcely explored open-chain quinolinone esters, expanding the medicinal chemistry toolbox with promising scaffolds for drug discovery. Keywords: antibacterial activity; 4-hydroxyquinolin-2(1H)-one; ʟ-proline catalysis; Meldrum’s acid; Michael addition; multicomponent reaction

• ) and cyclized (lactone) forms [35]. The γ-position of the propanoic acid side chain was further modified with a 3,4-dimethoxyphenyl group, inspired by earlier reports [36]. The carboxylic acid functionality was either retained or converted into methyl, ethyl, isopropyl, or cyclohexyl esters to evaluate

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

• soil. It can potentially serve as a phosphorus source in the syntheses of organic phosphates; however, this approach has not been utilized for the preparation of phosphate esters. In this study, we report the first successful synthesis of phosphate esters using phytic acid as a phosphorus source. Crude

• with a recovery of 4.2% and then conducted an esterification reaction using the extracted phytic acid and phenol. As a result, diphenyl phosphate with a yield of 44% was obtained. This work can facilitate the development of an environmentally friendly method for producing phosphate esters that does not

• rely on phosphate rock but instead uses biomass as a phosphorus source. Keywords: diaryl phosphates; phosphate esters; phosphate ester synthesis; phosphorus recovery; phytic acid; Introduction Phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate, Scheme 1) is a phosphorus-rich molecule, which is

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

•  1A) [15][16]. Oxidative rearrangements of carbonyl compounds are based on Dakin [17] and Baeyer–Villiger reactions [18] and their modifications. Cyclic and acyclic ketones were oxidized to afford lactones and esters, accordingly, involving catalytic reactions with hydrogen peroxide [19][20][21][22

Circumventing Mukaiyama oxidation: selective S–O bond formation via sulfenamide–alcohol coupling

• Guoling Huang,
• Huarui Zhu,
• Shuting Zhou,
• Wanlin Zheng,
• Fangpeng Liang,
• Zhibo Zhao,
• Yifei Chen and
• Xunbo Lu

Beilstein J. Org. Chem. 2026, 22, 158–166, doi:10.3762/bjoc.22.9

• /bjoc.22.9 Abstract A selective and efficient method for the synthesis of sulfinimidate esters via an NBS-promoted oxidative coupling of sulfenamides with alcohols has been developed. This operationally simple, metal-free protocol uses inexpensive and readily available reagents, operates under mild

• RU58841. Moreover, chiral alcohols such as ʟ-menthol are well tolerated, affording diastereomeric sulfinimidate esters that can undergo stereospecific Grignard substitutions to furnish enantioenriched sulfilimines with up to 93% ee. These results demonstrate the potential of sulfinimidate esters as

• versatile intermediates for enantioselective S–C bond formation under mild and metal-free conditions. Keywords: asymmetric synthesis; late-stage functionalization; selective oxidation; sulfenamides; sulfinimidate esters; Introduction Sulfur is a privileged heteroatom in organic chemistry, celebrated for

Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure

• Ilia A. Pilipenko,
• Mikhail V. Grigoriev,
• Olga Yu. Ozerova,
• Igor A. Litvinov,
• Darya V. Spiridonova,
• Aleksander V. Vasilyev and
• Sergey V. Makarenko

Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5

• of ring opening or expanding [11][12][13]. Thus, known trichloromethyl-containing cyclopropanes can serve as precursors for hard-to-access halogenated β,γ- and γ,δ-unsaturated esters [14][15]. Nitrocyclopropanes are known as highly electrophilic substrates and can form a carbanion stabilized by the

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

• conditions, delivering the desired ketones 12 in good yields. The reaction also tolerated a wide range of protecting groups, including esters, carbamates, and silyl ethers, without degradation (10f–k). Neopentyl iodide 10l and secondary alkyl iodide 10m were also competent substrates, although tertiary alkyl

• hydrogen atom from 1,4-cyclohexadiene, affording the hydrogenated product 36. The reaction proved broadly applicable to a wide range of alkyl chlorides. For example, primary alkyl chlorides bearing functional groups such as amides (34b), esters (34c), ketones (34d), and phosphoesters (34e) underwent smooth

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

• alkenyl chlorides isolated in purities below 85% (not shown) [59]. Transformations of enols to alkenyl chlorides with phosphorous pentachloride (PCl5): β-Chlorovinyl ketones and esters represent highly versatile intermediates, as the chloride moiety is readily displaced by a wide range of nucleophiles

• 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

• arylboronic esters (Scheme 52) [181]. They discovered that a rhodium/1,4-bis(diphenylphosphino)butane (DPPB) complex, in combination with a large excess of 1,2-trans-dichloroethene, facilitated monoselective cross-coupling reactions. In 1987, Minato, Suzuki, and Tamao reported the first monoselective coupling

One-pot synthesis of ethylmaltol from maltol

• Immanuel Plangger,
• Marcel Jenny,
• Gregor Plangger and
• Thomas Magauer

Beilstein J. Org. Chem. 2025, 21, 2755–2760, doi:10.3762/bjoc.21.212

• esters [25], we initially envisioned the formation of dianion I from maltol (2), which should undergo selective C-methylation with methyl iodide to furnish ethylmaltol (1) (Table 1). Typical deprotonation conditions employed for β-keto esters, i.e., sequential treatment of maltol (2) with equimolar

• ) from its naturally occurring congener maltol (2). Initial efforts focused on the methylation of a dianionic intermediate, reminiscent of γ-alkylation of β-keto esters. Although this successfully provided ethylmaltol (1), the presence of inseparable impurities and the need for industrially unattractive

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

• to be obtained in one stage using commercially available reagents [1][2][3]. Their ambident properties make 3-oxo esters convenient reagents for the use in multicomponent syntheses, with the Hantzsch [4][5] and Biginelli [6][7][8] reactions being the best known. In the transformations, 3-oxo esters

• starting substrates in multicomponent syntheses [17][18][19]; at the same time, they often show extraordinary reactivity. For example, the introduction of polyfluoroalkyl-3-oxo esters into the aforementioned Hantzsch and Biginelli reactions leads to the hydrated heterocycles, which can provide insight into

• the mechanistic aspects of these transformations. Our team has discovered a new multicomponent synthesis that is based on autocatalyzed reactions of ethyl trifluoroacetoacetate and other polyfluoroalkyl-3-oxo esters with α-methylenecarbonyl compounds and amines [9]. This approach is appropriate only

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

• cevanine-type alkaloids has been reported [13][38][39][40][41][42]. The common hexacyclic framework is often highly oxidized and the hydroxy groups are further functionalized as esters of various carboxylic acids. Apart from the hydroxylation pattern, structural diversity is also imparted through a cis- or

Synthesis of new tetra- and pentacyclic, methylenedioxy- and ethylenedioxy-substituted derivatives of the dibenzo[c,f][1,2]thiazepine ring system

• Gábor Berecz,
• András Dancsó,
• Mária Tóthné Lauritz,
• Loránd Kiss,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2645–2656, doi:10.3762/bjoc.21.205

• (22), an atypical antidepressant drug on the market [21][22][23][24][25], by hydrolysis of esters 20a and 21a (Scheme 3). Treatment of chloro derivative 19 with various alcohols afforded ethers 23, while its reaction with 2-(morpholin-4-yl)ethanethiol resulted in thioether 24 (Scheme 4). The structure

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

• carbenes (NHCs) with photocatalysts. The review encompasses transition-metal-based photocatalytic reactions for C–C and C–HA cross-coupling reactions involving various acyl fluorides, amides, aldehydes, carboxylic acids, and esters, highlighting their broad applications in organic synthesis and medicinal

• -photocatalyst, leading to various β-aryl keto ester derivatives 20 in good to excellent yields. The key steps of the reactions undergo radical–radical cross-coupling with the alkyl ester radical E and benzyl radical B to afford the desired keto-esters 20 in up to 88% yield. This catalytic process displayed good

• V vs SCE in CH3CN). The resulting oxidized Rh6G•+, with a ground-state oxidation potential of Eox = +1.23 V vs SCE in CH3CN. This catalysis enables an efficient and straightforward photocatalytic preparation of functionalized aryl esters 25 through a radical pathway (Scheme 10) [60]. The NHC