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

• Ivan Lyutin Grigory Kantin Olga Bakulina Dmitry Dar'in Institute of Chemistry, Saint Petersburg State University, 26 Universitetskyi prospekt, Peterhof 198504, Russian Federation 10.3762/bjoc.22.78 Abstract 2-Arylimidazolines were annulated with cyclic diazo-1,3-dicarbonyl compounds under Rh(III

• obtaining structurally related 5,6-disubstituted 2,3-dihydroimidazo[2,1-a]isoquinolines 4 (Figure 1c) fused with an additional ring via a Rh(III)-catalyzed chelation-assisted C–H activation/annulation with diazo compounds. 2-Arylimidazolines 2 and various substituted cyclic 1,3-dicarbonyl diazo compounds 3

• materials. The scope and limitations of this annulation were thoroughly investigated. Five types of cyclic diazo 1,3-dicarbonyl compounds (derived from dimedone, 5- or 6-substituted cyclohexanediones, cyclopentanedione, and cycloheptanedione) and two types of 2-arylimidazolines (with or without additional

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

• tolerated (Scheme 1B). Cyclic voltammetric studies revealed distinct Fe(II/I) and Fe(I/0) redox events for (P3P)Fe(II)(BF4)2. Notably, introduction of cobaltocene (Cp2Co) as a redox mediator enabled selective SET at a more anodic potential, thereby suppressing competitive hydrogen evolution and rendering

• , analogous experiments conducted under conventional silane-based HAT conditions using the same cobalt complex 8 failed to reproduce this reactivity, underscoring the unique feature of the electrochemical platform (Scheme 3C). Cyclic voltammetry analysis of the Z-selective alkyne semireduction system

• catalytic efficiency. Notably, the transformation proceeds with exceptionally high Faradaic efficiency (up to ≈99%), indicative of highly effective suppression of competing hydrogen evolution under mediator-governed electrochemical conditions. Mechanistic interrogation by cyclic voltammetry revealed two

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

• reactions of cyclic nitrones with organometallic compounds is a fruitful approach for the synthesis of sterically shielded radicals of the pyrrolidine, imidazoline, and imidazolidine series [23], including those with functional groups in the side chains [24]. Here we applied this strategy for the synthesis

• of sterically hindered piperidine nitroxyl radicals. Six-membered cyclic nitrones – 2,2,6-trialkyl-substituted 2,3,4,5-tetrahydropyridine-1-oxides were prepared via the acid-catalyzed reaction of 2-(2-aminoalkyl)-2-methyl-1,3-dioxolanes with ketones in analogy to literature procedures [25][26][27][28

• fragment ions corresponding to α-cleavage adjacent to the nitrogen atom, resulting in loss of the 2- or 6-alkyl substituent ([M−R]+) in agreement with established fragmentation patterns for cyclic amines [33]. The 2,2,6-trisubstituted piperidines 5a,b were oxidized to the corresponding ketonitrones 6a,b

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

• ) 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

• supports the copper–amido catalytic platform established by the Lee group. Recently, Kundu et al. demonstrated that cyclic(alkyl)(amino)carbene (CAAC)-ligated copper complexes significantly enhanced the copper-catalyzed conjugate addition of arylamines to electron-deficient olefins [42]. As illustrated in

• that this key step could occur through either four- or six-membered cyclic transition states (III-a vs III-b), depending on the nature of the electron-withdrawing group on the olefin. Finally, proton transfer from the amine substrate released the hydroamination product and regenerated the active Cu

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

• ; sequential reaction; Introduction Cyclic structures comprising nitrogen-containing multifused rings are extremely important because such heterocycle-fused cyclic structures [1][2] are found in various advanced materials [3][4] and biologically essential molecules [5][6][7]. Quinoline is a particularly

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

• -R) were studied by cyclic voltammetry (CV) (Table 1). All experimental electrochemical methods and conditions are presented in Supporting Information File 1. In the anodic area, the electrochemical profile of thioethers 1, 2, and 7 exhibit two successive oxidative stages consistent with previous

• performed in MeCN at controlled potentials of 1.25 V (for 5a) or 1.35 V (for 6a, 7a) for 1 h, with a charge consumption of 0.46–0.57 F/mol. After electrolysis, the cyclic voltammograms of these compounds showed a decrease in the first oxidation peak current, with conversions of 22%, 66%, and 48% for 5a, 6a

• in the solid state and in solution, highlighting the structural role of the sulfinyl group. Cyclic voltammetry demonstrated that the oxidation potential of the catechol fragment is systematically modulated by the oxidation state of the sulfur atom. The introduction of the S=O group shifts the first

Knoevenagel condensation of 4,5- and 1,8-diazafluorenes

• Darya S. Cheshkina,
• Christina S. Becker,
• Alina A. Sonina and
• Maxim S. Kazantsev

Beilstein J. Org. Chem. 2026, 22, 803–812, doi:10.3762/bjoc.22.62

• diazafluorenylidenes were characterized by NMR, HRMS, elemental analysis, cyclic voltammetry (CV), UV–vis spectroscopy (Figure 1) and X-ray data (Figure 2 and Figure S4 in Supporting Information File 1). Figure 1a demonstrates the cyclic voltammograms of DPDAFs in CH2Cl2 solution. Both compounds demonstrated

• -DPDAF) where Zn is four-coordinated to the nitrogens of the diazafluorene and pyridine rings forming a positively charged cyclic dimer (Figure 2d). The dimers are arranged in a herringbone-type structure via C–H···π, C–Cl···π and π-stacking interactions between diazafluorene and pyridine (Figure 2f

• molecules form stacks, while in the complex the dimers with Zn form a herringbone packing. The complex Zn–4,5-DPDAF represents a unique cyclic dimer structure and highlights a high potential of diazafluorenylidenes for coordination chemistry and materials science. Conclusion In summary, we elaborated

Halogenated azobenzene acrylates: from efficient solution photoswitching to stable solid-state photochromic materials

• Martina Vachtlová,
• Michaela Fecková,
• Vítězslav Zima,
• Jan Podlesný,
• Milan Klikar,
• Oldřich Pytela,
• Patrik Pařík,
• Jakub Opršal,
• Eliška Juhaňáková,
• Veronika Chrtová and
• Filip Bureš

Beilstein J. Org. Chem. 2026, 22, 782–794, doi:10.3762/bjoc.22.60

• calorimetry (DSC), thermogravimetric analysis (TGA), cyclic voltammetry (CV), UV–vis absorption spectroscopy, 1H and 13C NMR, and theoretical DFT calculations were employed. Furthermore, the target compounds are designed for incorporation as photoactive copolymers into the structure of functionalized

• (DCE) containing 0.1 M Bu4NPF6 in a three-electrode cell by cyclic voltammetry (CV). The recorded peak potentials are given vs Ag/AgCl reference electrode (SSCE). The acquired electrochemical data obtained in DCE are summarized in Table 2 including DFT-calculated values while the corresponding HOMO

Rongalite addition to dienones: diastereoselectivity in cyclic sulfone synthesis; stereochemical rationalization and prospects as a general conjugate nucleophile

• Melina Goga,
• Hao Zong,
• James Franco,
• Jazmine Prana,
• Rudolph Michel,
• Antonia Muro,
• Elana Rubin,
• Janet Brenya,
• Henk Eshuis and
• Magnus W. P. Bebbington

Beilstein J. Org. Chem. 2026, 22, 742–752, doi:10.3762/bjoc.22.56

• experimental and computational study of the diastereoselectivity of cyclic sulfone synthesis by reaction of Rongalite with doubly electrophilic dienones is presented. Computational methods, including density functional theory, conformational search methods, and internal reaction coordinate methods, have been

• , few reports documented this behavior for Rongalite (Scheme 1). This may have been due to its known reactivity as a conjugate reductant [17][20]. We recently published a preliminary report on the reaction of Rongalite with dienones leading to cyclic sulfones (Scheme 1) [21]. We now describe our efforts

• methanesulfinate or p-toluenesulfinate and 1 equivalent of Rongalite (50 °C, AcOH/H2O, o/n) led to a mixture of products. These results are tabulated in Table 1. Mixtures of cyclic and acyclic products were obtained in both cases. Our initial interpretation was that the ratios reflected the relative rates of

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

• , cyclic and acyclic unsaturated substrates, and fullerenes are useful dipolarophiles. This reaction method allows for the single-step creation of a wide variety of complex polyheterocyclic systems that may be useful for practical applications. Keywords: alkenes; α-amino acids; azomethine ylides; carbonyl

• amines) and to demonstrate their synthetic potential using a number of examples. The main strategies for synthesizing pyrrolidine derivatives via asymmetric and non-asymmetric 1,3-dipolar cycloaddition of azomethine ylides derived from cyclic and acyclic amino acids or amino esters with various carbonyl

Using generative AI to transform peptide hits into small molecule leads

• Joshua Mills and
• Yu Heng Lau

Beilstein J. Org. Chem. 2026, 22, 672–679, doi:10.3762/bjoc.22.51

• dynamics (MD) and docking (Figure 1). As an illustrative example, Yoshida and co-workers at Shionogi reported the design of small molecule inhibitors of nicotinamide N-methyltransferase [14] and β-herpesvirus proteases [15], starting from cyclic peptide hits obtained by mRNA display with flexible in vitro

Photoorganocatalytic trifluoromethylation of (het)arenes in green conditions

• Egor N. Boronin,
• Svetlana E. Kaurkina,
• Milena M. Svetlakova,
• Anton S. Bolshakov,
• Maxim V. Arsenyev,
• Vasilii F. Otvagin,
• Alexey Yu. Fedorov,
• Timothy Noël and
• Alexander V. Nyuchev

Beilstein J. Org. Chem. 2026, 22, 662–671, doi:10.3762/bjoc.22.50

• afforded no more than 6% yield (Table 1, entry 6). Interestingly, MTBE, in contrast to the cyclic ether THF, gave a satisfactory yield of 27% (Table 1, entry 7). BuOAc provided a comparable yield of 28% (Table 1, entry 7), likely due to its higher viscosity (0.685 cP at 25 °C) compared with EtOAc (0.423 cP

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

• (cyclic voltammetry), which is expected to give lower uncertainty. For less stable primary/secondary systems, precisely those that broaden the dataset beyond “classical” persistent carbocations, Cheng et al. instead determined potentials for photochemically generated radicals using photomodulation AC

Continuous-flow carbonyl hydrogenation under subatmospheric to atmospheric hydrogen pressure enabled by robust heterogeneous Pt–Fe catalysts

• Hiroyuki Miyamura,
• Ryosuke Kajiyama,
• Shun-ya Onozawa,
• Yoshihiro Kon and
• Shū Kobayashi

Beilstein J. Org. Chem. 2026, 22, 575–582, doi:10.3762/bjoc.22.43

• the ester moiety, and the product was isolated by simple evaporation of the solvent from the collected fraction eluted from the flow reactor (Table 2, entry 6). Cyclic ketones 1g, 1h, and 1i and an aliphatic ketone 1j were also hydrogenated in excellent yields at room temperature (Table 2, entries 7

• hydrogenated with 20% v/v hydrogen to afford the desired product quantitatively (Table 3, entry 1). A cyclic ketone 1i was converted to 2i in 84% yield with 10% v/v hydrogen and in 97% yield with 20% v/v hydrogen (Table 3, entries 2 and 3). An aliphatic aldehyde 1w was also hydrogenated to give the product in

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

• [4]resorcinarene hydroxamic acid has also shown a pronounced binding tendency and selectivity for uranyl and proved to be applicable for the determination of uranium in standard and environmental samples [34]. Importantly, more recent studies have demonstrated that pre-organized or cyclic hydroxamate

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

• successfully transformed into central chirality by epoxidation without loss of enantiomeric purity. Keywords: dynamic chirality; medium-sized heterocycle; orthocyclophene; planar chirality; stereochemical analysis; Introduction In the course of our study on planar chiral medium-sized cyclic molecules [1][2

• -substituted oxacyclophene 1ad We planned to construct the nine-membered cyclic ether skeleton of 1ad in the final step by an intramolecular Williamson etherification of haloalcohol 2 (Scheme 1). The iodine-substituted Z-alkene moiety of 2 was planned to be introduced through a trans-selective hydroiodination

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

• virtually any functional units attached to them via triazole groups. Keywords: calixarene amines; dimeric capsules; functionalization; tetraureacalixarenes; triazoles; Introduction Considered generally as multifunctional molecular cores, calixarenes in their native forms as cyclic oligophenols actually

• these cyclic tetramers may be regarded as virtually universal molecular platforms for the construction of unique multifunctional structures capable of diverse supramolecular interactions [1][2][3][4]. Amino groups attached directly to all four positions of the wide rim of the cores are among the most

• . In aprotic media, these compounds, referred to as ‘tetraureacalix[4]arenes’, assemble into well-defined homo- or heterodimeric capsules, which are held together by cyclic belts of hydrogen bonds between interpenetrated urea groups from two molecules and are able to include a single neutral molecule

Electrosynthetic access to unsymmetrical oxaza[8]helicenes with high chiral stability and strong circularly polarized luminescence (CPL)

• Tin Zar Aye,
• Rubal Sharma,
• Muthu Karuppasamy,
• Daiya Suzuki,
• Haruka Nakajima,
• Yoshitane Imai,
• Mitsuhiro Arisawa,
• Mohamed S. H. Salem and
• Shinobu Takizawa

Beilstein J. Org. Chem. 2026, 22, 372–382, doi:10.3762/bjoc.22.25

• products were detected under the optimized conditions (Scheme 2). Based on our previous reports [48][56], DFT calculations, and cyclic voltammetry (CV) analyses (Figure 1), anodic single-electron transfer (SET) is expected to occur first from 3, generating the electrophilic radical cation [3]·+ as 3 (Eox

• intense chiroptical responses, including mirror-image CD and strong CPL with |glum| values up to 0.0026 and CPL brightness approaching 30.8 M−1 cm−1. A plausible reaction mechanism: cyclic voltammetry (CV) analyses of hydroxycarbazole derivative 3 and 2-naphthol derivatives 4; DFT-based calculations of

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

• bioactive compounds underwent smooth esterification with TFE to give the corresponding 2,2,2-trifluoroethyl esters 82–85 in high yields. To elucidate the reaction mechanism, cyclic voltammetry experiments, control reactions, and DFT calculations were conducted. At the anode, bromide ions are oxidized to

• equivalents of LiHMDS, N-alkyl- and N-arylanilides were efficiently cleaved to afford the corresponding amides 64 and 162–165 in high yields. A broad range of N,N-dialkylamides, cyclic amides, and heterocyclic amides were also compatible, all delivering amide products 3, 4, and 166–172 in good to excellent

• amide using aniline hydrochloride salt. CO2-catalyzed transamidation of amides. Transamidation of formamides using cyclic dihydrogen tetrametaphosphate. BF3·OEt2-mediated transamidation of primary amides. Acyl iodide intermediate 121 generation from amides for the transamidation using HOTf and KI

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

• reaction, starting with a Schenck ene reaction of cholesterol to form the highly reactive hydroperoxide species 112a was the operational pathway [159][160][161][162]. Carbon bond migration in a process called Hock cleavage leads to a cyclic hemiacetal 112b which ring-opens and aldolises (112c) to give the

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

• synthesis of spirobarbiturates via a [3 + 2] cycloaddition reaction of azomethine ylides, we present for the first time a three-component diastereoselective synthesis of hybrid systems containing spiro-fused cyclic fragments of barbituric acid and pyrrolo[3,4-a]pyrrolizidine. It was found that azomethine

• preferential formation of the endo-adduct (upper pathway). The predominance of exo-isomers in some cases probably reflects insufficient stabilization due to secondary orbital interactions in the transition state [43]. It should be noted separately that secondary cyclic amino acids such as azetidine-2

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

• single and double bonds (Figure 1A) [5]. However, despite its strength in representing a planar cyclic arrangement of tetravalent carbon atoms, this formalism fails to accurately depict the observed reactivity, structure, and stability of benzene. It implies three rapidly equilibrating, localized double

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

• Fe3O4@SiO2–SO3H nanoparticles [39]. However, all previously reported multicomponent protocols inevitably terminate at the formation of the cyclic pyranoquinolinone scaffold, and no controlled access to open-chain quinolinone esters has been demonstrated so far. Herein, building upon previous studies and

• reactions of α,β-unsaturated aldehydes with 2a–c afforded only minor amounts of the 1,4-addition product, while the cyclic 1,2-addition product predominated (Scheme 4C). The reaction of α,β-unsaturated cyanoacrylate with 2c also failed to yield the desired product (Scheme 4D). For the reaction of α,β

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

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

• -Petersburg 199034, Russia 10.3762/bjoc.22.5 Abstract New highly electrophilic gem- and spiro-activated trichloromethylnitrocyclopropanes were obtained by the Michael-initiated ring closure (MIRC) reaction of 1-bromo-1-nitro-3,3,3-trichloropropene with linear and cyclic CH-acids catalyzed by bases

• nitro group upon breaking the C–C bond [16][17]. Substituted nitrocyclopropanes in reactions with various nucleophiles form linear precursors for the synthesis of γ-substituted α-aminobutyric acids [18][19], cyclic nitropyrrolines [20] and isoxazoline N-oxides [18]. The nitrocyclopropane fragment is a

• Michael-initiated ring closure (MIRC) reaction of gem-halonitroalkenes and CH-acids [37][38]. Thus, 2-nitrocyclopropanecarboxylates were obtained based on the tandem reactions of cyclic CH-acids with alkyl 3-bromo-3-nitroacrylates [39]. Despite the structural proximity and high activity of 1-bromo-1-nitro