Salen–scandium(III) complex-catalyzed asymmetric (3 + 2) annulation of aziridines and aldehydes

• Linqiang Wang and
• Jiaxi Xu

Beilstein J. Org. Chem. 2025, 21, 1087–1094, doi:10.3762/bjoc.21.86

• -containing five-membered saturated heterocycles. They are not only useful building blocks for the synthesis of biologically active compounds [1], for example, side-chain precursor of paclitaxel [2], but also widely exist in some pharmaceuticals [3][4], such as antibacterial agents of Gram-positive organisms

Synthesis of pyrrolo[3,2-d]pyrimidine-2,4(3H)-diones by domino C–N coupling/hydroamination reactions

• Ruben Manuel Figueira de Abreu,
• Robin Tiedemann,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2025, 21, 1010–1017, doi:10.3762/bjoc.21.82

• . Keywords: alkynes; catalysis; cyclizations; domino reactions; heterocycles; Introduction Pyrimidines and purines are one of the most important heterocyclic compounds with prevalent biological functions. Both are found in nucleosides and their corresponding polymeric DNA and RNA, and hence are vital for

Recent total synthesis of natural products leveraging a strategy of enamide cyclization

• Chun-Yu Mi,
• Jia-Yuan Zhai and
• Xiao-Ming Zhang

Beilstein J. Org. Chem. 2025, 21, 999–1009, doi:10.3762/bjoc.21.81

• cyclization modes that provide entries to various N-heterocycles, some of which serve as key structural motifs in natural alkaloids. This review highlights recent advancements in enamide-based cyclization reactions, including enamide–alkyne cycloisomerization, [3 + 2] annulation, and polycyclization, with a

• principles, tandem reactions or annulations can be designed to efficiently access N-heterocycles. As the enamides are also easily accessible via condensations, applications of these nitrogen-containing building blocks in the synthesis of N-heterocycles are synthetically straightforward. When applied properly

• . Cyclization/isomerization – collective total synthesis of fawcettimine-type alkaloids The bicyclic decahydroquinoline enamide motif can serve as a versatile precursor to access different types of tricyclic N-heterocycles. As demonstrated in the above work from She’s group, the aza-Prins cyclization renders

Study of tribenzo[b,d,f]azepine as donor in D–A photocatalysts

• Katy Medrano-Uribe,
• Jorge Humbrías-Martín and
• Luca Dell’Amico

Beilstein J. Org. Chem. 2025, 21, 935–944, doi:10.3762/bjoc.21.76

• behavior is supported by the DFT studies, which suggested a better spatial separation between the HOMO and LUMO. As expected, the HOMO–LUMO energy gap followed a trend that is dependent on the electron-donating capacity of the nitrogen heterocycles and amine present in compounds 5e (2.9 eV), 5d (3.5 eV

Silver(I) triflate-catalyzed post-Ugi synthesis of pyrazolodiazepines

• Muhammad Hasan,
• Anatoly A. Peshkov,
• Syed Anis Ali Shah,
• Andrey Belyaev,
• Chang-Keun Lim,
• Shunyi Wang and
• Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2025, 21, 915–925, doi:10.3762/bjoc.21.74

• isocyanides, followed by a silver(I) triflate-catalyzed intramolecular heteroannulation of the resulting pyrazole-tethered propargylamides occurring in a 7-endo-dig fashion. The approach is scalable and tolerates a diverse range of substitution patterns. Keywords: heterocycles; post-MCR transformations

• ; pyrazolodiazepines; silver catalysis; Ugi reaction; Introduction Synthetic chemists are continuously involved in the development of methodologies for accessing new heterocyclic scaffolds that resemble naturally occurring products and biologically active molecules [1][2]. Nitrogen heterocycles draw particular

• synthetic methods to access diazepines fused with other nitrogen-containing heterocycles towards their broader exploration in high-throughput screening for identifying new drug candidates. Traditional synthetic methods for producing medium-ring nitrogen-containing heterocycles often involve complex

4-(1-Methylamino)ethylidene-1,5-disubstituted pyrrolidine-2,3-diones: synthesis, anti-inflammatory effect and in silico approaches

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Luc Van Meervelt,
• Do Thi Thao and
• Nguyen Minh Thong

Beilstein J. Org. Chem. 2025, 21, 817–829, doi:10.3762/bjoc.21.65

• , Vietnam Academy of Science and Technology (VAST), Hanoi 10072, Vietnam 10.3762/bjoc.21.65 Abstract Pyrrolidine-2,3-diones are important intermediates in the synthesis of numerous nitrogen-containing heterocycles which possess a broad spectrum of biological and pharmacological activities. In this article

Synthesis and photoinduced switching properties of C₇-heteroatom containing push–pull norbornadiene derivatives

• Daniel Krappmann and
• Andreas Hirsch

Beilstein J. Org. Chem. 2025, 21, 807–816, doi:10.3762/bjoc.21.64

• catalytic back-conversion studies. Keywords: heterocycles; molecular solar thermal systems; norbornadiene; photochemistry; quadricyclane; Introduction In recent decades, the demand for renewable energy has increased tremendously [1]. A promising alternative to fossil fuels is the utilization of so-called

Regioselective formal hydrocyanation of allenes: synthesis of β,γ-unsaturated nitriles with α-all-carbon quaternary centers

• Seeun Lim,
• Teresa Kim and
• Yunmi Lee

Beilstein J. Org. Chem. 2025, 21, 800–806, doi:10.3762/bjoc.21.63

• are important intermediates in organic syntheses because of the versatility of the cyano group, which can be readily transformed into a wide range of functional groups, including amides, carboxylic acids, amines, aldehydes, ketones, and N-heterocycles [6][7][8]. However, the synthesis of all-carbon

New advances in asymmetric organocatalysis II

• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 766–769, doi:10.3762/bjoc.21.60

• organocatalytic cycloaddition reactions of unsaturated imines. A broad variety of activation modes, as well as catalyst structures, was covered and found to be useful in affording a diverse array of chiral N-heterocycles [27]. In my group, we recently became interested in atroposelective catalytic syntheses

Origami with small molecules: exploiting the C–F bond as a conformational tool

• Patrick Ryan,
• Ramsha Iftikhar and
• Luke Hunter

Beilstein J. Org. Chem. 2025, 21, 680–716, doi:10.3762/bjoc.21.54

• amine (e.g., a fluorinated analogue of the antidepressant drug, citalopram 93 [160]). We now turn our attention to cyclic amines. Fluorine has been shown to be capable of modifing the conformations of a variety of N-heterocycles, ranging in size from four- to eight-membered rings [48][161][162][163]. In

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

• Olesja Koleda,
• Janis Sadauskis,
• Darja Antonenko,
• Edvards Janis Treijs,
• Raivis Davis Steberis and
• Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

• facilitated the cyclization, and the 6-membered heterocycles 6h,i could be obtained in 27% and 18% yield, respectively. In addition to sulfonamides, carbamates such as N-Boc and benzamide are also suitable as nucleophiles for the anodic decarboxylation/cyclization reaction. However, the corresponding 2

Formaldehyde surrogates in multicomponent reactions

• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Bernhard Westermann

Beilstein J. Org. Chem. 2025, 21, 564–595, doi:10.3762/bjoc.21.45

• concerns and improved reaction control can be addressed, paving the way for more efficient and sustainable synthetic methodologies. Keywords: cascade reactions; formaldehyde surrogates; green chemistry; heterocycles; multicomponent reactions; Introduction Organic chemistry is a mature discipline that has

• the MCR product is possible thus increasing the versatility of these reactions in terms of structural diversity and molecular complexity. In this context, a wide variety of heterocycles and macrocycles as important biological scaffolds have been synthesized [6]. One of the most important components

• the cyclization process producing various highly diverse nitrogen-containing heterocycles, which are valuable scaffolds in medicinal chemistry [46]. Synthesis of non-aromatic heterocycles As stated above, DMSO can also hydrolytically decompose to formaldehyde. There are many examples of reactions in

Study of the interaction of 2H-furo[3,2-b]pyran-2-ones with nitrogen-containing nucleophiles

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2025, 21, 556–563, doi:10.3762/bjoc.21.44

• ][9]. Wherein, the wide variety of easily available starting butenolides and amines allows one to create a huge array of practically useful products. At the same time, the application of hydrazine derivatives expands the range of formed heterocycles. So, along with the aforementioned N-substituted

Vinylogous functionalization of 4-alkylidene-5-aminopyrazoles with methyl trifluoropyruvates

• Judit Hostalet-Romero,
• Laura Carceller-Ferrer,
• Gonzalo Blay,
• Amparo Sanz-Marco,
• José R. Pedro and
• Carlos Vila

Beilstein J. Org. Chem. 2025, 21, 533–540, doi:10.3762/bjoc.21.41

• diastereoselectivity (up to 7:1). Keywords: alcohols; diastereoselectivity; nitrogen heterocycles; pyrazoles; vinylogous reaction; Introduction Vinylogy refers to the transmission of electronic effects through a conjugated π-system, enabling the extension of a functional group's nucleophilic or electrophilic

• biologically active compounds, particularly antibacterial and antifungal agents [13][14]. This class of functionalized nitrogen heterocycles is notable for its synthetic versatility, because it shows different nucleophilic positions, making regioselectivity a synthetic challenge. Numerous studies have reported

Synthesis of electrophile-tethered preQ₁ analogs for covalent attachment to preQ₁ RNA

• Laurin Flemmich and
• Ronald Micura

Beilstein J. Org. Chem. 2025, 21, 483–489, doi:10.3762/bjoc.21.35

• novel compound DPQ1. Keywords: deazapurines; heterocycles; pyrrolopyrimidines; queuosine; riboswitches; ribozymes; RNA alkylation; RNA labelling; Introduction Pre-queuosine 1 (preQ1) is a biosynthetic precursor of the hypermodified nucleoside queuosine (Q) that is found in the wobble position of

New tandem Ugi/intramolecular Diels–Alder reaction based on vinylfuran and 1,3-butadienylfuran derivatives

• Yuriy I. Horak,
• Roman Z. Lytvyn,
• Andrii R. Vakhula,
• Yuriy V. Homza,
• Nazariy T. Pokhodylo and
• Mykola D. Obushak

Beilstein J. Org. Chem. 2025, 21, 444–450, doi:10.3762/bjoc.21.31

• and step-economy, making them promising for future commercial applications. Partly hydrogenated isoindoles and their derivatives exhibit broad biological activities and are considered privileged motifs in medicinal chemistry [20][21]. These compounds, when condensed with aromatics or heterocycles

Unraveling aromaticity: the dual worlds of pyrazole, pyrazoline, and 3D carborane

• Zahra Noori,
• Miquel Solà,
• Clara Viñas,
• Francesc Teixidor and
• Jordi Poater

Beilstein J. Org. Chem. 2025, 21, 412–420, doi:10.3762/bjoc.21.29

• ], offering enhanced properties and efficacy [28][30][33][34][35]. Therefore, the advancement of simple, efficient methodologies for synthesizing o-carborane-fused heterocycles is critically needed. However, the limited number of synthetic strategies for carborane functionalization [36] continues to constrain

• , whereas the boron cage is aromatic, the heterocyclic ring is clearly non-aromatic, with MCI that amount to 0.002, 0.000 and 0.003 a.u., respectively (Figure 4). At difference, based on NICS, these heterocycles should be considered aromatic (−8.5, −7.1, and −8.3 ppm, respectively). However, we have

• neighboring cycles exhibit high or very high NICS values. For a more reliable evaluation, it is important to also consider structural factors and additional indicators like the multicenter index (MCI) [54][55][56][57]. Thus, from now on, we will evaluate the aromaticity of heterocycles solely using the

Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones

• Yurii A. Sayapin,
• Eugeny A. Gusakov,
• Inna O. Tupaeva,
• Alexander D. Dubonosov,
• Igor V. Dorogan,
• Valery V. Tkachev,
• Anna S. Goncharova,
• Gennady V. Shilov,
• Natalia S. Kuznetsova,
• Svetlana Y. Filippova,
• Tatyana A. Krasnikova,
• Yanis A. Boumber,
• Alexey Y. Maksimov,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26

• ; Introduction 1,2-Benzoquinones represent unique building blocks for various classes of heterocyclic systems. Their structure depends on the reactivity of the initial heterocycles and 1,2-benzoquinones, as well as on the reaction conditions. In the series of 2-methylquinolines [1], 2-methylquinoxalines [2], 2

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• significant attention for their unique photophysical characteristics and versatility in NIR-driven reactions [51]. Cyanins consist of nitrogen-containing heterocycles connected by a polymethin chain [52][53], whose synthesis and modifications have been widely explored [54][55][56]. Such compounds exhibit

Heteroannulations of cyanoacetamide-based MCR scaffolds utilizing formamide

• Marios Zingiridis,
• Danae Papachristodoulou,
• Despoina Menegaki,
• Konstantinos G. Froudas and
• Constantinos G. Neochoritis

Beilstein J. Org. Chem. 2025, 21, 217–225, doi:10.3762/bjoc.21.13

• structure was obtained, revealing certain geometrical features. Keywords: 2-amino-substituted heterocycles; cyanoacetamide; Gewald reaction; multicomponent reaction (MCR); pyrimidine; Introduction The term “net-zero carbon” is becoming increasingly common as we consider a future marked by a rising global

• (hetero)aromatic, bulky and linear amines with different substitution patterns. The compounds 2–4 were purified by recrystallization and employed as such (Scheme 2). To our great delight, the heterocycles 2–4 could successfully be subjected to refluxing formamide under neat conditions, instantly yielding

• anthranilic acid and B) access to heteroannulated pyrimidones by MCRs of suitably substituted heterocycles and formamide as C1 source. Access to the key building blocks 2–4 by employing three different nonisocyanide-based MCRs. Diversity and complexity were the essential features of our library of starting

Dioxazolones as electrophilic amide sources in copper-catalyzed and -mediated transformations

• Seungmin Lee,
• Minsuk Kim,
• Hyewon Han and
• Jongwoo Son

Beilstein J. Org. Chem. 2025, 21, 200–216, doi:10.3762/bjoc.21.12

• . Review 1 Transformations via the formation of copper nitrenoids 1.1 C(sp3)–H amidation Lactams are recognized as one of the most significant nitrogen-containing heterocycles in drug discovery [69][70]. Among these, six-membered lactams, known as 2-piperidinones, have been extensively studied due to their

Recent advances in electrochemical copper catalysis for modern organic synthesis

• Yemin Kim and
• Won Jun Jang

Beilstein J. Org. Chem. 2025, 21, 155–178, doi:10.3762/bjoc.21.9

• decreasing the oxidation potential. A range of functional groups, such as halides, ethers, and heterocycles, were tolerated well, yielding the corresponding enantioenriched products 14 with high enantioselectivity in the presence of chiral bisoxazoline ligand L2. A possible mechanism is depicted in Figure 5

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• , Ankara 06800, Türkiye 10.3762/bjoc.20.273 Abstract Acenaphthylene-fused heteroarenes with a variety of five- and six-membered heterocycles such as thiophene, furan, benzofuran, pyrazole, pyridine and pyrimidine were synthesized via an efficient Pd-catalyzed reaction cascade in good to high yields (45–90

• total synthesis of the fungal natural product bulgarein. Keywords: acenaphthylene-fused heteroarenes; benzo[j]fluoranthenes; C–H arylation; fluoranthenes; heterocycles; Introduction An important subclass of polycyclic aromatic hydrocarbons (PAHs) [1] is comprised of fluoranthenes, which have been the

• heteroatoms or other heterocycles to obtain heterocyclic fluoranthene analogues offers numerous opportunities for structural and functional diversifications. For instance, azafluoranthenes such as triclisine (1) or imeluteine (2) constitute a common structural motif encountered in natural products isolated

Intramolecular C–H arylation of pyridine derivatives with a palladium catalyst for the synthesis of multiply fused heteroaromatic compounds

• Yuki Nakanishi,
• Shoichi Sugita,
• Kentaro Okano and
• Atsunori Mori

Beilstein J. Org. Chem. 2024, 20, 3256–3262, doi:10.3762/bjoc.20.269

• % yield, respectively. The related reaction is also carried out with amides of non-pyridine derivatives terephthal- and benzamides to afford multiply fused heterocyclic compounds in 81% and 89% yields, respectively. Keywords: intramolecular C–H arylation; multiply fused heterocycles; palladium acetate

• efficient and selective extraction of lanthanides and actinides and, furthermore, a number of heterocycles involving pyridine rings have been reported to exhibit biological activities [14][15][16][17][18][19][20][21][22]. We have recently reported, as shown in Figure 1, that the introduction of a multiply

• afford 8b in 89% yield under similar conditions, in which the result of carbocyclic amide (7a vs 7b) contrasted with the case of heterocyclic ones, 1c vs 3 and 5a vs 5b. Conclusion We have shown the facile synthesis of fused nitrogen-containing heterocycles and extended the scope of the intramolecular

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• -heterocycles using various catalytic systems such as chiral metal catalysts, chiral Lewis acids or chiral organocatalysts. This review presents an overview of the recent advances in enantioselective cyclization reactions of 1-azadienes catalyzed by non-covalent organocatalysts. Keywords: α,β-unsaturated

• imines; asymmetric organocatalysis; cyclization; N-heterocycles; inverse electron demand aza-Diels–Alder reaction; Introduction Nitrogen-containing heterocycles are abundant scaffolds present in natural products, biologically active compounds, pharmaceuticals, synthetic agrochemicals, and functional

• materials [1][2]. Due to their importance, different synthetic routes involving stoichiometric and catalytic approaches have been developed. The α,β-unsaturated imines, also known as conjugated imines or 1-azadienes, are useful precursors for the construction of aza-heterocycles. Due to their structure