A versatile route towards 6-arylpipecolic acids

• Erich Gebel,
• Cornelia Göcke,
• Carolin Gruner and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 1104–1115, doi:10.3762/bjoc.21.88

• structure of pipecolic acid is rather challenging and often necessitates early-stage derivatization followed by the formation of the six-membered ring [29][30][31][32]. An alternative is to utilise derivatization reactions such as Suzuki–Miyaura [33] or Sonogashira–Hagihara [34] cross-coupling reactions on

• a key intermediate product. This late-stage approach was previously described by us while utilising Suzuki–Miyaura or Sonogashira–Hagihara cross-coupling reactions to generate pipecolic acid derivatives with alkynyl substituents in the C6 position [35]. Here, we present a robust synthetic route to

• the Sonogashira–Hagihara cross-coupling products [35]. Furthermore, an in-depth NMR analysis was conducted on the resulting constraints leading to conformational structure predictions. ᴅ-2-Aminoadipic acid (1) [36], a side product formed in the pharmaceutical semisynthesis of 7-aminocephalosporanic

Recent advances in synthetic approaches for bioactive cinnamic acid derivatives

• Betty A. Kustiana,
• Galuh Widiyarti and
• Teni Ernawati

Beilstein J. Org. Chem. 2025, 21, 1031–1086, doi:10.3762/bjoc.21.85

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

• Abstract A variety of pyrrolo[3,2-d]pyrimidine-2,4(3H)-diones were prepared by a combination of Sonogashira reaction and subsequent cyclization by domino C–N coupling/hydroamination reaction. The optical properties (UV–vis absorption and fluorescence) depend on the substitution pattern of the compounds

• pyrrolopyrimidine derivatives. The envisioned methodology combines a Sonogashira–Hagihara reaction and a one-pot process comprising a Buchwald–Hartwig coupling reaction followed by a hydroamination [23][24]. Results and Discussion The bromination of 6-chloro-1,3-dimethyluracil (1) afforded, following a known

• procedure [25], 5-bromo-6-chloro-1,3-dimethyluracil (2) in 52% yield (Scheme 1). We previously reported Sonogashira reactions of the latter with various alkynes to give products 3a–d,g,h [26][27]. In this work, we extended the scope and prepared novel derivatives 3e and 3f. A nearly quantitative yield was

On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

• Daniel Straub,
• Markus Gross,
• Mona E. Arnold,
• Julia Zolg and
• Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

Studies on the syntheses of β-carboline alkaloids brevicarine and brevicolline

• Benedek Batizi,
• Patrik Pollák,
• András Dancsó,
• Péter Keglevich,
• Gyula Simig,
• Balázs Volk and
• Mátyás Milen

Beilstein J. Org. Chem. 2025, 21, 955–963, doi:10.3762/bjoc.21.79

• , versatile key triflate intermediate 3, which allowed the introduction of substituents attached by a C–C bond to position 4 of the β-carboline scaffold by cross-coupling reactions. Sonogashira reaction of compound 3 with N-(3-butynyl)phthalimide (4) led to coupled compound 5. Cleavage of the phthalimide

Emerging trends in the optimization of organic synthesis through high-throughput tools and machine learning

• Pablo Quijano Velasco,
• Kedar Hippalgaonkar and
• Balamurugan Ramalingam

Beilstein J. Org. Chem. 2025, 21, 10–38, doi:10.3762/bjoc.21.3

Synthesis of the 1,5-disubstituted tetrazole-methanesulfonylindole hybrid system via high-order multicomponent reaction

• Cesia M. Aguilar-Morales,
• América A. Frías-López,
• Nadia V. Emilio-Velázquez,
• Alejandro Islas-Jácome,
• Angelica Judith Granados-López,
• Jorge Gustavo Araujo-Huitrado,
• Yamilé López-Hernández,
• Hiram Hernández-López,
• Luis Chacón-García,
• Jesús Adrián López and
• Carlos J. Cortés-García

Beilstein J. Org. Chem. 2024, 20, 3077–3084, doi:10.3762/bjoc.20.256

• ]. Therefore, the key component for this reaction was methanesulfonyl 2-iodoaniline 17, as it has been reported that the use of 2-iodoaniline results in the formation of only the Sonogashira coupling product [29][30]. Moreover, as shown in Scheme 2, this high-order multicomponent protocol yielded fourteen 1,5

• to obtain the 1,5-disubstituted tetrazole-alkyne 19 is well-documented and hence, it is not herein described in detail [1][26][31]. Thus, based on Pal and co-workers’ proposal [32][33], the second process involves two catalytic cycles: 1) a Sonogashira coupling, and 2) a 5-endo-dig cyclization. The

• first catalytic cycle begins with the coupling of 1,5-disubstituted tetrazole-alkyne 19 and methanesulfonyl-2-iodoaniline 17 forming the intermediate 23. Following a reductive elimination, the Sonogashira-like product 24 is produced, which then progresses into the second catalytic cycle. In this cycle

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

• Robin Schulte,
• Dustin Schade,
• Thomas Paululat,
• Till J. B. Zähringer,
• Christoph Kerzig and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

• molecular system. Herein, we present the synthesis of mono-, bis-, and tris-norbornadiene derivatives with alkynylbenzene and alkynylnaphthalene core units, along with studies of their photochemical properties. The target compounds were synthesized by Sonogashira–Hagihara coupling reactions of 2

• ; Sonogashira–Hagihara coupling; Introduction The application of sustainable energy storage and supply has become a very important issue both from an economic and ecological point of view. In particular, the global energy demand is continuously expanding because of the increasing population, the development of

• . Results and Discussion The norbornadiene derivatives 1h–l,n were synthesized by Sonogashira–Hagihara coupling reaction of 2-bromonorbornadiene (1g) [36] with the corresponding arylacetylenes 3a–g (Scheme 2). As an exception, 1,4-bis-norbornadienylnaphthalene (1m) could not be obtained by this route

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• into the polymer system, further modification and structural analyses were performed [48][74]. The axle end was easily modified by bromination of the benzene ring and successive transition metal–catalyzed cross-coupling reaction, such as Suzuki or Sonogashira coupling (Figure 10A). Furthermore, the

Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones

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

Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228

• Ruben Manuel Figueira de Abreu Peter Ehlers Peter Langer Universität Rostock, Institut für Chemie, Albert-Einstein-Str. 3a, 18059 Rostock, Germany 10.3762/bjoc.20.228 Abstract We report the synthesis of polycyclic uracil derivatives. The method is based on palladium-catalysed Sonogashira–Hagihara

• known which allow for an individual introduction of substituents at both positions [37][38][51][52][53][54][55][56][57][58][59][60][61]. In our previous work, we developed a new method which enables both positions to be independently functionalised by Sonogashira- and Suzuki–Miyaura cross-coupling

• of palladium-catalysed Sonogashira–Hagihara and Suzuki–Miyaura cross-coupling reactions (Scheme 1). The final cyclisation step is accomplished by an acid-mediated cycloisomerisation. The synthesis of starting materials 4 was carried out by our previously reported protocol [65]. While compounds 4a–f

Synthesis of fluoroalkenes and fluoroenynes via cross-coupling reactions using novel multihalogenated vinyl ethers

• Yukiko Karuo,
• Keita Hirata,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 2691–2703, doi:10.3762/bjoc.20.226

• fluoroenynes via Suzuki–Miyaura and Sonogashira cross-coupling reactions using novel multihalogenated fluorovinyl ethers, which are easily prepared from the reaction between phenols and 2-bromo-2-chloro-1,1,1-trifluoroethane (halothane). These reactions make use of the unique structure of multihalogenated

• fluorovinyl ethers, which contains a reactive bromine atom, to afford a series of fluoroalkenes and fluoroenynes in moderate to high yields. Keywords: fluoroalkenes; fluoroenynes; multihalogenated vinyl ethers; Suzuki–Miyaura cross-coupling reactions; Sonogashira cross-coupling reactions; Introduction

• chlorine atoms as reported by Hosoya and Niwa et al. In this study, we investigated the synthesis of fluoroalkenes 2 or fluoroenynes 3 by Suzuki–Miyaura or Sonogashira cross-couplings with a key building block 1 (Scheme 1D). Results and Discussion Optimization of the conditions of cross-coupling reactions

Metal-free double azide addition to strained alkynes of an octadehydrodibenzo[12]annulene derivative with electron-withdrawing substituents

• Naoki Takeda,
• Shuichi Akasaka,
• Susumu Kawauchi and
• Tsuyoshi Michinobu

Beilstein J. Org. Chem. 2024, 20, 2234–2241, doi:10.3762/bjoc.20.191

• 5 was prepared from phthalimide (1, Scheme 1). Iodination followed by hydrolysis afforded 4,5-diiodophthalic acid (2) in 46.7% yield. Esterification with 1-hexanol yielded compound 3 in 56.8% yield and the subsequent Sonogashira coupling with trimethylsilylacetylene provided compound 4 in 80.0

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• -carbon alkynoyl building blocks [121][122] could be generated catalytically [123], thereby facilitating reactions under mild reaction conditions and opening novel one-pot pathways for consecutive multicomponent syntheses of pyrazoles. Sonogashira alkynylation of terminal alkynes and (hetero)aroyl

• solution and in the solid state [127]. Furthermore, even sugar-functionalized pyrazoles have been accessed by this approach [128], and it was readily implemented in a continuous flow reactor [129]. Besides traditional Sonogashira catalyst systems, highly reactive and reusable immobilized Pd-complexes, such

• and high optical refraction. Functionalized alkynes can alternatively be prepared in situ by a Kumada coupling [133] of aryl iodides and ethynylmagnesium bromide [134]. The Pd catalyst is reused in the subsequent Sonogashira coupling for the synthesis of alkynones in the sense of sequential catalysis

A new platform for the synthesis of diketopyrrolopyrrole derivatives via nucleophilic aromatic substitution reactions

• Vitor A. S. Almodovar and
• Augusto C. Tomé

Beilstein J. Org. Chem. 2024, 20, 1933–1939, doi:10.3762/bjoc.20.169

• -di(het)aryl groups via Suzuki–Miyaura [26][27][28] or Sonogashira [29][30][31] reactions. In this study, we report a straightforward method to obtain a diverse array of N-substituted DPP derivatives through a two-step process. Firstly, the N-alkylation of Pigment Red 254 (DPP 1) is achieved using

Synthesis and optical properties of bis- and tris-alkynyl-2-trifluoromethylquinolines

• Stefan Jopp,
• Franziska Spruner von Mertz,
• Peter Ehlers,
• Alexander Villinger and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1246–1255, doi:10.3762/bjoc.20.107

• /bjoc.20.107 Abstract Three bis- or tris-brominated 2-trifluoromethylquinolines have been successfully applied in palladium-catalysed Sonogashira reactions, leading to several examples of alkynylated quinolines in good to excellent yields. Optical properties of selected products have been studied by

• ][23], dyes, preservatives and as ligands in complex chemistry [24][25][26][27]. In the context of our interest in the application of cross-coupling reactions to polyhalogenated heterocycles [28][29][30][31], we studied Sonogashira reactions of brominated 2-trifluoromethylquinolines. The optical

• bromide gave 4. With quinoline 4 in hand, we studied palladium-catalysed Sonogashira reactions with phenylacetylene (5a). Gratifyingly, our initial test reaction, using Pd(OAc)2 as catalyst with XPhos as ligand, gave bis-alkynylated product 6a in quantitative yield. Reducing the catalyst loading from 5 to

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• , the Li’s group and Zeng and Alper developed two different methods for carrying out a direct carbonylation of indoles with alkynes. Li’s group reported the direct Sonogashira carbonylation coupling reaction of indoles and alkynes catalyzed by Pd/CuI in the presence of iodine as oxidant [71]. The

• secondary amines. The direct Sonogashira carbonylation coupling reaction of indoles and alkynes via Pd/CuI catalysis reported by Li et al. [71] (top). The Pd-catalyzed regio- and chemoselective direct coupling of indoles/CO/alkynyl carboxylates developed by Zeng and Alper [72] (bottom). Synthesis of indole

Synthesis and properties of 6-alkynyl-5-aryluracils

• Ruben Manuel Figueira de Abreu,
• Till Brockmann,
• Alexander Villinger,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80

• Abstract The development of a new and straightforward chemoselective method for the synthesis of uracil-based structures by combining Suzuki–Miyaura and Sonogashira–Hagihara cross-coupling is reported. The methodology was applied to synthesize a series of novel compounds. The tolerance of the combination

• this work, we report a new chemoselective method for the synthesis of a series of hitherto unknown uracil-based compounds by combining Suzuki–Miyaura and Sonogashira–Hagihara cross-coupling [60][61]. The method is designed to be flexible and could also be used to synthesize other structural motifs

• starting with commercially available 6-chloro-1,2-dimethyluracil (1), as depicted in Scheme 1. Subsequently, 5-bromo-6-chloro-1,3-dimethyluracil (2) was synthesized by brominating the starting material. The single Sonogashira–Hagihara cross-coupling afforded 3a–j and, by a two-fold approach, 4a–h could be

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• Suzuki–Miyaura and Sonogashira couplings on 4aa or 4ba afforded the desired products 5 and 6 in 47% and 74% yields, respectively. In the former case, the C–Br bond on the pyrazole moiety remained intact, highlighting the superior leaving group ability of the BX group. Cu-catalyzed Ullmann coupling

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• through scanning tunneling microscopy [85]. For TCBDs bearing unsubstituted anilino (p-H2NC6H4–) groups, their conversion into the p-iodophenyl derivatives via the Sandmeyer reaction and subsequent post-functionalization via the Suzuki and Sonogashira coupling reactions are achieved [86]. In the reaction

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• variety of reactions; that are, phosphite- or Lawesson’s reagent-mediated olefination reactions (to introduce DTF motifs), Ramirez/Corey–Fuchs dibromo-olefinations followed by Sonogashira couplings (to introduce enediynes motifs), and Knoevenagel condensations (to introduce the vinylic diester motif). By

• various elaborate systems [24][25][26][27]. Next, we wanted to explore IF-DTFs as motifs for acetylenic scaffolding (Scheme 4). Starting from IF-DTF building block 6, dibromo-olefinated compound 18 was obtained by a Ramirez/Corey–Fuchs reaction. Two-fold Sonogashira couplings with trimethylsilylacetylene

• , ethynylbenzene, or 4-ethynylbenzonitrile yielded compounds 19–21, while two-fold Sonogashira coupling with ((2-ethynylphenyl)ethynyl)triisopropylsilane resulted in compound 22. Desilylation of the alkynes of compound 22 with tetrabutylammonium fluoride (TBAF) and subsequent intramolecular Glaser–Hay coupling of

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• through Sonogashira cross-coupling reactions with alkynes featuring different protecting groups such as TIPS, TES, and TIBS. Scheme 7 illustrates the derivatization process using one of the chosen examples, specifically the TIPS group. Accordingly, the cross-coupling products 33a–c were obtained in yields

• selectively synthesize compound 87 through a hybrid approach involving the integration of both solution and surface chemistry techniques [53]. The key compound 96 to be used in the synthesis of POA 87 was synthesized in two steps. In the first step, 94 was obtained using a double Sonogashira cross-coupling

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• -dicarbazolyl-3,5-dicarbonitrile. The compounds are synthesized by Sonogashira coupling reactions and characterized by steady-state and time-resolved luminescence spectroscopy. The compounds show efficient intramolecular charge transfer (ICT) from the donor to the acceptor. The photoluminescence (PL) spectra of

• )-4-(4-bromophenyl)pyridine-3,5-carbonitrile (4) was obtained by the interaction of 3,6-di-tert-butyl-9H-carbazole with compound 3 in THF/DMF solution. The ethynylphenyl-substituted pyridine 5 was synthesized by Sonogashira coupling of 4 with ethynyltrimethylsilane in the presence of PdCl2(PPh3)2 and

• copper(I) iodide in DMF/DIPEA solution at 55 °C with subsequent desilylation with potassium carbonate. Finally, butadiyne 6 was prepared by a homocoupling reaction of 5 with 80% yield. Derivatives containing two dicyanopyridyl moieties, 7 and 8, were prepared starting with a Sonogashira coupling of

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• synthesis of 1,2,5-trisubstituted 7-azaindoles [34]. Inspired by the coupling–cyclization–alkylation sequence and the stepwise Sonogashira coupling–cyclization–iodination protocol to give valuable 3-iodoindoles by Amjad and Knight [35], we reasoned that the interception by an electrophilic iodination step

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• )benzene through Co-catalyzed cyclotrimerization in a 45% yield. Then monoiodide NG 49 was obtained through oxidative cyclodehydronation in a high yield. From the heptagon-containing NG 49, Sonogashira coupling with p-tert-butylphenylacetylene (50) afforded 51 in a quantitative yield. Subsequent Diels

• -workers synthesized a helical bilayer NG by using helicene in the initial step as the linker to fuse two HBC units [48]. As shown in Scheme 6, starting from the helical alkyne 54, Sonogashira coupling with 4-tert-butyliodobenzene (55) afforded structure 56 in a 77% yield. Subsequent Diels–Alder reaction

• Sonogashira cross-coupling reaction of phenylacetylene 50 and 1,4-dibromotetrafluorobenzene. The resulting bis[aryl(ethynyl)]tetrafluorobenzene 59 was able to undergo a 2-fold [4 + 2] cycloaddition reaction with cyclopentadienone 2, affording polyaromatic 60 in a 70% yield. The final step was the Scholl

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• relies on a double Sonogashira coupling [(i) and (iii)], reduction (iv), and bromination (v), followed by Buchwald–Hartwig amination (viii) (Scheme 14). While interesting, the reaction has limited substrate scope due to the reliance on a late-stage bromination. To achieve the correct ortho-bromo

• towards dibenzo[b,f]azepines and other dibenzo[b,f]heteropines, and the functionalisation thereof. Modern metal-catalyzed methods to introduce the C–C bridge include the Heck reaction, the Sonogashira reaction, Suzuki coupling and ring-closing metathesis, whereas Buchwald–Hartwig type reactions and Ullman