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

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

• acidification, however, the reaction afforded mixtures of the desired products and the corresponding carboxylic acids due to partial hydrolysis of the ester groups. This behavior was observed during cyclization of substrates 4a and 5a. In the case of substrate 6b, treatment with NaOMe resulted primarily in the

Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds

• Natalya Akhmetdinova,
• Ilgiz Biktagirov and
• Liliya Kh. Faizullina

Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185

• . Formylation of enantioenriched hexanone 93 (90% ee) with NaH/HCO2Et, followed by methylation produced two separable isomers, 94a and 94b, in yields of 24% and 31%, respectively. Treatment of these isomers with H2O2 smoothly delivered the carboxylic acids 96a and 96b stereospecifically with excellent

• phase. Benzyl esters were cleaved, and the resulting carboxylic acids were converted into corresponding benzylammonium salts by addition of two equivalents of benzylamine. Subsequent irradiation of these salts in the form of a crystalline suspension in hexane led to ring-contraction products with a 95

A m-quaterphenyl probe for absolute configurational assignments of primary and secondary amines

• Yuka Takeuchi,
• Mutsumi Kobayashi,
• Yuuka Gotoh,
• Mari Ikeda,
• Yoichi Habata,
• Tomohiko Shirai and
• Shunsuke Kuwahara

Beilstein J. Org. Chem. 2025, 21, 2211–2219, doi:10.3762/bjoc.21.168

• for determining the absolute configurations of chiral alcohols [8][9][10][11][12][13][14], primary amines [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32], secondary amines [33][34][35], carboxylic acids [36][37][38], sulfoxides [39], and cyanohydrins [40]. We have reported

C2 to C6 biobased carbonyl platforms for fine chemistry

• Jingjing Jiang,
• Muhammad Noman Haider Tariq,
• Florence Popowycz,
• Yanlong Gu and
• Yves Queneau

Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165

• -modified ultra-stable Zeolite Y (SY) [225] or PdNPs-TiO2/Al2O3/SiO2 [226]. Conversion to other carboxylic acids: Valeric acid (VA) and valerate esters (VEs), also named pentanoic acid or esters, are targeted as fuel additives and value-added chemicals. They are obtained by hydrogenation of levulinic acid

• because they are more prone to corrosion compared with noble-metal catalysts. This has encouraged the design of highly active and more stable heterogeneous non-noble metal-based catalysts able to tolerate the presence of carboxylic acids, such as those listed in Scheme 75 [236][237][238][239][240]. In

Switchable pathways of multicomponent heterocyclizations of 5-amino-1,2,4-triazoles with salicylaldehydes and pyruvic acid

• Yana I. Sakhno,
• Oleksander V. Buravov,
• Kostyantyn Yu. Yurkov,
• Anastasia Yu. Andryushchenko,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2030–2035, doi:10.3762/bjoc.21.158

• -triazoles, pyruvic acid, and salicylaldehydes were studied under different conditions. Upon conventional heating, benzotriazolooxadiazocine-5-carboxylic acids were formed in the three-component reactions as single reaction products. Upon ultrasonic activation or mechanical stirring at room temperature, the

• at reflux in acetic acid for 3 h for aminotriazole 1a or in n-BuOH for 7 h in case of aminotriazole 1b led to the formation of oxygen-bridged 2-(methylthio or methoxy)-11,12-dihydro-5H-5,11-methanobenzo[g][1,2,4]triazolo[1,5-c][1,3,5]oxadiazocine-5-carboxylic acids 4a–j (Scheme 2, Table 1). It should

• )-4H-1,2,4-triazol-5-yl)amino)-4,5,6,7-tetrahydro[1,2,4]triazolo[1,5-a]pyrimidine-7-carboxylic acids 5a–d and 5-(2-hydroxyphenyl)-7-hydroxy-2-(methylthio)-4,5,6,7-tetrahydro[1,2,4]triazolo[1,5-a]pyrimidine-7-carboxylic acids 6a–d (in a ratio of ca. 80:20 for compounds 5a–c and 6a–c; and 15:85 for

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

• employed including carboxylic acids [37], xanthates [38], electron-rich toluene or heteroatom-substituted species [39][40][41][42], organoboron compounds [43][44] and organosilanes [43][45]. Moreover, three-component radical relay processes employing styrene derivatives have also been widely studied. In

Stereoselective electrochemical intramolecular imino-pinacol reaction: a straightforward entry to enantiopure piperazines

• Margherita Gazzotti,
• Fabrizio Medici,
• Valerio Chiroli,
• Laura Raimondi,
• Sergio Rossi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2025, 21, 1897–1908, doi:10.3762/bjoc.21.147

• development of technology-driven sustainable strategies to alfa and beta amination of carbonyls and carboxylic acids derivatives- TECHNO”, financed by EU - Next Generation EU, Mission 4 Component 1 CUP G53D23003280006. M. Gazzotti thanks Università degli Studi di Milano for a PhD fellowship.

Chiral phosphoric acid-catalyzed asymmetric synthesis of helically chiral, planarly chiral and inherently chiral molecules

• Wei Liu and
• Xiaoyu Yang

Beilstein J. Org. Chem. 2025, 21, 1864–1889, doi:10.3762/bjoc.21.145

• synthesis of planarly chiral macrocycles via CPA-catalyzed coupling of carboxylic acids with alcohols via ynamide mediation. Kinetic resolution of substituted amido[2.2]paracyclophanes via CPA-catalyzed asymmetric electrophilic amination. Enantioselective synthesis of inherently chiral calix[4]arenes via

Influence of the cation in hypophosphite-mediated catalyst-free reductive amination

• Natalia Lebedeva,
• Fedor Kliuev,
• Olesya Zvereva,
• Klim Biriukov,
• Evgeniya Podyacheva,
• Maria Godovikova,
• Oleg I. Afanasyev and
• Denis Chusov

Beilstein J. Org. Chem. 2025, 21, 1661–1670, doi:10.3762/bjoc.21.130

• synthesis of esters of phosphonous or alkylphosphinic acids [33][34][35]. Only a single application of cesium hypophosphite was shown in the literature. CsH2PO2 was prepared in situ and used for formation C–P bond by radical addition to unsaturated carboxylic acids [36 ]To summarize the above, it is crucial

Photoredox-catalyzed arylation of isonitriles by diaryliodonium salts towards benzamides

• Nadezhda M. Metalnikova,
• Nikita S. Antonkin,
• Tuan K. Nguyen,
• Natalia S. Soldatova,
• Alexander V. Nyuchev,
• Mikhail A. Kinzhalov and
• Pavel S. Postnikov

Beilstein J. Org. Chem. 2025, 21, 1480–1488, doi:10.3762/bjoc.21.110

• significant attention within organic and medicinal chemistry. Commonly, amide bonds are formed via the reaction of carboxylic acids or their derivatives with appropriate amines (Scheme 1A) [4]. Although this conventional approach is effective and straightforward, it usually suffers from harsh conditions and

Oxetanes: formation, reactivity and total syntheses of natural products

• Peter Gabko,
• Martin Kalník and
• Maroš Bella

Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101

• 2020, Bull et al. published a short synthesis of 3-aryloxetan-3-carboxylic acids 152 employing a Friedel–Crafts alkylation (which builds on their previous alkylation of phenols [87]) and a selective furan oxidative cleavage (Scheme 37) [88]. The oxidation protocol uses a catalytic amount of a high

• heteroarenes. This practical synthesis of 3-aryloxetan-3-carboxylic acids potentially opened the door to installation of a wide range of substituents into the 3-position through a decarboxylative radical coupling, which was eventually exploited by Duarte and Bull et al. in 2023 (Scheme 38) [89]. The

• . In the same year, Mykhailiuk and co-workers exploited the inherent propensity of oxetane-carboxylic acids 219 for intramolecular ring openings to generate functionalised γ-butyrolactones 220, dioxanones 221 and valerolactones 222 (Scheme 52) [106]. The conditions of the reported method involve only

Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents

• Jiangfei Chen,
• Yi-Lin Qu,
• Ming Yuan,
• Xiang-Mei Wu,
• Heng-Pei Jiang,
• Ying Fu and
• Shengrong Guo

Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98

• -/trifluoroalkylation reagents, α-carbonyl alkyl bromides/alcohols, alkyl halides, and alkyl carboxylic acids, have been successfully applied to this transformation to afford 3-substituted indolin-2-ones. In 2013, Li’s group reported a novel DTBP(di-tert-butyl peroxide)-mediated oxidative 1,2-alkylarylation of

Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates

• Alexander S. Budnikov,
• Igor B. Krylov,
• Fedor K. Monin,
• Valentina M. Merkulova,
• Alexey I. Ilovaisky,
• Liu Yan,
• Bing Yu and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96

• oxyphosphorylation of styrenes [40], this strategy was further extended [41] to phenylacetylenes [42][43][44], cinnamic [45][46][47][48] and α,β-alkynyl carboxylic acids [42], and vinyl azides [49][50] (Scheme 1a). As a rule, transition metal catalysts (Fe [42][44][51][52], Cu [42][44][46][51][53], Ag [54], Mn [55

• synthetic step distinguishes them from the less accessible substituted vinylarenes, alkynes, cinnamic and α,β-alkynyl carboxylic acids, as well as vinyl azides. In addition, compared to similar silyl and alkyl enol ethers, enol acetates are more resistant to solvolysis, which prevents unwanted side

• oxides as PH-reagents. The developed protocol utilizes a simple copper catalyst under mild reaction conditions and synthetically available enol acetates (compared to traditionally employed alkenes, alkynes, cinnamic, and α,β-alkynyl carboxylic acids). The present approach showed good functional group

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

• group (2024) also investigated BH3·pyridine to catalyze amidation reactions with lower catalyst loading (Scheme 40B) [77]. Whiting and co-workers (2019) also used boranes to catalyze the direct amidation of carboxylic acids. In this work, they co-polymerized styrene, divinylbenzene and

Biobased carbon dots as photoreductants – an investigation by using triarylsulfonium salts

• Valentina Benazzi,
• Arianna Bini,
• Ilaria Bertuol,
• Mariangela Novello,
• Federica Baldi,
• Matteo Hoch,
• Alvise Perosa and
• Stefano Protti

Beilstein J. Org. Chem. 2025, 21, 1024–1030, doi:10.3762/bjoc.21.84

• ); triarylsulfonium salts; visible light; Introduction Carbon dots (CDs) are a class of zero-dimensional carbon-based semiconducting nanoparticles bearing on the surface a wide range of functional groups, such as carboxylic acids, alcohols, and amines, that garnered significant attention in the last decade among the

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

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

• , a library of acylamino acetamide derivatives 38 was synthesized from aliphatic and aromatic isocyanides and carboxylic acids, with good yields. When ammonia is replaced by methylamine, the main product incorporates methylamine as the amine component. This result indicates that HMTA is the main

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• are linear molecules able to direct functionality toward each other in a relatively rigid pincer orientation. One example featuring a pair of antipodal carboxylic acids demonstrated acetal hydrolysis catalysis (Figure 3B) [110]. However, as linear molecules, the clefts are difficult to develop past

• more than 104 compared to the background rate (298 K, CDCl3) (Figure 9B) [41]. Here, the strongly preorganized pair of carboxylic acids split duties: one covalently activates an acyl group while the other provides bifunctional acid/base activation. Together, they bind the transition state

• triad (red) was hoped to activate the benzyl alcohol nucleophile, but it does not activate (polarize) the electrophile (substrate ester group). (B) One of Rebek’s “clefts” [108][109]. The rigidly organized carboxylic acids both bind the substrate and the transition state for hydrolysis of an acetal. (A

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

• condensation of carboxylic acids with anilines, often promoted by activating agents such as thionyl chloride or peptide coupling agents [86][87][88][89]. However, these protocols rely on environmentally harmful reagents and produce unwanted byproduct wastes. Recently, the research group of Son showcased a

• approaches. Despite the synthetic strategies to generate the copper nitrenoid intermediates are gaining more attention [104][105], several limitations still remain. First, multiple steps are required to prepare dioxazolones, synthesized conventionally from carboxylic acids or acid chlorides over two steps

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

• desired annulation products. Moreover, the same products were generated using alkynyl carboxylic acids instead of terminal alkynes via decarboxylative C–H alkynylation and annulation. Cyclic voltammetry (CV) studies exhibited an oxidative current at 0.95 V vs SCE in the presence of the Cu(II) salt, base

• Cu(I)CN catalyst 108. The Cu(II)CN catalyst 109 is regenerated via anodic oxidation to complete its catalytic cycle. Decarboxylative functionalization Carboxylic acids are inexpensive, readily available, structurally diverse from both natural and synthetic sources, and easy to handle. Recently

• , various catalytic transformations of carboxylic acids have been developed, enabling chemists to access a variety of valuable products via diverse reaction pathways [73]. Particularly, decarboxylative cross-coupling of carboxylic acids using radical strategies has emerged as a robust method for the

Reactivity of hypervalent iodine(III) reagents bearing a benzylamine with sulfenate salts

• Beatriz Dedeiras,
• Catarina S. Caldeira,
• José C. Cunha,
• Clara S. B. Gomes and
• M. Manuel B. Marques

Beilstein J. Org. Chem. 2024, 20, 3281–3289, doi:10.3762/bjoc.20.272

• , commonly referred to as sulfa drugs. These include top seller drugs, e.g., antimicrobials, anti-inflammatories, antihypertensives, and antitumor agents [24][25][26]. Particularly, the sulfonamide motif can act as a bioisostere of carboxylic acids, establishing a set of hydrogen bonds similar to those

• formed by carboxylic acids, enhancing its versatility and effectiveness in drug design [27]. Traditional sulfonamide preparation involves combining sulfonyl chlorides and amines [25][28][29]. Despite the efficiency of traditional methods, challenges still remain, e.g., use of harsh conditions, like

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

• reaction of the corresponding heteroaromatic carboxylic acids with thionyl chloride followed by treatment with N-octyl-2-bromoaniline [15]. The reactions proceeded smoothly affording products 1a–c in good yields as shown in Scheme 1. We then studied the reaction of quinoline amide 1a under several

Synthesis of 2H-azirine-2,2-dicarboxylic acids and their derivatives

• Anastasiya V. Agafonova,
• Mikhail S. Novikov and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2024, 20, 3191–3197, doi:10.3762/bjoc.20.264

• -ylcarbonyl)-2H-azirines, 1-(2H-azirine-2-carbonyl)benzotriazoles, 2H-azirine-2-carbonyl azides, anhydrides, amides, esters, and thioesters of azirine carboxylic acids, as well as azirine carboxylic acids themselves, have been prepared over the last decade (see [2] and references therein). Azirine-2

Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• heterocyclic scaffold is subsequently formed [58]. In 2015, Xu et al. [59] reported the synthesis of 1,5-benzodiazepines using the UDC approach. The process begins with Ugi-4CRs, incorporating amines, glyoxaldehydes, 2-(N-Boc-amino)phenylisocyanide, and carboxylic acids. Following this, the Boc group is