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

• , and aryloxymethyl potassium trifluoroborate salt 10 under mild conditions. The described catalytic system exhibited broad functional group tolerance and efficiently employed terminal alkenes 11 to generate quaternary centers adjacent to the carbonyl group. The key step in this organocatalytic process

• conditions. This visible-light-mediated dual catalytic method permits the efficient acylsilylation of substituted terminal alkenes 11 via NHC catalysis. Remarkably, this method afforded silyl radicals, which are typically difficult to prepare using conventional HAT-based catalytic methods. This method is

• for 18 h (Scheme 6) [56]. Gao, Ye, and co-workers reported the iminoacylation of alkenes 17 via photoredox NHC dual catalysis in the presence of NHC (20 mol %), photocatalyst (5 mol %), with Na2CO3 (1.2 equiv) using a 36 W blue LED. In this method, the alkene-attached iminyl radicals A and the NHC

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

• contraction is demonstrated by the example of converting organoborane intermediates into alcohols, amines, and E-alkenes (Scheme 32). 4 Meinwald rearrangements of epoxides The rearrangements of oxiranes annelated to cyclohexane occupy an important place in the synthesis of cyclopentanes due to the

An Fe(II)-catalyzed synthesis of spiro[indoline-3,2'-pyrrolidine] derivatives

• Elizaveta V. Gradova,
• Nikita A. Ozhegov,
• Roman O. Shcherbakov,
• Alexander G. Tkachenko,
• Larisa Y. Nesterova,
• Elena Y. Mendogralo and
• Maxim G. Uchuskin

Beilstein J. Org. Chem. 2025, 21, 2383–2388, doi:10.3762/bjoc.21.183

• , a highly diastereoselective method for the synthesis of dihydrospiro[indoline-3,2'-pyrrole]-2-ones has been developed (Scheme 1, path a) [7]. This transformation proceeds via a Lewis acid-mediated conjugate addition of vinyl azides to electron-deficient alkenes, followed by denitrogenative

• under heating furnished chiral spiroindolylpyrroles in excellent yields and enantioselectivity (Scheme 1, path d) [11]. Moreover, a copper-catalyzed reaction of oxindole-derived alkenes with acetophenone O-acetyl oxime has also been employed to construct the spiroindolylpyrrole scaffold (Scheme 1, path

Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis

• Peng-Xi Luo,
• Jin-Xuan Yang,
• Shao-Min Fu and
• Bo Liu

Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177

• singlet state, which undergoes intersystem crossing (ISC) to form the excited triplet state B. An intramolecular 1,5-hydrogen atom transfer (HAT) then ensues, producing the 1,4-diradical C, which can be converted into diverse products such as alkenes and enols (Scheme 1a). Notably, the 1,4-diradical

Enantioselective radical chemistry: a bright future ahead

• Anna C. Renner,
• Sagar S. Thorat,
• Hariharaputhiran Subramanian and
• Mukund P. Sibi

Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174

• , a chiral Cu(III) complex forms from an achiral benzylic radical and a Cu(II)–CN species, and subsequent reductive elimination affords the enantioenriched benzylic nitrile product. Recently, X.-Y. Liu and co-workers reported an enantioselective aminofluoroalkylation of alkenes using a Cu(I)/chiral

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

Understanding the origin of stereoselectivity in the photochemical denitrogenation of 2,3-diazabicyclo[2.2.1]heptene and its derivatives with non-adiabatic molecular dynamics

• Leticia A. Gomes and
• Steven A. Lopez

Beilstein J. Org. Chem. 2025, 21, 2007–2020, doi:10.3762/bjoc.21.156

• starting materials for different types of reactions including thermal isomerization to cyclopentenes [36][37][38] and 1,4-pentadienes [37][38], chemical electron-transfer oxidations to cyclopentene [39] and cycloaddition reactions with electron-deficient alkenes and alkynes [38][40][41] (Scheme 1b

Photoswitches beyond azobenzene: a beginner’s guide

• Michela Marcon,
• Christoph Haag and
• Burkhard König

Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143

• and subsequent reduction of 45 (if substrates 43 and 44 contain a NO2 group, this will also be reduced, Scheme 13A) [54], or by Wittig reaction and reduction of the isomeric mixture of alkenes 48 (Scheme 13B) [57]. Oxidation of 49 with oxone [58] or m-chloroperbenzoic acid [54] yields 35. Wittig

Fe-catalyzed efficient synthesis of 2,4- and 4-substituted quinolines via C(sp²)–C(sp²) bond scission of styrenes

• Prafull A. Jagtap,
• Manish M. Petkar,
• Vaishnavi R. Sawant and
• Bhalchandra M. Bhanage

Beilstein J. Org. Chem. 2025, 21, 1799–1807, doi:10.3762/bjoc.21.142

• promising industrial relevance. Oxidative cleavage of alkenes to yield carbonyl compounds is one of the key transformations in synthetic organic chemistry [41][42]. Over the past two decades, this field has witnessed significant advancements, primarily through the use of organic oxidants and transition

• -metal catalysts. One of the key transformations in organic synthesis is the selective oxidative cleavage of alkenes to yield ketones or aldehydes [43][44][45][46][47]. Traditionally, such transformations have been achieved using various oxidizing agents, transition-metal-based systems, organo- and

• advanced strategies have been developed for cleavage of alkenes [48][49][50][51]. Owing to the abundance and versatile applications of styrenes in diverse fields of organic chemistry, some strategies have recently been developed for synthesizing 2,4-disubstituted and 4-substituted quinoline derivatives via

Photocatalysis and photochemistry in organic synthesis

• Timothy Noël and
• Bartholomäus Pieber

Beilstein J. Org. Chem. 2025, 21, 1645–1647, doi:10.3762/bjoc.21.128

• of alkenylboronic esters using energy transfer catalysis [26]. Gualandi and co-workers leveraged a combination of photoredox and HAT catalysis to realize the intramolecular nucleophilic amidation of alkenes with β-lactams [27]. Further, Luridiana and colleagues developed a method for the alkylation

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

• categorised into 6 synthetic strategies as depicted in Scheme 1: a) C–O bond-forming cyclisations, b) C–C bond-forming cyclisations, c) [2 + 2] cycloadditions between carbonyls and alkenes, d) ring expansions, e) ring contractions and f) O–H insertions. In the following subchapters, these strategies will be

• /Williamson etherification sequence (Scheme 8) [43]. In this case, however, the radicals were generated by irradiation of α-acetyloxy iodides 36, formed by treating the corresponding ketone precursors with acetyl iodide in the presence of catalytic Zn(OTf)2. The radical addition employed electron-rich alkenes

• and the resulting 1,3-acetyloxyiodides 37 were treated in situ with methanolic t-BuOK to promote the cyclisation. Best results for the oxetane formation were obtained for dimethylphenylvinylsilane, while alkenes without the silyl group afforded mainly homoallylic alcohols 39, presumably through an

Recent advances in amidyl radical-mediated photocatalytic direct intermolecular hydrogen atom transfer

• Hao-Sen Wang,
• Lin Li,
• Xin Chen,
• Jian-Li Wu,
• Kai Sun,
• Xiao-Lan Chen,
• Ling-Bo Qu and
• Bing Yu

Beilstein J. Org. Chem. 2025, 21, 1306–1323, doi:10.3762/bjoc.21.100

• abstracted a hydrogen atom from substrate 1. This HAT process returned the amidyl radical 5 to HRP-1, enabling the continuation of the HAT cycle in synchronization with the photocatalytic cycle. The resulting radical 4 then underwent Giese addition with activated alkenes, leading to the formation of products

• PCET process, involving the oxidation of excited 4CzIPN* and deprotonation by a base. The resulting amidyl radical 20 smoothly abstracted a hydrogen atom from the substrate via a HAT process, generating a radical 4. This C-centered radical subsequently underwent Giese addition with activated alkenes

• 29 in the presence of 4CzIPN and a base via a PCET process. Radical 29 subsequently engaged in a HAT process with substrate 26, generating either a Si radical or a Ge radical 28. Following this, radical 28 underwent Giese addition with activated alkenes. The reduction of species 31 was efficiently

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

• Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

• alkenes: A bismuth-catalysed cyclization of alkenes has been demonstrated as an efficient synthetic tool for the creation of benzenoid PAHs [89]. Murai and co-workers applied this approach to the synthesis of azulene-embedded nanographenes (Scheme 18) [90]. Vinyl ethers 133a–d were cyclized using Bi(OTf)3

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

• been extensively investigated by researchers. Keywords: carbon radical reagents; intramolecular transformations; N-arylacrylamides; oxidative difunctionalization; radical reactions; Introduction Alkenes, as abundant and versatile feedstocks, have been widely employed in organic synthesis

• primarily focused on substrates containing activated alkenes tethered within the molecular framework. N-Arylacrylamides were employed as model substrates, and a diverse range of functionalization reagents, including those with benzylic C–H bonds, C(sp3)–H bonds adjacent to heteroatoms, di

• activated alkenes involving benzylic C(sp3)–H bonds through a cascade cyclization process (Scheme 1) [2]. This organomediated approach can be facilitated by a catalytic amount of Lewis acid. Using DTBP as the oxidant and IrCl3 as the promoter, a range of benzylic C–H bonds in arylmethanes

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

• leading to β-ketophosphonates have been reported [41][42][43][44][45][46][47][48][49][50][61], challenges in this area still exist primely in the search for new available synthetic equivalents of alkynes and alkenes for effective radical C–P bond formation. Enol acetates are potentially versatile

• 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

Synthetic approach to borrelidin fragments: focus on key intermediates

• Yudhi Dwi Kurniawan,
• Zetryana Puteri Tachrim,
• Teni Ernawati,
• Faris Hermawan,
• Ima Nurasiyah and
• Muhammad Alfin Sulmantara

Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91

• reaction of a Grignard reagent derived from 133 to the aldehyde counterpart (Scheme 20). Compound 133 was prepared via a cross-metathesis reaction of 2-bromohexa-2,4-dienenitrile 134 and a selection of alkenes. Iqbal noted from the literature that cyano alkenes, such as acrylonitrile, predominantly yielded

• the Z-product during the cross-metathesis reactions. Therefore, the synthetic study was initiated by performing cross-metathesis reactions between both (E,E)- and (Z,E)-134 with various alkenes to investigate the Z- or E-selectivity of the reaction. Fortunately, Iqbal observed that all cross

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

• advancements in this area have recently been demonstrated to access conjugated alkenes, particularly cinnamic acid derivatives, with high stereoselectivity. For instance, Reeves and co-workers (2023) performed a Horner–Wadsworth–Emmons reaction of triethyl 2-fluoro-2-phosphonoacetate (390) and aldehydes to

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

• solution was examined, for solubility reasons. a) CDs-mediated 1,2-difunctionalization of alkenes by alkyl halides R–Y and b) light-driven reduction of triarylsulfonium salts in the presence of CDs. Carbon dots tested in this project and their main (photo)physical characteristics. Emission parameters 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

• resulting iminium ion can be readily captured by a wide variety of nucleophiles, including alkenes and alkynes. These aza-Prins cyclizations have potential applications in the synthesis of natural alkaloids, as exemplified by She’s total synthesis of (−)-dihydrolycopodine and (−)-lycopodine [17]. These

Harnessing tethered nitreniums for diastereoselective amino-sulfonoxylation of alkenes

• Shyam Sathyamoorthi,
• Appasaheb K. Nirpal,
• Dnyaneshwar A. Gorve and
• Steven P. Kelley

Beilstein J. Org. Chem. 2025, 21, 947–954, doi:10.3762/bjoc.21.78

• -trifluoroacetoxylation of alkenes [4]. In this protocol, an unusual N-alkoxy carbamate tether served as a precursor to a transient nitrenium ion [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], which subsequently attacked a pendant alkene to form an aziridinium intermediate. This aziridinium

• examples of alkene amino-hydroxylation reactions mediated by N-alkoxy nitreniums deliver amino-trifluoroacetate products (Scheme 1) [6]. Here, we describe the first examples of amino-sulfonoxylation reactions of alkenes, which make use of carbamate tethered N-alkoxy nitrenium ions. Results and Discussion

• unpurified reaction residues showed a complex mixture of products. There were some signals suggestive of terminal alkenes, implying that olefin transposition was a competing pathway. With alkyne substrate 59, decomposition occurred, and the 1H NMR of the unpurified reaction mixture was illegible. With

Recent advances in controllable/divergent synthesis

• Jilei Cao,
• Leiyang Bai and
• Xuefeng Jiang

Beilstein J. Org. Chem. 2025, 21, 890–914, doi:10.3762/bjoc.21.73

• , the Shu group developed a catalyst-controlled regioselective and enantioselective hydroamination reaction of electron-deficient alkenes (Scheme 7) [30]. By efficiently regulating the regioselectivity and enantioselectivity of alkene 23 hydrometallation through catalytic systems, they overcame the

Light-enabled intramolecular [2 + 2] cycloaddition via photoactivation of simple alkenylboronic esters

• Lewis McGhie,
• Hannah M. Kortman,
• Jenna Rumpf,
• Peter H. Seeberger and
• John J. Molloy

Beilstein J. Org. Chem. 2025, 21, 854–863, doi:10.3762/bjoc.21.69

• , Germany 10.3762/bjoc.21.69 Abstract The photoactivation of organic molecules via energy transfer (EnT) catalysis is often limited to conjugated systems that have low-energy triplet excited states, with simple alkenes remaining an intractable challenge. The ability to address this limitation, using high

• ). Pioneering studies have leveraged this platform with great effect, typically invoking π→π* transitions of conjugated alkenes to lower the bond order and generate a triplet diradical, primed for further reactivity. This key intermediate is pivotal in a plenum of synthetic transformations including geometric

• isomerization of alkenes [18][19], [2 + 2] cycloadditions [20][21][22][23][24], and dearomative [4 + 2] cycloadditions [25][26][27]. When considering conjugated alkenes, the triplet excited state energy and excited state lifetime are intrinsically linked to the degree of conjugation and substitution of a

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

• catalytic hydrocyanation of alkenes [22], including the industrially relevant DuPont adiponitrile process from 1,3-butadiene using nickel catalysts [23], the hydrocyanation of allenes to produce functionalized β,γ-unsaturated nitriles with quaternary carbon centers has not been investigated extensively [24

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• amides with electron-withdrawing or electron-donating groups on their aromatic ring, producing products with yields ranging from 51% to 82%. In 2023, Lei and co-workers [47] reported an electrochemical C–P bond formation via a coupling reaction of C–H bonds of alkynes, alkenes, and aryl compounds with

• followed by treatment with acridine to give the corresponding coupling product (Scheme 6). Vinylphosphonates have many applications in pharmaceutical, agricultural, and industrial processes. Zhang et al. [51] reported a novel electrochemical C–P coupling of specific alkenes with different types of

• and copper foam (CF) as a cathode at a constant current of 14 mA. Experiments confirmed that the trace amount of copper dissolved from the cathode had no catalytic effect on the reaction. The reaction proceeded via anodic oxidation of diphenylphosphine followed by a reaction with alkenes to give

Development and mechanistic studies of calcium–BINOL phosphate-catalyzed hydrocyanation of hydrazones

• Carola Tortora,
• Christian A. Fischer,
• Sascha Kohlbauer,
• Alexandru Zamfir,
• Gerd M. Ballmann,
• Jürgen Pahl,
• Sjoerd Harder and
• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2025, 21, 755–765, doi:10.3762/bjoc.21.59

• rearrangement under mild conditions [6], and the Nazarov-type electrocyclization of alkenyl aryl carbinols [7]. Exploiting the ease with which calcium forms hydrides, hydrogenation of aldimines, transfer hydrogenation of alkenes, and even deuteration of benzene by an SNAr mechanism, have been recently achieved

• transfer hydrocyanation of alkenes proceeds via (boron) isocyanides [50]. If calcium cyanide would be preferred over isocyanide, hydrocyanation would hardly be possible. A principally conceivable "hydroisocyanation" of hydrazone is therefore precluded. The relative stability of alkaline earth metal

• that might similarly occur also in related addition reactions of alkenes, for example. After 11E had reacted with TMSCN, adduct 13 forms, 3.8 kcal·mol−1 more stable than the competing unreactive adduct obtained from "Z" conformation. Outside from the catalytic cycle, 12 could be further hydrolyzed in a