Comparative analysis of complanadine A total syntheses

• Reem Al-Ahmad and
• Mingji Dai

Beilstein J. Org. Chem. 2025, 21, 2334–2344, doi:10.3762/bjoc.21.178

• strategies and creative tactics, reflecting how emerging synthetic capabilities and concepts can positively impact natural product total synthesis. Keywords: biomimetic synthesis; C–H functionalization; complanadine; lycopodium alkaloid; skeletal editing; total synthesis; transition metal catalysis

• efficiency and step-economy of natural product total synthesis. This symbiotic relationship has also helped to accelerate natural product biological evaluation and the subsequent biomedical development [1]. Lycopodium alkaloids are one of the largest families of natural products [2], from which famous

• and co-workers [19]. In this review article, we summarize these four total syntheses, comparatively analyze their strategic novelty and differences, and highlight the impact of enabling methodologies and concepts on the overall efficiency and economy of each total synthesis [20]. Review The Siegel

Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes

• Suvenika Perera,
• Peter Y. Zavalij and
• Lyle Isaacs

Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176

• environmental concern. We report the design, synthesis, and characterization of a series of methylene-bridged glycoluril dimers G2W1–G2W4 that are insoluble in water and that differ in the nature of their aromatic sidewalls (G2W4: benzene, G2W3: naphthalene, G2W1 and G2W2: triphenylene). We tested G2W1–G2W4

• that β-cyclodextrin (Figure 1)-based polymers could remove organic micropollutants from water [15][16]. For example, in 2021, Sessler and co-workers reported the synthesis of a calix[4]pyrrole (Figure 1)-based porous organic polymer, which exhibits the rapid uptake of dyes from water [17]. In addition

• , graphene functionalized with β-cyclodextrins [18], a starch-based β-cyclodextrin polymer [19], and pillar[5]arene-based crosslinked polymers have also been investigated as sequestrants for dyes [20]. The Isaacs group has a longstanding interest in the synthesis and mechanism of formation of macrocyclic

Halogenated butyrolactones from the biomass-derived synthon levoglucosenone

• Johannes Puschnig,
• Martyn Jevric and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2025, 21, 2297–2301, doi:10.3762/bjoc.21.175

• . Short procedures for their synthesis have been developed starting with levoglucosenone, which can be obtained in a single step from the pyrolysis of acid-treated cellulose. The processes use inexpensive reagents for the stereoselective C3 functionalization of the bicyclic ring system, with a subsequent

• intermediate in synthesis [1][2]. Several nucleoside analogue drugs are prepared using γ-butyrolactones, that when reduced give pentose sugars that can be used as glycosyl donors [3][4]. A number of these clinically used drugs contain fluorine as a hydroxy bioisostere at C2, most notably gemcitabine (1) and

• infections. The preparation of 2-halo-2-deoxy-ᴅ-ribose derivatives can be achieved via the modification of the parent sugar [9][10] or chain-elongation strategies from lower homologues. For example, Castro and co-workers have demonstrated the synthesis of a dichlorinated 2-deoxypentose via the addition of

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

• transformations is also discussed. Keywords: chiral Lewis acid; electrochemistry; enantioselective radical reaction; organocatalysis; photoenzymatic catalysis; photoredox; Introduction Asymmetric catalysis plays an integral role in the enantioselective synthesis of organic compounds. A wide variety of

• synthesis. Strategies for asymmetric radical reactions Stereoselectivity in radical reactions can be challenging to control. Many radicals are highly reactive, and radicals moreover have typically low inversion barriers, resulting in no permanent chirality at the radical center. Stereochemistry in radical

• transformations [43][44][45][46][47][48]. Using SOMO catalysis, MacMillan and co-workers developed a method for the synthesis of substituted pyrrolidines from β-aminoaldehydes and olefins in a formal [3 + 2] cycloaddition (Scheme 2) [44]. The transformation was proposed to proceed via a radical–polar crossover

Pathway economy in cyclization of 1,n-enynes

• Hezhen Han,
• Wenjie Mao,
• Bin Lin,
• Maosheng Cheng,
• Lu Yang and
• Yongxiang Liu

Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173

• rapid molecular diversification, offering transformative potential for green chemistry and pharmaceutical applications. By unifying mechanistic insights with practical synthetic design, this review provides valuable guidance for future innovations in precision organic synthesis. Keywords: economical

• synthesis; 1,n-enynes; pathway economy; small-molecule skeletons; Introduction As organic synthesis concepts continue to evolve, economical synthesis remains a foundational principle for synthetic chemists [1][2][3][4][5][6][7]. The essence of economical synthesis lies in the conservation of materials and

• time, thereby facilitating the synthesis of target molecules at lower cost while minimizing environmental pollution through minimized waste generation. In 1991, Trost first introduced the concept of “atom economy”, proposing that an ideal reaction should incorporate all atoms of the reactants, thereby

Research towards selective inhibition of the CLK3 kinase

• Vinay Kumar Singh,
• Frédéric Justaud,
• Dabbugoddu Brahmaiah,
• Nangunoori Sampath Kumar,
• Blandine Baratte,
• Thomas Robert,
• Stéphane Bach,
• Chada Raji Reddy,
• Nicolas Levoin and
• René L. Grée

Beilstein J. Org. Chem. 2025, 21, 2250–2259, doi:10.3762/bjoc.21.172

• CLK1 (from Mus musculus) and DYRK1A (from Rattus norvegicus). Docking of VS-77 in CLK3. Docking of VS-77 in Hs_DYRK1A (PDB ID: 8T2H [26]). Synthesis of the intermediate anilino-2-quinazolines 7a and 7b. Synthesis of the targeted anilino-2-quinazolines 10 and 13. Structures and in vitro activities of

• Chemveda Life Sciences for providing laboratory facility for carrying these research experiments. This research has been performed also as part of the Indo-French “Joint Laboratory for Natural Products and Synthesis towards Affordable Health”. We thank CSIR, CNRS and University of Rennes 1 for their

A chiral LC–MS strategy for stereochemical assignment of natural products sharing a 3-methylpent-4-en-2-ol moiety in their terminal structures

• Rei Suo,
• Raku Irie,
• Hinako Nakayama,
• Yuta Ishimaru,
• Yuya Akama,
• Masato Oikawa and
• Shiro Itoi

Beilstein J. Org. Chem. 2025, 21, 2243–2249, doi:10.3762/bjoc.21.171

• all compounds. In this study, we developed a method to determine the absolute configuration of the terminal MPO moiety with high accuracy and sensitivity by a combination of chemical degradation, chemical synthesis, and chiral LC–MS analysis. The applicability of this method was demonstrated through

• groups. Total synthesis is a powerful approach for determining absolute configuration through the comparison of specific rotation or chromatographic behavior; however, it requires considerable time and effort. In this context, we have been working on developing effective approaches to determine the

• absolute configuration of scarce natural products, including heptavalinamide A [11] and poecillastrin C [12][13] by a combination of chemical degradation, chemical synthesis, and liquid chromatography–mass spectrometry (LC–MS) analysis. The 3-methylpent-4-en-2-ol (MPO) moiety is commonly found at the

Pd-catalyzed dehydrogenative arylation of arylhydrazines to access non-symmetric azobenzenes, including tetra-ortho derivatives

• Loris Geminiani,
• Kathrin Junge,
• Matthias Beller and
• Jean-François Soulé

Beilstein J. Org. Chem. 2025, 21, 2234–2242, doi:10.3762/bjoc.21.170

• sterically tuned substrates promotes selective N-arylation at the terminal nitrogen. The protocol tolerates a wide range of functional groups and enables the synthesis of well-decorated azobenzenes, including tetra-ortho-substituted derivatives. Notably, the reaction proceeds under an O2 atmosphere and in

• rely on nitroso-aniline couplings, provide a route for the synthesis of non-symmetric azobenzenes, but their substrate specificity and use of hazardous precursors limit their practical applicability [25][26][27][28]. An alternative approach involves the SEAr reaction, which utilizes potentially

• hazardous diazonium salts and electron-rich arenes (mainly limited to phenols) [29][30][31], including metalated arenes [32][33]. The growing demand for structurally complex compounds across diverse applications has rendered the synthesis of non-symmetrical azoarenes with differently substituted azo bonds

Thiadiazino-indole, thiadiazino-carbazole and benzothiadiazino-carbazole dioxides: synthesis, physicochemical and early ADME characterization of representatives of new tri-, tetra- and pentacyclic ring systems and their intermediates

• Gyöngyvér Pusztai,
• László Poszávácz,
• Anna Vincze,
• András Marton,
• Ahmed Qasim Abdulhussein,
• Judit Halász,
• András Dancsó,
• Gyula Simig,
• György Tibor Balogh and
• Balázs Volk

Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169

• pharmacological activity of phthalazin-1(2H)-ones 1 (Figure 1) [1][2][3][4][5], we have devoted significant effort to the synthesis and pharmacological investigation of structurally related 1,2,3-benzothiadiazine 1,1-dioxides 2 over the last decade [6][7][8][9][10][11]. As 4-methyl-2H-1,2,3-benzothiadiazine 1,1

• exhibit diverse biological activities and have found application for the treatment of psychiatric disorders and neurodegenerative diseases [13][14][15][16][17]. Therefore, we now report our results in the synthesis and characterization of compounds 3 containing a 2,9-dihydro[1,2,3]thiadiazino[5,6-g]indole

• synthesis [18][19][20][21]. Sudhakara et al. described the advantages of using bismuth nitrate as catalyst in the synthesis of hydrazones and in the one-pot Fischer synthesis of indoles from ketones and hydrazines [22][23]. Adopting this method, hydrazone intermediates 7a–j were obtained by treatment of

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

• structure analysis was performed on a Bruker SMART diffractometer equipped with a CCD area detector at 120 K. Silica gel 60 F254 precoated plates on glass from Merck Ltd. were used for thin-layer chromatography (TLC). General procedure for the synthesis of conjugates 2a–h (S)-2-[2,10-Bis(4-methoxyphenyl

Synthesis of triazolo- and tetrazolo-fused 1,4-benzodiazepines via one-pot Ugi–azide and Cu-free click reactions

• Xiaoming Ma,
• Zijie Gao,
• Jiawei Niu,
• Wentao Shao,
• Shenghu Yan,
• Sai Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2025, 21, 2202–2210, doi:10.3762/bjoc.21.167

• methods for the synthesis of tetrazoles [25][26][27][28], the Ugi–azide reaction is a good approach for constructing 1,5-disubstituted-tetrazoles (1,5-DS-T) [29][30][31]. This scaffold can be subsequently linked to 1,2,3-triazole [32], 4H-chromen-4-one [33], pyrrolo[3,4-b]indolizine [34], and other

• heterocyclic scaffolds to obtain biologically interesting compounds (Scheme 1) [35][36][37][38][39][40][41]. The development of methods for the synthesis of triazole, tetrazole, piperazinone, and 1,4-benzodiazepine motifs are attractive from both synthetic and medicinal chemistry considerations [42][43][44][45

• ]. We herein propose a one-pot synthesis involving an Ugi–azide 4-component (4-CR) reaction followed by lactamization and azide–alkyne cycloaddition for assembling triazole-fused and tetrazole-tethered 1,4-benzodiazepines 7 and triazole-, tetrazole-, and piperazinone-fused 1,4-benzodiazepines 8 (Scheme

Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings

• Lifen Peng,
• Ting Wang,
• Zhiwen Yuan,
• Bin Li,
• Zilong Tang,
• Xirong Liu,
• Hui Li,
• Guofang Jiang,
• Chunling Zeng,
• Henry N. C. Wong and
• Xiao-Shui Peng

Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166

• Science and Technology, Xiangtan, Hunan 411201, P. R. China School of Science and Engineering, Shenzhen Key Laboratory of Innovative Drug Synthesis, The Chinese University of Hong Kong, Shenzhen, Shenzhen 518172, P. R. China Hunan Norchem Pharmaceutical Company, Ltd., Changsha 410000, P. R. China College

• of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, P. R. China 10.3762/bjoc.21.166 Abstract Organic five-membered rings have shown significant applications in the fields of organic synthesis, natural products, organic materials and pharmaceuticals for their unique

• organic synthesis [1][2][3][4][5][6][7][8][9][10][11][12][13][14] but also are critical moieties in natural products [15][16][17][18], organic materials [19] and pharmaceuticals [20][21][22][23][24] due to their unique chemical, electrical, optical, pharmacological and biological properties. Gracilioether

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

• of Science and Technology, 1037 Luoyu road, Wuhan 430074, China 10.3762/bjoc.21.165 Abstract The carbonyl group is central in organic synthesis, thanks to its ability to undergo a vast range of different chemical transformations on its carbon center or at the neighboring positions. Due to the high

• organic synthesis. Therefore, synthetic chemists can base strategies on the existing reactivity of carbonyl compounds for defining novel routes converting biobased platform molecules containing carbonyl groups to prepare fine organic chemicals [21][22]. Following this approach, researchers can obtain

• for the synthesis of GA and GCA using activated carbon deposited Cu catalysts and different biomass-derived polyols as feedstock with exceptionally high atom utilization ≈93% and up to 90% yield (Scheme 1) [28]. Glycolaldehyde (GCA), the smallest sugar molecule, was used by Sels et al. for the

The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products

• Dong-Xing Tan and
• Fu-She Han

Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164

• The desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds is a powerful tool for the construction of ring systems bearing multiple stereocenters including all-carbon quaternary stereocenters, which are widely useful chiral building blocks for the total synthesis of structurally

• synthesis of complex terpenoid and alkaloid natural products by strategically applying desymmetric enantioselective reduction. Advance before 2016 in this area has been overviewed in an elegant review article. Since then, a series of more challenging terpenoid and alkaloid natural products have been

• synthesized utilizing a desymmetric enantioselective reduction strategy of cyclic 1,3-dicarbonyl compounds as a key transformation. This review will summarize the application of this strategy in the total synthesis of terpenoid and alkaloid natural products from the year 2016 to 2025. We first focus on the

Multicomponent reactions IV

• Thomas J. J. Müller and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2082–2084, doi:10.3762/bjoc.21.163

• National Academy of Sciences of Ukraine, Nauky Av. 60, 61072 Kharkiv, Ukraine, Faculty of Chemistry, V. N. Karazin Kharkiv National University, Svobody Sq. 4, 61077 Kharkiv, Ukraine 10.3762/bjoc.21.163 Keywords: multicomponent reactions; The synthesis of complex molecules is a cornerstone of modern

• a strong emphasis on heterocycle synthesis. Beyond traditional condensation-based approaches, mechanistically innovative crossovers – linking metal catalysis with radical chemistry and, more recently, with photo(redox) catalysis – are opening entirely new avenues for MCR development. Finally, seven

• focused Reviews on heterocycles, reactivity patterns, and the role of MCRs as enabling tools at the interface with biosciences underscore the timeliness and enduring elegance of this powerful and concise concept in molecular synthesis. As the guest editors of this thematic issue, we would like to thank

Further elaboration of the stereodivergent approach to chaetominine-type alkaloids: synthesis of the reported structures of aspera chaetominines A and B and revised structure of aspera chaetominine B

• Jin-Fang Lü,
• Jiang-Feng Wu,
• Jian-Liang Ye and
• Pei-Qiang Huang

Beilstein J. Org. Chem. 2025, 21, 2072–2081, doi:10.3762/bjoc.21.162

• synthesis of (–)-isochaetominine A was increased from 25.4% to 30.8% over five steps. Secondly, a new protocol featuring the use of an aged solution of K2CO3/MeOH to quench the DMDO epoxidation-triggered cascade reaction was developed, which allowed the in situ selective mono- or double epimerization at C11

• /C14 as shown by the diastereodivergent synthesis of a pair of diastereomers of versiquinazoline H from its tripeptide precursor. This double epimerization at the last-step allowed the enantiodivergent synthesis of two enantiomers in either racemate form or two pure enantiomers from the same precursor

• . The former was demonstrated by the synthesis of alkaloid 14-epi-isochaetominine C that was used to determine the enantiomeric excess of the synthesized natural product (98.7% ee), while the latter was illustrated by the synthesis of both enantiomers of the alkaloid isochaetominine. Additionally, the

Discovery of cytotoxic indolo[1,2-c]quinazoline derivatives through scaffold-based design

• Daniil V. Khabarov,
• Valeria A. Litvinova,
• Lyubov G. Dezhenkova,
• Dmitry N. Kaluzhny,
• Alexander S. Tikhomirov and
• Andrey E. Shchekotikhin

Beilstein J. Org. Chem. 2025, 21, 2062–2071, doi:10.3762/bjoc.21.161

• Street, Moscow 11991, Russia 10.3762/bjoc.21.161 Abstract Indolo[1,2-c]quinazoline derivatives have emerged as promising chemotype in drug discovery due to their versatile biological activities, including antimicrobial and antiviral properties. In this study, we report the design, synthesis, and

• structural fusion of indole and quinazoline pharmacophores offers exceptional opportunities for designing new therapeutic agents, combining the proven bioactivities of both privileged scaffolds. Chemical ways for the synthesis of indolo[1,2-c]quinazolines (Figure 1, top) are numerous and cover different

• facilitates exploration of SAR study related to the position and nature of the aminoalkyl substituent. Shifting the aminoalkyl substituent from position 12 to position 6 enables a comparative assessment of biological activity across the series. In this context, the synthesis of 6-(chloromethyl)indolo[1,2-c

Bioinspired total syntheses of natural products: a personal adventure

• Zhengyi Qin,
• Yuting Yang,
• Nuran Yan,
• Xinyu Liang,
• Zhiyu Zhang,
• Yaxuan Duan,
• Huilin Li and
• Xuegong She

Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160

• , Guiyang 550025, P. R. China 10.3762/bjoc.21.160 Abstract Bioinspired total synthesis represents an important concept to guide the designing of powerful synthetic strategies. Our group has a long-time interest and experience in designing synthetic strategies through analyzing the biosynthetic pathway of

• natural products. Recently, we have achieved an array of bioinspired total syntheses, which showed the great power of this approach in natural product synthesis. Documented herein is a review of these achievements which include the detailed process of how we develop these strategies. Specifically

• , bioinspired total synthesis of three types of natural products, namely diterpenoids (chabranol, and monocerin), alkaloids (indole, hydroquinoline, and monoterpenoid−indolidinoid hybrid), and gymnothelignans are discussed. Based on these achievements on bioinspired total synthesis, we provide some information

Solar thermal fuels: azobenzene as a cyclic photon–heat transduction platform

• Jie Yan,
• Shaodong Sun,
• Minghao Wang and
• Si Wu

Beilstein J. Org. Chem. 2025, 21, 2036–2047, doi:10.3762/bjoc.21.159

• [35][36][37][38][39][40][41]. Notably, the utilization of azobenzene-based materials in solar thermal storage applications is gaining considerable attention due to their advantages in low synthesis cost, facile molecular design, exceptional cycling stability, and superior fatigue resistance [6][8

• ]. Since Olmsted’s pioneering exploration of azobenzene compounds as solar thermal fuels in 1983 [42], significant breakthroughs have been achieved through interdisciplinary integration of organic synthesis, functional materials engineering, photophysical mechanism analysis, and computational chemistry. So

• visible light under sunlight irradiation [59], achieving a solar efficiency of 0.4% and a solid-state isomerization efficiency of 72.7% (Figure 5b). Feng and co-workers reported the synthesis of three azopyridine polymers (ortho-, meta-, and para-) [60], with the m-azopyridine polymer exhibiting a

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

• formation of heterocyclic systems in a minimal number of steps and offer several ways to vary substituents and they are widely used in drug discovery and development, as well as in diversity-oriented synthesis [1][2][3][4]. In addition, the application of condition-based divergence strategy [5] and the

• depending on the conditions, can either be limited to a Biginelli condensation with the formation of hydroxytetrahydropyrimidines or proceed with further post-cyclization to form oxygen-bridged triazolobenzoxadiazocine derivatives. Furthermore, a multicomponent synthesis of oxygen-bridged pyrimidine systems

• -amino-5-methylthio-1,2,4-triazole (1a), salicylaldehydes 2a–c,f, and pyruvic acid (3) under different conditions. Synthesis of compounds 4a–j. Synthesis of compounds 5a–c. Supporting Information Supporting Information File 34: Experimental procedures, product characterization, and copies of NMR spectra

α-Ketoglutaric acid in Ugi reactions and Ugi/aza-Wittig tandem reactions

• Vladyslav O. Honcharov,
• Yana I. Sakhno,
• Olena H. Shvets,
• Vyacheslav E. Saraev,
• Svitlana V. Shishkina,
• Tetyana V. Shcherbakova and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2025, 21, 2021–2029, doi:10.3762/bjoc.21.157

• ; quinoxalinone derivative; Ugi reaction; Introduction Multicomponent reactions are powerful tools in organic chemistry that enable the synthesis of structurally complex and multifunctional compounds from three or more starting materials in a single synthetic step. They are widely used in drug discovery because

• , unlike conventional linear synthesis strategies, they enable the preparation of libraries of organic compounds in higher yields and with significantly less time, resources, and chemical waste [1][2][3][4][5]. The Ugi reaction, discovered in 1959 by Ivar Karl Ugi [6], is one of the classic multicomponent

• reactions, widely used as a green alternative for the synthesis of active pharmaceutical ingredients [7] and opens up the possibility of creating new compounds from the class of peptidomimetics [8][9][10], which often exhibit diverse biological effects [11] including antidiabetic [12], antiviral [13

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

• producing energy-dense compounds [2][3]. One promising strategy to access strained compounds involves gas-evolution (e.g., CO or N2) because of the associated entropic driving force; this approach has had wide utility in photomedicine and organic synthesis. For example, photochemical decarboxylation has

• synthesis of strained compounds such as bicyclo[1.1.0]butane (BCB) and bicyclo[2.1.0]pentane (housane). The energy stored in strained σCC bonds of BCB and housane makes them important building blocks in the synthesis of complex molecular structures. BCBs have been employed in ring-opening reactions with

• nucleophiles [7][8][9][10][11], radicals [12][13][14][15] and electrophiles [16][17][18] to give cyclobutanes and cyclobutenes [19][20], which are building blocks in regio- and stereoselective synthesis [21][22][23][24][25][26][27] (Scheme 1a). Additionally, BCB has been used in bioconjugation due to its high

Measuring the stereogenic remoteness in non-central chirality: a stereocontrol connectivity index for asymmetric reactions

• Ivan Keng Wee On,
• Yu Kun Choo,
• Sambhav Baid and
• Ye Zhu

Beilstein J. Org. Chem. 2025, 21, 1995–2006, doi:10.3762/bjoc.21.155

• Ivan Keng Wee On Yu Kun Choo Sambhav Baid Ye Zhu Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 2, Singapore 117543 10.3762/bjoc.21.155 Abstract Despite the rapid development of asymmetric synthesis, judging the remoteness of stereocontrol has

• chiral molecules. Keywords: asymmetric reactions; axial chirality; catalysis; planar chirality; stereocontrol; Introduction Chirality is a ubiquitous and fundamental phenomenon in nature and thus holds an irreplaceable position in organic synthesis. At its most rudimental definition, chirality in a

• among these scaffolds, the various types of chirality are permutations of substituents on diverse stereogenic elements (Scheme 1C). Although this analysis offers a unified view of chirality, the realization of these chiral systems through asymmetric synthesis is far from trivial. Stereogenic compounds

Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis

• Rasma Kroņkalne,
• Rūdolfs Beļaunieks,
• Armands Sebris,
• Anatoly Mishnev and
• Māris Turks

Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154

• Rasma Kronkalne Rudolfs Belaunieks Armands Sebris Anatoly Mishnev Maris Turks Institute of Chemistry and Chemical Technology, Faculty of Natural Sciences and Technology, Riga Technical University, P. Valdena str. 3, LV-1048, Riga, Latvia Latvian Institute of Organic Synthesis, Aizkraukles str. 21

• unidentified impurities. However, it turned out to be the key to achieving the best diene/indene ratio 10a/11a = 98:2. With the optimized conditions for aryldiene synthesis (Table 1, entries 16 and 17) we proceeded to explore the substrate scope (Table 2). Arylations employing aryl groups with electron

• in the context of 1,2-silyl shift and potential cyclization. Competing mechanistic pathways for diene 10 and indene 11 formation. Reaction scope for the synthesis of arylated tetrahydrofurans 8. Conditions: All reactions were performed on a 0.47 mmol scale. aStarting material 7d concentration: 0.1

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

• carboxylic acid derivatives involving hydrogen-atom transfer have not been reported despite the fundamental importance of carbonyl reduction processes in organic synthesis [46]. Here, we report the results of our investigation into such reactions using an acylazolium salt derived from benzoic acid as a model

• synthesis with complete reduction to the alcohol followed by partial re-oxidation often being conducted. Conclusion In conclusion, we have developed novel light-driven methodologies for the reduction of acylazolium salts using benzoylimidazolium triflate as a model substrate. In the presence of a

• . Given the importance of carboxyl reduction reactions in organic synthesis and the recent explosion in interest in light-mediated NHC-catalyzed coupling reactions, we believe this work will be of value to the community and further studies on these systems, including on the development of catalytic