Recent advances in total synthesis of illisimonin A

• Juan Huang and
• Ming Yang

Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199

• . However, subsequent density functional theory (DFT) calculations by the Tantillo group on rearrangements of potential biosynthetic precursors revealed that structure 10 corresponds to a transition state rather than a stable intermediate of the 1,2-alkyl migration [27]. Their study further indicated that

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 of six-membered cycles in the synthesis of functionalized cyclopentane/enones, which are biologically active compounds. The main synthetic methods of ring contraction (ozonolysis–aldol condensation, ozonolysis–Dieckmann reaction, Baeyer–Villiger cleavage–Dieckmann reaction) and rearrangements

• information. Keywords: biological activity; cyclopentane/enone; rearrangements; ring/cycle contractions; total synthesis; Introduction The functionalized cyclopentane/enone fragment is part of the structure of a large number of natural and synthetic biologically active compounds, including prostaglandins

• cyclohexane/ene ring contraction. The structure of the review includes examples of simple transformations (ozonolysis–aldol condensation, ozonolysis–Dieckmann reaction, and Baeyer–Villiger cleavage–Dieckmann reaction) and rearrangements (photochemical, benzil, semi-pinacol, Wolff, Meinwald, Wagner–Meerwein

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

• catalysis, C–H activation methods, biomimetic synthesis, classic rearrangements, skeletal editing logic, and others. In addition, these efforts enabled the identification of the potential cellular target of complanadine A, validation of its neurotrophic activity, establishment of preliminary structure

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

• ) through structural or bond rearrangements, thereby enabling solar energy storage. This reversible process is termed "energy charging", while the subsequent transformation of high-energy photoisomers back to their ground state – triggered by external stimuli such as light, heat, or catalysts – releases

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

• species are limited to aryl- [7][8][10] or heteroaryl groups [7][8]. In one example methyl ethers were used [9]. Under [Pd]-catalyzed conditions a syn-type addition is observed [8][11], while [Cu] catalysts promote anti-addition [7][10]. In substrates prone to cationic rearrangements (or hydride shifts

• rearrangements via the 1,2-silyl shift, enabled by the β-cation-stabilizing properties of silyl groups [19][20]. This phenomenon has been successfully employed in 1,3-difunctionalization events in both intermolecular [21] and intramolecular fashion [22] (Scheme 1B). Thus far such propargylsilane rearrangements

Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs

• Almaz A. Zagidullin,
• Emil R. Bulatov,
• Mikhail N. Khrizanforov,
• Damir R. Davletshin,
• Elvina M. Gilyazova,
• Ivan A. Strelkov and
• Vasily A. Miluykov

Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148

• (Figure 4). In many alkylation scenarios, crosslinking or other structural rearrangements can render previously oxidizable moieties inaccessible or shift the protein’s conformational state. This suppresses or altogether eliminates the characteristic oxidation wave of HSA. Based on established literature

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

• the photoswitch. Examples of photogenerated side reactions can be oxidation or irreversible rearrangements. In the following sections, seven classes of photoswitches beyond the classic azobenzene are introduced and discussed (Scheme 1). Each of them shows unique photophysical behaviour and has

•  14, box) and repulsion between the aryl and the carbonyl group in the E-isomer. Some studies on N-acylindigo derivatives reported, besides the expected spectral blue-shift, also a decrease in the fatigue resistance due to photochemical rearrangements [68][69]. Dube and co-workers reported a series of

Transition-state aromaticity and its relationship with reactivity in pericyclic reactions

• Israel Fernández

Beilstein J. Org. Chem. 2025, 21, 1613–1626, doi:10.3762/bjoc.21.125

• Cope rearrangements [20]. More recently, Alabugin and co-workers reported that the gold(I)-catalyzed propargyl rearrangement depicted in Scheme 1b also follows a concerted oxonia Claisen pathway (via an aromatic TS) rather than through a higher barrier 6-endo-dig cyclization [21], which provides

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

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

• unpredictability. Additional rearrangements and substitutions might occur making the exact outcome of the reaction difficult to predict. For example, Chi and co-workers unexpectedly obtained azulene-embedded nanographene 36 and its triflyloxylated derivative 37 from precursor 35 during the an attempted synthesis

• -embedded nanographenes. One of the main challenges in this area is that the outcome of reactions is often difficult to predict, and various skeletal rearrangements can occur under typical on-surface reaction conditions. The synthesis of most of the reported azulene-embedded PAHs involves the generation of

• revealed that none of the azulene subunits exhibits the characteristic azulene-like aromaticity. Additionally, both 186 and 187 show moderate open-shell biradical character, according to theoretical calculations. A similar strategy, leading to different types of skeletal rearrangements, was reported by Ma

A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids

• Zhiyang Zhang,
• Jialei Hu,
• Hanfeng Ding,
• Li Zhang and
• Peirong Rao

Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75

• oxidative truncation of apotirucallane or apoeuphane precursors coupled with subsequent β-furan annulation [1][2][3][4][5][6], constitute an architecturally sophisticated family of natural products. Based on their specific skeletal rearrangements, limonoids can be systematically categorized into four

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

• considering recent advances enabling subsequent intramolecular H-atom abstraction [51] and efficient rearrangements [73][74]. A) Energy transfer catalysis of alkenes in organic synthesis. B) Energy transfer catalysis of conjugated borylated alkenes. C) Energy transfer catalysis of simple alkenylboronic esters

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

• , various light-, heat-, and acid-induced rearrangements have been reported [35], complicating the distinct structural determination of these compounds. In comparison to published NMR and UV–vis data, formation of neither known species can be assumed with certainty. Last, through addition of mono-carboxylic

• potential further rearrangements or photodecomposition. To gain a better understanding of the ongoing conversion processes, we conducted NMR spectroscopy. The assignment of individual proton signals was supported by 2D correlation NMR spectroscopy (Supporting Information File 1). First, O-NBD2 is

• described a variety of potential rearrangements for oxa-NBD and oxa-QC derivatives [32][34][36][37]. Therefore, in-depth 2D NMR analysis combined with mass spectrometry was attempted to elucidate the structure of O-UnS2. Notably, an additional singlet proton signal (integrated as 1 proton) corresponding to

Photomechanochemistry: harnessing mechanical forces to enhance photochemical reactions

• Francesco Mele,
• Ana M. Constantin,
• Andrea Porcheddu,
• Raimondo Maggi,
• Giovanni Maestri,
• Nicola Della Ca’ and
• Luca Capaldo

Beilstein J. Org. Chem. 2025, 21, 458–472, doi:10.3762/bjoc.21.33

• rearrangements. Most organic molecules are colorless and, in fact, do not absorb visible light: highly energetic UV irradiation is typically needed. A milder approach is offered by photocatalytic approaches. Here, a photocatalyst is added to the reaction mixture to convert light energy into chemical potential to

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

• hydrophobic [160] products have been popular, including hydrolyses, ring openings, and rearrangements [22]. These reaction classes have been discussed [24][25][140]. Cavity-directed changes in ion-localization [161][162] and pKa are effective [37][107][163][164], and size-selectivity [36][165][166][167] and

Three-component reactions of conjugated dienes, CH acids and formaldehyde under diffusion mixing conditions

• Dmitry E. Shybanov,
• Maxim E. Kukushkin,
• Eugene V. Babaev,
• Nikolai V. Zyk and
• Elena K. Beloglazkina

Beilstein J. Org. Chem. 2025, 21, 262–269, doi:10.3762/bjoc.21.18

• the signal of the CH–O group at 5.03 ppm, as well as by ethyl bromide, which indicated the predominance of isomer 4a in the mixture. For isomers 5, preferential formation of dibromide 23 and products of carbocationic rearrangements containing an ester group, the precursor of which was compound 5b

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• , deuterium labelling, rearrangements on stereodefined substrates, and structural analyses (NMR and X-ray) of the reaction products. RT-NMR-derived data strongly supported a pathway of alkene activation by the iodane, as opposed to the formation of an N-I(III) adduct. The presence of 5-exo-products, with

From perfluoroalkyl aryl sulfoxides to ortho thioethers

• Yang Li,
• Guillaume Dagousset,
• Emmanuel Magnier and
• Bruce Pégot

Beilstein J. Org. Chem. 2024, 20, 2108–2113, doi:10.3762/bjoc.20.181

• , sigmatropic rearrangements have established themselves as robust and versatile tools for many transformations in organic synthesis [1][2][3]. They were widely employed with a wide range of substrates. With a peculiar type of scaffold, S-perfluoroalkyl aryl sulfoxides, in 2009, we were the first to demonstrate

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

Understanding X-ray-induced isomerisation in photoswitchable surfactant assemblies

• Beatrice E. Jones,
• Camille Blayo,
• Jake L. Greenfield,
• Matthew J. Fuchter,
• Nathan Cowieson and
• Rachel C. Evans

Beilstein J. Org. Chem. 2024, 20, 2005–2015, doi:10.3762/bjoc.20.176

• effect, but also as the medium for structural rearrangements. Effect of acidification The effect of acidification on isomerisation was further investigated using UV–vis absorbance spectroscopy, where excess hydrobromic acid (HBr) was added to AzoTAB and AAPTAB samples (25 μM) that had been preirradiated

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• phase catalyzed by BscA. (B) Oxidation phase and scaffold rearrangements by modification enzymes. Chemo-enzymatic total synthesis of cotylenol (1) and brassicicenes. (A) Chemical cyclization phase. (B) Chemical and enzymatic oxidation phase. (A) Biosynthetic pathway for trichodimerol (2) in Penicillium

Oxidative hydrolysis of aliphatic bromoalkenes: scope study and reactivity insights

• Amol P. Jadhav and
• Claude Y. Legault

Beilstein J. Org. Chem. 2024, 20, 1286–1291, doi:10.3762/bjoc.20.111

• gained popularity due to their commercial availability [1][2][3][4][5] and versatility for phenolic dearomatizations, oxidative annulations, fragmentations, and oxidative rearrangements [6][7][8][9][10][11]. In particular, iodine(III) reagents have been proven effective for a wide range of oxidative

Stability trends in carbocation intermediates stemming from germacrene A and hedycaryol

• Naziha Tarannam,
• Prashant Kumar Gupta,
• Shani Zev and
• Dan Thomas Major

Beilstein J. Org. Chem. 2024, 20, 1189–1197, doi:10.3762/bjoc.20.101

• isoprenoid allylic carbocation has the capability to engage in standard carbocation reactions, including cyclization via intramolecular olefin attack at the positively charged center, Wagner–Meerwein rearrangements, and hydride or proton shifts. This sequence concludes either through deprotonation, resulting

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• , respectively (Scheme 12B) [58]. Saponification of the ester moieties in these species followed by Curtius rearrangements then led to amines 114 and 116. Non-natural amino acid derivatives 113 and 117 are intermediates prepared using these methods that could be of interest to medicinal chemistry. Alcohol 111

Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions

• Martyn Jevric,
• Julian Klepp,
• Johannes Puschnig,
• Oscar Lamb,
• Christopher J. Sumby and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74

• -cleavage reactions and rearrangements when modified at the 4-position [15][16][17]. Baillargeon and Reddy first reported rearrangements of 6,8-dioxabicyclo[3.2.1]octane derivatives promoted by diethylaminosulfur trifluoride (DAST) [18], and later Karban and co-workers reported a migration of oxygen from

• angle of 176°, explaining the preference for the different skeletal rearrangements in the two possible configurations at C4 in these rigid ring systems [19][21]. The involvement of the ring-oxygen in nucleophilic displacement reactions in 1,6-anhydroglucose derivatives has also been invoked to explain