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Search for "rearrangement" in Full Text gives 699 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Total synthesis of natural products based on hydrogenation of aromatic rings
Beilstein J. Org. Chem. 2026, 22, 88–122, doi:10.3762/bjoc.22.4
- rearrangement and Lewis acid-promoted acetal–ene reaction provided the tetracyclic skeleton 101. With 101 in hands, a 6 step transformation afforded the alkyne 102 in an overall yield of 45%. After obtaining 102, the authors used a free radical reaction to initiate a one-step 6-exo-trig cyclization
- , Johnson–Claisen rearrangement, enol ester formation, and methylation afforded 140. Finally, hydrogenation of 140 via PtO2/H2 generated the target molecule (±)-corynoxine, and under acidic conditions, (±)-corynoxine could be isomerized to (±)-corynoxine B (Scheme 19). Total synthesis of (+)-serratezomine E
- one-pot reaction featuring a double oxidative rearrangement cascade of furans and indoles followed by nucleophilic cyclization. This methodology was applied to the formal synthesis of rhynchophylline/isorhynchophylline and the first total syntheses of (±)-(7R)- and (±)-(7S)-geissoschizol oxindoles
Reactivity umpolung of the cycloheptatriene core in hexa(methoxycarbonyl)cycloheptatriene
Beilstein J. Org. Chem. 2026, 22, 64–70, doi:10.3762/bjoc.22.2
- dynamic equilibrium or total rearrangement of 5 into 6 upon formation. Thus, halogenation of hexa(methoxycarbonyl)cycloheptatrienyl anion 2 formed from 3 led to different outcomes with chlorine, bromine and iodine (Scheme 1). Chlorination gave exclusively i-substituted symmetric cycloheptatriene 4a in an
- 11. The 1,5-arylazo shift has been previously investigated in cyclopentadiene systems [32]. Subsequent formation of norcaradienes 12 and azocyclopropane rearrangement [33][34][35] afford a mixture of isomeric dihydroindazole derivatives 8 and 9 which differ in positioning of one ester group. The
- sterically hindered 2-(methoxycarbonyl)phenyldiazonium ion afforded only one isomer of dihydroindazole 8k which indicates the influence of the steric factor on the azocyclopropane rearrangement. However, the reaction additionally gave the product of an i-substitution with subsequent proton migration to form
One-pot synthesis of ethylmaltol from maltol
Beilstein J. Org. Chem. 2025, 21, 2755–2760, doi:10.3762/bjoc.21.212
- adjustment through an Achmatowicz rearrangement [8] initiated by either anodic oxidation [7][9][10], chlorine gas [11][12], or tert-butyl hypochlorite [13] provides pyran-3-ones. Further oxidation and acid- or heat-induced rearrangement furnishes ethylmaltol (1). Of note, some of these procedures allow for
Sustainable electrochemical synthesis of aliphatic nitro-NNO-azoxy compounds employing ammonium dinitramide and their in vitro evaluation as potential nitric oxide donors and fungicides
Beilstein J. Org. Chem. 2025, 21, 2739–2754, doi:10.3762/bjoc.21.211
- estimated, as this step requires the change in spin-state. However, unexpectedly we found that addition of higher energy singlet nitrene C-s to A is not barrierless (ΔG≠ 10.9 kcal/mol). Moreover, according to our calculations C-s can easily (ΔG≠ 5.7 kcal/mol) undergo unimolecular rearrangement to the dimer
Mechanistic insights into hydroxy(tosyloxy)iodobenzene-mediated ditosyloxylation of chalcones: a DFT study
Beilstein J. Org. Chem. 2025, 21, 2703–2715, doi:10.3762/bjoc.21.208
- dearomatization [7], amination [8], oxidative coupling [9], ring contraction [10][11][12], oxidative rearrangement [13][14][15], dihydroxylation of alkenes, arylation [16], oxidation of sulfides [17] and many more. These hypervalent compounds contain iodine in higher oxidation state than its usual −(I) valence
- rearrangement is one of the important reactions induced by HTIB. Similar to other hypervalent iodine(III) compounds, HTIB is known to have higher electrophilicity towards olefinic bonds. HTIB dissociates, adds onto the olefinic bond and subsequently acts as a good leaving group resulting in generation of a
- )3/CH3OH, PhI(OCOCH3)2/CH3OH and PhI(OH)OTs/CH3OH in polar nucleophilic solvents [24][25][26][27][28]. A number of experimental and computational studies have explored the reaction pathway for these oxidative rearrangement reactions under metal-free conditions with the use of hypervalent iodine(III
Recent advancements in the synthesis of Veratrum alkaloids
Beilstein J. Org. Chem. 2025, 21, 2657–2693, doi:10.3762/bjoc.21.206
- the Giannis group in 2009 starting from dehydroepiandrosterone via a biomimetic rearrangement [21]. We will later discover and compare the improvements in the semisynthesis reported by Liu and Qin, which relies on a similar skeletal transformation toward (−)-cyclopamine and (−)-veratramine [26]. Key
- step of the first semisynthesis of (−)-cyclopamine (6) is a Wagner–Meerwein-type rearrangement of androstane-framework 22 toward the C-nor-D-homo skeleton in 23 (Scheme 5) [21]. The synthesis starts from commercially available dehydroepiandrosterone (DHEA, 24) by protection of the free hydroxy group in
- rearrangement was carried out with trifluoromethanesulfonic anhydride leading to a mixture of regioisomers 23 and 27, with 23 being convertible to 27 by addition of DBU. The A–E-rings have, thus, been installed with correct stereoconfiguration, therefore the last steps of the sequence focused on the
Visible-light-driven NHC and organophotoredox dual catalysis for the synthesis of carbonyl compounds
Beilstein J. Org. Chem. 2025, 21, 2584–2603, doi:10.3762/bjoc.21.200
- /organophotocatalyzed oxidative Smiles rearrangement of O-aryl aldehydes 26 has been developed using oxygen as the terminal oxidant under visible-light dual catalysis. This approach afforded highly functionalized 2-hydroxyarylbenzoates 27, tolerating electron-deficient and electron-rich substituents. The C–O bond
- /photoredox catalyzed borylacylation of alkenes. NHC-catalyzed oxidative functionalization of cinnamaldehyde. NHC/photocatalyzed oxidative Smiles rearrangement. NHC-catalyzed synthesis of cyclohexanones through photocatalyzed annulation. Dual organocatalyzed meta-selective acylation of electron-rich arenes
Recent advances in total synthesis of illisimonin A
Beilstein J. Org. Chem. 2025, 21, 2571–2583, doi:10.3762/bjoc.21.199
- only certain precursors with certain specific oxidation patterns are competent to undergo this rearrangement. The same as other Illicium sesquiterpenes, the highly oxgenated and strained skeleton of illisimonin A has posed a significant challenge to synthetic chemists. To date, the research groups of
- directly, the team adopted a strategy involving rearrangement from the more accessible cis-pentalene isomer. They first assembled the cis-pentalene core through an elegant intramolecular Diels–Alder (IMDA) reaction. Subsequently, the conversion from cis to trans-pentalene was achieved via a semipinacol
- rearrangement. Finally, a White–Chen C–H oxidation [33][34][35] was employed to install the lactone ring, thereby completing the synthesis. The synthesis began with commercially available compound 19 and known compound 20 (Scheme 2). These were joined via an intermolecular aldol reaction to give adduct 21
Total syntheses of highly oxidative Ryania diterpenoids facilitated by innovations in synthetic strategies
Beilstein J. Org. Chem. 2025, 21, 2553–2570, doi:10.3762/bjoc.21.198
- alkyne difunctionalization, furyl group installation, Achmatowicz rearrangement, and subsequent functional group manipulations provided intermediates 84 and 85. C5-acylation and methylation under kinetically controlled conditions followed by Sonogashira coupling yielded cyclization precursor 89
- ). The synthesis commenced with the preparation of key cyclization precursor 98 via Barbier coupling and Babler–Dauben oxidative rearrangement. A pivotal palladium-catalyzed Heck/carbonylative cyclization then efficiently furnished the ABC tricyclic core 99. Notably, adding N-formylsaccharin under a CO
Effect of a photoswitchable rotaxane on membrane permeabilization across lipid compositions
Beilstein J. Org. Chem. 2025, 21, 2498–2512, doi:10.3762/bjoc.21.192
- rearrangement required for permeability modulation. Similarly, rotaxane 2 and axle 3 exhibit minimal release upon the five irradiation cycles, resulting in releases of 5% and 11%, respectively (Figure 4b, Table 1, and Supporting Information File 1, Figure S17). The slightly higher release caused by axle 3 may
- release upon irradiation. Rotaxane 4 starts at 34%, yielding a Δ release of 31% (65–34) due to reversible azobenzene isomerizations, whereas 1 starts at 6%, resulting in a larger Δ release of 53% (59–6). This indicates that while 4 induces a strong initial perturbation due to early membrane rearrangement
Synthesis of the tetracyclic skeleton of Aspidosperma alkaloids via PET-initiated cationic radical-derived interrupted [2 + 2]/retro-Mannich reaction
Beilstein J. Org. Chem. 2025, 21, 2470–2478, doi:10.3762/bjoc.21.189
- conform to a sigmatropic rearrangement reaction [36]. Inspection of the changes in the bond lengths (Figure 2c) and Mayer bond orders (Figure 2d) along the IRC path clearly show that C19–C12 bond formation and C19–C3 bond cleavage are asynchronous. On the basis of these premises, we assume that the
Ex-situ generation of gaseous nitriles in two-chamber glassware for facile haloacetimidate synthesis
Beilstein J. Org. Chem. 2025, 21, 2465–2469, doi:10.3762/bjoc.21.188
- acetimidates through the Overman rearrangement [8][9]. Trifluoroacetonitrile is a highly toxic gas being of limited commercial availability and it can furthermore be difficult to get from the few commercial suppliers due to transport restrictions. This, together with local restrictions, because of the inherent
The intramolecular stabilizing effects of O-benzoyl substituents as a driving force of the acid-promoted pyranoside-into-furanoside rearrangement
Beilstein J. Org. Chem. 2025, 21, 2456–2464, doi:10.3762/bjoc.21.187
- equilibrium lie outside the carbohydrate ring system. Consideration of such effects is essential to rationalize the reactivity of structurally complex and densely protected carbohydrate compounds. Keywords: benzoylated galactofuranosides; DFT; DLPNO-CCSD(T); pyranoside-into-furanoside rearrangement
- furanose form through steric and electrostatic effects. In our previous work [24], we investigated the energetic aspects of the pyranoside-into-furanoside (PIF) rearrangement that proceeded under acid-promoted sulfation and whose mechanism was studied by us previously [25] along with the mechanism of
- observed another example of the PIF-rearrangement [31] where treatment with catalytic amounts of TfOH in CH2Cl2 unexpectedly shifted the equilibrium between selectively protected galactoside 1 and furanoside 2 in favor of the furanose form (Figure 3A), thus opening a new route towards Galf-containing
Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds
Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185
- intramolecular aldol reaction (recyclization or rearrangement). This method is applicable to triterpenoids, such as tirucallane, ursane, oleanane and dammarane types (pathway A), as well as for triterpenoids of the ursane and dammarane types (pathway B) [27]. In [28], a convenient method for ring contraction is
- (III) and iodine(III), and Wolff rearrangement. 2.1 Benzilic acid and semipinacol-type rearrangements The strategy of ring contraction using the benzilic acid-type rearrangement was used by Zhang et al. [38] for the asymmetric synthesis of 4β-acetoxyprobotryane-9β,15α-diol (52). This compound contains
- aldehyde 53 [39] (Scheme 10). The key steps in this synthesis are based on an asymmetric rhodium-catalyzed [4 + 2] cycloaddition reaction [40], followed by a unique benzilic acid-type rearrangement under very mild conditions [41]. A step-by-step mechanism for the benzilic acid-type rearrangement of
Comparative analysis of complanadine A total syntheses
Beilstein J. Org. Chem. 2025, 21, 2334–2344, doi:10.3762/bjoc.21.178
- Barton–McCombie deoxygenation. The extra ethyl carboxylate was removed via a sequence of LiOH hydrolysis and a Curtius rearrangement using DPPA to form the corresponding acyl azide. Ketone 50 was produced in 98% yield over two steps. The newly formed ketone functionality enabled the introduction of the
- sequence of Boekelheide rearrangement (56 → 57), acetate hydrolysis, DMP oxidation and Cbz removal. Based on these results, Tsukano and co-workers suggested that a mono-N-oxide intermediate could be involved in the biosynthesis of these dimeric complanadine alkaloids. Importantly, access to both
- of the electron-rich pyrrole group is essential for the key C–C bond formation. In the next step, the pyrrole group was converted to the pyridine group encoded by the natural product. This single-atom skeletal editing step (67 → 68) was achieved using the Ciamician–Dennstedt rearrangement, a reaction
Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis
Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177
- can further undergo ring-opening or rearrangement reaction to assemble complex molecular frameworks. Additionally, quinone photoredox reactions involving single-electron transfer (SET) processes provide novel strategies for the stereoselective synthesis of useful structures such as spiroketals. This
- by the Yang group [22]. Installation of the hydroxymethyl group in 4 was achieved through sequential formylation and reduction. Compound 4 then underwent a one-pot, substrate-controlled diastereoselective Johnson−Claisen rearrangement/acetylation to install ester 5. Treating 5 with m-CPBA (meta
- -chloroperoxybenzoic acid) induced epoxidation, which was then followed by a Meinwald rearrangement to accomplish aldehyde 7. From 7, a sequence involving silyl enol ether formation, Simmons−Smith cyclopropanation, and acid-mediated regioselective ring-opening installed the C8 quaternary methyl group in 10. Subsequent
Pathway economy in cyclization of 1,n-enynes
Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173
- dichloromethane (DCM), gold(I)-catalyzed alkyne activation initiated 6-endo-dig cyclization of the conjugated alkene. Subsequent alkyl migration formed four-membered ring intermediate 9, which underwent fragmentation and rearrangement to yield phenanthrene derivative 10 (Scheme 3, path a). When tetrahydrofuran
- terminal alkyne proceeded via a gold(I)-catalyzed propargyl-Claisen rearrangement, generating a β-allenic intermediate 35. This intermediate underwent a Markovnikov-type nucleophilic addition followed by a 5-exo-trig cyclization to stereoselectively construct the furo[3,2-b]furan bicyclic framework 36
- ] intermediate 62 (Scheme 14, path a). When a less nucleophilic indole was used as the nucleophile, a Wagner–Meerwein rearrangement occurred, leading to the formation of a pyrido[4,3-b]indole product 63. When Hantzsch ester (HEH) was used as the nucleophile, the imine intermediate 62 was reduced to product 64
C2 to C6 biobased carbonyl platforms for fine chemistry
Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165
- and hydroxyketones. The catalyst could be recovered and reused five times without decreasing its selectivity and activity. Mechanistically, the reaction involves a Heyns-type rearrangement and subsequent intramolecular olefination (Scheme 22) [96]. Arandia et al. reported the application of the
- toward useful biobased functional compounds or intermediates with applications in fuels, polymer chemistry and fine organic synthesis (CH activation, Piancatelli rearrangement, etc.). Conversion of furfural to alcohols, aldehydes and ketones: One of the most important transformations of furfural is its
- , arising from a nucleophilic attack of a furan carbon atom of one furfural molecule onto the aldehyde of a second one, giving 2-(4-furfur-2-al)-4-hydroxy-2-cyloepenten-1-one (Scheme 64), resulting from a Piancatelli rearrangement. This latter can further evolve towards more complex humin precursors by
The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products
Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164
- reduction of 72, affording the hydroxyketone 74 in 57% yield with 91% ee. Protection of the secondary alcohol in 74 followed by Beckmann rearrangement led to lactam 75. Oxidation state modifications and functional group transformations of 75 afforded ketone 76. Next, the 1,2-addition of 76 with vinyl iodine
Bioinspired total syntheses of natural products: a personal adventure
Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160
- as a single isomer, which further underwent a migratory rearrangement and afforded iboluteine. On the other hand, oxidation of ibogaine with molecular iodine achieved both indole and amine oxidations, delivering lactam 35. Intermediate 35 could be oxidized with H2O2 through C–C bond cleavage to give
- Friedel–Crafts reaction. Next, the cyclohexadienone moiety could be activated by an acid to undergo a rearrangement reaction to provide eupomatilone. The exocyclic THF ring might exist as diverse forms such as hemiacetal, acetal, lactone or acetal-linked dimer. The (hemi)acetal moiety could generate an
- rearrangement under the conditions of H2SO4/MeOH, since their isolation of the natural products [32]. However, other critical bioinspired transformations have not yet been explored, which prompted us to initiate this study. Guided by this biogenetic proposal, we conducted a series of reactions to probe the
Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis
Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154
- aminopentynes 16a–c underwent allylic rearrangement, affording tetrahydropyridines 9 (Scheme 6). The tetrahydropyridine core was confirmed unambiguously by X-ray structure analysis of dinitrobenzamide 9c. More electron-rich acylamides reacted faster and gave less side-products, compared to more electron-poor
Photochemical reduction of acylimidazolium salts
Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153
- recently proposed by Marzo and co-workers in an NHC-mediated coupling reaction with alkyl halides mediated by (TMS)3SiH [55]. The O-silylated product 5 could result from a subsequent radical C-silylation followed by a Brook-type rearrangement process [56]. Interestingly, performing the TESH-mediated
Enantioselective desymmetrization strategy of prochiral 1,3-diols in natural product synthesis
Beilstein J. Org. Chem. 2025, 21, 1932–1963, doi:10.3762/bjoc.21.151
- Lewis acid-mediated semi-pinacol rearrangement, this work involved a CRL-catalyzed desymmetrization of prochiral diol 51 (prepared from aldehyde 50 in four steps), providing monoester 53 in 57% yield with 83% ee. Notably, 1-ethoxyvinyl 2-furoate (52) was selected as the acyl donor in this step to
- induced rearrangement of 133 to form the pyranose skeleton of ʟ-cladinose (134). Finally, the derivative, thiocladinoside 135 was then prepared from 134 in two additional steps. The total synthesis of azithromycin [60] was reported shortly after completion of 135 (Scheme 19). For the synthesis of fragment
Preparation of spirocyclic oxindoles by cyclisation of an oxime to a nitrone and dipolar cycloaddition
Beilstein J. Org. Chem. 2025, 21, 1890–1896, doi:10.3762/bjoc.21.146
- ][10][11][12][13]. Of note, Cook and co-workers described an elegant approach using tryptophan as a starting material and an oxidative rearrangement of an indole that allows access to a variety of spirooxindole alkaloids from the Alstonia genus [14]. An efficient way to construct cyclic nitrogen
Photoswitches beyond azobenzene: a beginner’s guide
Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143
- rearrangement 127 (Scheme 42) [130]. Besides influencing the thermal stability, the presence of substituents also increases the conjugation, typically giving a red-shifted closed-ring isomer. Electron-donating substituents were also found to have a strong red-shift effect and to increase the molar absorption
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