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Search for "oxidation" in Full Text gives 1447 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Rapid access to the core of malayamycin A by intramolecular dipolar cycloaddition
Beilstein J. Org. Chem. 2025, 21, 2542–2547, doi:10.3762/bjoc.21.196
- cleavage of the N–O bond, oxidation and Baeyer–Villiger oxidation. The starting functional groups (including alkyne and nitrone) for the proposed oxazoline were established in literature precedents [29][30][31]. Moreover, the readily available intermediate 8 [32] bearing three defined stereogenic centers
- , several conditions to cleave the N–O bond in 11 or 12 had not yielded any successful outcome. Therefore, we turned to adjust the synthetic sequence to switch the oxidation states at C2 and C3 (Scheme 4). It should be noted that compound 16 [38] was obtained as a stereoisomeric mixture of olefin, resulting
- from the use of crotyl bromide as a mixture of geometric isomers. After installation of the crotyl group, hydrolysis of the acetonide group and oxidative cleavage of diol 16, oxime 17 was prepared through the condensation of the aldehyde with hydroxylamine in overall 59% yield. Upon oxidation with
Catalytic enantioselective synthesis of selenium-containing atropisomers via C–Se bond formations
Beilstein J. Org. Chem. 2025, 21, 2447–2455, doi:10.3762/bjoc.21.186
- alkyne insertion step may be rate-limiting, as it involves the participation of selenol, alkyne, and the rhodium catalyst. The Rh(III) mechanism appears to be more plausible than route B, which can be attributed to the enhanced ion-pairing effect resulting from the higher oxidation state of rhodium
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
- compound was synthesized from the Diels–Alder adduct 14 between LG and 1,3-butadiene by two methods – vicinal hydroxylation of the double bond followed by periodate cleavage of the vic-diols and ozonolysis of the double bond. Alternatively, Wagner oxidation of the double bond in adduct 14 by treatment with
- -Ethylformylation of compound 35 and subsequent oxidation of ketoenol 36 with 30% aqueous H2O2 in the presence of a 28% MeONa/MeOH solution resulted in the formation of a diacid, which was then converted into dimethyl ester 37 with a yield of 55%. Refluxing ester 37 with an excess of t-BuOK in benzene gave acid 39
- allylic oxidation using H2SeO3-dioxane system to form the C30 aldehyde 47, or by the ozonolytic cleavage of the double bond between C20 and C29 to produce 20-methyl-3-ethyldiketone 48 [36]. Intramolecular nitrile–anionic cyclization of ketone 46 or diketone 48 under conditions of basic catalysis proceeded
The high potential of methyl laurate as a recyclable competitor to conventional toxic solvents in [3 + 2] cycloaddition reactions
Beilstein J. Org. Chem. 2025, 21, 2389–2415, doi:10.3762/bjoc.21.184
- solvent in a wide range of organic reactions that necessitate elevated temperatures. Furthermore, the oxidative stability index of methyl laurate at temperatures of 80 °C and 110 °C is greater than 40 (h), and the oxidation onset temperature is 198.5 °C which is better than those of methyl oleate [105
An Fe(II)-catalyzed synthesis of spiro[indoline-3,2'-pyrrolidine] derivatives
Beilstein J. Org. Chem. 2025, 21, 2383–2388, doi:10.3762/bjoc.21.183
- pathway (Scheme 4). Initial Fe(II)-mediated reductive cleavage of the N–O bond in the ketoxime acetate generates an iminyl radical. This is followed by a 5-exo-trig cyclization to form a carbon-centered radical. Final single-electron oxidation by Fe(III) delivers the desired spirocyclic product. All
Synthetic study toward vibralactone
Beilstein J. Org. Chem. 2025, 21, 2376–2382, doi:10.3762/bjoc.21.182
- cyclopentene ring containing an all-carbon quaternary center [14], and inhibits pancreatic lipase with an IC50 of 0.4 µg/mL. Several congeners with varying oxidation state, as well as related β-hydroxy acids or esters have also been isolated from the culture broth of the basidiomycete [15][16][17][18][19][20
- lactone 13 through allylic oxidation and cross metathesis. For the construction of the cyclopentene ring, an alkylidene carbene-mediated C–H insertion would be applied [35]. The synthetic route could be traced back to β-lactone 14, which contains two continuous stereogenic centers with trans configuration
- this key intermediate in hand, β-hydroxy acid 29 was synthesized through deprotection, IBX oxidation, and Pinnick–Lindgren–Kraus oxidation and the β-lactone 13 was subsequently obtained through activation of the carboxylic acid. Although we successfully constructed the molecular scaffold of
Comparative analysis of complanadine A total syntheses
Beilstein J. Org. Chem. 2025, 21, 2334–2344, doi:10.3762/bjoc.21.178
- these lycopodium alkaloids [12]. Lysine could be advanced to 4-(2-piperidyl)acetoacetate (7) and pelletierine (8), which would react with each other to deliver phlegmarine (9). Double oxidation of 9 would give 10 for a subsequent intramolecular Mannich-type cyclization to forge the C4–C13 bond and
- produce 11, which could be further converted to 12 and 13 for an intermolecular Mannich-type dimerization to form the C2–C3’ linkage [13]. Further oxidation state adjustment would give complanadines A, B, D, and E. Since their isolation, the complanadines, especially complanadine A, have attracted a
- -oxidation at one of the two benzylic positions, they started with benzylic oxidation of 34 using SeO2 to provide 37, which was further oxidized to pyridine N-oxide 38. Treatment of 38 with POCl3 in DMF delivered 2-chloropyridine 39 for the subsequent Suzuki–Miyaura cross coupling with 35 to form the C2–C3
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
- proximal phenol, yielding the cyclization product H (Scheme 1b). Notably, the quinone is reduced, while the proximal C–H bond is subject to oxidation. Building on these mechanistic insights and the synthetic merits of dicarbonyls, Norrish–Yang cyclization and related photoredox reactions have been serving
- transformation of 10 via sequential Wittig reaction, dihydroxylation, and Swern oxidation generated 1,2-diketone 12, thus setting the stage for the Norrish–Yang reaction. Finally, irradiation of 12 with a compact fluorescent lamp (CFL) completed (+)-cyclobutastellettolide B (13) as the sole product in 95% yield
- moderate diastereoselectivity; this was followed by Mn(III)-catalyzed metal-hydride hydrogen atom (MHAT) transfer to reduce the endocyclic olefin, forming 41 as a single diastereomer. Subsequent transformations – including a Wittig reaction, demethylation, and oxidation of the resulting phenol to a p
Insoluble methylene-bridged glycoluril dimers as sequestrants for dyes
Beilstein J. Org. Chem. 2025, 21, 2302–2314, doi:10.3762/bjoc.21.176
- is, therefore, urgently needed. Numerous techniques have been explored and used for the removal of dyes from water including coagulation, flocculation, adsorption, oxidation, electrolysis, biodegradation, and photocatalytic approaches [4][5]. Among these approaches, adsorption is most commonly used
Halogenated butyrolactones from the biomass-derived synthon levoglucosenone
Beilstein J. Org. Chem. 2025, 21, 2297–2301, doi:10.3762/bjoc.21.175
- Baeyer–Villiger oxidation affording the fluorinated, chlorinated, and brominated dideoxyribonolactones. Keywords: butyrolactone; cyrene; fluorine; halogenation; levoglucosenone; Introduction The γ-butyrolactone ring is a privileged scaffold found in natural products and can be used as a valuable
- envisaged that halogenation could be combined with the Baeyer–Villiger oxidation which yields the butyrolactones by excision of C5, a reaction which is tolerant to substitution at C3 and can be carried out on a kilogram scale [30]. The present work was focussed on the development of additional halogenation
- reactions for 5 to give substrates for the Baeyer–Villiger oxidation resulting in halogenated butyrolactones, which is an unexplored chemical space for this biomass derivative. Results and Discussion The halogenated LGO derivatives 7a and 7b were prepared using literature procedures [22][23]. The reaction
Enantioselective radical chemistry: a bright future ahead
Beilstein J. Org. Chem. 2025, 21, 2283–2296, doi:10.3762/bjoc.21.174
- are photoenzymatic catalysis and electrochemical oxidation or reduction. Free radicals can undergo several types of basic reactions (Figure 1B), including atom or group transfer, addition to a π-bond, and radical–radical combination. In an atom or group transfer reaction, an atom or group is
- oxidation or reduction of the radical yields a cationic or anionic intermediate that participates in a subsequent step through a polar mechanism. An important aspect of many of these radical reactions is that they can result in the formation of new carbon–carbon bonds, a fundamental goal in organic
- ]. MacMillan obtained chiral free radicals by stoichiometric single electron transfer (SET) oxidation of enamines, formed by the reaction between chiral secondary amines and aldehydes. This mode of activation was called SOMO (singly occupied molecular orbital) catalysis and was employed in several organic
Pathway economy in cyclization of 1,n-enynes
Beilstein J. Org. Chem. 2025, 21, 2260–2282, doi:10.3762/bjoc.21.173
- ]. Similar to “atom and step economies”, this concept emphasizes prioritizing the minimization of redox manipulations during synthesis to achieve linear and stable progression of oxidation states in intermediates. In recent years, “pot economy” and “time economy” were proposed by Hayashi, underscoring the
- 2, path b). In the following years, Liu and co-workers discovered that the protonation of intermediate 2 triggered its conversion to intermediate 3, which subsequently underwent oxidation with oxygen, resulting in the generation of an indenone skeleton 6 [9]. This tunability achieved efficient and
- radical initiated intramolecular cascade cyclization of 1,n-enynes to provide structurally diverse heterocycles (Scheme 4) [11]. Solvent selection dictated divergent reaction pathways under I2/TBHP oxidation. When an acetonitrile/water mixed solvent was used, iodine radical addition to the alkyne
A chiral LC–MS strategy for stereochemical assignment of natural products sharing a 3-methylpent-4-en-2-ol moiety in their terminal structures
Beilstein J. Org. Chem. 2025, 21, 2243–2249, doi:10.3762/bjoc.21.171
- methods. We had also independently re-isolated compound 1 (1.2 mg) from the fungus Fusarium sp. (see Supporting Information File 1) and subsequently subjected 100 μg of 1 to the sequential degradation steps; (1) p-nitrobenzoylation of the two hydroxy groups, (2) RuO4 oxidation to cleave olefins including
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
Beilstein J. Org. Chem. 2025, 21, 2220–2233, doi:10.3762/bjoc.21.169
- derivatives 10a,b exhibiting an extended aromatic ring system were isolated instead of the expected primarily formed congeners 11a,b, due to in situ oxidation of the C–C bond. Alternatively, when the one-pot method (method B, bismuth nitrate pentahydrate + PPA, MeOH, closed vial, 110 °C) was applied for the
Electrochemical cyclization of alkynes to construct five-membered nitrogen-heterocyclic rings
Beilstein J. Org. Chem. 2025, 21, 2173–2201, doi:10.3762/bjoc.21.166
- in 66%–87% yields. Boc-amino ester (2e), dipeptide (2f), apivalate ester (2g) and ethinyl estradiol (2h) skeletons were also tolerated well. According to the previous works [163] and the experimental results, the authors proposed a plausible mechanism. Firstly, the anodic oxidation of [Cp2Fe
- ][194][195][196][197][198][199][200], the authors proposed a possible reaction mechanism. For the synthesis of 11a in Pt plate electrodes, two-electron anodic oxidation of I− formed I+. Addition of I+ to C≡C in 10 resulted in the production of A. Meanwhile, continuous reduction of H2O at the cathode
- reaction also showed high compatibility with 2-naphthyl (15h), 2-thiophenyl (15i), ferrocenyl (15j), cyclohexenyl (15k) and tert-butyl (15l) incorporated at the ethynyl moiety. According to the results of control experiments, a plausible mechanism was presented. Firstly, one-electron oxidation of 14a
C2 to C6 biobased carbonyl platforms for fine chemistry
Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165
- promising strategy for sustainable energy development involves the electrochemical oxidation of biomass-derived feedstocks. Recent work by Shen et al. demonstrates that glycolic acid (GA), also referred to as hydroxyacetic acid, can be synthesized from glycerol (GLY) using a copper single-atom
- electrocatalyst supported on nitrogen-doped carbon nanosheets (Cu/NCNSs). This catalyst exhibits high activity for the oxidation of various substrates, including GLY, gluconic acid (GLU), 5-hydroxymethylfurfural (HMF), benzyl alcohol (BA), furfuryl alcohol (FA), and ethylene glycol (EG) (Scheme 7) [35]. Park et
- wettability (Scheme 11). The group of Gupta et al. investigated the kinetics of the oxidation by tetrachloroaurate(III) in acetic acid–sodium acetate buffer medium of some neutralized α-hydroxy acids, including glycolic acid (GA), lactic acid (LA), α-hydroxybutyric acid (IB), mandelic acid (MA), atrolactic
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
- modification of the terminal double bond afforded ketoaldehyde 31. The 2-bromoallylation [15] of 31 with boronic ester 32 stereoselectively constructed the C3–OH group to give homoallylic alcohol 33. Next, a successive manipulation by removal of TBS group, CSA-catalyzed ketalization, and DMP oxidation of the
- to ketone 48 via a seven-step transformation. Finally, removal of the TBS group in 48 followed by a sequential reduction and selective oxidation of allylic primary alcohol achieved the total synthesis of (−)-cyrneine A (7). The authors then moved forward to the synthesis of other target molecules
- (Scheme 3) [31][32]. Oxidation state adjustment of 48 led to the ketone 49. Starting from this common intermediate, firstly, base-promoted double bond migration and oxidation at the γ-position gave tertiary alcohol 50. Deprotection of acetyl in 50 followed by selective oxidation delivered (−)-cyrneine B
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
Beilstein J. Org. Chem. 2025, 21, 2072–2081, doi:10.3762/bjoc.21.162
- synthesis of natural products [10][55][56], in early 2009, our group disclosed a highly efficient four-step, enantioselective and diastereodivergent synthesis of (–)-chaetominine (1) and with one more step, of another diastereomer [57][58]. The strategy features a DMDO oxidation-triggered [59] double
- synthesis of diastereomers of versiquinazoline H: the fourth generation strategy In all our previous syntheses of chaetominine and isochaetominine alkaloids [57][58][60][61][62][63][64][65], the key DMDO-oxidation triggered double cyclization always accompanied with a monocyclization product. It was
- anticipated that if we run the work-up procedure under more basic conditions, one would be able to obtain solely double cyclization products. Indeed, alternation of the work-up protocol by employing an aged solution of K2CO3/MeOH (stood at rt overnight, pH 11) to quench the DMDO oxidation reaction of
Discovery of cytotoxic indolo[1,2-c]quinazoline derivatives through scaffold-based design
Beilstein J. Org. Chem. 2025, 21, 2062–2071, doi:10.3762/bjoc.21.161
- introduce the carboxylic acid group a sequence of formylation/oxidation reactions was used. Vilsmeier–Haack reaction of 1 afforded 6-oxoindolo[1,2-c]quinazoline-12-carbaldehyde (2) (Scheme 1). All attempts to oxidize the aldehyde group of 2 to the corresponding carboxylic acid were hampered by the oxidative
- sensitivity of the indole moiety, resulting in poor selectivity and formation of complex product mixtures. In particular, Jones oxidation of 2 gave the corresponding 6-oxoindolo[1,2-c]quinazoline-12-carboxylic acid (3) in a low yield (Scheme 1) making it necessary to look another synthetic pathway. Of
- interest, compound 2 applied as a useful substrate for a Baeyer–Villiger oxidation mediated by oxone, which selectively converted the aldehyde to the formate ester, yielding 6-oxo-5,6-dihydroindolo[1,2-c]quinazolin-12-yl formate (4). Subsequent hydrolysis of 4 furnished indolo[1,2-c]quinazoline-6,12-dione
Bioinspired total syntheses of natural products: a personal adventure
Beilstein J. Org. Chem. 2025, 21, 2048–2061, doi:10.3762/bjoc.21.160
- TBS protection in one pot. Oxidation of the primary alcohol using Swern oxidation gave the hydroxy aldehyde 3, which was activated with a formal silicon cation to trigger the Prins cyclization terminated by the tertiary alcohol, affording silylated bicycle 9 directly through the designed bioinspired
- form a cis-substituted tetrahydrofuran (THF) moiety fused to the lactone with higher oxidation states. Notably, the phenyl ring contains three oxygen substituents in the form of alcohol and methoxy groups at different positions. Biosynthetically, the THF ring was supposed to be formed through a
- benzylic oxidation to generate a para-quinone methide (pQM) intermediate. Using fusarentin 6-methyl ether as an example, pQM intermediate 10 would be generated. The C10 alcohol should successively undergo an oxa-Michael addition reaction to close the THF ring, providing 7-O-demethylmonocerin. Similarly
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
- internal nucleophiles (Scheme 4), that could be used instead of the alcohol. The carboxylic acid-containing silane 7 (R = COOH), which was obtained by stepwise oxidation of the alcohol 7d, failed to give the desired lactone 8t product due to O-arylation of the carboxylic acid, leading to phenyl alkyl ester
Photochemical reduction of acylimidazolium salts
Beilstein J. Org. Chem. 2025, 21, 1973–1983, doi:10.3762/bjoc.21.153
- suitably electrophilic substrate at the carboxylic acid oxidation level provides an acylazolium species B, which typically reacts directly with nucleophiles or may first be transformed into the corresponding enolate derivative. Regardless of the individual pathway, NHC-catalyzed reactions of this type
- acid derivative substrates [16]. Over the last few years, a wide range of valuable NHC-catalyzed transformations have also been developed that incorporate redox steps. As an enamine species, single-electron oxidation of a Breslow intermediate is comparatively favored with the resulting open shell
- 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
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
- sequence including oxidation and subsequent hydrogenation. The Huang group reported their synthesis of (+)-brazilin and its racemic form in 2022 (Scheme 5) [34]. They first evaluated the feasibility of the Prins/Friedel–Crafts tandem reaction in the construction of the 6/6/5/6 tetracyclic skeleton
- 139, epoxide 136 was first prepared from (R)-130 in two steps. Parikh–Doering oxidation of 136 followed by addition with Et2Zn in the presence of ligand 137 afforded alcohol 138, which was subsequently converted into amine 139 via a seven-step sequence. With the fragments 135 and 139 in hand
- ) and the following acid-mediated cyclization formed another tetrahydrofuran ring. The resulting compound was then converted into lactone 174 via 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO)-mediated oxidation. Lactone 174 was then converted into aldehyde 175 in three steps, which underwent Horner
Synthesis, biological and electrochemical evaluation of glycidyl esters of phosphorus acids as potential anticancer drugs
Beilstein J. Org. Chem. 2025, 21, 1909–1916, doi:10.3762/bjoc.21.148
- alkylating agents 1–3. The motivation behind these experiments was to explore whether these compounds, which individually exhibit no appreciable redox activity in the potential window applied, can chemically modify (alkylate) serum albumin and thus suppress its characteristic oxidation peaks. Human serum
- albumin was chosen as a model protein because of its well‐characterized structure and the presence of reactive sites that are known to be susceptible to alkylation. In standard aqueous media, the electrochemical oxidation of HSA can be observed via LSV as a broad wave, which is often attributed to the
- oxidation of amide and other amino acid side‐chain fragments. By tracking changes in this oxidation signal upon addition of an alkylating agent, we can infer whether the agent has effectively reacted with (and thus structurally altered) the protein. As illustrated by the black trace in the LSV plot, pure
Photoswitches beyond azobenzene: a beginner’s guide
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
- be synthesised through oxidation of aminoheteroarenes 12 (Scheme 4A) or reduction of nitroheteroarenes 13 (B). Bayer–Mills coupling (Scheme 4C) is suitable for both symmetric and asymmetric targets, usually in acidic conditions. Basic conditions [14] are more effective with very electron-poor
- , the synthesis can be directed towards the desired target with the use of protecting groups [41]. For the synthesis of azothiazoles 25, the addition of phenylhydrazine (22) to ammonium thiocyanate followed by ring closure and oxidation was recently proposed (Scheme 6A) [42]. Heteroarylazo-1,2,3
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