Oxidation of benzylic alcohols to carbonyls using N-heterocyclic stabilized λ³-iodanes

• Thomas J. Kuczmera,
• Pim Puylaert and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 1677–1683, doi:10.3762/bjoc.20.149

• decomposition for thiophenylmethanol 3y. Regarding the reaction mechanism, two plausible pathways can be discussed based on literature examples (Scheme 1, path a [17] and path b [33]). In either path, initial ligand exchange to the hydroxy(chloro)iodane I-OH is proposed. For getting an indication of a chloride

• the alkyl hypochlorite IIa. The second mechanism (path b) requires a direct ligand exchange of I-OH with the alcohol and subsequent β-elimination of the alkoxy(hydroxy)iodane IIb to form the desired aldehyde 4. Conclusion In conclusion, this study has successfully introduced N-heterocycle-stabilized

Methyltransferases from RiPP pathways: shaping the landscape of natural product chemistry

• Maria-Paula Schröder,
• Isabel P.-M. Pfeiffer and
• Silja Mordhorst

Beilstein J. Org. Chem. 2024, 20, 1652–1670, doi:10.3762/bjoc.20.147

• (Mg2+-dependent, metal-independent, cobalamin-dependent), common structural folds (class I–V, with class I being the largest group, characterised by the Rossmann fold) [58], or catalytic mechanism (SN2 mechanism, radical mechanism, Figure 3) [59]. This review categorises RiPP MTs based on the acceptor

• broad range of reactions [60]. There are different rSAM MT classes, description of the classes follows below in the C-MT section. Unlike conventional MTs, which follow an SN2 mechanism, rSAM MTs can methylate non-activated carbons. O-Methyltransferases The predominant group of MTs are O-MTs, which

• binding domain (CBD) at the N-terminus and an rSAM domain at the C-terminus (Figure 9) [119]. In addition to its different enzyme structure, a distinct mechanism of methylation than the classical SN2 mechanism is employed. Reductive cleavage of SAM generates a 5'-deoxyadenosyl (dAdo) radical, which

Polymer degrading marine Microbulbifer bacteria: an un(der)utilized source of chemical and biocatalytic novelty

• Weimao Zhong and
• Vinayak Agarwal

Beilstein J. Org. Chem. 2024, 20, 1635–1651, doi:10.3762/bjoc.20.146

• hydrolases and lyases, based on their enzymatic mechanism. ChSase B6 is a chondroitinase originally identified in marine Microbulbifer sp. ALW1 [60] and was cloned and expressed in E. coli. ChSase B6 could digest chondroitin sulfate B into disaccharides with good thermostability and stability against

• fundamentally signaling molecules and enzymatic modification of AQs by Microbulbifer could represent a mechanism of ecological cross-talk among marine microbiomes. Enzymatic halogenation of other signaling molecules, such as that of acyl homoserine lactones, has been postulated to modulate bacterial

Divergent role of PIDA and PIFA in the AlX₃ (X = Cl, Br) halogenation of 2-naphthol: a mechanistic study

• Kevin A. Juárez-Ornelas,
• Manuel Solís-Hernández,
• Pedro Navarro-Santos,
• J. Oscar C. Jiménez-Halla and
• César R. Solorio-Alvarado

Beilstein J. Org. Chem. 2024, 20, 1580–1589, doi:10.3762/bjoc.20.141

• Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Avenida Francisco J. Múgica S/N 58030, Morelia, Michoacán, México 10.3762/bjoc.20.141 Abstract The reaction mechanism for the chlorination and bromination of 2-naphthol with PIDA or PIFA and AlX3 (X = Cl, Br), previously

• reported by our group, was elucidated via quantum chemical calculations using density functional theory. The chlorination mechanism using PIFA and AlCl3 demonstrated a better experimental and theoretical yield compared to using PIDA. Additionally, the lowest-energy chlorinating species was characterized by

• energy than our proposed species. The reaction mechanisms are described in detail in this work and were found to be in excellent agreement with the experimental yield. These initial results confirmed that our proposed mechanism was energetically favored and therefore more plausible compared to

Electrocatalytic hydrogenation of cyanoarenes, nitroarenes, quinolines, and pyridines under mild conditions with a proton-exchange membrane reactor

• Koichi Mitsudo,
• Atsushi Osaki,
• Haruka Inoue,
• Eisuke Sato,
• Naoki Shida,
• Mahito Atobe and
• Seiji Suga

Beilstein J. Org. Chem. 2024, 20, 1560–1571, doi:10.3762/bjoc.20.139

• ; however, the generation of 3a was not completely suppressed (Table 1, entry 6). The use of CH2Cl2/2,2,2-trifluoroethanol (TFE) gave similar results (Table 1, entry 7). A plausible mechanism for the reduction of 1a is shown in Scheme 1. First, the reduction of 1a afforded phenylmethanimine (A). Further

• H2 gas, 100 mL min−1; reaction temperature, room temperature; current density, 50 mA cm−2 (10 h). The solution was circulated until the passage of 50 F mol−1. The yields were determined by 1H NMR analysis using 1,1,2,2-tetrachloroethane as an internal standard. Plausible mechanism for the reduction

Benzylic C(sp³)–H fluorination

• Alexander P. Atkins,
• Alice C. Dean and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 1527–1547, doi:10.3762/bjoc.20.137

• for the efficient monofluorination of 4- and 2-alkylpyridines (Figure 4 – conditions [A]) [36]. The transformation relied on the polarisation of the heterobenzylic C–H bond, via the intermediate formation of an N-sulphonylpyridinium salt, to promote deprotonation. Following a polar mechanism with

• excess NFSI, the heterobenzyl fluoride is obtained. In the case of product 3, the authors suggested that the absence of radical clock rearrangement products supported a polar mechanism. Conveniently, when both benzylic and heterobenzylic C–H bonds were present in a substrate, the reaction was selective

• selective for primary benzylic fluorination (11) and secondary benzylic fluorination (12) in the presence of tertiary benzylic sites. Although no mechanism has been proposed, the authors concluded it likely proceeded via a radical pathway [23]. In 2017, Baxter and co-workers introduced a silver-catalysed

Primary amine-catalyzed enantioselective 1,4-Michael addition reaction of pyrazolin-5-ones to α,β-unsaturated ketones

• Pooja Goyal,
• Akhil K. Dubey,
• Raghunath Chowdhury and
• Amey Wadawale

Beilstein J. Org. Chem. 2024, 20, 1518–1526, doi:10.3762/bjoc.20.136

• measured by HPLC analysis using a stationary phase chiral column. Synthesis of 3aa on preparative scale. Proposed reaction mechanism. Optimization of reaction conditions.a Supporting Information Supporting Information File 2: Additional optimization studies, characterization data of compounds 3aa–na and

Tetrabutylammonium iodide-catalyzed oxidative α-azidation of β-ketocarbonyl compounds using sodium azide

• Christopher Mairhofer,
• David Naderer and
• Mario Waser

Beilstein J. Org. Chem. 2024, 20, 1510–1517, doi:10.3762/bjoc.20.135

• insights we also carried out our standard reaction (Table 1, entry 14) in the presence of well-established radical traps like TEMPO, di-tert-butylhydroxytoluene (BHT), or 1,1-diphenylethene (DPE). In neither case any influence on the yield was observed, thus ruling out a mechanism involving radical species

Photoswitchable glycoligands targeting Pseudomonas aeruginosa LecA

• Yu Fan,
• Ahmed El Rhaz,
• Stéphane Maisonneuve,
• Emilie Gillon,
• Maha Fatthalla,
• Franck Le Bideau,
• Guillaume Laurent,
• Samir Messaoudi,
• Anne Imberty and
• Juan Xie

Beilstein J. Org. Chem. 2024, 20, 1486–1496, doi:10.3762/bjoc.20.132

• rather similar Kd values. In order to rationalize this difference in binding mechanism, molecular models were obtained for selected low-energy conformations of E- and Z-isomers of a “model” scaffold of the para-azobenzene derivative in the binding site of LecA (Figure 5), by simple superpositioning of

Bioinformatic prediction of the stereoselectivity of modular polyketide synthase: an update of the sequence motifs in ketoreductase domain

• Changjun Xiang,
• Shunyu Yao,
• Ruoyu Wang and
• Lihan Zhang

Beilstein J. Org. Chem. 2024, 20, 1476–1485, doi:10.3762/bjoc.20.131

• , based on the syn-elimination mechanism, the ʟ-α-methyl,ʟ-β-hydroxy substrate produced by A2-type KR can also result in a trans (E) double bond [18][22], and some DH domains are reported to have epimerase activity on the α-substitution [23]. Thus, the stereochemical outcomes of KRs in γ- and δ-modules

• either A2- or B2-KRs, but are likely to contain mutations in NADPH binding site [31]. Sequence logo analysis of KRC from γ- and δ-modules In the actinobacterial γ- and δ-modules, the stereochemical outcome of a KR is obscured by further dehydration catalyzed by DH. The dehydration mechanism by DH has

• been investigated in several DH domains, which all follow the syn-elimination mechanism [5][21][33]. Based on the product configuration, we classified DHs into two types, E-type DHs (trans-double bond) and Z-type DHs (cis-double bond) and analyzed sequence logos of the DH-associated KRs. The sequence

Selectfluor and alcohol-mediated synthesis of bicyclic oxyfluorination compounds by Wagner–Meerwein rearrangement

• Ziya Dağalan,
• Muhammed Hanifi Çelikoğlu,
• Saffet Çelik,
• Ramazan Koçak and
• Bilal Nişancı

Beilstein J. Org. Chem. 2024, 20, 1462–1467, doi:10.3762/bjoc.20.129

• compounds 4a–j were also obtained in very good yields (60–98%, Scheme 2). Since the reaction mechanism proceeding with a Wagner–Meerwein rearrangement does not cause racemization or a diastereomeric mixture and preserves the initial enantiomeric excess in the camphene's fluoroalkoxy derivatives (Scheme 4

• mmol), scale-up experiments were conducted. The isolated yield of 4b (1.26 g, 90% yield) is quite satisfactory, as can be seen from Scheme 3. For the fluoroalkoxylation, we propose the mechanism given in Scheme 4. In this mechanism, first the double bond in (+)-camphene attacks the fluorine in the

• alcohol in 2 mL of CH3CN at 90 °C for 2 h. Isolated yields. Scale-up experiments. Reaction conditions: (+)-Camphene (1b) (1.0 g, 7.34 mmol), selectfluor (3.12 g, 8.81 mmol), MeOH (17.62 mmol), CH3CN (20 mL), 90 °C, 2 h. Proposed mechanism for fluoroalkoxylation of (+)-camphene by Wagner–Meerwein

Synthesis of 4-functionalized pyrazoles via oxidative thio- or selenocyanation mediated by PhICl₂ and NH₄SCN/KSeCN

• Jialiang Wu,
• Haofeng Shi,
• Xuemin Li,
• Jiaxin He,
• Chen Zhang,
• Fengxia Sun and
• Yunfei Du

Beilstein J. Org. Chem. 2024, 20, 1453–1461, doi:10.3762/bjoc.20.128

• by treatment with CH3MgBr in THF [56] (Scheme 4). Based on the previous reports [54][57][58][59], a possible mechanism of this selenocyanation reaction was proposed (Scheme 5). First, the reaction of PhICl2 with KSeCN produces selenocyanogen chloride (Cl–SeCN), which further reacts with selenocyanate

• 3a and their derivatization. Plausible reaction mechanism. Optimization of oxidative thiocyanation of pyrazole.a Supporting Information Supporting Information File 28: Synthetic details and compound characterization data. Funding We acknowledge the National Key Research and Development Program of

Rapid construction of tricyclic tetrahydrocyclopenta[4,5]pyrrolo[2,3-b]pyridine via isocyanide-based multicomponent reaction

• Xiu-Yu Chen,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2024, 20, 1436–1443, doi:10.3762/bjoc.20.126

• -position of the o-methoxyphenyl group. Therefore, compound 6g has the same relative configuration to that of the above mentioned product 3a, which also indicated that this reaction has same steric controlling effect. A plausible reaction mechanism is proposed in Scheme 1 to explain the formation of the

• . Molecular structure of compound 4a. Molecular structure of compound 6g. Proposed reaction mechanism. Optimizing reaction conditionsa. The synthesis of the tricyclic compounds 4a–ta. The synthesis of the tricyclic compounds 6a–ka. Supporting Information The crystallographic data of the compounds 4a (CCDC

Synthesis of cyclic β-1,6-oligosaccharides from glucosamine monomers by electrochemical polyglycosylation

• Md Azadur Rahman,
• Hirofumi Endo,
• Takashi Yamamoto,
• Shoma Okushiba,
• Norihiko Sasaki and
• Toshiki Nokami

Beilstein J. Org. Chem. 2024, 20, 1421–1427, doi:10.3762/bjoc.20.124

• product of monomer 6. The proposed mechanism is shown in Scheme 2. Anodic oxidation of thioglycoside 6 generated radical cation 11, which was converted to glycosyl triflate 12. 1,6-Anhydrosugar 7 was produced via 4C1-to-1C4 conformational change of the pyran ring to generate cation intermediate 13

• rate: 7.5 mL/min, recycle numbers: 3) to obtain pure cyclic oligosaccharide 16 (0.125 mmol, 79.7 mg, 62%). Preparation of cyclic oligoglucosamines a) via intramolecular glycosylation and b) via polyglycosylation and intramolecular glycosylation. Proposed reaction mechanism of the formation of 1,6

• -anhydrosugar 7. Electrochemical polyglycosylation of monomer 14 with a 2,3-oxazolidinone protecting group. Proposed reaction mechanism of the formation of cyclic trisaccharide 19a. Influence of the functional group in position C-2 on the formation of the cyclic product. Electrochemical polyglycosylation of

Challenge N- versus O-six-membered annulation: FeCl₃-catalyzed synthesis of heterocyclic N,O-aminals

• Giacomo Mari,
• Lucia De Crescentini,
• Gianfranco Favi,
• Fabio Mantellini,
• Diego Olivieri and
• Stefania Santeusanio

Beilstein J. Org. Chem. 2024, 20, 1412–1420, doi:10.3762/bjoc.20.123

• content of the reaction environment during the time. Then, to explain the related formation of 5 and 6, we hypothesized a plausible reaction mechanism in which iron is involved in two concomitant catalytic cycles (Scheme 4). Initially, FeCl3 forms an acid–base complex with one of the alkoxy groups of 4

• suitably N-3-functionalized (thio)hydantoins 4a–r. aDCM was utilized as solvent with isothiocyanates 3a–f, while bEtOH was utilized with isocyanates 3g,h. Substrate scope of the iron(III)-catalyzed synthesis of functionalized heterocyclic N,O-aminals 5a–r and hemiaminals 6a–p. Proposed mechanism for the

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• % enantioselectivity. They employed a double asymmetric induction with (+)/(−)-menthol (12), and CuX2 bis(oxazoline) catalyst where the corresponding chiral mandelate ester 13 was obtained in 81% yield and high selectivity (90% de) (Scheme 6). The proposed mechanism of the reaction is depicted below. Hong et al

• (R1 and R2) were obtained in good to excellent yields witnessing the feasibility of the methodology (Scheme 25). The mechanism depicting the proposed strategy for the Cannizzaro-aldol transformation involves an initial Cannizzaro reaction between paraformaldehyde and the isatin substrate, followed by

• aspects. The application of this highly valuable reaction to the functionalization of bioactive molecules with improved synthetic conditions, will broaden its use in the future. Types and mechanism of the Cannizzaro reaction. Various approaches of the Cannizzaro reaction. Representative molecules

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• facilitate important chemical reactions. Thus, we will focus on the reports detailing organic transformations that proceed via visible-light-induced deoxygenative generation of acyl radicals from carboxylic acids and acid anhydrides that have appeared since 2019. Review General mechanism of photoredox

• catalysis In recent times, visible-light-mediated photoredox chemistry has evolved as a unique tool for various organic transformations. In contrast to traditional catalysis, the photochemical process uses an electron or energy transfer mechanism to form reactive intermediates. Typically, a photocatalyst is

• conventional metal hydrides, such as tin or silicon hydrides. The reaction mechanism is interesting since first, a Lewis acid–base adduct is generated by interaction of Et3N with a boron atom of bis(catecholato)diboron (B2cat2, 19). As a result, one of the catecholate ligands experiences an increase in

Rhodium-catalyzed homo-coupling reaction of aryl Grignard reagents and its application for the synthesis of an integrin inhibitor

• Kazuyuki Sato,
• Satoki Teranishi,
• Atsushi Sakaue,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai,
• Hiroyuki Takeda,
• Tatsuo Kinashi and
• Masaaki Omote

Beilstein J. Org. Chem. 2024, 20, 1341–1347, doi:10.3762/bjoc.20.118

• previous results [21][22]. Consequently, we propose the reaction mechanism as shown in Figure 2. In the initial step, the Rh catalyst reacts with the Grignard reagent 4 to give the Rh(I)–aryl complex 7. Oxidative addition of 1,2-dibromoethane onto complex 7 then generates Rh(III)–aryl complex 8 along with

• . Conditions: a) The reaction was carried out at rt for 1–3 h without Mg. b) The side product 6h by SNAr reaction onto 3h was obtained in 8%. Tentative reaction mechanism. Ullmann and Ullmann-type homo-coupling reactions. Rh-catalyzed homo-coupling reactions. Rh-catalyzed homo-coupling reaction by using

Synthesis of 1,2,3-triazoles containing an allomaltol moiety from substituted pyrano[2,3-d]isoxazolones via base-promoted Boulton–Katritzky rearrangement

• Constantine V. Milyutin,
• Andrey N. Komogortsev and
• Boris V. Lichitsky

Beilstein J. Org. Chem. 2024, 20, 1334–1340, doi:10.3762/bjoc.20.117

• spectroscopy and high-resolution mass spectrometry. Moreover, X-ray analysis was used for confirmation of structure of compound 4g (Figure 1). A plausible mechanism of the studied rearrangement is presented in Scheme 5. At first, anion A is generated from starting hydrazone 3 under action of base. Next

• obtained the recyclized product 6a (Scheme 6), whose structure was confirmed by 1H, 13C NMR spectroscopy, high-resolution mass spectrometry and X-ray analysis. Based on the aforementioned reaction we have synthesized a set of pyrazolylisoxazoles 6 (Scheme 7). The proposed mechanism of investigated

• hydrazone 3a. Synthesis of hydrazone 3b using phenylhydrazine hydrochloride. Synthesis of target 1,2,3-triazoles 4. Reaction conditions: 1 (0.5 mmol), arylhydrazine hydrochloride (0.55 mmol), EtOH (5 ml), then K2CO3 (1.5 mmol, 0.21 g), EtOH (5 ml). Proposed reaction mechanism. Reaction of 1d with hydrazine

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116

• , providing the corresponding product 3aa in 74% yield. Several control experiments were conducted to gain insight into the reaction mechanism of the electroreductive process. The hydroarylation of cyclopropane-substituted styrene 2l resulted in the formation of ring-opening product 3al’, and the simple

• electroreductive reaction would proceed through a reductive radical-polar crossover pathway [57]. On the basis of mechanistic investigations and a literature report [47], a plausible mechanism for this electroreductive hydroarylation is depicted in Scheme 4. 1,3-DCB (Ep/2 = −1.9 V vs SCE in MeCN) [58] undergoes

• ), 1,3-DCB (50 mol %), H2O (5.0 mmol), Et4NCl (0.1 mmol), MeCN (3 mL), Al(+)-Pt(−), 7.5 mA/cm2, 4.5 F/mol, 0 °C, blue LEDs. a4.5 F/mol. b2 (5 equiv). cMeCN (3 mL). d5 F/mol. 1,3-DCB, 1,3-dicyanobenzene. Gram-scale reaction and control experiments. Plausible mechanism. Evaluation of reaction conditions.a

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• 2.160 Å. These bond lengths support path I, which is a more valid pathway in the reaction mechanism. As can be seen in Figure 4, the energies of both the exo transition state and the exo product are lower than those of the endo, which also supports the experimental results. Conclusion Vegetable oils

• , 47.03, 45.86; Anal calcd for C16H15NO4 (285.30): C, 67.36; H, 5.30; N, 4.91; found: C, 67.30; H, 5.26; N, 4.86. Reaction yields after seven uses of SSO and average recovery of the oil. Coupling constants of selected protons in compound 2a and its optimized geometric structure. Possible mechanism for the

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• triethylamine in methanol afforded benzocoumarines 18a–ac (Scheme 4) [33][34]. The formation of the product, which was obtained in a two-step one-pot reaction, can be explained by a mechanism similar to the one discussed for the formation of 17. 1,4-Addition gave intermediate D which was isolated, but used in

• -butadienes The reaction of 3-formyl- and 3-acetylchromones 10a–i with 1,3-bis(silyloxy)-1,3-butadienes 6a–h, catalysed by Me3SiOTf, afforded hydroxylated benzophenones 20a–ag (Scheme 6) [35][36]. The products are formed by a mechanism related to the one discussed for the formation of products 19a–d. The same

• with 1,3-bis(silyloxy)-1,3-butadienes 6a–z afforded azaxanthones 41a–am (Scheme 23) [45][46]. The formation of the products can be explained by the mechanism discussed for the formation of azaxanthone 40 that involves intermediates AF and AG. For most products, the yields were in the range of 30 to 66

Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis

• Johannes Rocker,
• Till J. B. Zähringer,
• Matthias Schmitz,
• Till Opatz and
• Christoph Kerzig

Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106

• cation was directly observed confirming the previously proposed mechanism of a three-component reaction. Several steps of the photoredox cycle were investigated separately, providing deep insights into the complex mechanism. The triplet-excited Aza-H, which was studied with quantitative LFP, is formed

• mechanism of the recently reported sulfonylation/arylation [45][46] reaction using laser flash photolysis (LFP). LFP is a powerful spectroscopic tool in photocatalysis that allows us not only to distinguish between energy and electron transfer but also to detect transient triplet states and radicals

• , yielding clear-cut evidence for the proposed reaction mechanism [47][48][49][50][51][52][53][54][55][56][57]. We found that quenching of the singlet-excited Aza-H by 4-cyanopyridine is the main pathway for the 3-CR, while the triplet state of our catalyst, which is formed with a quantum yield as high as

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• been used in oxyselenenylation of olefins, which follows an electrophilic addition mechanism [23][24][25]. However, such reagents are rarely used for electrophilic substitution of aromatic systems. Recently, notable progress has been made in the use of aromatic electrophilic substitution to synthesize

• after 24 h. Whereas at the same molar ratio, polymers 1 and 2 were obtained in larger quantities of ≈2.3 g after the short time of 3 h (see Experimental section for details). Mechanistic aspects Mechanism for the formation of diaryl monoselenides The plausible mechanism for the formation of diaryl

• rise to either diaryl selenoxide via dehydration or diaryl monoselenide via reductive elimination by eliminating H2O2 [39]. Observation of m/z peaks for compound 8 clearly confirmed the formation of diaryl selenoxide in the reaction. Mechanism for the formation of oxamides The possible reaction

Cofactor-independent C–C bond cleavage reactions catalyzed by the AlpJ family of oxygenases in atypical angucycline biosynthesis

• Jinmin Gao,
• Liyuan Li,
• Shijie Shen,
• Guomin Ai,
• Bin Wang,
• Fang Guo,
• Tongjian Yang,
• Hui Han,
• Zhengren Xu,
• Guohui Pan and
• Keqiang Fan

Beilstein J. Org. Chem. 2024, 20, 1198–1206, doi:10.3762/bjoc.20.102

• -dependent reactions of AlpJ-family oxygenases. Furthermore, the AlpJ- and JadG-catalyzed reactions of CR1 could be quenched by superoxide dismutase, supporting a catalytic mechanism wherein the substrate CR1 reductively activates molecular oxygen, generating a substrate radical and the superoxide anion O2

• •−. Our findings illuminate a substrate-controlled catalytic mechanism of AlpJ-family oxygenases, expanding the realm of cofactor-independent oxygenases. Notably, AlpJ-family oxygenases stand as a pioneering example of enzymes capable of catalyzing oxidative reactions in either an FADH2/FMNH2-dependent or

• bond cleavage, ring opening, and rearrangement reactions, yielding the respective products. Furthermore, the reactions of 8 catalyzed by JadG and AlpJ could be quenched by superoxide dismutase (SOD), supporting a catalytic mechanism involving the generation of a substrate radical and the superoxide