Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• glutamate decarboxylase, and incubated with BaeJ-KS2. Substrate binding was demonstrated through 13C NMR analysis of the products against the background of various control experiments. Keywords: bacillaene; biosynthesis; enzyme mechanisms; isotopes; trans-AT polyketide synthases; Introduction Polyketides

Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines

• Geng-Xin Liu,
• Xiao-Ting Jie,
• Ge-Jun Niu,
• Li-Sheng Yang,
• Xing-Lin Li,
• Jian Luo and
• Wen-Hao Hu

Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59

• (TEMPO) and the corresponding radical-trapping product A could be confirmed by HRMS of both reaction mixtures, unambiguously supporting radical mechanisms (Scheme 4a). The reaction with styrene was conducted under standard conditions, but no product X could be detected, indicating the cationic

• amine and the traces amount of water in this reaction system may serve as proton sources for the formation of hybrid α-ester alkylpalladium radical. On the basis of above mechanistic studies and previous reports [47][48][49][50][52][58], the following plausible mechanisms are proposed for the palladium

• ) Radical trapping experiments with TEMPO. b) Exclusion of possible intermediate. c) Subjecting the product Z-6i to the standard conditions. d) The control reaction with HPd(PPh3)2Cl. e) UV–visible absorption analysis. Proposed mechanisms for the carboamination of 1,3-dienes or allenes with diazo esters and

Enhanced reactivity of Li⁺@C₆₀ toward thermal [2 + 2] cycloaddition by encapsulated Li⁺ Lewis acid

• Hiroshi Ueno,
• Yu Yamazaki,
• Hiroshi Okada,
• Fuminori Misaizu,
• Ken Kokubo and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2024, 20, 653–660, doi:10.3762/bjoc.20.58

• +) reference couple. Working electrode: Pt, counter electrode: Pt, reference electrode: Ag/Ag+ in acetonitrile, solvent: o-dichlorobenzene, supporting electrolyte: 50 mM TBAPF6. Reaction mechanisms of thermal and photoinduced [2 + 2] cycloaddition on C60 [19][22][23]. Thermal [2 + 2] reaction of Li+@C60 TFSI

Production of non-natural 5-methylorsellinate-derived meroterpenoids in Aspergillus oryzae

• Jia Tang,
• Yixiang Zhang and
• Yudai Matsuda

Beilstein J. Org. Chem. 2024, 20, 638–644, doi:10.3762/bjoc.20.56

• the structures of 1 and 2 were deduced based on their HRMS spectra and the predicted biosynthetic pathway. Biosynthetic mechanisms of the 5-MOA-derived meroterpenoids obtained in this study. In the reaction by InsA7, the cyclization should proceed via a pre-boat-chair conformation, and the

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• gene cluster for compounds 1 and 2, highlighting ShnA, ShnB, ShnC, ShnD, and ShnE as core genes. B: The diagram proposes biosynthetic pathways for compounds 1 and 2, detailing three potential mechanisms that could convert the five-membered ring structure of compound 2 into the six-membered ring

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• that no new atoms are introduced into the molecule, thus ensuring first-order kinetics of the process without complexity. One of the possible mechanisms of redox-induced switching involves an intramolecular bond formation that introduces non-covalent interactions between tweezers endpoints leading to a

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• competing Brønsted acid catalysis in gold-catalyzed alkene functionalization remains a consideration [2], and while it is assumed that alkene activations follow the same prototypical mechanisms as allene and alkyne activations, that is (1) π-activation with nucleophilic attack followed by (2

• gold and HOTf, however, they are not easily explained by simple either/or mechanisms [14][32][33]. Due in part to optimization challenges and in part to remaining gaps in characterizing structure–activity relationships for alkene hydroamination, we sought to obtain additional understanding by

• -withdrawing substituents accelerate the reaction. Within the binary paradigm of gold-catalyzed mechanisms, where either π-activation or protodeauration is rate limiting, this electronic effect would suggest rate limiting π-activation [40], since protodeauration is fastest with strong donor ligands (tert

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• 1,3-diphenylpropane-1,3-dione with Selectfluor. Synthesis of 2,2-difluoro-1,3-diphenylpropane-1,3-dione (3a). Proposed mechanism of the quinuclidine-mediated difluorination of 1,3-dicarbonyl substrates. Proposed mechanisms of carbonate and chloride ion-mediated difluorination of 1,3-dicarbonyl

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• catalyst due to present moisture or formation of adducts with the substrate, long reaction times, lower yields, and production of large amounts of toxic waste during work-up. The general mechanisms of protic acid and Lewis acid-catalyzed syntheses of BIMs is shown in Scheme 2. In either case, the first

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

• of parameters with which to control reactivity. In this perspective, we provide an overview of the different mechanisms for radical reactions involving NHPI esters, with an emphasis on recent applications in radical additions, cyclizations and decarboxylative cross-coupling reactions. Within these

• reaction classes, we discuss the utility of the NHPI esters, with an eye towards their continued development in complexity-generating transformations. Keywords: decarboxylative couplings; mechanisms; NHPI-esters; radical reactions; Introduction The historical challenges of using radicals in synthetic

• , which incorporate both radical and ionic bond-forming steps into a single synthetic operation [16][17]. The success of radical reactions is intimately linked to the mechanisms of their initiation and the radical progenitor employed. Amongst the many progenitors that are available, carboxylic acids are

Catalytic multi-step domino and one-pot reactions

• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2024, 20, 254–256, doi:10.3762/bjoc.20.25

• through concerted or stepwise mechanisms. An enantioselective palladium-catalyzed three-component reaction of glyoxylic acid, sulfonamides, and aryltrifluoroborates toward synthetically useful α-arylglycine compounds is described by the Manolikakes group [11]. Moreover, Šebesta and co-workers report a

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• thermal half-lives of the photoisomers range from seconds to days. Detailed photophysical and photochemical studies have provided insight into the photoswitching mechanisms of indigo derivatives and enabled control of their photochemical properties through targeted design of the molecular structure. The

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• ]quinolizinium ions 3b–g (yields in % refer to isolated products). Proposed mechanisms for the photoinduced DNA damage initiated by photoexcitation of benzoquinolizinium 3f. Absorption and emission maxima of 3c–g in the absence and presence of ct DNA and binding constants of their complexes with ct DNA. Gel

Electron-beam-promoted fullerene dimerization in nanotubes: insights from DFT computations

• Laura Abella,
• Gerard Novell-Leruth,
• Josep M. Ricart,
• Josep M. Poblet and
• Antonio Rodríguez-Fortea

Beilstein J. Org. Chem. 2024, 20, 92–100, doi:10.3762/bjoc.20.10

• singlet state [10]. Although only a few analyses of the reaction mechanisms have been studied due to the complexity of the system, several intermediates inside the CNT have been proposed [3][11][12], which may be different from those proposed to take place in the gas phase or in the solid state at high

• pressures and high temperatures [13][14][15]. We aim to shed light in these reaction mechanisms and energy profiles by using complementary methodologies as standard density functional theory (DFT) calculations and first-principles Car–Parrinello molecular dynamics (CPMD) simulations. Firstly, we have

Beyond n-dopants for organic semiconductors: use of bibenzo[d]imidazoles in UV-promoted dehalogenation reactions of organic halides

• Kan Tang,
• Megan R. Brown,
• Chad Risko,
• Melissa K. Gish,
• Garry Rumbles,
• Phuc H. Pham,
• Oana R. Luca,
• Stephen Barlow and
• Seth R. Marder

Beilstein J. Org. Chem. 2023, 19, 1912–1922, doi:10.3762/bjoc.19.142

• -zero intercept, a behavior which conforms with a rate law consisting of the sum of two terms, one first order in [D2] and one first order in both [D2] and [RX] and is similar to doping behavior we have recently seen for some weakly bonded dimers where both “cleavage-first” and “ET-first” mechanisms are

• -iodobenzyl chloride. Reaction mechanisms for the reactions of dimeric reductants (D2) such as (Y-DMBI)2 derivatives with acceptors (A) such as organic semiconductors or, in this work, organic halides that react further (the relative rates of steps are indicated for cases where the A reduction potential falls

Anion–π catalysis on carbon allotropes

• M. Ángeles Gutiérrez López,
• Mei-Ling Tan,
• Giacomo Renno,
• Augustina Jozeliūnaitė,
• J. Jonathan Nué-Martinez,
• Javier Lopez-Andarias,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2023, 19, 1881–1894, doi:10.3762/bjoc.19.140

• consistent with the existence of OEEF catalysis with a destabilized transition state XIX. It also disfavored contributions from SN1-type mechanisms and, most important, from electron transfer. Anion–π catalysis on graphite Beginning with spherical fullerenes, expansion of the aromatic surface of carbon

Recent advancements in iodide/phosphine-mediated photoredox radical reactions

• Tinglan Liu,
• Yu Zhou,
• Junhong Tang and
• Chengming Wang

Beilstein J. Org. Chem. 2023, 19, 1785–1803, doi:10.3762/bjoc.19.131

• advancements in the iodide/phosphine catalytic photoredox system. The primary focus of the paper is to delve into the unique catalytic reactivity exhibited by the iodide/phosphine photoredox system, while also exploring potential reaction mechanisms. It is mainly organized around different types of reactions

• -involved reactions is crucial for gaining a deeper understanding of their underlying mechanisms and expediting the process of designing new reactions. Overall, addressing these challenges and advancing the field through innovative approaches and mechanistic insights will contribute to the continued

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• should focus on understanding degradation mechanisms, developing effective device encapsulation strategies, and ensuring environmental compatibility to guarantee sustained performance and viability in commercial applications. Additionally, scalability and cost-effective manufacturing processes are key

Benzoimidazolium-derived dimeric and hydride n-dopants for organic electron-transport materials: impact of substitution on structures, electrochemistry, and reactivity

• Swagat K. Mohapatra,
• Khaled Al Kurdi,
• Samik Jhulki,
• Georgii Bogdanov,
• John Bacsa,
• Maxwell Conte,
• Tatiana V. Timofeeva,
• Seth R. Marder and
• Stephen Barlow

Beilstein J. Org. Chem. 2023, 19, 1651–1663, doi:10.3762/bjoc.19.121

• by various quinone derivatives [63]. For both mechanisms, the first steps are typically rate determining and thus, in general, the rate law is: where k1 and k2 are rate constants for the first steps of the “cleavage first” and “ET-first” pathways respectively, k1 being negligible in the case of

• the rise in VII•– absorption is neither zero-order nor first-order in VII, consistent with both mechanisms contributing, as previously demonstrated by more extensive investigations in the case of 1c2, 1d2, and (RhCp*Cp)2 [14][61]. Thus, the Y = alkyl derivative (1h2, “ET-first” only) appears to be

• more strongly bonded than its Y = aryl counterparts (1b2, 1g2, both mechanisms), consistent with previous DFT calculations for 1b2 and 1e2 (ΔUdiss = 163 and 210 kJ mol–1, respectively) and with the expected impact of the different Y substituents on monomer radical stability. In addition, the reaction

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• Freund's adjuvant-induced arthritis in rats [12]. However, the molecular mechanisms of these anti-inflammatory effects have not been investigated. In our ongoing search for bioactive natural products, we have isolated three new spiroketals – breynin J (1), epibreynin J (2), and probreynogenin (3) – and

Radical chemistry in polymer science: an overview and recent advances

• Zixiao Wang,
• Feichen Cui,
• Yang Sui and
• Jiajun Yan

Beilstein J. Org. Chem. 2023, 19, 1580–1603, doi:10.3762/bjoc.19.116

• considered to have two mechanisms, degenerative transfer and reversible termination, which are comparable to RAFT and NMP, respectively (Scheme 7) [70]. Iodine transfer polymerization (ITP) is also a commonly used degenerate chain-transfer method. Its origin can be traced back to the 1970s [71] and it is

• using benzophenone. Depolymerization mechanism of common photoresists. (a) A possible mechanism of radiation decomposition of poly(methyl methacrylate). (b) A proposed mechanism of simultaneous radical/cationic decomposition of poly(olefin sulfone) upon radiation [197]. Proposed mechanisms of

Unraveling the role of prenyl side-chain interactions in stabilizing the secondary carbocation in the biosynthesis of variexenol B

• Moe Nakano,
• Rintaro Gemma and
• Hajime Sato

Beilstein J. Org. Chem. 2023, 19, 1503–1510, doi:10.3762/bjoc.19.107

• . Several terpene cyclizations with an exomethylene group are known, such as with caryolene and crotinsulidane diterpenoids, and the reaction mechanisms have been analyzed [27][28][29][30]. It would be interesting to see how the exomethylene group reacts in the cyclization of variexenol B. In this study, we

• follow similar reaction mechanisms, however, when comparing path a and path b, the most striking energy difference is in the step from IM2a/b to IM3a/b (Figure 2B). The energy barrier of this step is 6.3 kcal/mol for path a, whereas 13.6 kcal/mol for path b, with a difference of 7.3 kcal/mol. Although

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• is no need to use a metal catalyst, base, or additive. N-(Sulfenyl)succinimide/phthalimide acted as an active electrophilic sulfur source, acted in the reaction mechanisms. However, mechanistic studies need further exploration to define a valid reaction pathway. Therefore, we believe that the use of

Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid

• Vladislav A. Sokolov,
• Andrei A. Golushko,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2023, 19, 1460–1470, doi:10.3762/bjoc.19.105

• mechanisms for the cyclization of compounds 1 and 2 into indanones 3 in TfOH (Scheme 7). Protonation of the carbonyl oxygen of enone 2 gives rise to cation B which is followed by cyclization into indanone 3 through mesomeric form B'. The hydroxy ketone 1 is protonated at the oxygen atoms leading to cation A

• -4,4,4-trichlorobut-2-en-1-ones 2 into 3-trichloromethylindan-1-ones 3 in TfOH. Cyclization of 1-aryl-4,4,4-trichloro-3-hydroxybutan-1-ones 1 into 3-trichloromethylindan-1-ones 3 in TfOH. Plausible mechanisms for the cyclization of compounds 1 and 2 into indanones 3 in TfOH. Transformations of hydroxy

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• modulation of membrane proteins that represent a pertinent strategy for some diseases like cancers. Beside the use of synthetic ether lipids for the prevention or the treatment of cancers via different mechanisms, it must be noted that some synthetic ether lipids (e.g., Ino-C2-PAF) have also the ability to