Development of a chemical scaffold for inhibiting nonribosomal peptide synthetases in live bacterial cells

• Fumihiro Ishikawa,
• Sho Konno,
• Hideaki Kakeya and
• Genzoh Tanabe

Beilstein J. Org. Chem. 2024, 20, 445–451, doi:10.3762/bjoc.20.39

• modular synthases [5]. They used the inhibitors of individual domains to investigate the biosynthetic pathway of blue pigment synthetase A, which produces the blue pigment indigoidine, and demonstrated that their results complement the proposed biosynthetic pathway. Furthermore, among the catalytic domain

Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives

• Nahed Ketata,
• Linhao Liu,
• Ridha Ben Salem and
• Henri Doucet

Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37

• (Table 1, entries 14–16). The decisive influence of the base for this reaction is probably due to a concerted metalation–deprotonation mechanism [27][28][29][30]. Then, the scope of the Pd-catalyzed direct arylation for access to fluoranthenes was investigated (Scheme 2). The first step of the catalytic

• -aryl-8-bromonaphthalene A (Scheme 2). This catalytic cycle is followed by a second involving oxidative addition of 1-aryl-8-bromonaphthalene A, followed by intramolecular C–H coupling of the two aryl rings to give the fluoranthene derivative. Consequently, the use of arenes bearing substituents at the

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

• counterparts, due to their recyclability, ease of handling, and low cost [40]. Carbon-based solid acid catalysts especially are an interesting catalyst class, because they display low corrosiveness, toxicity, and higher catalytic activity, while also being insoluble in most organic solvents. The large amount

• of strong acidic sites that are on the carbon-based solid acids enhance their catalytic ability, compared to traditional Lewis and protic acids [41][42][43]. The most common examples in literature for the reaction of the synthesis of BIMs under solvent-free conditions utilize either protic acids

• . Finally, another nucleophilic attack by a second molecule of indole to IV is occurring, forming the desired BIM 12, while simultaneously releasing the catalyst, rendering it available for another catalytic cycle [80]. Halogen bonding processes Recently, halogen bonding (XB) interactions have emerged as an

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

• (3.15 to 2.06 × 105 s−1) [34] when employing catalytic IrIII excited state reductants with moderate reducing potentials (E1/2red[IrIV/*IrIII] ≈ −1.13 V vs Fc0/Fc+ in MeCN) [35]. This suggests that in the absence of a sufficiently strong driving force, BET and fragmentation compete to influence the

• resulting concentration of radicals. In such instances, opting for a stronger catalytic reductant or utilizing a stoichiometric electron donor can greatly improve the efficiency of radical generation. On the other hand, additional factors such as the ability of Brønsted and Lewis acid additives to promote

• hydrogen atom transfer (HAT) or sequential electron transfer and proton transfer (ET/PT) steps. Alternatively, redox-neutral transformations can be envisioned using catalytic reductants, which can enable a complementary scope of downstream functionalizations (Scheme 2B). In this perspective, we present an

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• condensation and Schiff base formation, which is then cyclized [12][16]. The reaction of 1 with arylamines 2a is performed in toluene solution in the presence of a catalytic amount of p-toluenesulfonic acid. This readily affords 6,8-di-tert-butyl-N-aryl-3H-phenoxazin-3-imines 3 but proceeds smoothly only with

Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

• Sharmila Neupane,
• Marcelo Rodrigues de Amorim and
• Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

• of several catalytic domains organized into modules. Typically, a module possesses an adenylation (A) domain for selecting and activating amino- or keto acids, a thiolation (T) domain for shuttling intermediates between catalytic domains, and a condensation (C) domain that catalyzes amide or ester

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• one of the three potential binding sites. In contrast to other R-type lectins such as ricin, it lacks a catalytic domain. As R-type lectins are both a well-investigated family of lectins and widely used in research and beyond, we first wanted to analyze where CMA1 would be situated in the broader

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• to be able to produce meaningful changes in the reactivity of the cage [28][29][30][31][32]. In 2018, our group reported a catalytic process to transform C60 in bis(fulleroid) derivatives [33][34][35]. This transformation encompassed a partially intermolecular Rh-catalyzed [2 + 2 + 2] cycloaddition

• were run using other solvents such as toluene and chlorobenzene, increasing the C70 concentration from 1.2 M to 2.4 M, and decreasing the catalytic load to 5 mol % (Table S1 in Supporting Information File 1). However, none of these trials improved the yield of bis(fulleroid) 2a. The same reaction was

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

• simple compounds. In particular, catalytic domino reactions and one-pot processes with excellent selectivity and functional-group tolerance are of significant interest to industrial and academic research. In the so-called domino reactions, all of the required reagents, the catalyst, and a solvent are

• steps, which is superior to conventional organic synthesis. The Thematic Issue “Catalytic multi-step domino and one-pot reactions” in the Beilstein Journal of Organic Chemistry, which I had the pleasure to edit, covers the recent strategies of domino reactions and one-pot syntheses and presents the

• nucleophilic substitution of benzylic bromides with sodium azide and a subsequent copper(I)-catalyzed double click reaction in one pot [17]. In summary, these contributions by renowned experts demonstrate the broad diversity of impressive catalytic domino, tandem, and one-pot processes towards many valuable

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

• crystalline form [55]. It was found that the aliphatic substituents (diacetyl- and distearoyl-) supported faster relaxation rates than the aryl-containing substituents (dibenzoyl- and bis(3,5-dinitrobenzoyl)-). Moreover, addition of catalytic amounts of amines accelerated the backward Z–E isomerization of Z

• working for Battelle Development Corporation, published a patent “Catalytic extraction of stored solar energy from photochemicals”, where the Ν,Ν'-diacylindigo derivatives were utilized as an energy storage element [78]. The mechanism of the energy storage relied upon the photoinduced E–Z isomerization of

• the indigo derivatives (energy accumulation) and the follow-up catalytic or heat-triggered Z–E reaction (energy release). Another example of a patent is “Sunlight-energy-storing substances and sunlight-energy-storing method using the same”, published in 1983 by Matsushita Electric Industrial

Copper-catalyzed multicomponent reaction of β-trifluoromethyl β-diazo esters enabling the synthesis of β-trifluoromethyl N,N-diacyl-β-amino esters

• Youlong Du,
• Haibo Mei,
• Ata Makarem,
• Ramin Javahershenas,
• Vadim A. Soloshonok and
• Jianlin Han

Beilstein J. Org. Chem. 2024, 20, 212–219, doi:10.3762/bjoc.20.21

• catalytic cycle. Finally, the acetimidic anhydride D undergoes a Mumm rearrangement to furnish the desired β-trifluoromethyl diacylamino ester 4a. The final goal of this work is the examination of the scale-up applicability of this three-component tandem reaction (Scheme 5). To our delight, the reaction

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• either 1,2-dibromobenzene or 2-bromophenylboronic acid. The 10,11-dihydro-5H-dibenzo[b,e][1,4]diazepinone could be synthezised in good yield using a sequential catalytic procedure, using both C–L and B–H approaches. Gratifingly, the use of the C–L reaction was more impressive, and afforded the

• carried out with Cu. The aminocarbonylation reaction which was introduced by Schoenberg and Heck in 1974 is an efficient catalytic route to carboxamides [11]. It was a major step forward and has been amply applied in a number of carbonylation reactions over the years [12]. In 2011, Buchwald and

• via a cross-coupling reaction with NH3 [13]. The reaction was undertaken in the presence of a catalytic amount of a palladium catalyst and afforded a library of dibenzodiazepinones in good to excellent yields (Scheme 1a). In 2013, Zhang et al. developed a synthetic route leading to structurally

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• 4.95 ppm with a J value of 3.6 Hz in the 1H NMR spectrum proving the anomeric α-configuration. The presence of Troc-rotamers was also apparent, with a ratio of 19:6 being observed by 1H NMR in CDCl3 at 25 °C. Catalytic amounts of NaOMe (0.005 M) in MeOH were used to remove the acetate from compound 4

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

• Changdong Shao,
• Chen Ma,
• Li Li,
• Jingyi Liu,
• Yanan Shen,
• Chen Chen,
• Qionglin Yang,
• Tianyi Xu,
• Zhengsong Hu,
• Yuhe Kan and
• Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

• , entries 3–6). The catalytic efficiency of MnSO4·H2O was consistent with FeCl3, affording 3aa in 64% yield (Table 1, entry 2). The reaction was further examined with a series of bases such as Li2CO3, Na2CO3, K2CO3, Cs2CO3, K2HPO4, KHCO3, KH2PO4, and KOAc, and the results demonstrated that the reaction

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• emphasis must also be placed on upscaling reactors and catalytic systems to facilitate the transition to cleaner energy sources. There are mainly three categories of solar to hydrogen generation methods based on semiconductors, namely photovoltaic-powered electrolysis (PV-E), photoelectrochemical (PEC

• catalytic sites) is still not rate-limiting in this regime [38]. Figure 14b shows the predicted maximum hydrogen generation rate for varying photocatalyst loadings. It is obvious that the modified model deviates less from the experimental results. Despite this, it also becomes clear that the quadratic model

• photocatalytic materials to cope, e.g., with mass transport issues on a larger scale. Consequently, reaction engineering studies should not only be conducted after a catalytic system was developed but should be an integral part of research on light-driven systems already during development of photocatalytic

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• the mentioned reactions, the first step of the catalytic cycle is the nucleophilic attack of the phosphine on the electrophile, in many cases an electron-deficient olefin. The zwitterion formed from this conjugate addition can subsequently act as a nucleophile or as a base [3][4][5]. The efficiency of

• this zwitterion formation is of great importance since it is the initiation step for the catalytic cycle in Michael reactions [8]. Generally, the conjugate addition is favored for strong nucleophiles, which is why electron-rich trialkylphosphines were among the first catalysts used in this type of

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• -coumaric acid via diazotization-dependent deamination. The diazotase CmaA6 had a high catalytic activity, which enabled us to determine the kinetics of the denitrification reaction catalyzed by AvaA7. Furthermore, careful comparison between ava and cma clusters provided insights into (i) the mechanism of

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• -Markovnikov addition, respectively. On the other hand, the hydration of an internal unsymmetrical alkyne can lead to the formation of the two possible regioisomeric ketones. The hydration reaction requires a catalytic species, able to polarize the alkyne triple bond to facilitate water attack. Initially, in

• hexafluorophosphate (BMIm-PF6) as co-solvent with methanol and water to allow recycling of a phosphine-based Au(I) complex, as an efficient catalytic system for the hydration of terminal alkynes [87]. Moreover, the interesting properties of ILs have also been exploited to synthesize new solid polymeric catalysts for

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• system (G) was first investigated by Albrecht et al. in 2008 [23]. Because the heterocyclic precursors needed to prepare 1,2,3-triazol-5-ylidenes are readily available through the [3 + 2] cycloaddition of an azide and an alkyne, these compounds are currently the most popular MICs for catalytic and other

• ). The active catalytic species for the CuAAC reaction were generated by reducing copper(II) sulfate with sodium ascorbate according to literature procedures [66][67]. 2-Azido-1,3,5-trimethylbenzene (mesityl azide) was easily synthesized in a distinct, preliminary step through the Sandmeyer reaction of

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• hypothesis that electrons can indeed be delocalized through the 4-membered ring system in the POAs. Following their work reported in 2017 [38], Xia and his group directed their attention towards refining the electronic properties of POAs through structural variations [39]. Using catalytic annulation

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

• –16 was as in the amide series from 8 and thus supported entropic contributions to anion–π catalysis. Steric increase of the secondary amide in 17 impeded anion–π catalysis, presumably because the catalytic π surface next to the ammonium cation became inaccessible for anions paired with the tethered

• fullerenes act as anion–π catalyst without additional activating groups, usually a tethered base to inject a negative charge into the substrate directly on top of the catalytic π surface [69]. The tert-butyl esters in Bingel fullerene 31 serve only to improve solubility and are not expected to participate in

• fullerenes as well. The unique polarizability of fullerene monomers like 1 is thought to induce strong anion–π interactions and thus account for the observed catalytic activity (Figure 7A) [12]. This polarizability should further increase in fullerene dimers like 36 [80]. Anions, anionic reactive

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• acknowledged to be effective in introducing substituents to the nitrogen atoms of NH-heterocycles by means of carbene insertion into the N–H bond upon catalytic or photolytic decomposition of diazo compounds [25]. Furthermore, the reaction of N-heterocycles containing multiple non-equivalent nitrogen atoms

• tetrazoles, had not been previously utilized in the CRBN ligands design. Catalytic decomposition reactions of diazo compound 5 with NH-heterocycles were conducted in a dry DCM solution using dirhodium espinoate (Rh2(esp)2, 0.06–0.18 mol %). The Rh2(esp)2 catalyst was selected for its excellent versatility

• , resulting in glutarimides with a heterocyclic fragment at the α-position 1a–e – structures in demand for the design of CRBN ligands and immunomodulatory drugs. In compound 6n, catalytic hydrogenation was used to reduce the nitro group, resulting in the production of a benzotriazole analog of pomalidomide

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• , acetonitrile, with 91–100% efficiency, and the catalyst was reused in five reaction cycles without the loss of activity and selectivity. Keywords: baclofen; catalyst recovery; lipophilic cinchona squaramide; organocatalysis; stereoselective catalysis; Introduction In today’s chemical industry, catalytic

• homogeneous reaction. For example, by incorporating a lipophilic side chain [28] on the organocatalyst that does not interfere with its catalytic activity thanks to a linker between the catalyst and lipophilic units. In this way, a significant difference in polarity can be achieved between the catalyst and

• cinchona squaramide organocatalyst. Its catalytic activity and recyclability were examined in a new stereoselective synthesis of baclofen, which is used to treat muscle spasms [30]. Finally, the catalyst was easily recycled by centrifugation over five reaction cycles without significant loss of activity

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

• transformations such as alkenylation, alkylation, cyclization, amination, iodination, and many others. The discovery of these conversions has significantly expanded the scope and versatility of the NaI/PPh3 catalytic system, now making it a powerful tool in synthesis. Alkenylation In 2020, Shang, Fu, and

• mechanistic aspects of the reaction and highlighted the potential of the NaI/PPh3 catalytic system for achieving efficient and transition-metal-free photocatalytic transformations. Following that, Li and his research group documented similar results (Scheme 4) [10]. They extensively investigated the

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• (versus NHE), respectively [3]. However, the molecular hydrogen evolution might compete, as it occurs at a more favorable reduction potential, lowering the selectivity of the catalytic system. While the addition of a proton source is beneficial to lower the overpotential, a metal-hydride (M–H

• complex [Cu(dmp)DPEPhos](BF4), well-investigated and used in several photocatalytic reactions [20][21][41], acting as a cost-effective benchmark photosensitizer. Herein, we present a study for the selectivity control of the novel Co(II) catalyst 1, aiming at maximizing the catalytic efficiency, and

• detect, if the two polymorphs show different catalytic activity, as in the following investigations the amorphic powder was used. Spectroscopic and electrochemical characterization The Co(II) complex 1 was characterized by UV–vis absorption spectroscopy in N,N-dimethylacetamide (DMA), as it was the