Enantioselective regiospecific addition of propargyltrichlorosilane to aldehydes catalyzed by biisoquinoline N,N’-dioxide

• Noble Brako,
• Sreerag Moorkkannur Narayanan,
• Amber Burns,
• Layla Auter,
• Valentino Cesiliano,
• Rajeev Prabhakar and
• Norito Takenaka

Beilstein J. Org. Chem. 2024, 20, 3069–3076, doi:10.3762/bjoc.20.255

• pure propargyltrichlorosilane, it clearly demonstrated that this class of chiral Lewis bases regiospecifically catalyzed the addition of propargyltrichlorosilane to aldehydes, and that these catalysts did not induce the propargyl–allenyl metallotropic rearrangement albeit activating the C–Si bond. Thus

Extension of the π-system of monoaryl-substituted norbornadienes with acetylene bridges: influence on the photochemical conversion and storage of light energy

• Robin Schulte,
• Dustin Schade,
• Thomas Paululat,
• Till J. B. Zähringer,
• Christoph Kerzig and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 3061–3068, doi:10.3762/bjoc.20.254

• intersystem crossing (ISC), internal conversion (IC), or quenching by structural relaxation, etc. Finally, the half-life, t1/2, of the quadricyclane derivatives 2h–l,n was determined by kinetic analysis of the thermally induced cycloreversion to the corresponding norbornadiene derivatives 1h–l,n at 60 °C

• bis- and tris-norbornadienyl-substituted benzene derivatives. Photometric monitoring of the irradiation of 1h (A), 1i (B), 1j (C), 1k (D), 1l (E), and 1n (F); λex = 315 nm (1h, 1i, 1k, and 1l) or 340 nm (1j, 1n). Insets: plot of absorption at long-wavelength maximum versus irradiation time t

Chemical structure metagenomics of microbial natural products: surveying nonribosomal peptides and beyond

• Thomas Ma and
• John Chu

Beilstein J. Org. Chem. 2024, 20, 3050–3060, doi:10.3762/bjoc.20.253

• of an NRP despite the fact that this feature is known to be important for bioactivity [79][80]. Typically, the C-terminus of the NRP intermediate is covalently linked via a thioester bond to the phosphopantetheine prosthetic arm of the peptide carrier protein (also known as the thiolation (T) domain

• based on a dataset of known pairs of nonribosomal code/substrate BB. c) An analysis that compared the known vs predicted NRP BBs grouped based on their chemical structures found both oversampled (green)/underexplored (blue) niches in the NRP chemical space; the analysis was performed across all bacteria

• (overall) and for the top four most common phyla (Actinobacteria (A), Proteobacteria (P), Cyanobacteria (C), Firmicutes (F), and others (O)). d) and e) are the most oversampled and underexplored groups of NRP BBs, respectively. Syn-BNPs were synthesized in accordance to predicted NRP structures; shown

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

• the urea end-capping synthesis method (Figure 9) [46][47]. First, [3]rotaxane 3 synthesized using 2-bromophenyl isocyanate (yield: 73%) was confirmed to be a size-complementary rotaxane whose desilippage was observed in a DMSO solvent by heating at approximately 80 °C (Figure 9A,B). As the

• acylation of the 36 hydroxy groups on the CDs of [3]rotaxane proceeded effectively under the standard reaction conditions to yield perfectly acylated species (Figure 10B). Interestingly, the acylation of [3]rotaxane 7 at 60 °C did not proceed completely even after two weeks, although it did within 2.5 h at

• 80 °C. Additionally, that for a single native α-CD molecule proceeded completely at 60 °C within 2.5 h. Thus, the reaction temperature was confirmed as the key to completing the acylation reaction, probably because of the huge steric hindrance of the densely packed hydroxy groups on the [3]rotaxane

Tunable full-color dual-state (solution and solid) emission of push–pull molecules containing the 1-pyrindane moiety

• Anastasia I. Ershova,
• Sergey V. Fedoseev,
• Konstantin V. Lipin,
• Mikhail Yu. Ievlev,
• Oleg E. Nasakin and
• Oleg V. Ershov

Beilstein J. Org. Chem. 2024, 20, 3016–3025, doi:10.3762/bjoc.20.251

• rigidity along the C–C bond between the heterocycle and ethene bridge due to the fused cyclic fragment. As a consequence of the additional ring, the fluorescence efficiency increased. At the same time, solid-state emission was observed due to the steric hindrance, which prevented intermolecular

• ,1H-NOESY spectrum of compound 1c in DMSO-d6. Absorption (left) and normalized emission spectra (right) of compound 1i in various solvents (c = 10−5 M). Solvatochromic behavior of compounds 1c and 1i: plots of arithmetic mean of emission/absorption wavenumbers vs Kawsk–Chamma–Viallet polarity function

• (left) and photos of fluorescent solutions in various solvents taken under a 365 nm UV lamp (right). Absorption spectra of compounds 1a–i in toluene (left) and DMSO (right, c = 10−5 M). Normalized emission spectra of compounds 1a–i in toluene (left) and DMSO (right, c = 10−5 M). Photos of fluorescent

Tailored charge-neutral self-assembled L₂Zn₂ container for taming oxalate

• David Ocklenburg and
• David Van Craen

Beilstein J. Org. Chem. 2024, 20, 3007–3015, doi:10.3762/bjoc.20.250

• determined by NMR (see Supporting Information File 1, Figures S7, S9, S11, S13, S15, and S17). 1H NMR dicarboxylate binding studies were carried out with oxalate (C22−) and longer variants C(2+n)2− up to adipate (with n = 4). Oxalate addition to [L2Zn2] results in an intermediate exchange with broadened NMR

• which is observed for acetate, benzoate, and oxalate. a) 1H NMR titration (500 MHz, 500 µM, DMSO-d6, 25 °C) of [L2Zn2] with oxalate showing intermediate-like exchange. b) Negative ESI-MS spectrum of [L2Zn2] with 5 equiv oxalate showing the formation of [(C2)@L2Zn2]2− as host–guest complex. a) Optimized

• experiments (500 MHz, 500 µM, DMSO-d6, 25 °C) with mixtures of studied analytes showing the selective formation of the 1:1 oxalate host–guest complex [(C2)@L2Zn2]2− in all cases. Two-synthon approach for ligand preparation via CuAAC click reaction of an azide-functionalized, protected 8-hydroxyquinoline and a

Advances in radical peroxidation with hydroperoxides

• Oleg V. Bityukov,
• Pavel Yu. Serdyuchenko,
• Andrey S. Kirillov,
• Gennady I. Nikishin,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2024, 20, 2959–3006, doi:10.3762/bjoc.20.249

• the radical Kharasch-type functionalization of organic molecules with OOR fragment including free-component radical couplings. The discussion has been structured by the type of the substrate of radical peroxidation: C(sp3)–H substrates; aromatic systems; compounds with unsaturated C–C or C–Het bonds

• . Keywords: C–H functionalization; oxidation; peroxidation; radical reactions; TBHP; Introduction Organic peroxides are used in many different areas of human activities. The traditional and most developed field is the use of peroxides as initiators in the polymerization process for the production of a wide

• functional groups can be functionalized for any synthetic need via HAT or β-scission with subsequent C-centered radical formation [10][11][12][13]. Also, peroxy radicals play a key role in the chemistry of the Earth's lower atmosphere [14][15][16]. The traditional approaches to organic peroxide synthesis

Synthesis of fluorinated acid-functionalized, electron-rich nickel porphyrins

• Mike Brockmann,
• Jonas Lobbel,
• Lara Unterriker and
• Rainer Herges

Beilstein J. Org. Chem. 2024, 20, 2954–2958, doi:10.3762/bjoc.20.248

• ether synthesis with 2-hydroxy-3,4,5-trimethoxybenzaldehyde (21). Conditions: a) K2CO3, benzyl bromide, abs. MeCN, N2, reflux, 18 h; b) TEMPO, KBr, NaOCl, NaHCO3, MeCN, rt, 76 h; c) MeOH, H2SO4, reflux, 18 h; d) Pd/C, H2, EtOH, rt, 24 h; e) Tf2O, pyridine, DCM, rt, 18 h. Synthesis of perfluoroalkyl

• ester-functionalized aldehydes 22, 23, and 24. Conditions: a) NIS, TFA, Na2CO3, MeCN, reflux, 18 h; b) Cu2O·H2O, 2-pyridinaldoxime, TBAB, CsOH, H2O, N2, rt, 18 h; c) Cs2CO3, DMAc, N2, rt, 3 h. Porphyrin synthesis. a) Rothemund porphyrin synthesis of metal-free porphyrins 26, 27, and 28; b) metalation of

• porphyrins with Ni(acac)2; c) ester hydrolysis to generate the free acids 32, 33, and 34. Conditions: a) 1) 22/23/24, TFA, abs. DCM, N2, reflux, 30 min, 2) pyrrole, reflux, 2.5 h, 3) DDQ, reflux, 2 h; b) Ni(acac)2, toluene, reflux, 20 h; c) 1) LiOH, MeOH, rt, 1 h, 2) HCl. Supporting Information Supporting

gem-Difluorovinyl and trifluorovinyl Michael acceptors in the synthesis of α,β-unsaturated fluorinated and nonfluorinated amides

• Monika Bilska-Markowska,
• Marcin Kaźmierczak,
• Wojciech Jankowski and
• Marcin Hoffmann

Beilstein J. Org. Chem. 2024, 20, 2946–2953, doi:10.3762/bjoc.20.247

• laboratory [25], for our model reaction. The reactions were carried out under inert gas conditions in anhydrous solvents (THF or DCM) at −78 °C for 3 h, using several bases and electrophiles (Table 1). The use of electrophiles in the first test reactions was to confirm the generation of a carbanion, which

• scope, we observed that gem-difluoroalkenes produced β-fluoro-unsaturated amides 11a–d (Scheme 3). In these reactions, we used conditions previously optimised for derivatives 1a–d (n-BuLi 4 equiv, THF, −78 °C, 3 h). The amides 11a–d preferred HF elimination over engaging in another Michael reaction

4,6-Diaryl-5,5-difluoro-1,3-dioxanes as chiral dopants for liquid crystal compositions

• Maurice Médebielle,
• Peer Kirsch,
• Jérémy Merad,
• Carolina von Essen,
• Clemens Kühn and
• Andreas Ruhl

Beilstein J. Org. Chem. 2024, 20, 2940–2945, doi:10.3762/bjoc.20.246

• from neat chiral mesogens, or through the addition of a chiral dopant to an achiral nematic liquid crystal [5][6]. The ability of the dopant to induce chirality in the nematic phase is defined as the helical twisting power [HTP; β = (pc)−1; with p the helical pitch and c the molar concentration]. The

Structure and thermal stability of phosphorus-iodonium ylids

• Andrew Greener,
• Stephen P. Argent,
• Coby J. Clarke and
• Miriam L. O’Duill

Beilstein J. Org. Chem. 2024, 20, 2931–2939, doi:10.3762/bjoc.20.245

• -centre-4-electron bond is slightly distorted from linear geometry by 5–20° (Table 1). The short C–P and C–C bonds (d and e) in the phosphorus ylid moiety confirm Moriarty and Zhdankin’s observation that the ylid exists mainly in its enolate form (Figure 1B) [24][25] to stabilise the build-up of negative

• by the absence of a trans effect. While studies by Ochiai and Suresh found that strong sigma donors X cause a lengthening and weakening of the trans I–R bond in R–I(Ar)–X iodanes [32][33], little variation is observed in the I–C(ylid) (b) and I–C(arene) (c) bonds across the range of compounds

• File 1.) All compounds show a multi-step mass loss behaviour with a range of TGA decomposition onset temperatures (Tonset) between 107–137 °C, with the exception of three compounds that are stable to higher temperatures (1a: Tonset = 176 °C, ΔH = 134 J/g; 1j: 172 °C, 130 J/g; 2: 225 °C, 274 J/g; Table

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives

• Sondos A. J. Almahmoud,
• Joseph Cameron,
• Dylan Wilkinson,
• Michele Cariello,
• Claire Wilson,
• Alan A. Wiles,
• Peter J. Skabara and
• Graeme Cooke

Beilstein J. Org. Chem. 2024, 20, 2921–2930, doi:10.3762/bjoc.20.244

• dicyanomethylene-functionalised violanthrone derivatives (3a, 3b and 3c) featuring different alkyl substituents. It is found that the introduction of the electron-deficient dicyanomethylene groups significantly improves the optical absorption compared to their previously reported precursors 2a–c. All compounds are

• studied to determine the effect of the different side chains. Results and Discussion Synthesis The synthesis of compounds 2a–c and 3a–c is shown in Scheme 1. Compounds 2a–c were synthesised through a well-established etherification protocol [30] via the reaction of the commercially available compound

• 16,17-dihydroxyviolanthrone with 2-ethylhexyl bromide (a), 1-bromooctane (b), and 1-bromododecane (c) resulting in compounds, 2a, 2b and 2c, respectively. The final target compounds 3a–c were synthesised in 13%, 48% and 36% yield, respectively, following the reported procedure for anthraquinone, where

Recent advances in transition-metal-free arylation reactions involving hypervalent iodine salts

• Ritu Mamgain,
• Kokila Sakthivel and
• Fateh V. Singh

Beilstein J. Org. Chem. 2024, 20, 2891–2920, doi:10.3762/bjoc.20.243

• unsymmetrical forms of these salts serve as effective electrophilic arylating reagents in various organic syntheses. The use of diaryliodoniums in C–C and carbon–heteroatom bond formations, particularly under metal-free conditions, has further enhanced the popularity of these reagents. In this review, we

• overview of arylation of carbon and heteroatom substrates via diaryliodonium salts in metal-free conditions. This review emphasizes the significance and potential of DIASs in contemporary organic chemistry. Review C-Arylation Over the past decade, there has been a surge of interest in metal-catalyzed C

• -arylation of α-cyano-α-fluoroacetamides (9, R = CN), too. Aryl(mesityl)iodonium salts 6 (which are unsymmetrical diaryliodonium salts) were used as hypervalent iodine salts in both reactions. To achieve the C(sp3)-arylation of the α-nitro derivative of compounds 9 within 2 h to yield products 10, K2CO3 as

C–H Trifluoromethylthiolation of aldehyde hydrazones

• Victor Levet,
• Balu Ramesh,
• Congyang Wang and
• Tatiana Besset

Beilstein J. Org. Chem. 2024, 20, 2883–2890, doi:10.3762/bjoc.20.242

• /Education Center for Excellence in Molecular Sciences Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China 10.3762/bjoc.20.242 Abstract The selective C–H trifluoromethylthiolation of aldehyde hydrazones afforded interesting fluorinated building blocks, which could be used as a

• synthetic platform. Starting from readily available (hetero)aromatic and aliphatic hydrazones, the formation of a C–SCF3 bond was achieved under oxidative and mild reaction conditions in the presence of the readily available AgSCF3 salt via a one-pot sequential process (28 examples, up to 91% yield

• ). Mechanistic investigations revealed that AgSCF3 was the active species in the transformation. Keywords: C–H bond functionalization; C–S bond formation; hydrazones; synthetic method; trifluoromethylthiolation; Introduction Fluorinated molecules are of paramount importance [1][2][3][4][5][6][7][8][9][10][11

Synthesis of pyrrole-fused dibenzoxazepine/dibenzothiazepine/triazolobenzodiazepine derivatives via isocyanide-based multicomponent reactions

• Marzieh Norouzi,
• Mohammad Taghi Nazeri,
• Ahmad Shaabani and
• Behrouz Notash

Beilstein J. Org. Chem. 2024, 20, 2870–2882, doi:10.3762/bjoc.20.241

• , we investigated the reaction in dichloromethane at room temperature and at 40 °C (Table 1, entries 1 and 2) and we found that the reaction progressed slightly at 40 °C. This promising result prompet us to examine the reaction in multiple anhydrous solvents such as CH3CN, toluene, EtOH, THF, EtOAc

• , and DMF at different temperatures (Table 1, entries 3–9). The result obtained from the study of solvents showed that pyrrole-fused dibenzoxazepine 4a was obtained with a yield of 56% in ethanol as solvent at a temperature of 78 °C (Table 1, entry 4). To achieve a higher yield of product 4a, the

• reaction was also attempted under solvent-free conditions at different temperatures (Table 1, entries 10–13). Interestingly, the highest yield of 70% of the desired product was achieved by conducting the reaction at 100 °C without using any solvent (Table 1, entry 12). After having identified the optimal

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• , indirubin, and isoindigo which can be regarded as blue, red, and yellow sugars, respectively. Review Indigo-N-glycosides (blue sugars) In 2002, Laatsch and Maskey reported the isolation of the akashins A, B and C, indigo-N-glycosides, from terrestric Streptomyces (Scheme 2) [17][18]. These natural products

• exhibit an absorption at 618 nm and show a blue color. In contrast to biologically inactive indigo, akashines A–C are active against various human tumor cell lines (CNCL SF268, LCL H460, MACL, colon carcinoma CCL HT29, melanoma MEXF 514L, lung carcinoma LXFA 526L and LXFL 529L, breast cancer MCF-7, kidney

• (4a) initially resulted in the glycosylation of the oxygen atom to give intermediate A (−20 °C, 1.5 h). Extension of the reaction time (20 °C, 12 h) afforded N-indigoglycoside 5a which was isolated in 35% yield. The product contained an α-rhamnosyl moiety with 4C1 conformation. The formation of the

Multicomponent synthesis of α-branched amines using organozinc reagents generated from alkyl bromides

• Baptiste Leroux,
• Alexis Beaufils,
• Federico Banchini,
• Olivier Jackowski,
• Alejandro Perez-Luna,
• Fabrice Chemla,
• Marc Presset and
• Erwan Le Gall

Beilstein J. Org. Chem. 2024, 20, 2834–2839, doi:10.3762/bjoc.20.239

• Paris, France 10.3762/bjoc.20.239 Abstract The use of alkylzinc bromides in the multicomponent Mannich reaction is described. Heteroleptic organozinc compounds were obtained in THF or 2-MeTHF by direct insertion of zinc dust into the C–Br bond of alkyl bromides. It was found that the presence of a

• ]. Thus, whereas Rieke et al. reported the insertion of activated zinc into alkyl bromides in THF at room temperature [16][17], Knochel et al. described the direct metalation of alkyl iodides in THF at 30 °C [18]. More recently, Knochel et al. improved their original method by the use of zinc dust in the

• presence of LiCl in THF for the metalation of alkyl bromides at room temperature [19]. Besides, Huo described the insertion of zinc dust into alkyl bromides at 80 °C in DMA or DMF [20]. Despite the high synthetic interest in mixed organozinc compounds, their use in the preparation of α-branched amines

Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

• Kento Iwai,
• Akari Hikasa,
• Kotaro Yoshioka,
• Shinki Tani,
• Kazuto Umezu and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

• was reacted with lithium acetylide, which was prepared from ethynylbenzene (3a) and butyllithium at 0 °C, the solution turned black, resulting in a complex reaction mixture (Table 1, entry 1). This complication persisted even when the reaction was conducted at −78 °C and then warmed to room

• temperature without addition of acetic acid. To address this, the reaction was performed at −78 °C, and acetic acid was added at the same temperature, yielding adduct 4a in 13% yield (Table 1, entry 2). The reaction yield was significantly influenced by the amounts of 3a and butyllithium used. The yield of 4a

•  3) [13][14]. To a dry THF solution of adduct 4a, butyllithium was added, and the reaction mixture was stirred at −78 °C for 5 min. Following the addition of acetic acid, the reaction mixture was concentrated and subjected to silica gel column chromatography, resulting in the isolation of ethyl 5

Investigation of a bimetallic terbium(III)/copper(II) chemosensor for the detection of aqueous hydrogen sulfide

• Parvathy Mini,
• Michael R. Grace,
• Genevieve H. Dennison and
• Kellie L. Tuck

Beilstein J. Org. Chem. 2024, 20, 2818–2826, doi:10.3762/bjoc.20.237

• − in the aqueous state at a pH of 7.4 due to its weak acidic nature and high solubility in water (80 mM at 37 °C) [6]. Elevated levels of H2S in groundwater pose high risks to both human health and aquatic ecosystems [7], compelling rigorous monitoring of water sources. Even though sensors for

• were measured at room temperature utilizing a Varian Cary 1E UV–vis spectrophotometer with a quartz cell of 10 mm path length. Luminescence emission spectra of aqueous solutions were captured at 23 °C using a Varian Cary-Eclipse fluorescence spectrophotometer set to phosphorescence mode, employing a

• HEPES buffer (pH 7.4), solutions contained <5% DMSO). The solutions were incubated at 23 °C for 5 min prior to use. Na2S-dependent luminescence spectra. A solution of [Tb.1·3Cu]3+ (5 μM), in 10 mM buffer (final concentration 10 mM Tris–HCl or 10 mM HEPES buffer (pH 7.4), solutions contained <5% DMSO

Synthesis and antimycotic activity of new derivatives of imidazo[1,2-a]pyrimidines

• Dmitriy Yu. Vandyshev,
• Daria A. Mangusheva,
• Khidmet S. Shikhaliev,
• Kirill A. Scherbakov,
• Oleg N. Burov,
• Alexander D. Zagrebaev,
• Tatiana N. Khmelevskaya,
• Alexey S. Trenin and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2024, 20, 2806–2817, doi:10.3762/bjoc.20.236

• ]. It has already been noted that the preferred medium for recyclizations involving imides of itaconic and malic acids by various N,N- and C,N-dinucleophiles, in particular by 1,2-diaminoimidazole derivatives, 5-aminopyrazoles, and 3-aminocyclohexen-2-ones, are mixtures of polar solvents with acetic

• spectra of the imidazopyrimidine 4d there are cross peaks of the methine proton at C-5 with the amide proton of the acetamide fragment (Figure 3), which are not possible in the case of the hypothetical imidazoimidazoles 10 and 12. Also the observed cross peak of the same methine proton with the proton at

• C-3 of the imidazole core, would not be possible for the alternative imidazopyrimidine system. These results allowed us to reject the structure 11. The lack of correlation in the HMBC spectra between the protons of the amide fragment and the C-5 carbon atom, as well as the presence of cross-peaks of

Mechanochemical difluoromethylations of ketones

• Jinbo Ke,
• Pit van Bonn and
• Carsten Bolm

Beilstein J. Org. Chem. 2024, 20, 2799–2805, doi:10.3762/bjoc.20.235

• difluoromethyl enol ethers, which have the potential for further functionalization. Overview over difluoromethyl enol ether syntheses from acyclic and cyclic 1,3-diones (A), acyclic ketones (B), and cyclic ketones (C). Attempted difluoromethylation of 1a in solution. The reactions were performed on a 0.2 mmol

• yields were determined by 1H NMR spectroscopy using 1,2-dichloroethane as the internal standard. In parentheses: yields after column chromatography (with product purities of ca. 90%). aWith CsCl. bWith KCl. Proposed mechanism (A) and mechanistic investigations (B and C). The yields were determined by 1H

C–C Coupling in sterically demanding porphyrin environments

• Liam Cribbin,
• Brendan Twamley,
• Nicolae Buga,
• John E. O’ Brien,
• Raphael Bühler,
• Roland A. Fischer and
• Mathias O. Senge

Beilstein J. Org. Chem. 2024, 20, 2784–2798, doi:10.3762/bjoc.20.234

• , Germany 10.3762/bjoc.20.234 Abstract Unlike their planar counterparts, classic synthetic protocols for C–C bond forming reactions on nonplanar porphyrins are underdeveloped. The development of C–C bond forming reactions on nonplanar porphyrins is critical in advancing this field of study for more complex

• , borylation of a dodecasubstituted porphyrin’s meso-phenyl position was explored and a subsequent C–C coupling showed the polarity of the reaction can be reversed resulting in higher yields. X-ray analysis of the target compounds revealed the formation of supramolecular assemblies, capable of accommodating

• substrates in their void. Keywords: C–C coupling; conformational analysis; nonplanar porphyrin; Pd-catalysis; porphyrin; Introduction Porphyrins are tetrapyrrolic macrocycles that perform essential processes in nature, such as oxygen transport in hemoglobin and photosynthesis [1]. Porphyrins are often

Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction

• Yuta Kabumoto,
• Eiichiro Yoshimoto,
• Bing Xiaohuan,
• Masato Morita,
• Motohiro Yasui,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2776–2783, doi:10.3762/bjoc.20.233

• Science and Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Japan 10.3762/bjoc.20.233 Abstract Treatment of various (R)-N-(2,2,3,3-tetrafluoropent-4-en-1-ylidene)-1-phenylethylamine derivatives with 2.4 equiv of DBU in toluene at room temperature to 50 °C for 24 h led to

• reaction at 0 °C gave unsatisfactory results and a large amount of (R)-16b was recovered (Table 1, entry 14). Based on these results, the reaction conditions in entry 11 (Table 1) were determined as the optimum ones, which gave the highest yield, although the formation of the byproduct azocine derivative

• when the reaction was performed at 50 °C. The substrates with an aromatic ring substituted by not only an electron-withdrawing halogen atom but also an electron-donating group such as methoxy and methyl group also smoothly underwent the [1,3]-proton shift reaction, affording the desired products with

Copper-catalyzed yne-allylic substitutions: concept and recent developments

• Shuang Yang and
• Xinqiang Fang

Beilstein J. Org. Chem. 2024, 20, 2739–2775, doi:10.3762/bjoc.20.232

• -abundant, inexpensive, relatively stable, and low toxic. Copper-catalyzed asymmetric allylic [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] and propargylic [23][24][25][26][27][28][29][30][31][32] substitutions are effective strategies for constructing new C–C and C

• , 6a–w). Interestingly, both Cu(I) and Cu(II) can promote the reaction and the reaction is not sensitive to water (Scheme 7, 6g). The intramolecular decarboxylative yne-allylic substitution can also be achieved (Scheme 8, 6a–u). O-Nucleophiles and C-nucleophiles are all suitable reactants, yielding

• yielded mono yne-allylic substituted products (Scheme 15, 3a–w), but while pyrroles were used as nucleophiles, double yne-allylic substituted products can be obtained with high dr and ee values (Scheme 16, 15a–c). They also demonstrated the importance of terminal alkyne through control experiments and

Interaction of a pyrene derivative with cationic [60]fullerene in phospholipid membranes and its effects on photodynamic actions

• Hayato Takagi,
• Çetin Çelik,
• Ryosuke Fukuda,
• Qi Guo,
• Tomohiro Higashino,
• Hiroshi Imahori,
• Yoko Yamakoshi and
• Tatsuya Murakami

Beilstein J. Org. Chem. 2024, 20, 2732–2738, doi:10.3762/bjoc.20.231

• generation by C60 and its derivatives [17][18][19]. The most important: upon the addition of PyBA to catC60-lip, the signal intensities of both types of ROS (1O2 and •OH) were decreased (Figure 5a(iii), b(iii), c(iv)). These results indicate that PyBA suppresses ROS generation by catC60-lip in liposome

• °C to prepare the lipid films. The lipid films were then dried overnight in vacuo. Then, the films were hydrated with PBS(–) (137 mM NaCl, 2.68 mM KCl, 8.1 mM Na2HPO4, 1.47 mM KH2PO4) so that the theoretical value of DMPC concentration was 3 mg/mL, and the resulting suspension was sonicated at 30 °C

• ). Measurements were performed following equilibration at 10 °C at a scan rate of 180 °C/h. Measurements were also performed after mixing of 50, 100 or 500 µM PyBA (Sigma-Aldrich, St. Louis, MI, USA) and DMPC liposomes without catC60 or C60 followed by dialysis of the mixture against 3 L PBS for 2 h to remove