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

• , employing activated and unactivated alkyl bromides as the halogenation reagents without additional external oxidants. This method features outstanding site selectivity, broad substrate scope, and excellent yields. Keywords: aminoquinolines; C–H bromination; copper catalysis; regioselectivity; Introduction

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

• reactive in chloroform solution, while in methanol the corresponding phosphonium phenolate is formed. Keywords: Lewis-base catalysis; Michael acceptor reactivity; phospha-Michael reaction; phosphonium phenolate zwitterion; Introduction Organocatalysis has emerged in recent years as a valuable and

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• -doped nanocarbon g-C3N4 was achieved using aromatic micelle (PA-OCH3)n (Figure 6a). The multiple N-atoms bestow g-C3N4 with unique properties that are responsible for its widespread use in catalysis [28]. Subjecting yellow solid PA-OCH3 (1.2 mg, 1.9 μmol) and pale yellow solid g-C3N4 (1.0 mg) to the

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

• anions could coordinate the Lewis acid BF3 through the negatively charged oxygen [107], decreasing availability of BF3 for catalysis. Otherwise, ILs possessing bis(trifluoromeylsulfonyl)imide and hexafluorophosphate anions afforded hydrated product 2a with slightly better yields (87%) compared to those

• pseudobenzylic position, as observed in Lewis acid-assisted Brønsted acid (LBA) catalysis [47][48][49][50]. Internal alkynes afforded the corresponding products in good to excellent yields (Table 4, entries 1–3). In particular, the unsymmetrical alkyl(aryl)alkynes 1b and 1c showed a higher reactivity compared to

• available for catalysis. A similar behaviour was observed with ethyl 3-(4-chlorophenyl)propiolate (1n), although with lower yield due to the deactivating effect of the chlorine substituent in the para position of the phenyl ring (Table 4, entry 14). Importantly, for the experiments involving the same alkyne

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

• Nedra Touj Francois Mazars Guillermo Zaragoza Lionel Delaude Laboratory of Catalysis, MolSys Research Unit, Université de Liège, Institut de chimie organique (B6a), Allée du six août 13, 4000 Liège, Belgium Unidad de Difracción de Rayos X, RIAIDT, Universidade de Santiago de Compostella, Edificio

• just three decades (Figure 1) [2]. In particular, cyclic diaminocarbenes based on the imidazoline, benzimidazole, or imidazole ring system (A–C) have led to a myriad of applications in organometallic chemistry, homogeneous catalysis, and materials science, to name just a few [3][4][5]. Due to their

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

• M. Angeles Gutierrez Lopez Mei-Ling Tan Giacomo Renno Augustina Jozeliunaite J. Jonathan Nue-Martinez Javier Lopez-Andarias Naomi Sakai Stefan Matile Department of Organic Chemistry, University of Geneva, Geneva, Switzerland 10.3762/bjoc.19.140 Abstract Anion–π catalysis, introduced in 2013

• , stands for the stabilization of anionic transition states on π-acidic aromatic surfaces. Anion–π catalysis on carbon allotropes is particularly attractive because high polarizability promises access to really strong anion–π interactions. With these expectations, anion–π catalysis on fullerenes has been

• introduced in 2017, followed by carbon nanotubes in 2019. Consistent with expectations from theory, anion–π catalysis on carbon allotropes generally increases with polarizability. Realized examples reach from enolate addition chemistry to asymmetric Diels–Alder reactions and autocatalytic ether cyclizations

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

• , including both aromatic and saturated NH-substrates. This yields structures that are appealing for generating cereblon ubiquitin-ligase ligands and for potential use in crafting PROTAC molecules. Keywords: CRBN ligands; diazocarbonyl compounds; N–H insertion reaction; N-heterocycles; Rh(II)-catalysis

• -phenylpyrazolin-3-one, an exceptionally low conversion of the starting heterocycle was observed. In the next step, we have demonstrated the possibility of removing the protective Boc group under mild conditions without acid or base catalysis (Scheme 4). Deprotection occurs in high, near quantitative yields

• diazocarbonyl reagent is presented for the first time. The protective group is removed without acid catalysis with near quantitative yields. New benzotriazole derivatives containing functional groups capable of participating in the subsequent modification for linker attachment to assemble the PROTAC molecule

Substituent-controlled construction of A₄B₂-hexaphyrins and A₃B-porphyrins: a mechanistic evaluation

• Seda Cinar,
• Dilek Isik Tasgin and
• Canan Unaleroglu

Beilstein J. Org. Chem. 2023, 19, 1832–1840, doi:10.3762/bjoc.19.135

• of porphyrinogen and hexaphyrinogen forms. Keywords: A4B2-hexaphyrin; A3B-porphyrin; N-tosylimine; Cu(OTf)2 catalysis; HRESI–TOF analysis; Introduction Porphyrins and expanded porphyrins have found widespread applications in supramolecular chemistry [1][2][3][4]. Expanded porphyrins are utilized as

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

• stereoselective Michael addition reactions. Homogeneous catalysis was carried out in non-polar solvents (i.e., toluene), which allows the high performance of the lipophilic organocatalyst in terms of yield and stereoselectivity. To facilitate the pharmaceutical use of the lipophilic organocatalyst, we

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• , limiting the reaction time to 60–90 min under these conditions allowed some of the N-hydroxy derivatives 4 to be isolated in good yield (Table 5), even though it did not entirely prevent the formation of products 5. Palladium catalysis was not appropriate for the hydrogenation of compounds 3f and 3g

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

• Tinglan Liu Yu Zhou Junhong Tang Chengming Wang Department of Chemistry, Jinan University, Guangzhou 511443, P. R. China UNITEST, Weifang 261000, P. R. China 10.3762/bjoc.19.131 Abstract Photoredox catalysis plays a crucial role in contemporary synthetic organic chemistry. Since the

• , numerous remarkable breakthroughs and notable progresses have been achieved in the realm of photoredox catalysis [1][2][3]. This domain has profoundly transformed modern organic synthesis, resulting in a considerable surge in research efforts centered on free radical reactions [4]. Presently, photoredox

• catalysis has risen to prominence as an incredibly effective methodology, establishing itself as a powerful tool for crafting various C–X (X = C, N, O, F, Cl…) bonds owing to its advantageous traits, such as sustainability, practicality, and environmental compatibility [5]. Despite its broad synthetic

Active-metal template clipping synthesis of novel [2]rotaxanes

• Cătălin C. Anghel,
• Teodor A. Cucuiet,
• Niculina D. Hădade and
• Ion Grosu

Beilstein J. Org. Chem. 2023, 19, 1776–1784, doi:10.3762/bjoc.19.130

• ; Department of Organic Chemistry, Biochemistry and Catalysis, Research Centre of Applied Organic Chemistry, 90-92 Panduri Street, RO-050663 Bucharest, Romania 10.3762/bjoc.19.130 Abstract Mechanically interlocked molecules (MIMs) have been important synthetic targets in supramolecular chemistry due to their

• in 2016. While initially obtained as chemical curiosities, rotaxanes offer now exciting opportunities for scientific advancements in supramolecular chemistry and applications in various fields ranging from molecular machines and switches [4][5][6][7][8][9] to catalysis [10][11], molecular electronics

• -functonalized stopper 3 after substitution of bromine with azide. The dialkyne-decorated pyridine 5 was prepared starting from 2,6-bis(bromomethyl)pyridine that was reacted with compound 4, under phase transfer catalysis (Scheme 1). Finally, the axle 6, as well as the reference macrocycles M1 and M2 [44], were

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

• (helping in the deprotonation of the radical cation BIH•+ formed after the reductive quenching of the PS), but also can actively assist the catalysis, by capturing CO2 [50][51][52]. On the other hand, having three hydroxy groups, TEOA is also considered a proton donor and the formation of metal hydrides is

• possible. In some cases, this metal hydride favors the production of formate [51]. However, it may induce the concomitant formation of H2. This might have been the case of the photo-driven catalysis by complex 1 in DMA/TEOA (Table 2, entries 2–4), where upon decreasing the concentration of TEOA down to

• with a TON ≈ 61 after 4 h (Table 3, entry 5). Longer irradiation times (15 h) were evaluated for the concentration of 10 μM and 5 μM of complex 1, showing that the catalysis continued beyond 4 hours and reached a TON higher than 80 and 50, for [1] of 5 and 10 μM, respectively (Table 3, entries 6 and 7

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

• Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

• catalysis, for the synthesis of trifluoromethylated dihydropyridazines under simple reaction conditions and the chemistry displayed very good enantioselectivities and high functional group tolerance (Scheme 4) [40]. Zhan et al. reported an efficient and highly selective method for the synthesis of CF3

• Brønsted acid-assisted Lewis base catalysis. Synthesis of CF3-pyrazoles and CF3-1,6-dihydropyridazines. Asymmetric reactions of trifluoromethylimines with organometallic reagents. Mannich-type reaction of trifluoroacetaldehyde hydrazones. Synthesis of trifluoromethylated hydrazonoyl halides. Early work of

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• agents for magnetic resonance imaging, radiopharmaceuticals, sensors, NMR shift reagents, luminescent materials, catalysis, etc. To date, a large variety of PAMs with various ring sizes, number and location of nitrogen atoms, levels of unsaturation, etc. have been prepared and studied. Nevertheless, the

Decarboxylative 1,3-dipolar cycloaddition of amino acids for the synthesis of heterocyclic compounds

• Xiaofeng Zhang,
• Xiaoming Ma and
• Wei Zhang

Beilstein J. Org. Chem. 2023, 19, 1677–1693, doi:10.3762/bjoc.19.123

• under the catalysis of AcOH at 110 °C for 6 h afforded the monocycloaddition product 19a in 93% LC yield [71]. The isolated compound 19a was used for an N-propargylation to produce compound 20a in 94% LC yield. The following Cu-catalyzed click reaction afforded triazolobenzodiazepine 21a in 88% LC yield

• ]isoquinolines. The reaction of 2-bromobenzaldehydes, 2-aminoisobutyric acid, and maleimides in MeCN under the catalysis of AcOH at 110 °C for 6 h afforded the cycloaddition products 26. The purified intermediates were used for the one-pot N-allylation with allyl bromide to afford intermediate 25 followed by a

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• porphyrins as multitopic receptors, sensors, and supramolecular hosts, with applications in ion transport, catalysis, and polymeric materials [22][40][41][42][43][44][45]. In 1984 Lehn, Sessler and co-workers developed double-side-strapped crowned porphyrins, which served as tritopic and tetratopic receptors

• multitopic receptors capable of binding ions and ion-pairs, which have been used in ion binding and catalysis, to name a few applications [47][48][49]. A primary example of a crown ether-annulated porphyrin, i.e., β-crowned porphyrin, was established in 1996 by Murashima and co-workers [50]. The macrocycle

C–H bond functionalization: recent discoveries and future directions

• Indranil Chatterjee

Beilstein J. Org. Chem. 2023, 19, 1568–1569, doi:10.3762/bjoc.19.114

• its combination with organometallic chemistry for site-selective C−H bond functionalization [3][4]. Recent years have witnessed many viable strategies for the synthesis of complex targets utilizing photoredox catalysis, electroorganic catalysis, Lewis acid catalysis, and transition-metal-free

Morpholine-mediated defluorinative cycloaddition of gem-difluoroalkenes and organic azides

• Tzu-Yu Huang,
• Mario Djugovski,
• Sweta Adhikari,
• Destinee L. Manning and
• Sudeshna Roy

Beilstein J. Org. Chem. 2023, 19, 1545–1554, doi:10.3762/bjoc.19.111

• are typically accessed in two ways: (1) direct synthesis using metal or metal-free catalysis and (2) post-functionalization of disubstituted-1,2,3-triazoles [17][18]. The direct synthesis of fully substituted triazoles entails either metal-free carbonyl-based [19][20][21] or metal-mediated and strain

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

• nucleophilic attack of TMSN3 to deliver product 11 (Scheme 7). Tian and Chang et al. could synthesize 3‑sulfenylated coumarin compounds 13 by using N-sulfanylsuccinimides 1 under a Lewis acid catalysis system (Scheme 8) [48]. Additionally, oxidation of 3-sulfenylated coumarins utilizing (diacetoxyiodo)benzene

• -(arylthio)succinimides 1 or N-(arylseleno)succinimides 1’’ was developed under a Lewis acid catalysis system. This reaction involves ring-opening of the substituted cyclopropane 49, amination at the C1-site, and thiolation at the C3-site. In the transformation, sulfonamide acted as a nucleophile

• an effective catalysis system (Scheme 29) [63]. Kinetic studies in this cross coupling-reaction indicated that N-(arylthio)succinimides 1 with electron-deficient arene 4 undergoe thioarylation catalyzed by Fe(NTf2)3. Related molecules bearing an electron-rich arene showed an autocatalytic pathway

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• . A number of excellent reviews on different aspects of NHC chemistry has been published during this period [12][13][14]. NHCs have been widely employed in homogeneous catalysis [12] and as ligands for the preparation of coordination compounds of different metals [13]. The M–NHC bond is relatively

• stable; as a result, the stability of the resulting metal complexes is enhanced [14]. This has led to the development of a variety of NHC-incorporating metal compounds exhibiting increased activity/selectivity in catalysis [15]. Nature of the NHC–metal bond NHCs constitute a well-established class of

• [(IMes)2Cu]+FHF− (91) was also obtained. These complexes exhibit an interesting catalytic activity that will be described later. 2 Application as catalysts In 2001, Woodward, for the first time, reported an NHC–Cu-mediated catalysis in the conjugate addition of diethylzinc to enones (Scheme 33) [46

One-pot nucleophilic substitution–double click reactions of biazides leading to functionalized bis(1,2,3-triazole) derivatives

• Hans-Ulrich Reissig and
• Fei Yu

Beilstein J. Org. Chem. 2023, 19, 1399–1407, doi:10.3762/bjoc.19.101

• carbohydrate mimetics, but the reductive cleavage of the 1,2-oxazine rings to aminopyran moieties did not proceed cleanly with these compounds. Keywords: alkynes; azides; copper catalysis; nucleophilic substitution; 1,2-oxazines; Introduction The concept of click reactions [1][2], in particular, the

• reductive ring openings of bis(1,2,3-triazole) derivative 21 to divalent carbohydrate mimetics with hydrogen under palladium catalysis or with samarium diiodide did not proceed cleanly and need further optimization. Earlier approaches to multivalent carbohydrate mimetics B, D or F based on enantiopure

Functional characterisation of twelve terpene synthases from actinobacteria

• Anuj K. Chhalodia,
• Houchao Xu,
• Georges B. Tabekoueng,
• Binbin Gu,
• Kizerbo A. Taizoumbe,
• Lukas Lauterbach and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1386–1398, doi:10.3762/bjoc.19.100

• -α-eudesmol synthase from S. viridochromogenes [29][30]. In order to expand the knowledge about terpene synthase catalysis, fifteen uncharacterised terpene synthase homologs as listed in Table 1 were selected for further studies from different branches of the tree (indicated by red arrows in Figure 2

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• state, in good yield. Keywords: alkynylation; catalysis; cyclization; indoles; iodination; multicomponent reactions; Introduction Indoles and their derived substitution patterns are omnipresent heterocyclic structural motifs in nature [1], many natural products [2][3], drugs [4][5][6][7][8], and dyes

• transition-metal catalysis [31], we disclosed an activating group-free alkynylation–cyclization sequence to (aza)indoles [32][33] that could be readily concatenated with a concluding N-alkylation of the 7-azaindole intermediate in the sense of consecutive three-component coupling–cyclization–alkylation

Visible-light-induced nickel-catalyzed α-hydroxytrifluoroethylation of alkyl carboxylic acids: Access to trifluoromethyl alkyl acyloins

• Feng Chen,
• Xiu-Hua Xu,
• Zeng-Hao Chen,
• Yue Chen and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2023, 19, 1372–1378, doi:10.3762/bjoc.19.98

• trifluoromethyl alkyl acyloins in good yields with broad substrate compatibility. The complex bioactive molecules were also compatible with this catalytic system to afford the corresponding products. Keywords: alkyl carboxylic acids; cross coupling; EDA complex; nickel catalysis; trifluoromethyl acyloins