Ring opening of photogenerated azetidinols as a strategy for the synthesis of aminodioxolanes

• Henning Maag,
• Daniel J. Lemcke and
• Johannes M. Wahl

Beilstein J. Org. Chem. 2024, 20, 1671–1676, doi:10.3762/bjoc.20.148

• Henning Maag Daniel J. Lemcke Johannes M. Wahl Department Chemie, Johannes Gutenberg-Universität, Duesbergweg 10–14, 55128 Mainz, Germany 10.3762/bjoc.20.148 Abstract α-Aminoacetophenones are identified as promising building blocks for the synthesis of highly substituted dioxolanes. The presented

• , accessing strained molecules continues to pose a synthetic challenge because many reported methods require harsh conditions for the preparation. An attractive alternative to traditional synthesis can be found in photochemical methods, bypassing energetic constraints by the utilization of photon energy. Thus

• , endergonic transformations can be realized [3]. A promising strategy for the synthesis of complex products lies in the combination of photochemical cyclization and strain-release reaction (Scheme 1a) [4]. In this ‘build and release approach’, a simple precursor is cyclized upon irradiation. Subsequently, a

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

• allowing methylation at various positions. The different possible acceptor regions in ribosomally synthesised peptides are described in this article. Furthermore, we will discuss the potential application of these methyltransferases as powerful biocatalytic tools in the synthesis of modified peptides and

• three main routes for the synthesis of methylated peptides: chemical synthesis [33][34], in vitro ribosomal synthesis [35], and enzymatic synthesis. Chemical synthesis. Three main categories of reactions are commonly used: reductive amination, reductive ring openings, and the use of methylating agents

• . Additionally, stereoselectivity can be achieved by using potassium bis(trimethylsilyl)amide for deprotonation and methylation with MeI [33][39]. Any of these routes would yield methylated amino acids that can then be incorporated into an oligopeptide in solid-phase peptide synthesis (SPPS). Additionally, N

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

• electron transport in the photosynthetic light reactions by interfering with the synthesis of plastoquinone-9 [17]. Global genome sequence analyses confirmed the ubiquitous presence of biosynthetic gene clusters (BGCs) encoding the production of 26 in diverse marine bacterial species, suggesting it to be a

New triazinephosphonate dopants for Nafion proton exchange membranes (PEM)

• Fátima C. Teixeira,
• António P. S. Teixeira and
• C. M. Rangel

Beilstein J. Org. Chem. 2024, 20, 1623–1634, doi:10.3762/bjoc.20.145

• report the synthesis of a new series of triazinephosphonate derivatives and their use as dopants in the preparation of new modified Nafion membranes. The triazinephosphonate derivatives were prepared by substitution of chlorine atoms in cyanuric chloride. Diverse conditions were used to obtain the

• efforts and investments in the research and development of new membranes that might be able to surpass the actual limitations. Our studies started with the synthesis of phosphonate and phosphonic acid compounds to be used as membrane dopants [24][25]. These studies were followed by the incorporation of

• -triazine isomers [30]. There have been reported several and diverse applications to a large number of compounds with a triazine moiety, ranging from biological applications [31][32][33][34], such as fungicide, herbicide, antiviral, antimicrobial, antitumor, to their use in organic synthesis, including

pKalculator: A pK_a predictor for C–H bonds

• Rasmus M. Borup,
• Nicolai Ree and
• Jan H. Jensen

Beilstein J. Org. Chem. 2024, 20, 1614–1622, doi:10.3762/bjoc.20.144

• , respectively, when correlating with QM-computed pKa values. Both methods are freely available under the MIT license. Our workflow can function as a filtering tool for computer-aided synthesis planning for the synthesis of various pKa-dependent reactions (aldol, Michael, and Claisen), evidenced by its accurate

Generation of multimillion chemical space based on the parallel Groebke–Blackburn–Bienaymé reaction

• Evgen V. Govor,
• Vasyl Naumchyk,
• Ihor Nestorak,
• Dmytro S. Radchenko,
• Dmytro Dudenko,
• Yurii S. Moroz,
• Olexiy D. Kachkovsky and
• Oleksandr O. Grygorenko

Beilstein J. Org. Chem. 2024, 20, 1604–1613, doi:10.3762/bjoc.20.143

• involving the use of Sc(OTf)3 and TsOH as the catalysts were tested on a broad substrate scope, and prevalence of the first method was clearly demonstrated. Furthermore, the scope and limitations of the procedure were established. A model 790-member library was obtained with 85% synthesis success rate

• purposes [1][2][3][4][5][6]. Isonitrile-based multicomponent reactions, such as the Groebke–Blackburn–Bienaymé (GBB) reaction, is an important tool in chemical synthesis providing easy access to a huge compound diversity and complexity [7][8][9][10][11][12][13][14][15][16][17]. Essentially, the GBB

• last two decades, the GBB reaction has been studied in more than 200 research papers [21] and a number of works (including the original publication by Blackburn and coauthors [20]) described its parallel synthesis version [24][25][26][27][28][29]. Recently, we have shown that other (pseudo-)three

Supramolecular assemblies of amphiphilic donor–acceptor Stenhouse adducts as macroscopic soft scaffolds

• Ka-Lung Hung,
• Leong-Hung Cheung,
• Yikun Ren,
• Ming-Hin Chau,
• Yan-Yi Lam,
• Takashi Kajitani and
• Franco King-Chi Leung

Beilstein J. Org. Chem. 2024, 20, 1590–1603, doi:10.3762/bjoc.20.142

• -responsiveness, and molecular functional tunability of synthetic supramolecular systems can be precisely controlled through the delicate design and synthesis of organic molecules [9][10][11][12][13][14]. Synthetic supramolecular systems can respond to various external stimuli, e.g., light, pH, organic solvents

• -material interfaces [34]. Alternatively, the visible-light-responsiveness of DASAs was firstly reported by Read de Alaniz [47][48]. The significant structural changes upon transformation of the open-isomer to the cyclized-isomer, and the simple modular synthesis of DASAs, enabled various applications in

• could open up new prospects in the development of biomedical materials with visible-light-controlled microenvironments and future soft robotic systems. Results and Discussion Synthesis and design of DAs We designed and synthesized a series of DAn with different chain lengths of the alkyl linker, i.e

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

• straightforward conditions (Scheme 1). The synthesis of aryl halides is of great academic and industrial importance. Recently, our research group has developed a new procedure for the ortho-selective chlorination of phenols under mild conditions in a short reaction time [26]. The chlorinating species was

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

• ; quinoline; Introduction Nitrogen-containing molecules are important bioactive compounds and intermediates in chemical synthesis. Therefore, the chemical transformations of nitrogen-containing compounds have been widely studied in the field of organic synthesis [1][2][3][4]. For instance, the reduction of

• cyanoarenes is a straightforward and powerful method for the synthesis of primary amines [5], and the reduction of nitroarenes is useful for the synthesis of aniline derivatives [6][7][8][9][10][11]. Nitrogen-containing aliphatic heterocycles, such as piperidines and tetrahydroquinolines, are key motifs in

• , and pyridines using PEM reactors [51][52]. In this context, we have focused on the synthesis of nitrogen-containing molecules using a PEM reactor. Herein, we report the application of a PEM reactor for the reduction of cyanoarenes, nitroarenes, quinolines, and pyridines. These reductions proceeded

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

• compound, carry that functional group through synthesis and also protect any potentially labile group that would otherwise displace during the installation of the fluorine atom [6][7][8]. Therefore, methodologies for the selective C–H fluorination represent a valuable class of reactions [1][9][10], for

• pervasive in organic synthesis and can also be used to efficiently fluorinate benzylic C(sp3)–H bonds. The general blueprint for this transformation follows a metal insertion into the C(sp3)–H bond followed by C–F reductive elimination [11][22][38]. In 2006, Sanford and co-workers published a seminal and

• shown, this report provided important precedent for the ability of copper fluoride species to deliver fluorine to carbon radicals. Following on from this, Stahl and co-workers reported in 2020 an efficient synthesis of secondary and tertiary benzyl fluorides via a copper-catalysed radical relay

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

• organocatalyzed asymmetric Michael addition reaction of 4-monosubstituted pyrazol-5-ones to simple enones for the synthesis of pyrazolone derivatives [25]. Despite these progresses, arylidene/heteroarylideneacetones have remained untapped by 4-unsubstituted pyrazolin-5-ones under asymmetric organocatalytic or

• , and the desired product 3ch was obtained in 87% yield and 90% ee. In general, enantiomers of a bioactive molecule have different biological activities. Therefore, there is a huge demand to develop methods to access both enantiomers of a chiral compound. We turned our attention to the synthesis of

• (Scheme 2) were obtained in good to excellent yields (71–97%) and enantioselectivities (83.5–98% ee). Molecules containing two or more biologically relevant heterocycle motifs are receiving attention in drug discovery research [31][32][33]. The enantioselective synthesis of such hybrid molecules is

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

• . Keywords: azidation; nitration; organocatalysis; oxidation; quaternary ammonium iodides; Introduction Organic compounds containing an azide functionality are highly valuable synthesis targets that offer considerable potential for various applications and further manipulations [1][2][3][4][5][6][7][8][9

• consequence, the synthesis of organic azides is an important task and it comes as no surprise that a variety of conceptually complementary strategies to install azide groups in organic molecules have been reported [1][2][3][4][5][6][7][8]. α-Azido carbonyl derivatives are especially interesting targets which

• stoichiometry and catalyst loading (Table 1, entries 11–15). Hereby we found the use of 1.2 equiv of NaN3 with 1.2 equiv of DBPO and 20 mol % Bu4NI as the best-suited and most economic reagent/catalyst combination, which allowed for the synthesis of 2a in high isolated yield on 1 mmol scale as well (Table 1

Towards an asymmetric β-selective addition of azlactones to allenoates

• Behzad Nasiri,
• Ghaffar Pasdar,
• Paul Zebrowski,
• Katharina Röser,
• David Naderer and
• Mario Waser

Beilstein J. Org. Chem. 2024, 20, 1504–1509, doi:10.3762/bjoc.20.134

• ; quaternary ammonium salt catalysis; Introduction The development of asymmetric synthesis routes to access non-natural amino acids has for decades been one of the most heavily investigated tasks in organic synthesis and catalysis-oriented research [1][2][3][4][5][6][7][8][9][10][11][12][13]. As a consequence

• synthesis approaches. Our group has a longstanding focus on the development of asymmetric organocatalytic methods to access non-natural chiral α- and β-AA [14][15][16][17][18][19]. Hereby we are especially interested in utilizing simple (prochiral) starting materials and carry out stereoselective α

• the use of 3 equiv Cs2CO3 in toluene (0.05 M) at room temperature as the best-suited conditions (Table 1, entry 13), allowing for the synthesis of 5a in moderate yield (61%) and enantioselectivity (81:19 er). With optimized conditions for the synthesis of enantioenriched (−)-5a at hand, we next

Electrophotochemical metal-catalyzed synthesis of alkylnitriles from simple aliphatic carboxylic acids

• Yukang Wang,
• Yan Yao and
• Niankai Fu

Beilstein J. Org. Chem. 2024, 20, 1497–1503, doi:10.3762/bjoc.20.133

• synthesis; electrophotocatalysis; radical decarboxylation; Introduction Alkylnitriles and their derivatives are widely found in pharmaceuticals and biologically active compounds [1][2][3]. In addition, within the field of synthetic organic chemistry, nitriles are synthetically useful handles that can be

• intermediates in organic synthesis for the construction of all-carbon-substituted quaternary centers (Figure 1A). However, conventional methods for the synthesis of tertiary alkylnitriles such as direct functionalization of alkylnitriles [10] and hydrocyanation of alkenes [11][12][13][14] are typically hindered

• Cu(III) center [49][50][51]. Conclusion In summary, we have developed an efficient and practical protocol for the synthesis of alkylnitriles directly from readily available aliphatic carboxylic acids. The reaction proceeds under mild conditions and exhibits exceptional substrate generality and

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

• is introduced on the azobenzene to increase the water solubility. The influence of ortho, meta, and para-substitution patterns of the azobenzene on the lectin binding has also been studied. Synthesis The β-O-galactosyl p,p'-bis-substituted azobenzene derivative 1 was prepared from galactose and

• crystalline complexes. The protein is represented by orange ribbon, His53 by lines, and calcium by green sphere. Synthesis of photoswitchable LecA inhibitors. Reagents and conditions: (i) DMC, Et3N, H2O, −10 °C to rt, 8 h, 50% for 7, 40% for 10; (ii) BrCH2CH2NHBoc, K2CO3, DMF, 60 °C, 15 h, 91% for 8, 80% for

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

• Changjun Xiang Shunyu Yao Ruoyu Wang Lihan Zhang Department of Chemistry, Fudan University, Shanghai 200433, China Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake

• product structures were experimentally determined, such as by crystallography, nuclear magnetic resonance (NMR) analysis or by chemical synthesis, were obtained for further analysis. The modules in PKSs were categorized as α-module (containing KS-AT-ACP tridomain), β-module (KS-AT-KR-ACP), γ-module (KS-AT

Synthesis of 2-benzyl N-substituted anilines via imine condensation–isoaromatization of (E)-2-arylidene-3-cyclohexenones and primary amines

• Lu Li,
• Na Li,
• Xiao-Tian Mo,
• Ming-Wei Yuan,
• Lin Jiang and
• Ming-Long Yuan

Beilstein J. Org. Chem. 2024, 20, 1468–1475, doi:10.3762/bjoc.20.130

• additive-free synthesis of 2-benzyl N-substituted anilines from (E)-2-arylidene-3-cyclohexenones and primary amines has been reported. The reaction proceeds smoothly through a sequential imine condensation–isoaromatization pathway, affording a series of synthetically useful aniline derivatives in

• -cyclohexenones with nucleophilic nitrogen sources like ammonia, amines and hydrazine [14]. The reactions were regarded as via simple nucleophilic addition along with Pd-catalyzed dehydrogenative aromatization in these elegant works (Scheme 1, (1)). The Semmler–Wolff reaction is often implemented in the synthesis

• Morita–Baylis–Hillman (MBH) adducts [20][21], we were interested in further utilizing (E)-2-arylidene-3-cyclohexenones that can be facilely synthesized from MBH alcohols to build functionalized molecules. Herein, we wish to report our preliminary study on a catalyst- and additive-free synthesis of 2

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

• distinct advantageous such as (i) the methodology does not require the presence of any metal moities, (ii) enables the synthesis of corresponding oxyfluorinated analogues with high yields and selectivity, (iii) allows derivatization of natural chiral molecules, (iv) uses a safe solvent in mild reaction

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

• thioethers [27]. Likewise, selenocyanates can be used as versatile precursors for the synthesis of a variety of selenium-containing compounds [28][29][30][31][32]. As the S/SeCN-containing organic compounds play an important role in organic and medicinal chemistry, organic chemists have devoted a great deal

• , we have accomplished the synthesis of a series of C-4 thio/selenocyanated pyrazoles via a hypervalent iodine-mediated electrophilic thio/selenocyanation approach under mild reaction conditions. Furthermore, the obtained S/SeCN-containing pyrazoles can be converted to S/SeCF3- and S/SeMe-containing

• selenocyanation of pyrazoles. Reaction conditions: under N2 atmosphere, a mixture of PhICl2 (2.00 mmol) and KSeCN (2.00 mmol) in toluene (5 mL) was stirred at 0 °C for 0.5 h, then 1a (1.00 mmol) was added and stirring continued at 0 °C for 8 h. Isolated yields are given. Gram-scale synthesis of compounds 2a and

Predicting bond dissociation energies of cyclic hypervalent halogen reagents using DFT calculations and graph attention network model

• Yingbo Shao,
• Zhiyuan Ren,
• Zhihui Han,
• Li Chen,
• Yao Li and
• Xiao-Song Xue

Beilstein J. Org. Chem. 2024, 20, 1444–1452, doi:10.3762/bjoc.20.127

• ; machine learning; Introduction Hypervalent iodine reagents are increasingly gaining attention in the fields of organic synthesis and catalysis due to their environmental benefits, accessibility, and cost-efficiency [1][2][3][4][5][6][7][8][9][10][11]. Over the last three decades, a series of cyclic

• applications [27][28][29][30]. For example, hypervalent bromine(III) reagents enable C–H amination and alkene aziridination reactions without the need for additional Lewis acid activation [31][32][33]. However, challenges in the synthesis and stabilization of cyclic hypervalent bromine and chlorine reagents

• especially crucial for designing novel reagents. Yet, the BDE values of hypervalent bromine(III) and chlorine(III) reagents remain largely elusive, hampering the design and synthesis of novel reagents. In recent years, machine learning has emerged as a promising and cost-effective alternative to traditional

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

• Xiu-Yu Chen Ying Han Jing Sun Chao-Guo Yan College of Chemistry & Chemical Engineering, Yangzhou University, Jiangsu, Yangzhou 225002, China 10.3762/bjoc.20.126 Abstract An efficient protocol for the synthesis of polyfunctionalized tetrahydrocyclopenta[4,5]pyrrolo[2,3-b]pyridine-3,4b,5,6,7(1H

• on alkyl isocyanides, electron-deficient alkynes and other reagents have been successfully developed for the synthesis of various carbocyclic and heterocyclic compounds [27][28][29][30][31][32][33][34][35]. The 5,6-unsubstituted 1,4-dihydropyridine is one of special kinds of 1,4-dihydropyridines. It

• but-2-ynedioates and 5,6-unsubstituted dihydropyridines for the efficient synthesis of polyfunctionalized tetrahydrocyclopenta[4,5]pyrrolo[2,3-b]pyridine-3,4b,5,6,7(1H)-pentacarboxylates. Results and Discussion Initially, the reaction conditions were examined by employing cyclohexyl isocyanide (1a

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

• , Tottori University, 4-101 Koyamacho-minami, Tottori city, 680-8552 Tottori, Japan 10.3762/bjoc.20.124 Abstract The synthesis of protected precursors of cyclic β-1,6-oligoglucosamines from thioglycosides as monomers is performed by electrochemical polyglycosylation. The monomer with a 2,3-oxazolidinone

• reactions. Therefore, electrochemical polymerizations can be utilized for selective synthesis. Cyclic oligosaccharides are an important class of host molecules, and some natural cyclic oligosaccharides are produced by enzymatic processes. However, the corresponding chemical syntheses are still primitive [6

• intramolecular glycosylation (Scheme 1a) [14]. One-pot two-step synthesis via electrochemical polyglycosylation and intramolecular glycosylation has also been achieved in order to synthesize unnatural cyclic oligosaccharides of glucosamine (Scheme 1b) [15]. Here, we report the direct synthesis of cyclic

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

• preparation by using small building blocks and that lead, through appropriate transformations, to a product that becomes a substrate for another complexity-generating reaction, merit investigation [13][14][15]. Herein, we report a 3-CR-based synthesis of new properly decorated (thio)hydantoin framework able

• of diversity-oriented synthesis of N-heterocycles via sequential multicomponent approaches, we envisioned that α-aminoacetals could act as bifunctional building blocks along with 1,2-diaza-1,3-diene (DD) coupling partners [22][23], in obtaining functionalized N-aminohydrazones as key intermediates

• catalytic cycle. Similar to what was previously observed, the elimination of the trichloro(alkoxy)ferrate(III) anion from intermediate C provides the iminium ion D, susceptible to nucleophilic attack by a water molecule present in the reaction medium, leading to the carbinolamines 6. This latter synthesis

Hypervalent iodine-catalyzed amide and alkene coupling enabled by lithium salt activation

• Akanksha Chhikara,
• Fan Wu,
• Navdeep Kaur,
• Prabagar Baskaran,
• Alex M. Nguyen,
• Zhichang Yin,
• Anthony H. Pham and
• Wei Li

Beilstein J. Org. Chem. 2024, 20, 1405–1411, doi:10.3762/bjoc.20.122

• ; lithium salt activation; olefin oxyamination; oxazoline; Introduction Hypervalent iodine(III) reagents, also known as λ3–iodanes, have been well established and used in organic synthesis for the past decades [1][2][3][4][5]. The pioneering works of Fuchigami and Fugita, Ochiai, Kita, and later the

• of handling, and versatile reactivity, etc. render these catalysts highly attractive for adoption in organic synthesis. In particular, the field of olefin difunctionalization, known for its rapid assembly of molecular complexity, has been a fertile ground for innovation for hypervalent iodine

Synthesis of substituted triazole–pyrazole hybrids using triazenylpyrazole precursors

• Simone Gräßle,
• Laura Holzhauer,
• Nicolai Wippert,
• Olaf Fuhr,
• Martin Nieger,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2024, 20, 1396–1404, doi:10.3762/bjoc.20.121

• of Technology, Kaiserstraße 12, 76131 Karlsruhe, Germany 10.3762/bjoc.20.121 Abstract A synthesis route to access triazole–pyrazole hybrids via triazenylpyrazoles was developed. Contrary to existing methods, this route allows the facile N-functionalization of the pyrazole before the attachment of

• addition, the compatibility of the method with solid-phase synthesis is shown exemplarily. Keywords: azide; click reaction; CuAAC; pyrazole; triazene; triazole; Introduction Nitrogen-containing heterocycles are central scaffolds in medicinal chemistry and are incorporated in most small-molecule drugs [1

• -mediated reaction with alkyl halides [21]. So far, the literature-reported methods are most often limited to N-unsubstituted pyrazoles or triazoles and pyrazoles being fused to a second (hetero)cycle; the synthesis of promising multi-substituted structures such as 1 has not yet been described