Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• Aurelie Claraz Institut de Chimie des Substances Naturelles, CNRS, Univ. Paris-Saclay, 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France 10.3762/bjoc.20.175 Abstract Hydrazones are important structural motifs in organic synthesis, providing a useful molecular platform for the

• versatile reagents in organic synthesis. They have for instance been frequently employed for the construction of azacycles through various cyclization protocols or cycloaddition reactions [6][7][8][9][10]. Early work in this field includes the well-known Fischer indole synthesis [11]. Additionally, they

• drive oxidative and reductive processes precludes the reliance on toxic or dangerous redox reagents [32]. The explosive renewal of interest in this technology and the resulting recent achievements have brought it at the forefront of organic synthesis. Electrooxidative transformations of hydrazones offer

Novel oxidative routes to N-arylpyridoindazolium salts

• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2024, 20, 1906–1913, doi:10.3762/bjoc.20.166

• organic synthesis. In the present paper, convenient, easily reproducible, straightforward synthetic routes to N-arylpyridoindazolium salts were elaborated, based on both electrochemical and chemical (using bis(trifluoroacetoxy)iodobenzene, PIFA) oxidation of the ortho-pyridine-substituted diarylamines

Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles

• Ivan Lyutin,
• Vasilisa Krivovicheva,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 1894–1899, doi:10.3762/bjoc.20.164

• organic synthesis as a route to generate ketenes is being actively investigated, involving both acyclic and carbocyclic diazocarbonyl compounds [26]. At the same time, the use of diazoheterocyclic reagents (including diazotetramic acids) in this transformation, with the formation of heterocyclic ring

The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

• precursors which can be involved in further modifications. In addition, the GBB-like reactions can also be used to deliver other heterocyclic motifs. 3.1 One-pot synthesis As an efficient approach in organic synthesis, one-pot synthesis has been exploited in the post-modification of GBB products. This

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

• -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

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

• compounds with the PEM-type reactor. The chemoselective reduction of nitrogen-containing compounds under mild conditions is important for organic synthesis, and we believe that the PEM reaction system is a powerful tool that can be applied to a wide variety of nitrogen-containing compounds. Schematic of (a

• ® electrode, respectively. Funding This work was supported in part by JST CREST Grant No. JP65R1204400, Japan, JSPS KAKENHI Grant Numbers JP22H02122 (to K.M.), JP23K17917 (to K.M.), JP22K05115 (to S.S.), and JP21H05214 (Digitalization-driven Transformative Organic Synthesis) (to S.S.),

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

• 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

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

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

• 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

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

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

Synthetic applications of the Cannizzaro reaction

• Bhaskar Chatterjee,
• Dhananjoy Mondal and
• Smritilekha Bera

Beilstein J. Org. Chem. 2024, 20, 1376–1395, doi:10.3762/bjoc.20.120

• , solvents, and technologies for the Cannizzaro reaction reflects the broader trend in organic synthesis towards more sustainable and efficient practices. The focus of this review is to highlight some recent advances in synthetic strategies and applications of the Cannizzaro reaction towards the synthesis of

• Cannizzaro reaction as an important synthetic tool in organic synthesis. Certain developments in the Cannizzaro reaction with regard to reagents, solvents, and technologies are worth mentioning. Generally, the classical version of the Cannizzaro reaction is conducted at elevated temperatures using

• future [71][72]. Herein, we discuss recent advances in the Cannizzaro reaction, focusing on the synthetic developments of natural products and important building blocks in the last two decades. Applications of the Cannizzaro reaction in organic synthesis The Cannizzaro reaction has been significantly

Generation of alkyl and acyl radicals by visible-light photoredox catalysis: direct activation of C–O bonds in organic transformations

• Mithu Roy,
• Bitan Sardar,
• Itu Mallick and
• Dipankar Srimani

Beilstein J. Org. Chem. 2024, 20, 1348–1375, doi:10.3762/bjoc.20.119

• ][40][41][42]. However, these protocols have a limited scope and suffer from prefunctionalization and waste generation. Photons are considered the greenest reagent in organic synthesis. Thus, photomediated alkyl radical generation from easily accessible alcohols for organic synthesis is highly

• β-scission, NHC 72 was found to be most effective. Unstrained secondary alcohols were efficiently activated with the help of NHC 65. Deoxygenation of sterically congested alcohols, which has been a longstanding challenge in organic synthesis, was achieved by using a more electrophilic alcohol

• heightened by the current energy crisis and the adverse impacts of industrialization. The development of green and energy-efficient methods in organic chemistry that use renewable sources of starting materials is considered highly sustainable [1][2][3]. Radical reactions have profound applications in organic

Transition-metal-catalyst-free electroreductive alkene hydroarylation with aryl halides under visible-light irradiation

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2024, 20, 1327–1333, doi:10.3762/bjoc.20.116

• chemical reagents; however, these methods have some drawbacks, such as reagent toxicity/stability and limited substrate scope [12][13][14]. While recent advances in photochemistry have remarkably expanded the synthetic utility of (hetero)aryl radicals in organic synthesis [15][16][17][18][19][20], visible

Sustainable tandem acylation/Diels–Alder reaction toward versatile tricyclic epoxyisoindole-7-carboxylic acids in renewable green solvents

• Ayhan Yıldırım

Beilstein J. Org. Chem. 2024, 20, 1308–1319, doi:10.3762/bjoc.20.114

• ][34][35][36][37][38]. In addition to their unique properties, vegetable oils are known to be useful as green solvents in many applications [39][40][41][42]. The evaluation of vegetable oils as alternative solvents in organic synthesis is very limited [43][44][45][46][47]. Synthetic chemists are still

Oxidative hydrolysis of aliphatic bromoalkenes: scope study and reactivity insights

• Amol P. Jadhav and
• Claude Y. Legault

Beilstein J. Org. Chem. 2024, 20, 1286–1291, doi:10.3762/bjoc.20.111

• alternative reaction pathway. Keywords: bromoalkenes; bromoketones; hypervalent iodine; oxidative hydrolysis; Ritter-type; Introduction Organic synthesis heavily relies on oxidative transformations to facilitate chemical reactions. One popular method for achieving these transformations is using redox-active

Bismuth(III) triflate: an economical and environmentally friendly catalyst for the Nazarov reaction

• Manoel T. Rodrigues Jr.,
• Aline S. B. de Oliveira,
• Ralph C. Gomes,
• Amanda Soares Hirata,
• Lucas A. Zeoly,
• Hugo Santos,
• João Arantes,
• Catarina Sofia Mateus Reis-Silva,
• João Agostinho Machado-Neto,
• Leticia Veras Costa-Lotufo and
• Fernando Coelho

Beilstein J. Org. Chem. 2024, 20, 1167–1178, doi:10.3762/bjoc.20.99

• classical Nazarov reaction. With the growing environmental concern and the need to use green reagents, interest in the use of bismuth in organic synthesis has increased significantly, as is reflected by the large number of works dedicated to this topic [52][53][54]. In addition to the replacement of toxic

• heavy metals, the use of bismuth compounds to promote reactions has the advantages of low cost and insensitivity to water and air. As such, the handling does not require special experimental techniques, such as an inert atmosphere and anhydrous solvents [55]. The use of bismuth salts in organic

• synthesis has been reported for several transformations, such as epoxide opening [56], ketal formation and deprotection [57][58], Mannich reaction [59], intramolecular Sakurai cyclization [60], alcohol oxidation [61], aromatic hydrocarbon nitration [62], imine allylation [63], Knoevenagel condensation [64

Manganese-catalyzed C–C and C–N bond formation with alcohols via borrowing hydrogen or hydrogen auto-transfer

• Mohd Farhan Ansari,
• Atul Kumar Maurya,
• Abhishek Kumar and
• Saravanakumar Elangovan

Beilstein J. Org. Chem. 2024, 20, 1111–1166, doi:10.3762/bjoc.20.98

• importance in organic synthesis and is widely used in the pharmaceutical and other chemical industries. Palladium-catalyzed cross-coupling reactions are one of the compelling methods for building C–C and C–N bonds [1][2]. However, using organohalide reagents and harsh reaction conditions in this process

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• relevant intermediates in organic synthesis [52][53]. Therefore, the significance of 6H-isoindolo[2,1-a]indol-6-ones has led to a longstanding interest in the development of efficient and versatile methods for their synthesis. In 2016, four independent studies reported the first successful application of a

Innovative synthesis of drug-like molecules using tetrazole as core building blocks

• Jingyao Li,
• Ajay L. Chandgude,
• Qiang Zheng and
• Alexander Dömling

Beilstein J. Org. Chem. 2024, 20, 950–958, doi:10.3762/bjoc.20.85

• the Passerini and Ugi reactions amenable to convenient, efficient, simple, and fast synthesis of diverse scaffolds library to afford variously functionalized tetrazole-based drug-like molecules. In order to achieve the synthesis of novel tetrazole building blocks and their use in organic synthesis we

• was also unsuccessful to increase the product yield. The increased use of microwave conditions in organic synthesis [20] and our previous promising studies on microwave-assisted MCRs [21], motivated us to use microwave conditions for further optimization. Accordingly, we investigated several sets of

• developed building block approach, we decided to incorporate an oxo-tetrazole into an Ugi four-component reaction, the most studied and versatile MCR in organic synthesis and drug discovery [31][32]. Despite tremendous exploration, finding novel substrates or bioisosteres as a starting material in the Ugi

Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents

• Lilian M. Maas,
• Alex Haswell,
• Rory Hughes and
• Matthew N. Hopkinson

Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82

• . Keywords: acyl fluorides; amides; benzothiazolium salts; carboxylic acids; deoxygenative reactions; Introduction Acyl fluorides are attracting much attention as versatile reagents for different applications in organic synthesis. In addition to their use as sources of fluoride ions, they are most commonly

• fluorides were also observed as by-products. Given the increasing interest in acyl fluorides in organic synthesis and the attractive features of BT-SRF salts as reagents for organofluorine chemistry, we considered whether optimisation of the reaction conditions could allow for the selective synthesis of

Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins

• Ke Jiang,
• Cheng Pan,
• Limin Wang,
• Hao-Yang Wang and
• Jianwei Han

Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76

• . Keywords: annulation; arylocyclization; 3,4-benzocoumarin; diaryliodonium salts; naphthol; Introduction Diaryliodonium salts as electrophilic reagents have attracted significant attention in the field of organic synthesis owing to their efficiency and selectivity [1][2][3][4][5][6][7]. Particularly, they

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• focusing on hydrochlorination reactions. Firstly, an outstanding overview, including extensive research from the former Soviet Union, was reported in 1982 by Sergeev and co-workers [12]. Secondly, the chapter on “Addition of H-X Reagents to Alkenes and Alkynes” in comprehensive organic synthesis gives a

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• Julien Borrel Jerome Waser Laboratory of Catalysis and Organic Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL SB ISIC LCSO, BCH 4306, 1015 Lausanne, Switzerland 10.3762/bjoc.20.64 Abstract We report the detailed background for the

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• , Latvia Latvian Institute of Organic Synthesis, Aizkraukles Str. 21, Riga, LV-1006, Latvia 10.3762/bjoc.20.61 Abstract 2-Chloro-4-sulfonylquinazolines undergo functional group swap when treated with an azide nucleophile: 1) the azide replaces the sulfonyl group at the C4 position; 2) the intrinsic azide