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

• pharmaceutical molecules. Considering the synthetic applications of sulfur-based compounds, a large number of researchers have noted that these scaffolds have promising potential for the research and development of new biomedicines. In the sulfenylation of organic compounds, the sulfenylating agents are

• intermediate led to intramolecular cyclization. In 2020, electrophilic cyclization of allylic amides 134 using N-(phenylthio)succinimide 1 in the presence of camphorsulfonic acid (CSA) as a Brønsted acid and tetrabutylammonium chloride (TBAC) led to 5-[(phenylthio)methyl]oxazoline scaffolds 135 (Scheme 57) [89

Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

• Alessandro Brusa,
• Debora Iapadre,
• Maria Edith Casacchia,
• Alessio Carioscia,
• Giuliana Giorgianni,
• Giandomenico Magagnano,
• Fabio Pesciaioli and
• Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

• organic synthesis to build complex scaffolds starting from simple starting materials. The Enders three-component cascade reaction was a cornerstone in the field and a plethora of organocatalyzed cascade reactions followed. However, acetaldehyde was not shown as a successful reaction partner, probably

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• indicated that only one diastereoisomer was predominately produced in the reaction, while the other possible diastereomers were not detected. This result shows that this reaction has a high diastereoselectivity due to the large steric effect of two oxindole scaffolds and the thermodynamically controlling

• effect. The single crystal structure of compound 3a was determined by X-ray crystallographic diffraction (Figure 1). From Figure 1 it can be seen that the two scaffolds of oxindole at neighboring positions are in trans-configuration. The ethoxycarbonyl group is also in trans-position to the carbonyl

• different reactivity to that of the adducts of 3-ethoxycarbonylmethyleneoxindoles. For confirming the chemical structures of dispirooxindoles 4a–i, the single crystal structure of compound 4a was determined by X-ray diffraction (Figure 2). In Figure 2, the two oxindole scaffolds are in trans-position. The

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• addition to alkenes and radical decarboxylation, with many of these being driven by light energy. RLT in alkene functionalization Outside of the realm of C–H activation, RLT has been leveraged to afford complex medicinal scaffolds in alkene difunctionalization. A recent example can be found in the merger

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• ; multicomponent synthesis; one-pot reaction; trichloroacetic acid; Introduction π-Conjugated porphyrin macrocycles are known for their applications in numerous areas ranging from oxygen transport, photosynthesis, catalysis and medicine [1][2][3]. In the past several years, diverse organic scaffolds have been

• contruction of periphery-modified porphyrinoids [30][31][32][33][34][35][36][37][38][39][40][41], we thought to assemble benzo[f]chromeno[2,3-h]quinoxalinoporphyrins by incorporating porphyrin, quinoxaline and xanthene scaffolds in a single molecular framework using a multicomponent synthetic strategy. The

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• indoline scaffolds (22a,b) via a radical-polar crossover mechanism (Figure 12C) [65], showcasing the power of conPET in dearomatization reactions. Finally, the synthesis of tetraphenylphosphonium chloride (20a) could be scaled up efficiently in an operationally very simple continuous-flow setup with only

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• ketimines 49 to construct an aza-quaternary stereocenter at the C3 position of oxindole scaffolds 61 bearing a β-naphtholyl substituent (Scheme 16b) [44]. In 2020, Meng, Chan, Zhao and co-workers reported another C3-selective aza-Friedel–Crafts reaction of 4-aminoindole derivatives 63 utilizing N-Boc-α

• than with indole (Scheme 19) [47]. In 2021, Zhang and co-workers used 5-aminoisoxazole scaffolds 82 in an enantioefficient aza-Friedel–Crafts reaction with isatin-derived N-Boc ketimines 49. A 2-oxindole-substituted aza-quaternary stereocenter was installed at the C4 position of the heteroaromatic ring

• -derived ketimines 49 was reported by Vila, Pedro and co-workers. Regioisomeric hydroxyquinolines were tested in this reaction to facilitate the electrophilic aromatic substitution on the ortho-carbon atom with respect to the hydroxy group in quinolines 15. The reaction affords oxindole scaffolds 116 with

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• obtained by other conjugate addition reactions. Keywords: acylimidazole; asymmetric catalysis; carbocation; conjugate addition; enolate; Introduction Asymmetric metal-catalyzed conjugate additions provide access to numerous chiral scaffolds. This type of C–C bond formation efficiently enables the

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• Adrian Saura-Sanmartin Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, 30100 Murcia, Spain 10.3762/bjoc.19.64 Abstract Light-responsive rotaxane-based solid-state materials are ideal scaffolds in order to develop smart materials due to the properties provided by the

• counterparts and/or macroscopic motion of the interlocked materials are achieved. Although further development is needed, these materials are envisioned as privileged scaffolds which will be used for different advanced applications in the area of molecular machinery. Keywords: light irradiation; light

• scaffolds [11]. In particular, rotaxanes and pseudorotaxanes have led to a greater number of applications due to their inherent dynamics and the switching possibility through a rational design [12]. Thus, rotaxane-based materials have attracted the interest of the scientific community due to their enhanced

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• of several methods for the synthesis of functionalized pyridines or their integration into an organic molecule, new methodologies for the direct functionalization of pyridine scaffolds have been developed during the past two decades. In addition, transition-metal-catalyzed C–H functionalization and

• the mechanisms involved. Keywords: C–H functionalization; heterocycles; pyridine; rare earth metal; transition-metal-catalyzed; Introduction Pyridine, one of the most important azaheterocyclic scaffolds, is found in a diverse range of bioactive natural products, pharmaceuticals, and functional

• serve as bioisostere for aromatic rings, amines, amides, and N-containing heterocycles. Due to the aforementioned qualities, numerous U.S. FDA-approved medications have pyridine scaffolds in their molecules (Figure 1). In this context, the synthesis of the pyridine motif is always there in trend. Many

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• , Fernández et al. presented a Cu-catalyzed tandem borylation/transannular aldol cyclization using decane and undecane macrocyclic substrates 151 (Scheme 39) [80]. This methodology enabled the synthesis of complex bicyclic scaffolds in a completely diastereoselective and straightforward manner. Based on their

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• scaffolds 147 through a domino ARO reaction followed by cyclization reaction of oxabicyclic alkenes 30 with sodium cyanate (146) (Scheme 26) [72]. This reaction proceeded smoothly with electron-rich oxabenzonorbornadiene derivatives; however, electron-poor oxabenzonorbornadiene derivatives resulted in

Computational studies of Brønsted acid-catalyzed transannular cycloadditions of cycloalkenone hydrazones

• Manuel Pedrón,
• Jana Sendra,
• Irene Ginés,
• Tomás Tejero,
• Jose L. Vicario and
• Pedro Merino

Beilstein J. Org. Chem. 2023, 19, 477–486, doi:10.3762/bjoc.19.37

• catalysis in route to enantiomerically pure bicyclic 1,3-diamines (Scheme 1) [29]. The reaction led to excellent results when decalines and octahydro-1H-indene bicyclic scaffolds were formed (series a and b) but failed in other cases (series c, d, and k). Series e, f, g, h, and i have not been tested

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• approaches, the transition-metal-catalyzed functionalization of various scaffolds with a panel of fluorinated groups (XRF, X = S, Se, O) offered straightforward access to high value-added compounds. This review will highlight the main advances made in the field with the transition-metal-catalyzed

• -fluorinated molecules [1][2], their incorporation in various scaffolds afforded high value-added compounds as demonstrated by their numerous applications in the industrial sector such as drugs, agrochemicals, and materials. To further illustrate the ubiquity of fluorinated compounds, almost 20% of

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• majority of porphyrin hybrids are synthesized by modifying β- and meso-positions of porphyrin, thus numerous chromophoric groups and biologically important scaffolds have been attached to porphyrins at these positions in recent years. In the past, many synthetic procedures have been utilized to covalently

Continuous flow synthesis of 6-monoamino-6-monodeoxy-β-cyclodextrin

• János Máté Orosz,
• Dóra Ujj,
• Petr Kasal,
• Gábor Benkovics and
• Erika Bálint

Beilstein J. Org. Chem. 2023, 19, 294–302, doi:10.3762/bjoc.19.25

• readily reduced to mono(6-amino-6-deoxy)-CDs (NH2-CDs) opening the way for the preparation of amine, thioureido or amide-linked CD scaffolds [14]. Several other nucleophiles can react with mono-6-O-tosyl-CDs, such as iodide, dithiol, hydroxylamine, alkylamine or polyalkylamine to give iodo- [15], thio

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series

• Cécile Alleman,
• Charlène Gadais,
• Laurent Legentil and
• François-Hugues Porée

Beilstein J. Org. Chem. 2023, 19, 245–281, doi:10.3762/bjoc.19.23

An efficient metal-free and catalyst-free C–S/C–O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides

• Shubham Sharma,
• Dharmender Singh,
• Sunit Kumar,
• Vaishali,
• Rahul Jamra,
• Naveen Banyal,
• Deepika,
• Chandi C. Malakar and
• Virender Singh

Beilstein J. Org. Chem. 2023, 19, 231–244, doi:10.3762/bjoc.19.22

• scaffolds for the design and construction of pharmacologically relevant compounds [1][2][3]. Their effectiveness has been witnessed in agrochemicals [4][5][6], chemicals, and pharmaceutical industries. Moreover, recent findings have affirmed the potential of the pyrazole nucleus as CB1 receptor antagonists

• diseases (Figure 1). Accordingly, as a part of our ongoing research project, it was planned to incorporate thioamide and amide functional groups into a pyrazole framework to develop new scaffolds. An extensive literature survey revealed that several approaches are well-documented for the construction of

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

• extracellular matrix in 3D cultures of colorectal cancer cell lines prepared using polymer-based scaffolds. Murine or human colon cancer cells were seeded on poly-HEMA-coated cell plates prepared as described in the methods section, and the plates were centrifuged. The cells were found to be collected in the

1,4-Dithianes: attractive C2-building blocks for the synthesis of complex molecular architectures

• Bram Ryckaert,
• Ellen Demeyere,
• Frederick Degroote,
• Hilde Janssens and
• Johan M. Winne

Beilstein J. Org. Chem. 2023, 19, 115–132, doi:10.3762/bjoc.19.12

• and carbohydrates to various carbocyclic scaffolds. This versatility arises from the possibility to chemoselectively cleave or reduce the sulfur-heterocycle to reveal a versatile C2-synthon. Keywords: 1,4-dithianes; 1,4-dithiins; 2,3-dihydro-1,4-dithiins; heterocycles; target synthesis; Introduction

• products related to different competing reaction pathways. However, when suitable cation-stabilizing substituents are present, especially on the central carbon atom, very useful transformations can result for the rapid assembly of cycloheptanoid scaffolds [91]. Oxyallyl cations (when Z is an oxygen-based

• allowed the assembly of complex terpenoid frameworks. Examples from our research group include various daucanoid and kauranoid terpene scaffolds such as 108, 109, and 110, which can be assembled from dihydrodithiin 3 as a building block in just a few synthetic operations with good to excellent control of

Synthesis and characterisation of new antimalarial fluorinated triazolopyrazine compounds

• Kah Yean Lum,
• Jonathan M. White,
• Daniel J. G. Johnson,
• Vicky M. Avery and
• Rohan A. Davis

Beilstein J. Org. Chem. 2023, 19, 107–114, doi:10.3762/bjoc.19.11

• sulfinate-based reagents (marketed by Merck as Diversinates™) to functionalise heteroaromatic C–H bonds of unprotected systems in a variety of solvents at room temperature and without the requirement of an inert atmosphere or solvent purification [11][12][13]. In our previous work on OSM Series 4 scaffolds

• yields. This paper reports additional and more thorough Diversinate™ studies on three phenethyl ether substituted triazolopyrazine scaffolds, with a particular focus on incorporating the fluoro fragments -CF3, -CF2H and -CF2Me into the OSM Series 4 structures via LSF chemistry. The new library of

• , cyano, nitro, or halogenated groups at the para-position were crucial for activity [5][16][20]. Thus, compounds 1–3 with a para-phenyl-OCHF2, -Cl or -CN substituent at the C3 position of the triazole were selected as scaffolds in this study. In addition, the reported SAR data also indicated that the use

Practical synthesis of isocoumarins via Rh(III)-catalyzed C–H activation/annulation cascade

• Qian-Ci Gao,
• Yi-Fei Li,
• Jun Xuan and
• Xiao-Qiang Hu

Beilstein J. Org. Chem. 2023, 19, 100–106, doi:10.3762/bjoc.19.10

• for the synthesis of isocoumarin scaffolds. Traditional synthetic strategies including 1) intramolecular cyclization of 2-alkenyl benzoic acids or o‑alkynylbenzoates (Scheme 1b, I) [6][7][8][9][10], 2) oxidation of isochromans (Scheme 1b, II) [11][12], or 3) metal-catalyzed cross-coupling/cyclization

• easily available, which have been established as versatile synthetic building blocks for the synthesis of cyclic scaffolds [25]. In 2016, Zhu et al. reported the first example of a Rh-catalyzed C–H functionalization of enaminones with alkynes and α-diazo-β-ketoesters to access naphthalenes [26]. Very

Revisiting the bromination of 3β-hydroxycholest-5-ene with CBr₄/PPh₃ and the subsequent azidolysis of the resulting bromide, disparity in stereochemical behavior

• Christian Schumacher,
• Jas S. Ward,
• Kari Rissanen,
• Carsten Bolm and
• Mohamed Ramadan El Sayed Aly

Beilstein J. Org. Chem. 2023, 19, 91–99, doi:10.3762/bjoc.19.9

• -azidocholest-5-ene (5) in high yield. The same product was recently obtained by direct dehydroxyazidation of cholesterol upon treatment with N-acetyl azidobenziodazolone (ABZ) and PPh3 in THF [19], Table 1. While synthesizing new potential biologically active probes with cholesterol scaffolds in the Port Said

Catalytic aza-Nazarov cyclization reactions to access α-methylene-γ-lactam heterocycles

• Bilge Banu Yagci,
• Selin Ezgi Donmez,
• Onur Şahin and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2023, 19, 66–77, doi:10.3762/bjoc.19.6

• or more heteroatoms in the dienone core have the potential to provide efficient access to a variety of heterocyclic scaffolds. Among such variants, the aza-Nazarov reaction appears as a highly suitable cyclization reaction that presents opportunities for the construction of a diverse array of five

NaI/PPh₃-catalyzed visible-light-mediated decarboxylative radical cascade cyclization of N-arylacrylamides for the efficient synthesis of quaternary oxindoles

• Dan Liu,
• Yue Zhao and
• Frederic W. Patureau

Beilstein J. Org. Chem. 2023, 19, 57–65, doi:10.3762/bjoc.19.5

• attention due to their propensity to build important oxindole scaffolds. These are broadly found in natural products, pharmaceuticals, and bioactive molecules (Figure 1) [7][8][9][10][11][12][13]. Although a number of synthetic approaches have already been explored [14][15][16][17][18][19][20], these

• can operate as an efficient photoredox catalyst, providing an economical access to construct important oxindole scaffolds containing a quaternary carbon center. This synthetic method features a broad substrate scope, good functional group tolerance and operational simplicity. Mechanistic