Arene activation via π-bond localization: concepts and opportunities

• Paul Meiners,
• Julian J. Melder and
• Tobias Morack

Beilstein J. Org. Chem. 2026, 22, 257–273, doi:10.3762/bjoc.22.19

• ], allylgrignards [78], amines [79], and allenylstannanes [80], thereby accessing the corresponding propargyl-functionalized products (Scheme 6B). In parallel, Bao and co-workers demonstrated that the dearomatization manifold extends beyond simple benzenoid systems to include heteroarenes such as furans, thiophenes

Transition-state aromaticity and its relationship with reactivity in pericyclic reactions

• Israel Fernández

Beilstein J. Org. Chem. 2025, 21, 1613–1626, doi:10.3762/bjoc.21.125

• defined by Doering and Detert [6], this concept has been extended well beyond benzenoid molecules to organometallic, inorganic, and even saturated molecules. As a result, besides classical π-aromaticity, other aromaticity types such as Möebius, spherical, or excited-state aromaticity (to name a few) have

Recent advances and future challenges in the bottom-up synthesis of azulene-embedded nanographenes

• Bartłomiej Pigulski

Beilstein J. Org. Chem. 2025, 21, 1272–1305, doi:10.3762/bjoc.21.99

• Bartlomiej Pigulski Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland 10.3762/bjoc.21.99 Abstract In recent years, significant progress has been made in the synthesis of various nanographenes incorporating non-benzenoid rings, expanding the scope of molecular

• nanographenes, with a particular focus on the synthetic strategies. Additionally, it explores selected aspects of aromaticity and spectroscopic properties. Keywords: azulene; nanographenes; non-alternant; non-benzenoid; polycyclic aromatic hydrocarbons; Introduction The discovery of graphene and fullerenes

• benzenoid nanographenes, also known as polycyclic aromatic hydrocarbons (PAHs) [8][9]. PAHs can be considered molecular models of bulk graphene, offering invaluable insights into structure–property relationships in graphene and graphene-based materials. Structural defects appear to be inevitable in real

On the photoluminescence in triarylmethyl-centered mono-, di-, and multiradicals

• Daniel Straub,
• Markus Gross,
• Mona E. Arnold,
• Julia Zolg and
• Alexander J. C. Kuehne

Beilstein J. Org. Chem. 2025, 21, 964–998, doi:10.3762/bjoc.21.80

Ceratinadin G, a new psammaplysin derivative possessing a cyano group from a sponge of the genus Pseudoceratina

• Shin-ichiro Kurimoto,
• Kouta Inoue,
• Taito Ohno and
• Takaaki Kubota

Beilstein J. Org. Chem. 2024, 20, 3215–3220, doi:10.3762/bjoc.20.267

• existence of a substituted benzenoid chromophore was suggested by the UV absorption maximum at 258 nm. The presence of hydroxy and/or amino groups and a carbonyl group was indicated by IR absorptions at 3337 cm−1 and 1671 cm−1, respectively. The analysis of the HSQC spectrum, along with the 1H and 13C NMR

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

• underscored by the successful conversion of various α,α-difluoromethyl ketone groups into corresponding esters, amides, and difluoromethyl groups [58]. In 2021, Nilova and colleagues outlined an approach for the synthesis of highly hindered 1,2,3,4-tetrasubstituted benzenoid rings 15 using arynes generated

Regioselective alkylation of a versatile indazole: Electrophile scope and mechanistic insights from density functional theory calculations

• Pengcheng Lu,
• Luis Juarez,
• Paul A. Wiget,
• Weihe Zhang,
• Krishnan Raman and
• Pravin L. Kotian

Beilstein J. Org. Chem. 2024, 20, 1940–1954, doi:10.3762/bjoc.20.170

• position of the NH hydrogen atom: 1H-indazole (5a, benzenoid 1H-indazole tautomer) and 2H-indazole (5b, quinonoid 2H-indazole tautomer) (Figure 2) [21][22][23]. Since 1H-indazole is thermodynamically more stable than 2H-indazole, 5a is the predominant tautomer [24][25][26]. Conventionally, indazoles are

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• benzenoid→quinonoid excitonic transitions, respectively, which was characteristic of polyaniline existing as emeraldine free base [41][42]. The polyaniline nature was further confirmed by FTIR spectroscopy (Figure S2, Supporting Information File 1). The broad peak observed in the range of 3300–3400 cm−1 was

Light on the sustainable preparation of aryl-cored dibromides

• Fabrizio Roncaglia,
• Alberto Ughetti,
• Nicola Porcelli,
• Biagio Anderlini,
• Andrea Severini and
• Luca Rigamonti

Beilstein J. Org. Chem. 2024, 20, 1076–1087, doi:10.3762/bjoc.20.95

• ” first-ring-then-benzylic halogenation methods are compared. Conclusion In summary, the peroxide-bromide halogenation method, originally developed for the monobromination of benzenoid structures, has been extended to synthesize aryl-cored polybromides with high yield and high atom economy. This method

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• distorted structures can be obtained and their intrinsic properties investigated, and on the other hand, with a subtle choice of the chalcogen element and its oxidation state, controlled extrusion coupled to 7-membered ring contraction will lead to planar benzenoid π-CPCs in situ, in response to diverse

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• helical bilayer, non-benzenoid nanographene 58 which contains a [10]helicene with two embedded heptagons as a novel chiral moiety (Scheme 11). By using the same intermediate 43, the iodine-NG 101 together with NG 44 was obtained in a 22% yield. Then compound 101 was coupled with 4-tert

The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet–Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids

• Marco Keller,
• Karl Sauvageot-Witzku,
• Franz Geisslinger,
• Nicole Urban,
• Michael Schaefer,
• Karin Bartel and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2716–2725, doi:10.3762/bjoc.17.183

• activation by TPC2-A1-P is better targetable than by TPC2-A1-N. This result is in accordance with our previous observations that TPC2-blocking activity is only observed for monomeric benzyltetrahydroisoquinolines if they are decorated with aromatic residues, which imitate the two benzenoid rings of the

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• -containing homo- and copolymers, including brief descriptions of their key properties. Keywords: azulene; chemical synthesis; copolymer; non-alternant hydrocarbon; organic electronics; polyazulene; Introduction Azulene (C10H8) is a non-alternant, non-benzenoid, 10 π electron aromatic hydrocarbon containing

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• treatment with ferrocyanide. A Cu powder-mediated reduction gives the N-protected bis(indol-2-yl)tellane 147. The final desulfonated product 148 is a potent thiol peroxidase reducing agent [100]. The benzenoid C4 and C7 linkages The syntheses of bisindolyl non-metallides connected through benzenoid rings of

• review summarizes the various (un)catalytic synthetic techniques of the symmetric and unsymmetric bis/tris(indolyl)-containing non-metallides consisting of multiple indole molecules covalently connected via C2, C3 (pyrrole ring) and C4–C7 (benzenoid ring) by different central atoms. Like the bis(indolyl

Regioselective N-alkylation of the 1H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution

• Ryan M. Alam and
• John J. Keating

Beilstein J. Org. Chem. 2021, 17, 1939–1951, doi:10.3762/bjoc.17.127

• indazole core facilitated excellent N-2 regioselectivity under conditions A (Table 4, entries 3 and 4). To further examine the positional effect of benzenoid ring substitution on N-alkylation regioselectivity, 6-, 5-, and 4-CO2Me substituted indazole derivatives were alkylated, under conditions A and B

• , solvent, and temperature.a Indazole C-3 substituent effects. Effect of NaH and THF on N-1 regioselectivity.a Effect of indazole benzenoid ring substituents on N-1:N-2 regioselectivity.a Effect of 15-crown-5 on the regioselective N-alkylation of indazole 9, in the presence of NaH in THF.a Alkylating

Synthesis of 4-amino-5-fluoropyrimidines and 5-amino-4-fluoropyrazoles from a β-fluoroenolate salt

• Tobias Lucas,
• Jule-Philipp Dietz and
• Till Opatz

Beilstein J. Org. Chem. 2020, 16, 445–450, doi:10.3762/bjoc.16.41

• products. Subsequently, benzamidine derivatives with a broad variety of substituents on the benzenoid core were evaluated as the nucleophiles. Benzamidine hydrochloride itself yielded compound 10h with an excellent yield of 93%. A variety of substituted products including electron-donating (compounds 10i–k

Design, synthesis and spectroscopic properties of crown ether-capped dibenzotetraaza[14]annulenes

• Krzysztof M. Zwoliński and
• Julita Eilmes

Beilstein J. Org. Chem. 2019, 15, 617–622, doi:10.3762/bjoc.15.57

• ], little research has been undertaken regarding DBTAAs functionalized with crown ether moieties (see Figure 1). Kruse and Breitmaier [24] reported annulated DBTAA‘s containing benzo-15-crown-5 scaffolds fused with benzenoid rings of the macrocyclic core. Both nickel(II) and cobalt(II) complexes were

Correction: Varioloid A, a new indolyl-6,10b-dihydro-5aH-[1]benzofuro[2,3-b]indole derivative from the marine alga-derived endophytic fungus Paecilomyces variotii EN-291

• Peng Zhang,
• Xiao-Ming Li,
• Xin-Xin Mao,
• Attila Mándi,
• Tibor Kurtán and
• Bin-Gui Wang

Beilstein J. Org. Chem. 2018, 14, 2394–2395, doi:10.3762/bjoc.14.215

• benzenoid derivatives; cytotoxicity; marine alga-derived fungus; Paecilomyces variotii; TDDFT-ECD calculation; The authors wish to rename compounds 1 and 2 (shown in Figure 1 of the original article [1]) as varioloids C and D, respectively (Figure 1), as the synonyms varioloids A and B have already been

Some mechanistic aspects regarding the Suzuki–Miyaura reaction between selected ortho-substituted phenylboronic acids and 3,4,5-tribromo-2,6-dimethylpyridine

• Piotr Pomarański,
• Piotr Roszkowski,
• Jan K. Maurin,
• Armand Budzianowski and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2018, 14, 2384–2393, doi:10.3762/bjoc.14.214

• , Tanaka presented an atropselective synthesis of axially chiral all-benzenoid biaryls by gold-catalysed intramolecular hydroarylation of alkynones to give the desired atropisomeric product with a good ee value of 70% [26]. Conventional approaches to the synthesis of biaryl compounds having axial chirality

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• . Benzotropolones Benzannulation to the tropolone scaffold can give numerous tautomeric hydroxybenzotropones or benzotropolenes. Figure 10 shows 238A (or 241A–240) as single tautomers, whereas 239 and 174 are depicted as a mixture of tautomers. Moreover, benzenoid structures as 238A are more stable than o-quinoidal

Syntheses, structures, and stabilities of aliphatic and aromatic fluorous iodine(I) and iodine(III) compounds: the role of iodine Lewis basicity

• Tathagata Mukherjee,
• Soumik Biswas,
• Andreas Ehnbom,
• Subrata K. Ghosh,
• Ibrahim El-Zoghbi,
• Nattamai Bhuvanesh,
• Hassan S. Bazzi and
• John A. Gladysz

Beilstein J. Org. Chem. 2017, 13, 2486–2501, doi:10.3762/bjoc.13.246

• powder in 89% yield. This material was stable at room temperature and gave a microanalysis consistent with a monohydrate. Hence, the iodine atom in benzenoid compounds with two Rf8CH2CH2 substituents is sufficiently Lewis basic to support a dichloride, but analogs with two Rf6 substituents are not

Synthesis and optical properties of new 5'-aryl-substituted 2,5-bis(3-decyl-2,2'-bithiophen-5-yl)-1,3,4-oxadiazoles

• Anastasia S. Kostyuchenko,
• Tatyana Yu. Zheleznova,
• Anton J. Stasyuk,
• Aleksandra Kurowska,
• Wojciech Domagala,
• Adam Pron and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2017, 13, 313–322, doi:10.3762/bjoc.13.34

• ). Moderate to large values of Stokes shifts are observed for compounds 15b–g originating from bond order switching (benzenoid to quinoid) in the excited state. Moderate values of Stokes shifts (0.52–0.63 eV) are observed for 15b–e and the Stokes shift increases with an increase of the aryl substituent size

Varioloid A, a new indolyl-6,10b-dihydro-5aH-[1]benzofuro[2,3-b]indole derivative from the marine alga-derived endophytic fungus Paecilomyces variotii EN-291

• Peng Zhang,
• Xiao-Ming Li,
• Xin-Xin Mao,
• Attila Mándi,
• Tibor Kurtán and
• Bin-Gui Wang

Beilstein J. Org. Chem. 2016, 12, 2012–2018, doi:10.3762/bjoc.12.188

• varioloid B (2). Both compounds 1 and 2 exhibited cytotoxicity against A549, HCT116, and HepG2 cell lines, with IC50 values ranging from 2.6 to 8.2 µg/mL. Keywords: bisindolyl benzenoid derivatives; cytotoxicity; marine alga-derived fungus; Paecilomyces variotii; TDDFT-ECD calculation; Introduction The

• cyclized bisindolyl benzenoid derivatives (compounds 1 and 2) (Figure 1). The rare planar structure of compound 2 was previously reported but the full NMR data were not disclosed and the relative and absolute configuration had not been determined [13]. Herein we describe the isolation, structural

• one isolated sp3-methine proton (δH 6.42, H-2), which were unambiguously designated by the HSQC experiment. A comprehensive analysis of the COSY spectrum (Figure 2) revealed the existence of two 1,2-disubstituted benzenoid rings (sequential COSY correlations from H-4 to H-7 and from H-4’ to H-7

SmI₂-mediated dimerization of indolylbutenones and synthesis of the myxobacterial natural product indiacen B

• Nils Marsch,
• Peter G. Jones and
• Thomas Lindel

Beilstein J. Org. Chem. 2015, 11, 1700–1706, doi:10.3762/bjoc.11.184

• not effect any reaction, as we learned when trying to dimerize the natural product verticillatine B (20) from the Brazilian plants Borreria verticillata and Raputia simulans [2][3]. We had speculated on the participation of the benzenoid double bond in dimerization reactions which would have

Star-shaped tetrathiafulvalene oligomers towards the construction of conducting supramolecular assembly

• Masahiko Iyoda and
• Masashi Hasegawa

Beilstein J. Org. Chem. 2015, 11, 1596–1613, doi:10.3762/bjoc.11.175

• oligomers with radially expanded structures can be expected to demonstrate multifunctional properties because a central core and TTF branches exhibit individual and/or cooperative functionalities [25]. For example, dendrimers composed of central benzenoid cores and TTF branches are cited as representative