Reactions of 2-carbonyl- and 2-hydroxy(or methoxy)alkyl-substituted benzimidazoles with arenes in the superacid CF₃SO₃H. NMR and DFT studies of dicationic electrophilic species

• Dmitry S. Ryabukhin,
• Alexey N. Turdakov,
• Natalia S. Soldatova,
• Mikhail O. Kompanets,
• Alexander Yu. Ivanov,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1962–1973, doi:10.3762/bjoc.15.191

• superacids or coordination by a Lewis superacid to produce a di- (tri- or higher) cationic species, the study of superelectrophilic activation became a very active area of research [11][12][13]. The acid-catalyzed condensation of ketones and aldehydes with aromatic compounds is known as the hydroxyalkylation

Complexation of chiral amines by resorcin[4]arene sulfonic acids in polar media – circular dichroism and diffusion studies of chirality transfer and solvent dependence

• Bartosz Setner and
• Agnieszka Szumna

Beilstein J. Org. Chem. 2019, 15, 1913–1924, doi:10.3762/bjoc.15.187

• , Supporting Information File 1). It should be noted that chirality induction can be exploited to design chirality sensing ensembles [17]. This strategy was successfully implemented by the Nau group for sensing of chiral aromatic compounds. Ternary complexes between cucurbit[8]uril, dicationic dyes, and chiral

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Molecular basis for the plasticity of aromatic prenyltransferases in hapalindole biosynthesis

• Takayoshi Awakawa and
• Ikuro Abe

Beilstein J. Org. Chem. 2019, 15, 1545–1551, doi:10.3762/bjoc.15.157

• Aromatic prenyltransferases (PTases) are enzymes that catalyze Friedel–Crafts reactions between aromatic compounds and isoprenoid diphosphates. In hapalindole biosynthesis, the aromatic PTases AmbP1 and AmbP3 exhibit surprisingly plastic selectivities. AmbP1 not only transfers the geranyl group on the C-3

• (DMATS)-type [6][7], and the membrane-bound type PTases [8][9]. Some of them exhibit broad substrate specificities and accept various aromatic compounds as prenyl acceptors. For example, NphB (also called Orf-2), the first reported ABBA-type PTase in naphtherpin biosynthesis, accepts several aromatic

• compounds, including dihydroxynaphthalenes, flavonoids, and resorcinols as prenyl acceptors, and C10 geranyl diphosphate (GPP) as a prenyl donor, to generate a variety of O- or C-prenylated aromatic compounds [4][10]. Some PTases accept multiple lengths of isoprenoid diphosphates, as exemplified by the ABBA

Volatiles from the hypoxylaceous fungi Hypoxylon griseobrunneum and Hypoxylon macrocarpum

• Jan Rinkel,
• Alexander Babczyk,
• Tao Wang,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 2974–2990, doi:10.3762/bjoc.14.277

• . A peculiar problem in the analysis of aromatic compounds with multiple substituents is that constitutional isomers with the same types of substituents, but different substitution patterns often have very similar mass spectra. Furthermore, some of the isomers may also have similar retention indices

• diastereomers usually also produce very similar mass spectra [16], a phenomenon that is also reported for E and Z stereoisomers and can lead to wrong structural assignments, if no authentic standards are used for comparison [17]. We have recently reported on two chlorinated aromatic compounds from an endophytic

• characteristic and strong odour, as was already mentioned in the literature for H. macrocarpum [22][23], but the nature of the odoriferous compounds remained unknown. As will be shown, the bouquets of both species are composed mainly of highly substituted aromatic compounds whose structures were only securely

Learning from B₁₂ enzymes: biomimetic and bioinspired catalysts for eco-friendly organic synthesis

• Keishiro Tahara,
• Ling Pan,
• Toshikazu Ono and
• Yoshio Hisaeda

Beilstein J. Org. Chem. 2018, 14, 2553–2567, doi:10.3762/bjoc.14.232

• the presence of photosensitizers. 1,2-Migration of a phenyl group mediated by the visible-light-driven catalytic system composed of 1 and Irdfppy. Ring-expansion reactions mediated by the B12-TiO2 hybrid catalyst with UV-light irradiation. Trifluoromethylation and perfluoroalkylation of aromatic

• compounds achieved through electrolysis with catalyst 1. Acknowledgements This work was partially supported by JSPS KAKENHI Grant Number JP18H04265 in Precisely Designed Catalysts with Customized Scaffolding and Grant Number JP16H04119. The authors would like to thank Enago (http://www.enago.jp) for the

Cobalt- and rhodium-catalyzed carboxylation using carbon dioxide as the C1 source

• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2018, 14, 2435–2460, doi:10.3762/bjoc.14.221

• reductant, carboxyzincation and the four-component coupling reaction between alkyne, acrylates, CO2, and zinc occur efficiently. Rh complexes also catalyze the carboxylation of arylboronic esters, C(sp2)–H carboxylation of aromatic compounds, and hydrocarboxylation of styrene derivatives. The Rh-catalyzed

• efficiently. Rh complexes also catalyze the carboxylation of aryl and vinylboronic esters, the C(sp2)–H carboxylation of aromatic compounds, and the hydrocarboxylation of styrene derivatives. The Rh-catalyzed [2 + 2 + 2] cycloaddition of diynes and CO2 proceeds to afford pyrenes. Combinations of metals

Practical tetrafluoroethylene fragment installation through a coupling reaction of (1,1,2,2-tetrafluorobut-3-en-1-yl)zinc bromide with various electrophiles

• Ken Tamamoto,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2018, 14, 2375–2383, doi:10.3762/bjoc.14.213

• -substituted aromatic compounds 4b–r (Figure 3). Aromatic iodides with an electron-donating group, such as OMe (3b) and Me (3c), at the para position on the benzene ring were successfully coupled with 2-Zn under the optimized conditions to form 4b and 4c in 43% and 36% isolated yields, respectively. p-Chloro

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• properties which are very helpful for observing the molecular switching in MIMs are charge-transfer bands. The π-donor TTF can form donor–acceptor complexes with π-electron-poor aromatic compounds often indicated by a green color of the solution [33]. Therefore, the assembly and disassembly of these

• complexes π-electron-rich aromatic compounds such as dihydroxynaphthalenes or dihydroxybenzenes. The π-donor TTF (1) also forms a 1:1 complex 13 with this host molecule as shown in solution experiments and by crystallography. The complex formation is immediately visible by an emergent green color of these

Direct electrochemical generation of organic carbonates by dehydrogenative coupling

• Tile Gieshoff,
• Vinh Trieu,
• Jan Heijl and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2018, 14, 1578–1582, doi:10.3762/bjoc.14.135

• method for the generation of organic carbonates using inexpensive starting materials without the necessity of catalysts. Generally, alcohols serve as starting materials for the DPC and DMC synthesis. However, efficiency increases if non-functionalized aromatic compounds serve as feedstock. Boron-doped

• studies on a potential scope of aromatic compounds, the symmetric 1,3,5-threefold substitution pattern showed best selectivity according to GC–MS measurements. Since the nucleophilic attack is controlled by sterics, non-symmetric substitution patterns gave weak signals and product mixtures. Generally, the

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

• Claudia Lar,
• Adrian Woiczechowski-Pop,
• Attila Bende,
• Ioana Georgeta Grosu,
• Natalia Miklášová,
• Elena Bogdan,
• Niculina Daniela Hădade,
• Anamaria Terec and
• Ion Grosu

Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115

• reported cage-box [11] is able to complex a plethora of aromatic compounds (e.g., anthracene, pyrene, perylene), while in the cases of several metallo-based cryptands the formation of layered host–guest supramolecular structures (with many guests in the cavity of the host) were reported [12][13][14][15

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

Volatiles from three genome sequenced fungi from the genus Aspergillus

• Jeroen S. Dickschat,
• Ersin Celik and
• Nelson L. Brock

Beilstein J. Org. Chem. 2018, 14, 900–910, doi:10.3762/bjoc.14.77

• encoded terpene synthases for each strain. Besides terpenes, a series of aromatic compounds and volatiles derived from fatty acid and branched amino acid metabolism were identified. Some of these compounds have not been described as fungal metabolites before. For the compound ethyl (E)-hept-4-enoate known

Volatiles from the xylarialean fungus Hypoxylon invadens

• Jeroen S. Dickschat,
• Tao Wang and
• Marc Stadler

Beilstein J. Org. Chem. 2018, 14, 734–746, doi:10.3762/bjoc.14.62

• The volatiles emitted by agar plate cultures of the xylarialean fungus Hypoxylon invadens were investigated by use of a closed loop stripping apparatus in combination with GC–MS. Several aromatic compounds were found that could only be identified by comparison to all possible constitutional isomers

• α-cadinene (5). The same problem applies to the unambiguous identification of regioisomers of aromatic compounds. We have recently reported on the GC–MS-based identification of the fungal volatiles 1-chloro-3,4-dimethoxybenzene (6) and 1,3-dichloro-4,5-dimethoxybenzene (7) from an endophytic

• to select a culture initiated from the germinating ascospores of H. invadens among a panel of hypoxylaceous fungi that were studied for comparison of their volatile profiles [13]. Several aromatic compounds were detected in the headspace extracts of Hypoxylon invadens MUCL 54175 for which an

Cobalt-catalyzed directed C–H alkenylation of pivalophenone N–H imine with alkenyl phosphates

• Wengang Xu and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2018, 14, 709–715, doi:10.3762/bjoc.14.60

• , directing group-assisted arene C–H activation reactions have been extensively studied over the last few decades to offer a broad array of atom and step-economical methods for the synthesis of functionalized aromatic compounds [1][2][3][4][5][6]. Among various C–H transformations, the introduction of alkenyl

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• secondary amine. Recently, one of its special variations called modified Mannich reaction, has gained ground, in which the C–H acid is replaced by electron-rich aromatic compounds such as 1- and 2-naphthols as active hydrogen sources [6]. At the beginning of the 20th century, Mario Betti reported the

• of Evodia rutaecarpa alkaloids, starting from 6-methoxy-4,9-dihydro-β-carboline and various substituted 1-aminoalkyl-2-naphthols [84] (Scheme 5). Reactions with electron rich aromatic compounds The formation of aza-o-QMs is also possible, if the initial phenolic Mannich base bears an aromatic moiety

• transferred as building blocks into several natural or biologically active compounds. Thanks to the immense number of possibilities for Mannich reaction through the use of various amines, aldehydes and electron-rich aromatic compounds, the continued evolution of the literature on these reactions appears to be

Palladium-catalyzed ortho-halogenations of acetanilides with N-halosuccinimides via direct sp² C–H bond activation in ball mills

• Zi Liu,
• Hui Xu and
• Guan-Wu Wang

Beilstein J. Org. Chem. 2018, 14, 430–435, doi:10.3762/bjoc.14.31

• , traditional halogenations of aromatic compounds by direct electrophilic halogenation [3] and Sandmeyer reaction [4] have several drawbacks such as low regioselectivities, complicated reaction procedures and even a risk of danger. Thus, it is necessary to discover new approaches to the regioselective

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• trifluoromethylation reagents. Review Copper-catalyzed trifluoromethylation of aryl and alkyl halides The first example of copper-promoted perfluoroalkylation of aromatic halides was presented in a US patent 1968 [9]. Since then, the copper-catalyzed trifluoromethylation of aromatic compounds has entered a stage of

Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)

• Tao Wang,
• Kathrin I. Mohr,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9

• different compound classes including fatty acid derivatives and polyketides, aromatic compounds, terpenes, sulfur and nitrogen compounds, and halogenated compounds is produced by ascomycete fungi [1]. Possibly the most widespread volatile secondary metabolite from fungi is (R)-oct-1-en-3-ol (1, Scheme 1), a

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• group imparts enhanced lipophilicity of aromatic compounds in comparison with aryl–CF3 analogues (Hansch’s hydrophobic parameter π(SCF3) = 1.44; π(OCF3) = 1.04 versus π(CF3) = 0.88). Trifluoromethyl sources are manifold displaying nucleophilic, electrophilic or radical reactivities [11]. The most

• °C) soluble in water and slightly soluble in acetonitrile, methanol and acetone [13]. Although this reagent was prepared in 1955 by Haszeldine [14] and in 1976 by Roesky [15], it is only in 1991 that Langlois reported the trifluoromethylation of aromatic compounds under oxidative conditions [16

• arenes and heteroarenes: In 1991, Langlois and co-workers reported the first trifluoromethylation of aromatic compounds with sodium trifluoromethanesulfinate under oxidative conditions (Scheme 34) [16]. The scope was quite narrow with electron-rich aromatics and mixtures of regioisomers were often

Synthesis and supramolecular properties of regioisomers of mononaphthylallyl derivatives of γ-cyclodextrin

• Markéta Bláhová,
• Sergey K. Filippov,
• Lubomír Kováčik,
• Jiří Horský,
• Simona Hybelbauerová,
• Zdenka Syrová,
• Tomáš Křížek and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2017, 13, 2509–2520, doi:10.3762/bjoc.13.248

• parentheses because of their low reliability. Nevertheless, even those values, as well as those for 2-O-NA-γ-CD and 3-O-NA-γ-CD at all three temperatures correspond to values found for γ-CD and aromatic compounds [39]. Binding of the 2-O-regioisomer is stronger than that of the 3-O-regioisomer, and

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

• structure of CF3ICl2 could even be obtained. However, consistent with our observations, the compound decomposed above −35 °C. Syntheses and reactions, aryl iodides with one perfluoroalkyl group. Aromatic compounds are challenging to render highly fluorophilic [16][30][44]. For example, the singly-phase

Direct catalytic arylation of heteroarenes with meso-bromophenyl-substituted porphyrins

• Alexei N. Kiselev,
• Olga K. Grigorova,
• Alexei D. Averin,
• Sergei A. Syrbu,
• Oskar I. Koifman and
• Irina P. Beletskaya

Beilstein J. Org. Chem. 2017, 13, 1524–1532, doi:10.3762/bjoc.13.152

• using the Pd(OAc)2/DavePhos/PivOH catalytic system (DavePhos = 2-dicyclohexylphosphine-2’-dimethylaminobiphenyl, PivOH = t-BuCOOH) [26][27], and also bromo derivatives of condensed aromatic compounds were employed in this process [28]. The results of the Osuka group and other researchers in this field

Nitration of 5,11-dihydroindolo[3,2-b]carbazoles and synthetic applications of their nitro-substituted derivatives

• Roman A. Irgashev,
• Nikita A. Kazin,
• Gennady L. Rusinov and
• Valery N. Charushin

Beilstein J. Org. Chem. 2017, 13, 1396–1406, doi:10.3762/bjoc.13.136

• as one more example of electrophilic substitution in this series of scaffolds. In general, nitration of aromatic compounds, one of the well-known reactions, has a great significance for various fields of industrial chemistry, as it has been exploited extensively for large-scale processes, obtaining

• NMR spectra of nitro derivatives 9, while this singlet is observed at 8.01–8.04 ppm in the 1H NMR spectra of the starting aromatic compounds 8. We have demonstrated that mono C6-nitration of ICZ compounds 8a,b has afforded 6-nitro-ICZs 10a,b (Scheme 4). It has turned out that further nitration of 6,12