Electrochemical synthesis of cyclic biaryl λ³-bromanes from 2,2’-dibromobiphenyls

• Andrejs Savkins and
• Igors Sokolovs

Beilstein J. Org. Chem. 2025, 21, 451–457, doi:10.3762/bjoc.21.32

• ester moieties is critical for the synthesis of Br(III) species: the removal of one ester group (4i–k), or its replacement by NO2 (4l) or SO2t-Bu (4m) substituents in 2,2'-dibromo-1,1'-biphenyls resulted in starting material degradation with no formation of the desired product (for a complete list of

• substrates that do not form the desired electrochemical oxidation product see Supporting Information File 1, Scheme S1). A series of control experiments was performed to rationalize the observed reactivity trends (Scheme 2). The measured redox potentials EP/2 for 2,2'-dibromo-1,1'-biphenyls 4a–g (from 1.77 V

• '-dibromo-1,1'-biphenyls 4a–m. A closer inspection of the electrochemical behaviour of compound 4a revealed an irreversible electron transfer at scan rates up to 1 V s−1 (Scheme 3A) indicating that one or more rapid chemical steps are following the electrochemical step [22][23]. Besides, the observed linear

Efficient synthesis of fluorinated triphenylenes with enhanced arene–perfluoroarene interactions in columnar mesophases

• Yang Chen,
• Jiao He,
• Hang Lin,
• Hai-Feng Wang,
• Ping Hu,
• Bi-Qin Wang,
• Ke-Qing Zhao and
• Bertrand Donnio

Beilstein J. Org. Chem. 2024, 20, 3263–3273, doi:10.3762/bjoc.20.270

• variety of triphenylene derivatives (Figure 1) [44][45][46][47] based on the nucleophilic substitution of various electrophilic perfluoroarenes, including C6F2H4, C6F6, C10F8, and C6F5-Ph, by nucleophilic organolithium reagents. e.g., 2,2’-dilithio-4,4’,5,5’-tetrakis(alkoxy)-1,1’-biphenyls, 2Li-BPn

4,6-Diaryl-5,5-difluoro-1,3-dioxanes as chiral dopants for liquid crystal compositions

• Maurice Médebielle,
• Peer Kirsch,
• Jérémy Merad,
• Carolina von Essen,
• Clemens Kühn and
• Andreas Ruhl

Beilstein J. Org. Chem. 2024, 20, 2940–2945, doi:10.3762/bjoc.20.246

• range of chiral, twisted molecules such as binaphthyls [23][24][25], biphenyls [26][27], TADDOLs [16][17] and 1,2-diphenylethane-1,2-diol [28] to reveal possible relationships between the molecular structure of chiral dopants and their HTP value. However, quantitative structure–property relationships

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

• series of primary benzylic biphenyls and two secondary substrates by comparing to the pulsed technique (pDC) to the traditional direct current (DC) technique (Figure 43B and C). Under a constant potential (CP) regime no product was observed, but it was demonstrated that the introduction of a resting

Domino reactions of chromones with activated carbonyl compounds

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 1256–1269, doi:10.3762/bjoc.20.108

• with 2-fluoro-1,3-bis(silyloxy)-1,3-butadienes 42a–z afforded separable mixtures of azaxanthones 43a–aa and biphenyls 44a–ac (Scheme 24) [47]. In case of 4-unsubstituted 2-fluoro-1,3-bis(silyloxy)-1,3-butadienes, azaxanthones 43 were exclusively formed in 33–56% yields. A similar result was obtained

• for the corresponding 2-chloro-1,3-bis(silyloxy)-1,3-butadiene [48]. In case of 4-alkyl-2-fluoro-1,3-bis(silyloxy)-1,3-butadienes, biphenyls 44 were formed as the major products in 63–79% yields. In some cases, these products were exclusively formed. In other cases, azaxanthones 43 were isolated as

• minor products as well (7–20% yields). The formation of biphenyls 44 can be explained by 1,4-addition and ring-cleavage to give intermediate AH, aldol reaction (intermediate AI), migration of the ester group from the quaternary carbon to the phenolic oxygen atom (intermediate AJ) and aromatization. The

Correction: Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2024, 20, 170–172, doi:10.3762/bjoc.20.16

Synthesis of N-acyl carbazoles, phenoxazines and acridines from cyclic diaryliodonium salts

• Nils Clamor,
• Mattis Damrath,
• Thomas J. Kuczmera,
• Daniel Duvinage and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2024, 20, 12–16, doi:10.3762/bjoc.20.2

• followed by a ring-closure starting from 2,2'-diiodo-1,1'-biphenyls [15][16][17]. Related one-pot procedures are also described (Scheme 1b) [18][19]. Such 2,2´-dihalobiphenyls are established starting materials for synthesizing a variety of heterocycles. Usually, their utilization leads to the production

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• 2,2'-dihalogenated biphenyls 4 as starting materials [24][25]. Although the cobalt-mediated alkyne trimerization route frequently used by Vollhardt and co-workers is not the first choice for the synthesis of the biphenylene itself, it has led to the synthesis of structurally demanding substituted

Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone

• Ilya A. P. Jourjine,
• Lukas Zeisel,
• Jürgen Krauß and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2668–2679, doi:10.3762/bjoc.17.181

• good yields via metal- and additive-free TBHP-promoted cross-dehydrogenative coupling (CDC) of readily accessible N-methyl-2-(aminomethyl)biphenyls and 2-(aminomethyl)biphenyls. This methodology is compatible with numerous functional groups (methoxy, cyano, nitro, chloro, and SEM and TBS-protective

• ], CBr4 [22], or peroxides like tert-butyl hydroperoxide (TBHP) [35]. Other oxidative cyclizations have been developed starting from biarylglyoxylic acids (using Na2S2O8) [36], and even 2-methylbiphenyls and 2-(hydroxymethyl)biphenyls can be converted into fluorenones by means of TBHP oxidation [37]. In

• published for fluorenone syntheses starting from other functionalized biphenyls with a key oxidative cyclization step. Starting from biphenyl-2-carbaldehyde (2l), Shi and Glorius [34] reported a fluorenone yield of 68%, utilizing potassium persulfate/tetraethylammonium bromide, the Singh group [35] reported

Chemical constituents of Chaenomeles sinensis twigs and their biological activity

• Joon Min Cha,
• Dong Hyun Kim,
• Lalita Subedi,
• Zahra Khan,
• Sang Un Choi,
• Sun Yeou Kim and
• Chung Sub Kim

Beilstein J. Org. Chem. 2020, 16, 3078–3085, doi:10.3762/bjoc.16.257

• [11]. As a part of the continuing studies to identify bioactive constituents from the Korean medicinal plants [13][16][17][18][19][20], previous phytochemical investigations on the MeOH extract of the twigs of C. sinensis have led to the isolation and characterization of triterpenoids [13], biphenyls

Synthesis and characterization of S,N-heterotetracenes

• Astrid Vogt,
• Florian Henne,
• Christoph Wetzel,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2020, 16, 2636–2644, doi:10.3762/bjoc.16.214

• derivatives by Cadogan reaction of nitro-substituted precursors. Another possibility for the preparation of fused pyrrole rings is established by the Cadogan reaction [40]. Well-known examples are the reductive cyclization of 2-nitro-1,1’-biphenyls with triethyl phosphite or phosphanes as reducing agent to

Synthesis of six-membered silacycles by borane-catalyzed double sila-Friedel–Crafts reaction

• Yafang Dong,
• Masahiko Sakai,
• Kazuto Fuji,
• Kohei Sekine and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2020, 16, 409–414, doi:10.3762/bjoc.16.39

• benzosiloles [39]. We have also contributed to the synthesis of silafluorenes from biphenyls and dihydrosilanes using a borane-catalyzed double sila-Friedel–Crafts reaction [40][41]. Subsequently, we envisaged that the catalytic reaction between diaryl ethers and dihydrosilanes may be a useful protocol to

Atom-economical group-transfer reactions with hypervalent iodine compounds

• Andreas Boelke,
• Peter Finkbeiner and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2018, 14, 1263–1280, doi:10.3762/bjoc.14.108

• ]. Here, symmetrical diaryliodonium salts 1 were used in a palladium-catalysed cross-coupling reaction with sodium tetraphenylborate (Scheme 3). This reaction not only provides excellent yields of the respective biphenyls 3 but also exhibits a high AE (57% for Ar = Ph). However, its general synthetic

• utility is limited since it requires highly reactive boron compounds as nucleophiles. Symmetrical biphenyls 3’ can be generated from the corresponding symmetrically substituted diaryliodonium salts 1 and bis(pinacolato)diboron as demonstrated by Muñiz and co-workers [25]. In the first step, a mild carbon

• –boron bond formation gives one equivalent of arylboronic ester 4 and an iodoarene 2 through a metal-free boron arylation. Subsequent cross coupling under Suzuki conditions affords symmetrical biphenyls 3’ in good yields. Due to the temporary introduction and cleavage of the boron moiety the formal atom

Heterogeneous Pd catalysts as emulsifiers in Pickering emulsions for integrated multistep synthesis in flow chemistry

• Katharina Hiebler,
• Georg J. Lichtenegger,
• Manuel C. Maier,
• Eun Sung Park,
• Renie Gonzales-Groom,
• Bernard P. Binks and
• Heidrun Gruber-Woelfler

Beilstein J. Org. Chem. 2018, 14, 648–658, doi:10.3762/bjoc.14.52

• with phenylboronic acids yielding the corresponding biphenyls as product [7]. The biphenyl unit is a common structural motif in various pharmaceutically active agents and plays a crucial role in the binding affinity and the oral bioavailability of diverse APIs [8], including antihypertensive [9] and

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• ][30]. Alternative approaches by utilizing chiral backbones like, e.g., tartaric acid, biphenyls, or tricyclic ammonium salts were also heavily investigated [31][32][33][34][35], thus leading to an enormous recent progress in the field with respect to catalyst design and the development of new

New electroactive asymmetrical chalcones and therefrom derived 2-amino- / 2-(1H-pyrrol-1-yl)pyrimidines, containing an N-[ω-(4-methoxyphenoxy)alkyl]carbazole fragment: synthesis, optical and electrochemical properties

• Daria G. Selivanova,
• Alexei A. Gorbunov,
• Olga A. Mayorova,
• Alexander N. Vasyanin,
• Igor V. Lunegov,
• Elena V. Shklyaeva and
• Georgii G. Abashev

Beilstein J. Org. Chem. 2017, 13, 1583–1595, doi:10.3762/bjoc.13.158

• groups terminated with an aromatic moiety (substituted or non-substituted benzenes, carbazoles, biphenyls, etc.) can be used for these purposes [8][9]. The incorporation of bulky side chains is applied in order to exclude the possible interaction of polymer chains with each other. Such interaction often

Substitution of fluorine in M[C₆F₅BF₃] with organolithium compounds: distinctions between O- and N-nucleophiles

• Anton Yu. Shabalin,
• Nicolay Yu. Adonin and
• Vadim V. Bardin

Beilstein J. Org. Chem. 2017, 13, 703–713, doi:10.3762/bjoc.13.69

• , the known 2,3,5,6-tetrafluorobiphenyl (14) [35][36] and 2,3,4,5-tetrafluorobiphenyl (15) [35][36] were obtained (Scheme 6). Then a mixture of borates 10-K, 11-K, 12-K, and 13-K was converted to biphenyls 14, 15, and terphenyls 20, 21, respectively, and characterized by 19F NMR spectroscopy, GC–MS and

Antioxidant potential of curcumin-related compounds studied by chemiluminescence kinetics, chain-breaking efficiencies, scavenging activity (ORAC) and DFT calculations

• Adriana K. Slavova-Kazakova,
• Silvia E. Angelova,
• Timur L. Veprintsev,
• Petko Denev,
• Davide Fabbri,
• Maria Antonietta Dettori,
• Maria Kratchanova,
• Vladimir V. Naumov,
• Aleksei V. Trofimov,
• Rostislav F. Vasil’ev,
• Giovanna Delogu and
• Vessela D. Kancheva

Beilstein J. Org. Chem. 2015, 11, 1398–1411, doi:10.3762/bjoc.11.151

• biological activity of curcumin, hydroxylated biphenyls, which resemble the curcumin structure, were synthesized (Figure 1b). The most important features of their structure are: conformational flexibility, simplicity, reduced toxicity due to the presence of an ortho-methoxyphenol moiety, a sufficient number

• the synthesis of pharmacologically and agrochemically active new compounds. The present study demonstrates experimental and theoretical models for assessing radical scavenging and antioxidant activity of curcumin-related hydroxylated biphenyls (dimers) and their corresponding monomers. Four models

• reported for different plant extracts. Model 4: DFT calculations In order to explain the structure–activity relationships of the hydroxylated biphenyls and their corresponding monomers, we have optimized the geometries of the compounds and possible phenoxyl radical species of the parent compounds. The

Weakly nucleophilic potassium aryltrifluoroborates in palladium-catalyzed Suzuki–Miyaura reactions: relative reactivity of K[4-RC₆F₄BF₃] and the role of silver-assistance in acceleration of transmetallation

• Vadim V. Bardin,
• Anton Yu. Shabalin and
• Nicolay Yu. Adonin

Beilstein J. Org. Chem. 2015, 11, 608–616, doi:10.3762/bjoc.11.68

• corresponding biphenyls than K[C6F5BF3] (1a) (Table 1, entry 1) [19]. Potassium 2,3,5,6-tetrafluoropyridyltrifluoroborate (6) exhibits extremely low reactivity toward both 2 and 3 gives the corresponding 4-(3'-fluorophenyl)- (7) and 4-(4'-fluorophenyl)- (8) -2,3,5,6-tetrafluoropyridines with yields no more than

• 5% (19F NMR) (Scheme 3). It should be noted that 2,3,5,6-tetrafluoropyridine was not observed in the reaction mixtures in both cases. The use of the electron-rich C-electrophile, 4-IC6H4CH3 (9), instead of 3 leads to biphenyls 4-(4'-CH3C6H4)C6F4R (10c–f,h–p) in 60–80% preparative yields (see Table 2

• , entries 2–14) while 4-CH3C6H4C6F5 (10a) was isolated in 93% yield (see Table 2, entry 1) [19]. Although aryl bromides are less reactive than iodides, the substitution of 4-IC6H4CH3 (9) for 4-BrC6H4CH3 (11) does not affect the yields of the corresponding biphenyls (Scheme 4). The obtained results show a

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• asymmetrically substituted derivatives at phenanthridine side-rings and unsubstituted central ring [24]. The recently reported photo-conversion of various isocyanide biphenyls into alkylated phenanthridine derivatives under rather mild reaction conditions introduced several novelties (Scheme 8) [25]. The most

Flexible synthesis of anthracycline aglycone mimics via domino carbopalladation reactions

• Markus Leibeling and
• Daniel B. Werz

Beilstein J. Org. Chem. 2013, 9, 2194–2201, doi:10.3762/bjoc.9.258

• preparation of anthracycline derivatives. Therefore, the D-ring was exchanged for a pyranose, as described in our previous synthetic approaches for the syntheses of chromans, isochromans and biphenyls, respectively. These 2-bromoglycals 15 are well-known compounds and their synthesis was accomplished

Homolytic substitution at phosphorus for C–P bond formation in organic synthesis

• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 1269–1277, doi:10.3762/bjoc.9.143

• )-bridged biphenyls (Scheme 20) [46]. Subsequently, Liu reported an efficient synthesis of bis(phosphoryl)-bridged ladder triphenylene by means of the radical clipping with (Me3Sn)2PPh (Scheme 21) [47]. In light of the increasing importance of phosphoryl-bridged π-conjugated skeletons in organic material

• phosphorus. Plausible mechanism of radical phosphination (Si = (Me3Si)3Si). Stereoselective phosphination leading to (S,S)-aminophosphine derivative. Phosphination with retention of axial chirality. Chemodivergent phosphination. Bis(phosphoryl)-bridged biphenyls by radical phosphination. Bis(phosphoryl

Palladium-catalyzed synthesis of N-arylated carbazoles using anilines and cyclic diaryliodonium salts

• Stefan Riedmüller and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2013, 9, 1202–1209, doi:10.3762/bjoc.9.136

• , the efficient synthesis of N-arylated carbazoles is an attractive goal and numerous synthetic methods are known so far from the literature. The main synthetic routes are shown in Scheme 1. The majority are transition-metal mediated. Starting from functionalized 2,2'-biphenyls (path A) [10][11][12][13

Thermotropic and lyotropic behaviour of new liquid-crystalline materials with different hydrophilic groups: synthesis and mesomorphic properties

• Alexej Bubnov,
• Miroslav Kašpar,
• Věra Hamplová,
• Ute Dawin and
• Frank Giesselmann

Beilstein J. Org. Chem. 2013, 9, 425–436, doi:10.3762/bjoc.9.45

• phase [2]. Due to microsegregation of the hydrophilic regions from aromatic segments in the absence of flexible alkyl chains, the thermotropic and lyotropic smectic and columnar phases have been detected for 4-benzyloxy-4’-(2,3-dihydroxypropyloxy)biphenyls with lateral methyl substituents [19]. Several

Phytoalexins of the Pyrinae: Biphenyls and dibenzofurans

• Cornelia Chizzali and
• Ludger Beerhues

Beilstein J. Org. Chem. 2012, 8, 613–620, doi:10.3762/bjoc.8.68

• Cornelia Chizzali Ludger Beerhues Institut für Pharmazeutische Biologie, Technische Universität Braunschweig, Mendelssohnstr. 1, 38106 Braunschweig, Germany 10.3762/bjoc.8.68 Abstract Biphenyls and dibenzofurans are the phytoalexins of the Pyrinae, a subtribe of the plant family Rosaceae. The

• Pyrinae correspond to the long-recognized Maloideae. Economically valuable species of the Pyrinae are apples and pears. Biphenyls and dibenzofurans are formed de novo in response to infection by bacterial and fungal pathogens. The inducible defense compounds were also produced in cell suspension cultures

• after treatment with biotic and abiotic elicitors. The antimicrobial activity of the phytoalexins was demonstrated. To date, 10 biphenyls and 17 dibenzofurans were isolated from 14 of the 30 Pyrinae genera. The most widely distributed compounds are the biphenyl aucuparin and the dibenzofuran γ