Synthesis of polycyclic aromatic quinones by continuous flow electrochemical oxidation: anodic methoxylation of polycyclic aromatic phenols (PAPs)

• Hiwot M. Tiruye,
• Solon Economopoulos and
• Kåre B. Jørgensen

Beilstein J. Org. Chem. 2024, 20, 1746–1757, doi:10.3762/bjoc.20.153

• our previous work [18]. Substrates 3a–c and 6c were synthesised by photochemical cyclisation of stilbenes [58], while 3d was prepared according to literature [59]. The substrates were oxidized under galvanic (constant current) conditions in a Syrris Asia flow system with a 225 μL electrochemical flow

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

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

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• the synthesis of intermediate stilbenes 61 by Wittig coupling. The authors elected to use a Pd2dba3/DPEphos (L4)/Cs2CO3 system (dba = dibenzylideneacetone; DPEphos = bis[(2-diphenylphosphino)phenyl] ether) in toluene after catalyst and ligand screening. Cyclisation of several substituted 2,2

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• quantities for the evaluation of biological/pharmacological activities. Review 1 Isolation 1.1 Isolation of combretastatins D series Combretastatins comprise a large family of structurally diverse natural products divided into the “A” (cis-stilbenes), “B” (dehydrostilbenes), “C” (phenanthrenes), and “D

A Streptomyces P450 enzyme dimerizes isoflavones from plants

• Run-Zhou Liu,
• Shanchong Chen and
• Lihan Zhang

Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113

• plate. We further identified a cytochrome P450 monooxygenase, CYP158C1, which is able to catalyze the dimerization of isoflavones. CYP158C1 can also dimerize plant-derived polyketides, such as flavonoids and stilbenes. Our work represents a unique bacterial P450 that can dimerize plant polyphenols

Azo-dimethylaminopyridine-functionalized Ni(II)-porphyrin as a photoswitchable nucleophilic catalyst

• Jannis Ludwig,
• Julian Helberg,
• Hendrik Zipse and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2119–2126, doi:10.3762/bjoc.16.179

• , spiropyranes, and stilbenes [2]. Diarylethenes were reported in the context of photoswitchable catalysis as inhibitors of the Karstedt´s catalyst [3] and for pKa modulation in acid–base-controlled processes [4]. Molecular motors for stereodivergent anion binding catalysis [5], azopeptides for the acetylation

Photocatalyzed syntheses of phenanthrenes and their aza-analogues. A review

• Alessandra Del Tito,
• Havall Othman Abdulla,
• Davide Ravelli,
• Stefano Protti and
• Maurizio Fagnoni

Beilstein J. Org. Chem. 2020, 16, 1476–1488, doi:10.3762/bjoc.16.123

• of the Mallory photocyclization of stilbenes [10] leading to phenanthrenes, the interest in protocols for the construction of poly(hetero)aromatic cores under photochemical conditions has increased steadily, especially when solar light may be used [11]. Moreover, aza-analogues of phenanthrenes, in

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

• of biaryl products with triazole. For this, 4-bromoaryl derivatives were initially treated with phenylboronic acid. The biaryl derivatives were then reacted with phenylacetylene to give triazole-containing biaryl compounds in high yields. Stilbenes were also applied in the reaction under similar

• conditions to obtain triazoles containing stilbenes. The nanocatalyst 78 could be readily recovered seven times without a significant loss of catalytic activity. Naeimi and Ansarian reported a new, effective, and reusable catalyst comprised of a polytriazole copper(I) complex supported on graphene oxide, GO

Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo

• Alexander Sailer,
• Franziska Ermer,
• Yvonne Kraus,
• Rebekkah Bingham,
• Ferdinand H. Lutter,
• Julia Ahlfeld and
• Oliver Thorn-Seshold

Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14

• scaffold could best be reduced in volume by "shortening" this substituent, maintaining the abovementioned non-polar interaction. Secondly, since the torsion angle of the HTI is far lower than that of (Z)-stilbenes or biaryl compounds, we considered that even with shortening, their SARs might not directly

Reversible photoswitching of the DNA-binding properties of styrylquinolizinium derivatives through photochromic [2 + 2] cycloaddition and cycloreversion

• Sarah Kölsch,
• Heiko Ihmels,
• Jochen Mattay,
• Norbert Sewald and
• Brian O. Patrick

Beilstein J. Org. Chem. 2020, 16, 111–124, doi:10.3762/bjoc.16.13

• switching of binding properties [36]. Apparently, styryl-substituted aromatic derivatives could fill this gap because the [2 + 2] photocyclization reaction of stilbenes and derivatives thereof is a well-established reversible photoreaction [37][38][39][40][41][42][43][44][45][46], and styryl dyes, in

• . Supporting Information File 1) that may have been followed by a [2 + 2] photodimerization (Scheme 2). However, it is difficult to explain why the photocycloaddition of the Z-isomers Z-3b and Z-3c led exclusively to the dimer, because such a selectivity has not been reported so far for (Z)-stilbenes. On the

Probing of local polarity in poly(methyl methacrylate) with the charge transfer transition in Nile red

• Aydan Yadigarli,
• Qimeng Song,
• Sergey I. Druzhinin and
• Holger Schönherr

Beilstein J. Org. Chem. 2019, 15, 2552–2562, doi:10.3762/bjoc.15.248

• fluorescence (Figure 2a). This behavior for NR [35] is similar to donor–acceptor-substituted stilbenes [36][37], benzenes [38][39] and aminocoumarins [35][40][41]. This effect is caused by solvent relaxation around dipolar solutes that possess in the lowest excited state a substantially higher dipole moment

In search of visible-light photoresponsive peptide nucleic acids (PNAs) for reversible control of DNA hybridization

• Lei Zhang,
• Greta Linden and
• Olalla Vázquez

Beilstein J. Org. Chem. 2019, 15, 2500–2508, doi:10.3762/bjoc.15.243

• translation [24][25]. Except a handful of current examples [22][24][26], most of these photoresponsive oligonucleotides are canonical ones where the classical azobenzene is the prominently used photoswitch; although spiropyrans [27], stilbenes [28], diarylethanes [29] and overcrowded alkenes [30] have also

Effect of ring size on photoisomerization properties of stiff stilbene macrocycles

• Sandra Olsson,
• Óscar Benito Pérez,
• Magnus Blom and
• Adolf Gogoll

Beilstein J. Org. Chem. 2019, 15, 2408–2418, doi:10.3762/bjoc.15.233

• the resulting macrocycle. Keywords: DFT; molecular mechanics; photostability; photo-switch; ring-strain; stiff stilbene; Introduction The stiff stilbene (SS) molecule has drawn a lot of interest due to its photodynamic properties [1]. Stiff stilbenes typically undergo light triggered isomerization

• from Z to E at 300 nm and from E to Z at 360 nm (Scheme 1) [2]. The photochemical mechanism of this reaction is thoroughly described by Quick et al. [2]. The stiff stilbenes ability to photoisomerize has made it a useful building block of photodynamic triggers, switches and machines [3][4][5][6][7][8

• ][31][32][33][34][35][36][37]. The photoisomerization of stiff stilbenes involves a complex potential energy surface with several excited species in equilibria, eventually reaching the cis or trans ground state [2]. Macroscopic parameters such as extinction coefficients and quantum yields also affect

Azologization and repurposing of a hetero-stilbene-based kinase inhibitor: towards the design of photoswitchable sirtuin inhibitors

• Christoph W. Grathwol,
• Nathalie Wössner,
• Sören Swyter,
• Adam C. Smith,
• Enrico Tapavicza,
• Robert K. Hofstetter,
• Anja Bodtke,
• Manfred Jung and
• Andreas Link

Beilstein J. Org. Chem. 2019, 15, 2170–2183, doi:10.3762/bjoc.15.214

• ‐time photomodulation of sirtuins in vitro. Keywords: azo compounds; epigenetics; photoswitch; sirtuins; stilbenes; Introduction Sirtuins are protein deacylases that cleave off not only acetyl, but also other acyl groups from the ε-amino group of lysines in histones and many other substrate proteins

• physicochemical properties upon irradiation with light, represent one major approach to this. One of the most common light-driven transformations exploited in molecular photoswitches is the E–Z isomerization of double bonds [18]. In this context, the photochemistry of stilbenes and the closely related azobenzenes

• has been studied intensely in the past [19][20][21][22][23]. Due to the multifaceted photoreactivity of unsubstituted stilbenes, an appropriate modification of the stilbene core is necessary to prevent unwanted irreversible side reactions [24][25]. On the contrary, the photochemical properties of

Synthesis of the aglycon of scorzodihydrostilbenes B and D

• Katja Weimann and
• Manfred Braun

Beilstein J. Org. Chem. 2019, 15, 610–616, doi:10.3762/bjoc.15.56

• stilbenes that would serve as the precursors of scorzodihydrostilbenes had failed, presumably due to steric hindrance caused by the accumulation of substituents at the acetophenone moiety [10]. We felt that a straightforward access to the scorzodihydrostilbene aglycons would be possible by using the

Oxidative and reductive cyclization in stiff dithienylethenes

• Michael Kleinwächter,
• Ellen Teichmann,
• Lutz Grubert,
• Martin Herder and
• Stefan Hecht

Beilstein J. Org. Chem. 2018, 14, 2812–2821, doi:10.3762/bjoc.14.259

• DAEs without the geometric constraint of the central endocyclic olefin bridge yet with two rings each involving one of the bridge’s carbon atoms to lock the photoreactive antiparallel conformation and thus provide stiff dithienylethenes (sDTEs), in analogy to stiff stilbenes [30][31][32]. Due to

Synergistic approach to polycycles through Suzuki–Miyaura cross coupling and metathesis as key steps

• Sambasivarao Kotha,
• Milind Meshram and
• Chandravathi Chakkapalli

Beilstein J. Org. Chem. 2018, 14, 2468–2481, doi:10.3762/bjoc.14.223

• with Suzuki–Miyaura cross coupling in combination with metathesis (or vice-versa). Several cyclophanes, polycycles, macrocycles, spirocycles, stilbenes, biaryls, and heterocycles have been synthesized by employing a combination of Suzuki cross-coupling and metathesis. Various popular reactions such as

Liquid-assisted grinding and ion pairing regulates percentage conversion and diastereoselectivity of the Wittig reaction under mechanochemical conditions

• Kendra Leahy Denlinger,
• Lianna Ortiz-Trankina,
• Preston Carr,
• Kingsley Benson,
• Daniel C. Waddell and
• James Mack

Beilstein J. Org. Chem. 2018, 14, 688–696, doi:10.3762/bjoc.14.57

• used in liquid-assisted grinding (LAG) and properly chosen counter-ion pairing increases the percentage conversion of stilbenes in a mechanochemical Wittig reaction. Utilizing stepwise addition/evaporation of ethanol in liquid-assisted grinding also allows for the tuning of the diastereoselectivity in

• . Conclusion Both a high dielectric constant of the solvent used in liquid-assisted grinding (LAG) and proper ion pairing were found to increase the percent conversion to stilbenes under mechanochemical conditions. Choosing appropriate ion pairs when LAG is utilized in the system also allowed tuning the

An effective Pd nanocatalyst in aqueous media: stilbene synthesis by Mizoroki–Heck coupling reaction under microwave irradiation

• Carolina S. García,
• Paula M. Uberman and
• Sandra E. Martín

Beilstein J. Org. Chem. 2017, 13, 1717–1727, doi:10.3762/bjoc.13.166

• Mizoroki–Heck coupling reactions under microwave irradiation (MW) were carried out with a colloidal Pd nanocatalyst stabilized with poly(N-vinylpyrrolidone) (PVP). Many stilbenes and novel heterostilbenes were achieved in good to excellent yields starting from aryl bromides and different olefins. The

• electrochemical synthesized PVP-Pd NPs for Mizoroki–Heck coupling reaction. By the efficient coupling reaction with aryl bromides, many stilbenes and novel hetero-stilbenes were obtained employing the Pd NPs in aqueous medium under relatively mild conditions, using MW irradiation. Results and Discussion The PVP

• bromides with electron-withdrawing groups as coupling partners, such as 4-bromoacetophenone (1a) and 4-bromobenzophenone (1b), the reactions were carried out in short times, employing low catalyst loading, obtaining the (E)-stilbenes 3 and 4 with excellent yields and selectivity (entries 1 and 2, Table 2

Solid-phase enrichment and analysis of electrophilic natural products

• Frank Wesche,
• Yue He and
• Helge B. Bode

Beilstein J. Org. Chem. 2017, 13, 405–409, doi:10.3762/bjoc.13.43

• entomopathogenic Photorhabdus bacteria. Keywords: azides; click chemistry; enrichment; electrophilic natural products; epoxides; glidobactin; Photorhabdus; stilbenes; Introduction Microorganisms are a major source for novel natural products and the subsequent development of new drugs for all kinds of

Matsuda–Heck reaction with arenediazonium tosylates in water

• Ksenia V. Kutonova,
• Marina E. Trusova,
• Andrey V. Stankevich,
• Pavel S. Postnikov and
• Victor D. Filimonov

Beilstein J. Org. Chem. 2015, 11, 358–362, doi:10.3762/bjoc.11.41

• ; diazonium salts; Matsuda–Heck reaction; microwave-assisted synthesis; stilbenes; Introduction Diazonium salts are known as one of the most valuable building blocks in organic synthesis [1]. Today, their most common use is the construction of carbon–carbon bonds in palladium-catalyzed reactions. Starting

• be effective catalysts for the Matsuda–Heck arylation of styrene and ethyl acrylate in water [7]. It is noteworthy that these catalysts are not commercially available and must be synthesized from Pd(OAc)2. Roglands et al. prepared a range of tert-butyl cinnamates and stilbenes from arenediazonium

• tetrafluoroborates in water with 5 mol % of commercial PdCl2(CH3CN)2 as a catalyst. The yields of cinnamates were rather high, while stilbenes were obtained with modest yields [8]. Up to date only one example of a simple palladium diacetate-catalyzed arylation of alkenes by diazonium salts in water has been

Recent advances in the electrochemical construction of heterocycles

• Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

• construction of thiochroman frameworks in a sequential intermolecular cyclization reaction (Scheme 28) [77]. A cation pool of methoxycarbenium ions is generated at −78 °C from the corresponding thioacetal using anodically formed ArS(ArSSAr)+, and converted at 0 °C with 4,4’-disubstituted stilbenes and ArSSAr

On the mechanism of photocatalytic reactions with eosin Y

• Michal Majek,
• Fabiana Filace and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2014, 10, 981–989, doi:10.3762/bjoc.10.97

• various applications of eosin Y to visible light-driven syntheses of biaryls [15], stilbenes [16], benzothiophenes [17], α-phenylketones [18], phenanthrenes [19], arylsulfides [20] and arylboron pinacolates [21] (Scheme 1). Numerous mechanistic studies have been performed at reactions with organometallic

Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

• Phei Li Lau,
• Ray W. K. Allen and
• Peter Styring

Beilstein J. Org. Chem. 2013, 9, 2886–2897, doi:10.3762/bjoc.9.325

• used was either styrene to yield the stilbenes 1 or methyl acrylate to yield the cinnamate ester 2. For each reaction there are three possible regioisomers. The thermodynamically favoured trans- (t) isomer is most common in standard organic solvents although under certain conditions the cis- (c) isomer

• [5]. Synthesis stilbenes under stirred tank and continuous flow conditions The synthesis of 4-methoxystilbene (1) was carried out under continuous flow conditions and also in a stirred autoclave reactor to compare the processes. In the autoclave reaction (Figure 1) a single composition was