Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations

• Tsuyuka Sugiishi,
• Hideki Amii,
• Kohsuke Aikawa and
• Koichi Mikami

Beilstein J. Org. Chem. 2015, 11, 2661–2670, doi:10.3762/bjoc.11.286

• − source and [CF3Cu] species with CuI are generated in situ. In the presence of CuI, CF3CO2Na undergoes trifluoromethylation with aryl halides via decarboxylation [33][34] (Scheme 1). A pentafluoroethyl group (C2F5) was fixed at the arene with sodium pentafluoropropionate [35] (Scheme 2). The reaction

Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

• Zhan-Jiang Zheng,
• Ding Wang,
• Zheng Xu and
• Li-Wen Xu

Beilstein J. Org. Chem. 2015, 11, 2557–2576, doi:10.3762/bjoc.11.276

• opposite side of the thiacalix[4]arene cavity [38]. The authors found that receptor 52 (Scheme 18) could selectively bind Cl− through hydrogen bonding interaction with the urea NH protons, and 52 can also bind with Ag+ through complexation with the pyrene-appended bistriazole. In homogeneous catalysis

• bistriazoles. The pyrene-appended thiacalix[4]arene-based bistriazole. The synthesis of triazole-based tetradentate ligands. The synthesis of phenanthroline-2,9-bistriazoles. The three-component reaction for the synthesis of bistriazoles. The one-pot synthesis of bistriazoles. The synthesis of polymer-bearing

Friedel–Crafts-type reaction of pyrene with diethyl 1-(isothiocyanato)alkylphosphonates. Efficient synthesis of highly fluorescent diethyl 1-(pyrene-1-carboxamido)alkylphosphonates and 1-(pyrene-1-carboxamido)methylphosphonic acid

• Anna Wrona-Piotrowicz,
• Janusz Zakrzewski,
• Anna Gajda,
• Tadeusz Gajda,
• Anna Makal,
• Arnaud Brosseau and
• Rémi Métivier

Beilstein J. Org. Chem. 2015, 11, 2451–2458, doi:10.3762/bjoc.11.266

• relevance which have attracted the interest of biologically-oriented chemists and biochemists [9][10][11][12]. Furthermore, the phosphonate group offers various possibilities of metal binding or anchoring to solid surfaces [13][14][15][16][17][18][19][20]. For our purposes we chose pyrene as a model arene

• observed features of solid-state emission of this compound (vide suppra). Conclusion We demonstrated the feasibility of the Friedel–Crafts reaction with 1-(isothiocyanato)alkylphosphonates by using pyrene as an arene. The pyrenyl thioamidoalkylphosphonates formed in this reaction can be readily transformed

C–H bond halogenation catalyzed or mediated by copper: an overview

• Wenyan Hao and
• Yunyun Liu

Beilstein J. Org. Chem. 2015, 11, 2132–2144, doi:10.3762/bjoc.11.230

• catalysis in modern organic synthesis, herein, we would like to highlight the recent progress in the C–H bond halogenation with copper catalysis or mediation. Review Copper-catalyzed/mediated halogenation of the C(sp2)–H bond Halogenation of the arene C(sp2)–H bond In the synthesis of aryl halides employing

• a few examples giving mixed mono- and dihalogenated products. In all these known arene C–H halogenation protocols with pyridine as directing group (DG), the chemo-selectivity remained as a challenge since either mixed mono- and dihalogenated products or only one of the two potential products could

• -functionalized arene dimerization [37]. Besides the issue of selectivity, another major challenge in the DG-assisted C–H activation lied in the removal of the DG, which undermined the efficiency of the synthetic procedure. To alternate the hardly removable DG of the pyridine ring, Carretero and co-workers [38

Supramolecular chemistry: from aromatic foldamers to solution-phase supramolecular organic frameworks

• Zhan-Ting Li

Beilstein J. Org. Chem. 2015, 11, 2057–2071, doi:10.3762/bjoc.11.222

• project: constructing calix[4]arene-derived catenanes, such as 7a–c [15] (Scheme 3). I chose this project because I believed that I could make progress in a short time. Most of the work was done by myself, but I also received assistance from several young technicians. We succeeded in investigating the

• effect of the calix[4]arene moiety on the relative rotation of the two rings using 1H NMR, and from 1998 to 2000, we published four papers from this project. However, this was generally a tough period for me. Due to some nonacademic reasons, I could not build an efficient research group after several

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• step starting with 2-methoxyphenol. Later, compound 316 was subjected to a RRM under the influence of catalyst 2 in the presence of ethylene (24) to deliver the expected rearranged product 317 (Scheme 68). Vanderwal and co-workers [66] described the synthesis of polycyclic lactams obtained by arene

Synthesis and spectroscopic properties of β-triazoloporphyrin–xanthone dyads

• Dileep Kumar Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2015, 11, 1434–1440, doi:10.3762/bjoc.11.155

• –tetrathiafulvalenes [14], porphyrin–cyanines [15], porphyrin–carotenes [16], porphyrin–arene diimide [17] and porphyrin–fluorocene or rhodamine [18] have also been synthesized in which the porphyrin unit acts as an electron acceptor. Recently, the 1,2,3-triazole scaffold has been successfully employed to connect

Pd(OAc)₂-catalyzed dehydrogenative C–H activation: An expedient synthesis of uracil-annulated β-carbolinones

• Biplab Mondal,
• Somjit Hazra,
• Tarun K. Panda and
• Brindaban Roy

Beilstein J. Org. Chem. 2015, 11, 1360–1366, doi:10.3762/bjoc.11.146

• reaction of an unactivated arene and N-acetylindole [53]. Driven by the same logic and guided by our previous work we envisioned that an intramolecular dehydrogenative cross coupling reaction could be achievable between the electron deficient uracil C6–H bond adjacent to the nitogen atom and the electron

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• key building block for the synthesis of calix[4]arene. Here, α,ω-bis(p-methoxyphenyl)alkanes 264 were used as starting materials. Compound 264 was treated with acetic anhydride and AlCl3 in nitrobenzene and 1,1,2,2-tetrachloroethane to generate diketone 265 in 58–93% yield. Diketone 265 was then

Tuning of tetrathiafulvalene properties: versatile synthesis of N-arylated monopyrrolotetrathiafulvalenes via Ullmann-type coupling reactions

• Vladimir A. Azov,
• Diana Janott,
• Dirk Schlüter and
• Matthias Zeller

Beilstein J. Org. Chem. 2015, 11, 860–868, doi:10.3762/bjoc.11.96

• . Although being reported in the literature, it has so far not found wide spread use and was employed only with a narrow scope of aromatic derivatives with electron-donating substituents and alkylthio-substituted (R = SAlkyl) MPTTFS. Being interested in the preparation of calix[4]arene receptors with MPTTF

• reaction with bromophenol 8d to form the adduct 4f also confirmed the possibility of the reaction with hydroxy-substituted aryl derivatives, paving the way for application of this method with non-protected calix[4]arene derivatives [27]. Compounds 4a–c,e,f (Figure 3) display UV–vis spectra typical for TTF

Enhancing the reactivity of 1,2-diphospholes in cycloaddition reactions

• Almaz Zagidullin,
• Vasili Miluykov,
• Elena Oshchepkova,
• Artem Tufatullin,
• Olga Kataeva and
• Oleg Sinyashin

Beilstein J. Org. Chem. 2015, 11, 169–173, doi:10.3762/bjoc.11.17

• approaches have been employed to enhance the reactivity of 1-alkyl-1,2-diphospholes – the introduction of electron-withdrawing groups either at the phosphorus atoms or in the para-position of the arene ring. The alkylation of sodium 1,2-diphospha-3,4,5-triphenylcyclopentadienide with alkyl halides Hal-CH2-R

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• arenes (Scheme 4). The pyridine, pyrimidine, or pyrazole moiety serves as the directing group in the oxidative ortho-alkoxylation of arenes 16 with the Cu(OAc)2/AgOTf/O2 system giving coupling products 17 (Scheme 5) [47]. It is supposed that copper is inserted into the C–H bond of arene, the resulting Cu

• (PyrDipSi) [72][73] directing groups were proposed by the research group of Prof. V. Gevorgyan. The PyDipSi group was used for selective monoacetoxylation or pivaloyloxylation of the arene ortho-position [70][71], whereas the PyDipSi group allowed to achieve one-pot sequential acyloxylation of both ortho

• commonly employed in the oxidative coupling of OH-reagents with carbonyl compounds. Methods were developed for the sulfonyloxylation of ketones, in which iodoarene is generated in situ by the iodination of arene with molecular iodine [183] or NH4I [184] in the presence of m-chloroperbenzoic acid. In the

Inherently chiral calix[4]arenes via oxazoline directed ortholithiation: synthesis and probe of chiral space

• Simon A. Herbert,
• Laura J. van Laeren,
• Dominic C. Castell and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2014, 10, 2751–2755, doi:10.3762/bjoc.10.291

• examined as ligands in the palladium-catalyzed Tsuji–Trost allylation reaction, returning results comparable to their planar chiral ferrocene counterparts pointing towards future application of these types of compounds. Keywords: calix[4]arene; inherently chiral; ortholithiation; oxazoline; Tsuji–Trost

• other efforts relying on various resolution techniques [16][19][20][21][22][23][24][25][26]. We, however, have reported that stereocontrolled meta-functionalization of a calix[4]arene is possible via chiral oxazoline-directed ortholithiation [27][28]. This has allowed for a range of functionalized

• speculated that the additional steric bulk surrounding the coordination centre is responsible for the instability of the complex, thus promoting the formation of palladium black. When comparing the enantiomeric ratios, the results show that all four inherently chiral calix[4]arene ligands promote the

Phosphinocyclodextrins as confining units for catalytic metal centres. Applications to carbon–carbon bond forming reactions

• Matthieu Jouffroy,
• Rafael Gramage-Doria,
• David Sémeril,
• Dominique Armspach,
• Dominique Matt,
• Werner Oberhauser and
• Loïc Toupet

Beilstein J. Org. Chem. 2014, 10, 2388–2405, doi:10.3762/bjoc.10.249

• the P–Ru bond and the Ru–arene bond are both restricted. Thus, the ROESY spectrum of this complex showed correlations between the Me group of the p-cymene ligand and protons belonging to glucose units G and A, but not with protons from the PPh ring or glucose units B and C. In keeping with these

• findings, the only cross peaks associated with the CHMe2 proton of 7 involved protons from the PPh ring. Similar observations, which establish the same blocked rotations about the P–Ru and the Ru–arene bonds were made for 8. It should be emphasised that prolonged heating of 7 in refluxing toluene did not

N–O Cleavage reactions of heterobicycloalkene-fused 2-isoxazolines

• Jaipal R. Nagireddy,
• Geoffrey K. Tranmer,
• Emily Carlson and
• William Tam

Beilstein J. Org. Chem. 2014, 10, 2200–2205, doi:10.3762/bjoc.10.227

• mediation. These results are summarized in Table 2. Compared to the parent compound 10a which gave an appreciable 93% yield of the corresponding β-hydroxyketone (Table 2, entry 1), replacement of two of the arene hydrogens for bromine atoms in 10b resulted in a lower tendency toward N–O bond cleavage (Table

• reasonably good (Table 3, entries 2 and 3), and even with electron-withdrawing C1 substituents in compounds 10h–j, the yields did not suffer to any extreme (Table 3, entries 4–6). In addition, the transformation to β-hydroxyketone succeeded with compound 10k bearing both arene and C1 substituents to furnish

• isoxazolines. Effects of arene substitution on Raney Ni/AlCl3-mediated cleavage of symmetrical 7-oxabenzonorbornadiene-fused 3-methyl-2-isoxazolines. Effects of bridgehead substitution on Raney Ni/AlCl3 mediated cleavage of 7-oxabenzonorbornadiene-fused 3-methyl-2-isoxazolines. Supporting Information

Clicked and long spaced galactosyl- and lactosylcalix[4]arenes: new multivalent galectin-3 ligands

• Silvia Bernardi,
• Paola Fezzardi,
• Gabriele Rispoli,
• Stefania E. Sestito,
• Francesco Peri,
• Francesco Sansone and
• Alessandro Casnati

Beilstein J. Org. Chem. 2014, 10, 1672–1680, doi:10.3762/bjoc.10.175

• Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy 10.3762/bjoc.10.175 Abstract Four novel calix[4]arene-based glycoclusters were synthesized by conjugating the saccharide units to the macrocyclic scaffold using the CuAAC reaction and using long and hydrophilic ethylene glycol spacers

• efficient multivalent ligands for a series of pathological lectins. For instance, cholera toxin is bound rather efficiently by calix[4]arene [16] and calix[5]arene [17] derivatives, while examples of Pseudomonas aeruginosa LecB binding were reported with galactosylcalixarenes blocked in different

• reaction between a 1-ethynyl-C-glycoside with a tetraazidocalix[4]arene (dipolarophile-on-the sugar strategy). It was suggested by the authors that the first intermolecular reaction, leading to a Cu-triazolide adduct, allows the copper ion to coordinate an ethynyl glycoside, thus entailing an

Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions

• Andreas Gansäuer,
• Andreas Okkel,
• Lukas Schwach,
• Laura Wagner,
• Anja Selig and
• Aram Prokop

Beilstein J. Org. Chem. 2014, 10, 1630–1637, doi:10.3762/bjoc.10.169

• A–D shown in Figure 2 were used as amino-substituted azides. They are readily obtained from the corresponding diazides through a Staudinger reaction (see Supporting Information File 1 for details) [45][46]. As for the carboxylates the different tether lengths and substitution patterns of the arene

Orthogonal dual thiol–chloroacetyl and thiol–ene couplings for the sequential one-pot assembly of heteroglycoclusters

• Michele Fiore,
• Gour Chand Daskhan,
• Baptiste Thomas and
• Olivier Renaudet

Beilstein J. Org. Chem. 2014, 10, 1557–1563, doi:10.3762/bjoc.10.160

• in our group to prepare tetravalent structures displaying two sugars either in 2:2 or 3:1 relative proportions [20]. In the meanwhile, the group of A. Dondoni has developed a sequential orthogonal TEC in combination with CuAAC for grafting two different sugar motifs on calix[4]arene scaffold [21

Synthesis, characterization and DNA interaction studies of new triptycene derivatives

• Sourav Chakraborty,
• Snehasish Mondal,
• Rina Kumari,
• Sourav Bhowmick,
• Prolay Das and
• Neeladri Das

Beilstein J. Org. Chem. 2014, 10, 1290–1298, doi:10.3762/bjoc.10.130

• ; ethynyl; pUC19 plasmid; triptycene tripod; Introduction Triptycene is the simplest member of the class of compounds called iptycenes. Structurally, iptycenes have a number of arene rings joined together to form the bridges of [2.2.2]bicyclic ring systems. In triptycene, the bicyclic ring is decorated

Cyclization–endoperoxidation cascade reactions of dienes mediated by a pyrylium photoredox catalyst

• Nathan J. Gesmundo and
• David A. Nicewicz

Beilstein J. Org. Chem. 2014, 10, 1272–1281, doi:10.3762/bjoc.10.128

• demonstrated that the electron-rich arene was necessary for reactivity (cf. 2e and 2f; Table 2, entries 4 and 6). The importance of the electron-rich arene may lie in the necessary distonic cation radical intermediate: the electron-rich arene may provide greater stability to the distonic intermediate formed

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

• with arenediazonium salts are often more selective than traditional methods such as copper(II)-mediated Meerwein arylations [11] or protocols employing stoichiometric iron(II) or titanium(III) reductants in aqueous media [12][13][14]. This renaissance of arene diazonium chemistry has recently led to

• different mechanisms in these aromatic substitution reactions with arene diazonium salts. The redox potentials of most substituted arene diazonium salts cluster with very little deviation around 0.0 V vs. SCE (±0.2 V) [23][24] so that the observed differences in Φ can be largely attributed to different

• -catalyzed substitutions with arene diazonium salts. Acid–base behaviour of eosin Y. Eosin Y-catalyzed and dye-free photolytic borylation. Eosin Y-catalyzed and dye-free reactions with ethyl propiolate. Quantum yield determinations of selected visible-light-driven aromatic substitutions. Supporting

Nonanebis(peroxoic acid): a stable peracid for oxidative bromination of aminoanthracene-9,10-dione

• Vilas Venunath Patil and
• Ganapati Subray Shankarling

Beilstein J. Org. Chem. 2014, 10, 921–928, doi:10.3762/bjoc.10.90

• ) can be increased by carrying out bromination at 50–55 °C. The electron deficient arene 1k (Table 4, entry 11) also undergoes bromination at 50–55 °C. In case of substrates like 1,4-diaminoanthracene-9,10-dione and 1-amino-4-hydroxyanthracene-9,10-dione, the protocol was found to be unsuccessful. It

Phosphinate-containing heterocycles: A mini-review

• Olivier Berger and
• Jean-Luc Montchamp

Beilstein J. Org. Chem. 2014, 10, 732–740, doi:10.3762/bjoc.10.67

• . Four helical phosphafluorenes 14a–d were prepared in yields up to 40% and enantiomeric excesses up to 73% (Scheme 6) [20]. Chen and Duan have synthesized one phosphinoline 17 in 60% yield by the alkyne–arene annulation of ethyl phenyl-H-phosphinate (15) using 2 equivalents of Ag2O (Scheme 7) [21

• -Dieckmann condensation. Palladium-catalyzed oxidative arylation. Tandem cross-coupling/Dieckmann condensation. Rhodium-catalyzed double [2 + 2 + 2] cycloaddition. Silver oxide-mediated alkyne–arene annulation. Silver acetate-mediated alkyne–arene annulation. Cyclization through phosphinylation/alkylation of

Recent advances in transition metal-catalyzed Csp²-monofluoro-, difluoro-, perfluoromethylation and trifluoromethylthiolation

• Grégory Landelle,
• Armen Panossian,
• Sergiy Pazenok,
• Jean-Pierre Vors and
• Frédéric R. Leroux

Beilstein J. Org. Chem. 2013, 9, 2476–2536, doi:10.3762/bjoc.9.287

• -catalyzed perfluoroalkylation of arenes in the absence of directing groups [70]. Perfluoroalkyl iodides were used as the source of the fluorinated alkyl group. Under the optimized reaction conditions, a mixture of the iodide, 5 mol % Pd2dba3, 20 mol % BINAP, cesium carbonate (2 equiv) and the arene (large

• interest of this reaction resides in the fact that the Ir-catalyzed borylation with bis(pinacolato)diboron is highly influenced by the steric bulk of the arene, and therefore leads to regioselective functionalization of the substrate. Arenes and heteroarenes, variously substituted, could undergo the

• bond, a byproduct corresponding to the functionalization of a methylene sp2-C–H bond was also obtained. The authors later applied this methodology to the perfluoroalkylation of arene C–H bonds (Table 41) [121]. The addition of methanol as an additive appeared critical playing the role of “hole shuttle

Synthetic scope and DFT analysis of the chiral binap–gold(I) complex-catalyzed 1,3-dipolar cycloaddition of azlactones with alkenes

• María Martín-Rodríguez,
• Luis M. Castelló,
• Carmen Nájera,
• José M. Sansano,
• Olatz Larrañaga,
• Abel de Cózar and
• Fernando P. Cossío

Beilstein J. Org. Chem. 2013, 9, 2422–2433, doi:10.3762/bjoc.9.280

• -bromophenyl)maleimide a good enantioselection was observed when the reaction was run at −20 °C furnishing enantiomerically pure 7af in good chemical yields (Table 2, entries 9 and 10). The variation of the arene substituent of the azlactones promoted also excellent to good enantioselections in compounds 7ba