Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• ·TM-βCD in water. As can be seen from Table 3, quite similar values were obtained in diiodomethane for the reference 3 and 3·TM-γCD polyrotaxane. These results are typical of surfaces covered with a close packing of hydrocarbon chains [55]. In contrast, a lower θ value is observed for 3·TM-βCD. Such

Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

• David Porter,
• Belinda M.-L. Poon and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 2549–2556, doi:10.3762/bjoc.11.275

• ) are established catalysts of C–O bond formation, oxidising hydrocarbon substrates via hydroxylation, epoxidation and dihydroxylation pathways. Herein we report the capacity of these catalysts to promote C–N bond formation, via allylic amination of alkenes. The combination of N-Boc-hydroxylamine with

• iron-catalysed hydrocarbon oxidation using systems inspired by the non-heme iron-dependent enzyme family [42][43][44][45][46][47], we have investigated the capacity of iron complexes of simple tetramine ligands to promote the reaction between an alkene and N-Boc-hydroxylamine. Herein we report that

• intermediate. Conclusion FeTPA (4) and FeBPMEN (5) are established catalysts for the hydroxylation, dihydroxylation and epoxidation of hydrocarbon substrates [48][58][59][60]. In this study we have shown that they can also catalyse the allylic hydroxyamination of alkenes with N-Boc-hydroxylamine. Mechanistic

Active site diversification of P450cam with indole generates catalysts for benzylic oxidation reactions

• Paul P. Kelly,
• Anja Eichler,
• Susanne Herter,
• David C. Kranz,
• Nicholas J. Turner and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2015, 11, 1713–1720, doi:10.3762/bjoc.11.186

• low cost starting materials [1]. One of the most attractive reagents in terms of cost and environmental impact for hydrocarbon oxidation is oxygen in the presence of a catalyst. In this context enzymatic oxidations are attractive, in particular cytochrome P450 monooxygenases (P450s or CYPs) due to

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

• ), zingerone (3), (2Z,5E)-ethyl 2-hydroxy-6-(4-hydroxy-3-methoxyphenyl)-4-oxohexa-2,5-dienoate (4), ferulic acid (5) and their corresponding C2-symmetric dimers 6–9. Four models were applied: model 1 – chemiluminescence (CL) of a hydrocarbon substrate used for determination of the rate constants (kA) of the

• were applied: model 1 – chemiluminescence of a hydrocarbon substrate used for determination of the rate constants (kA) of the reactions of the antioxidants with peroxyl radicals (RO2•); model 2 – lipid autoxidation used for assessing the chain-breaking antioxidant efficiency and reactivity; model 3

• = 15.6 Hz, 2H); 13C NMR δ 14.04, 55.96, 62.44, 100.58, 109.76, 115.11, 120.59, 123.88, 126.94, 143.74, 146.99, 148.80, 162.22, 172.98, 185.95; Anal. calcd for C30H30O12: C, 61.85; H, 5.19; found: C, 61.99; H, 5.28. Model 1: Chemiluminescence with model hydrocarbon ethylbenzene The chemiluminescence time

The chemical behavior of terminally tert-butylated polyolefins

• Dagmar Klein,
• Henning Hopf,
• Peter G. Jones,
• Ina Dix and
• Ralf Hänel

Beilstein J. Org. Chem. 2015, 11, 1246–1258, doi:10.3762/bjoc.11.139

• Lebensmittelsicherheit (BVL), Messeweg 11/12, D-38104 Braunschweig, Germany 10.3762/bjoc.11.139 Abstract The chemical behavior of various oligoenes 2 has been studied. The catalytic hydrogenation of diene 3 yielded monoene 4. Triene 7 was hydrogenated to diene 8, monoene 9 and saturated hydrocarbon 10. Bromine addition

• extend the packing, again by translation, to layers parallel to the bc plane at z ≈ ¼ and z ≈ ¾. The hydrogenation mixture yielded no evidence for the formation of a 1,2-adduct (5) or of the fully saturated hydrocarbon 6. In fact, the primary adduct 4 was inert towards hydrogen even under very harsh

• . Even under mild conditions (Pd/C, EtOH/hexane, room temp.) it is readily reduced (Scheme 3). After 5 minutes of hydrogenation, three products were detected: the 1,6-adduct 8, a diene (main product); the mono olefin 9; and the fully saturated hydrocarbon 10. When the reaction time was increased, the

The preparation of new functionalized [2.2]paracyclophane derivatives with N-containing functional groups

• Henning Hopf,
• Swaminathan Vijay Narayanan and
• Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 437–445, doi:10.3762/bjoc.11.50

• start with the parent hydrocarbon [2.2]paracyclophane (12), convert this to the dibromide 13, metalate it to the corresponding dilithio derivative, from which 14 is finally obtained by a CO2 quench [25][26]. On treatment of 14 with oxalyl chloride in anhydrous dichloromethane in the presence of

Attempts to prepare an all-carbon indigoid system

• Şeref Yildizhan,
• Henning Hopf and
• Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 363–372, doi:10.3762/bjoc.11.42

• reaction, it dimerized to the bis-indene derivative 17, rather than providing the tetramethyl derivative of 4, the hydrocarbon 14. In a second approach, indan-1-one (18) was dimerized to the conjugated enedione 21 through the bis-1-indene dimer 19. All attempts to methylenate 21 failed, however. When 19

• direct conjugation, whereby a third such system is excluded from interaction [3]. Typical examples are 2-vinyl-buta-1,3-diene ([3]dendralene, 3-methylene-penta-1,4-diene), benzophenone or urea. Whereas the hydrocarbon parent systems, the [n]dendralenes, have long been a neglected class of oligoenes [4

• . Results and Discussion Our first attempt to prepare hydrocarbon 4 started from indene (6, Scheme 2). Epoxidation with m-chloroperbenzoic acid (MCPBA) according to a literature method [15] yielded the epoxide 7 in meager yields (Scheme 2). The methylation of 7 to 8 was achieved by the treatment with

An unusually stable chlorophosphite: What makes BIFOP–Cl so robust against hydrolysis?

• Roberto Blanco Trillo,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2015, 11, 313–322, doi:10.3762/bjoc.11.36

• striking differences regarding their reaction with water. While BIFOP–Cl is nearly completely unreactive, its oxo-derivative O–BIFOP–Cl reacts instantly with water, yielding a tricyclic hydrocarbon unit after rearrangement. The analysis of the crystal structure of O–BIFOP–Cl and BIFOP–Cl revealed that the

Photovoltaic-driven organic electrosynthesis and efforts toward more sustainable oxidation reactions

• Bichlien H. Nguyen,
• Robert J. Perkins,
• Jake A. Smith and
• Kevin D. Moeller

Beilstein J. Org. Chem. 2015, 11, 280–287, doi:10.3762/bjoc.11.32

• double layer immediately around the electrode surface that can prevent molecules from reaching the electrode. For example, a “greasy” hydrocarbon-based electrolyte will form a hydrophobic double layer and exclude polar molecules from the region surrounding the electrode. This was the case when Et4NOTs

Synthesis of an organic-soluble π-conjugated [3]rotaxane via rotation of glucopyranose units in permethylated β-cyclodextrin

• Jun Terao,
• Yohei Konoshima,
• Akitoshi Matono,
• Hiroshi Masai,
• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2014, 10, 2800–2808, doi:10.3762/bjoc.10.297

• Jun Terao Yohei Konoshima Akitoshi Matono Hiroshi Masai Tetsuaki Fujihara Yasushi Tsuji Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, Japan 10.3762/bjoc.10.297 Abstract We synthesized symmetrically insulated oligo(para

Microsolvation and sp²-stereoinversion of monomeric α-(2,6-di-tert-butylphenyl)vinyllithium as measured by NMR

• Rudolf Knorr,
• Monika Knittl and
• Eva C. Rossmann

Beilstein J. Org. Chem. 2014, 10, 2521–2530, doi:10.3762/bjoc.10.263

• -BuBr to yield hydrocarbon 7. In THF as the solvent, such a mixing problem was encountered already at −70 °C: During the cautious addition of n-BuLi to bromoalkene 3, 4 was generated and rapidly converted into 6, 7, and 8a despite the presence of residual n-BuLi. In consideration of these various

Formal total syntheses of classic natural product target molecules via palladium-catalyzed enantioselective alkylation

• Yiyang Liu,
• Marc Liniger,
• Ryan M. McFadden,
• Jenny L. Roizen,
• Jacquie Malette,
• Corey M. Reeves,
• Douglas C. Behenna,
• Masaki Seto,
• Jimin Kim,
• Justin T. Mohr,
• Scott C. Virgil and
• Brian M. Stoltz

Beilstein J. Org. Chem. 2014, 10, 2501–2512, doi:10.3762/bjoc.10.261

• quaternary centers, two of which are stereogenic. Being a hydrocarbon, (−)-thujopsene (10) has few natural handles for retrosynthetic analysis. Inspired by the complexity of this relatively small natural product, several total syntheses of racemic 10 have been reported [25][26][27][28][29] along with at

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• functional groups weaken C–H bonds, yielding relatively stable radicals, in turn resulting in selective CO2 fixation [150]. Another patented system uses electrogenerated bases to deprotonate a weakly acidic hydrocarbon group forming anions which are carboxylated in the presence of CO2. Meanwhile, proton

• reaction product. The base precursor should be more easily electroreduced than the weakly acidic hydrocarbon group and carbon dioxide, and should not undergo a nucleophilic attack by either the hydrocarbon anion or the electrogenerated base. Therefore, the base precursor should be sterically hindered at or

• near the site(s) where reduction will occur. The electrogenerated base must be a strong enough Brønsted base to deprotonate the weakly acidic hydrocarbon group. Ethenetetracarboxylate tetraesters are typical base precursors, suited for the electrocarboxylation of N-alkyldiglycolimides (Scheme 22). This

Building complex carbon skeletons with ethynyl[2.2]paracyclophanes

• Ina Dix,
• Lidija Bondarenko,
• Peter G. Jones,
• Thomas Oeser and
• Henning Hopf

Beilstein J. Org. Chem. 2014, 10, 2013–2020, doi:10.3762/bjoc.10.209

• -diethynyl[2.2]paracyclophane, i.e., the hydrocarbon with two ethynyl groups in vicinal position in the same ring [2][3]. If, however, our target molecules are to have the two triple bonds in different benzene rings, the pseudo-gem-diethynyl[2.2]paracyclophane 2 is the analog of 1 (Scheme 1). Analogously

• The oxidative dimerization (Glaser coupling) of the achiral hydrocarbon 2 took place effortlessly and in high yield (Scheme 3). However, we have been unable so far to determine the exact structure of the isolated dimer. As shown in Scheme 3, in principle, two different dimers of 2 could be formed: one

• /propan-2-ol, 9:1) and [α]D25 = 43 ° (c 0.533, hexane/propan-2-ol, 9:1). The later eluting dimer is the “parallel” hydrocarbon 12 (Figure 2). This compound (Figure 2) crystallizes with imposed inversion symmetry (and is thus achiral), but the effective symmetry is C2h (2/m) with r.m.s.d. 0.14 Å. Compound

Supercritical carbon dioxide: a solvent like no other

• Jocelyn Peach and
• Julian Eastoe

Beilstein J. Org. Chem. 2014, 10, 1878–1895, doi:10.3762/bjoc.10.196

• environmental hazards [64][65][66][67]. Investigations focusing on partially fluorinated hybrid surfactants as a way to reduce fluorine content began in 1994 with the design and synthesis of F7H7, a partially fluorinated surfactant with an n-C7 fluorocarbon chain and an n-C7 hydrocarbon chain (Table 1, compound

• relationship between Φsurf, Ptrans and γcmc (surface tension of aqueous solutions) has been identified, with Φsurf increasing with decreased Ptrans and γcmc. This has been observed with a range of surfactants, including fully and partially fluorinated and hydrocarbon-based surfactants (Figure 2). Surfactant

• tails – siloxane, hydrocarbon and oxygenated surfactants: Though the use of fluorocarbons can be significantly reduced through the development of hybrid, semi-fluorinated surfactants, the race toward the development of a non-fluorinated, CO2 soluble surfactant is of primary focus in this field. These

Aryl substitution of pentacenes

• Andreas R. Waterloo,
• Anna-Chiara Sale,
• Dan Lehnherr,
• Frank Hampel and
• Rik R. Tykwinski

Beilstein J. Org. Chem. 2014, 10, 1692–1705, doi:10.3762/bjoc.10.178

• ; pentacene; π-stacking; polycyclic aromatic hydrocarbon; solid-state structure; Introduction Conjugated organic molecules are promising candidates for use in optoelectronic applications including OLEDs [1], photovoltaics [2], and OFETs [3]. Even though there is literally an infinite number of possibilities

Influence of perylenediimide–pyrene supramolecular interactions on the stability of DNA-based hybrids: Importance of electrostatic complementarity

• Christian B. Winiger,
• Simon M. Langenegger,
• Oleg Khorev and
• Robert Häner

Beilstein J. Org. Chem. 2014, 10, 1589–1595, doi:10.3762/bjoc.10.164

• sciences. They play a crucial role in the stacking of nucleobases, thus stabilising the DNA double helix. The following paper describes a series of chimeric DNA–polycyclic aromatic hydrocarbon (PAH) hybrids. The PAH building blocks are electron-rich pyrene and electron-poor perylenediimide (PDI), and were

• molecular scaffold for arranging various types of chromophores [39][40][41][42][43][44]. Recently, we reported that oligoarenotides (oligomers with an alternating phosphodiester-aromatic hydrocarbon motif) exhibit similar structural properties as nucleic acids, and although the aromatic hydrocarbons cannot

The search for new amphiphiles: synthesis of a modular, high-throughput library

• George C. Feast,
• Thomas Lepitre,
• Xavier Mulet,
• Charlotte E. Conn,
• Oliver E. Hutt,
• G. Paul Savage and
• Calum J. Drummond

Beilstein J. Org. Chem. 2014, 10, 1578–1588, doi:10.3762/bjoc.10.163

• cycloaddition (CuAAC) reaction. The tails were synthesised from two core alkyne-tethered intermediates, which were subsequently functionalised with hydrocarbon chains varying in length and degree of unsaturation and branching, while the five sugar head groups were selected with ranging substitution patterns and

• interfaces that curve towards the aqueous domain) are desirable as they maintain the same lyotropic structure upon dilution [8]. Inverse phases typically form from amphiphiles with multiple hydrocarbon-chain tails. Therefore, to tune our amphiphiles towards inverse phase formation, we undertook the synthesis

• that enabled a late-stage, modular addition of the hydrocarbon chains; the products of which could be taken straight into the high-throughput CuAAC reaction. To this end, diol 2 was synthesised by esterification of commercially available 3-hydroxy-2-(hydroxymethyl)-2-methylpropanoic acid (1), according

Syntheses of fluorooxindole and 2-fluoro-2-arylacetic acid derivatives from diethyl 2-fluoromalonate ester

• Antal Harsanyi,
• Graham Sandford,
• Dmitri S. Yufit and
• Judith A.K. Howard

Beilstein J. Org. Chem. 2014, 10, 1213–1219, doi:10.3762/bjoc.10.119

• corresponding reactivity profiles [14]. However, it does not necessarily follow that reactions for which regio- and stereoselectivity profiles are well established for hydrocarbon systems will be similar to those for corresponding selectively fluorinated systems and, indeed, this is often not the case [15]. The

Site-selective covalent functionalization at interior carbon atoms and on the rim of circumtrindene, a C₃₆H₁₂ open geodesic polyarene

• Hee Yeon Cho,
• Ronald B. M. Ansems and
• Lawrence T. Scott

Beilstein J. Org. Chem. 2014, 10, 956–968, doi:10.3762/bjoc.10.94

• reactions and to probe the magnetic environment of the concave/convex space around the hydrocarbon bowl. For both classes of functionalization, computational results are reported to complement the experimental observations. Keywords: Bingel–Hirsch reaction; buckybowl; carbon nanomaterials; cyclopropanation

• ; polycyclic aromatic hydrocarbon; Prato reaction; Introduction Investigations into the structures and properties of geodesic polyarenes began with the synthesis of corannulene (1, C20H10) in 1966 [1][2] and were greatly stimulated by the discovery of buckminsterfullerene (2, C60) in 1985 (Figure 1) [3

• formation at an interior carbon atom, despite the long history of aromatic hydrocarbon chemistry [41][42]. These PAHs (1 and 10) are obviously nonplanar and have the same patterns of pentagons and hexagons as that found on the surface of fullerene C60. The distortions of the π-systems in these molecules

Conformational analysis of 2,2-difluoroethylamine hydrochloride: double gauche effect

• Josué M. Silla,
• Claudimar J. Duarte,
• Rodrigo A. Cormanich,
• Roberto Rittner and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2014, 10, 877–882, doi:10.3762/bjoc.10.84

• -difluoroethylamine hydrochloride; gauche effect; hydrogen bonding; Introduction The conformational isomerism of alkylamines devotes interest because intramolecular effects relative to hydrocarbon analogues are affected by the electronegativity of the nitrogen atom and by the basicity of the amino group. However

Metal and metal-free photocatalysts: mechanistic approach and application as photoinitiators of photopolymerization

• Jacques Lalevée,
• Sofia Telitel,
• Pu Xiao,
• Marc Lepeltier,
• Frédéric Dumur,
• Fabrice Morlet-Savary,
• Didier Gigmes and
• Jean-Pierre Fouassier

Beilstein J. Org. Chem. 2014, 10, 863–876, doi:10.3762/bjoc.10.83

• under a red laser line exposure at 635 nm. This result was very important as cationic polymerization in these irradiation conditions was not possible previously. Changing Vi or the anthracene derivative for a hydrocarbon (e.g. pyrene, naphthacene, pentacene) allows a tunable absorption of the system

• from 400 nm to 650 nm: exposure of the hydrocarbon/Ph2I+/TTMSS system to soft purple (405 nm), blue (457, 462 or 473 nm), green (514, 532 nm), yellow (591 nm) or red (630, 635 nm) LED bulbs or laser diodes becomes successful. In rare examples, the PIC/methyldiethanolamine MDEA/phenacyl bromide R-Br

• recently achieved in FRP for the first time [54][55]: they involve hydrocarbon derivatives (e.g., pyrene, naphtacene, pentacene), an amine (e.g., ethyl dimethylaminobenzoate) and an alkyl halide (e.g., phenacyl bromide); the mechanism is similar to that shown in Scheme 12. As above, a tunable absorption of

Structure elucidation of female-specific volatiles released by the parasitoid wasp Trichogramma turkestanica (Hymenoptera: Trichogrammatidae)

• Armin Tröger,
• Teris A. van Beek,
• Martinus E. Huigens,
• Isabel M. M. S. Silva,
• Maarten A. Posthumus and
• Wittko Francke

Beilstein J. Org. Chem. 2014, 10, 767–773, doi:10.3762/bjoc.10.72

• identified as the hydrocarbon 2,6,8,12-tetramethyltrideca-2,4-diene (A) and the corresponding allylic alcohol 2,6,8,12-tetramethyltrideca-2,4-diene-1-ol (B) [12]. Since the two proposed structures were deduced from analytical data only, the aim of the present study was to scrutinize these suggestions by

• unambiguous synthesis. Results and Discussion The 70 eV EI mass spectra of the two natural products A and B are depicted in Figure 1 [12]. Because the carbon skeleton had been reported to be the same in both compounds, we used the hydrocarbon A as the first target for the preparation of a reference sample. As

Carbenoid-mediated nucleophilic “hydrolysis” of 2-(dichloromethylidene)-1,1,3,3-tetramethylindane with DMSO participation, affording access to one-sidedly overcrowded ketone and bromoalkene descendants^§

• Rudolf Knorr,
• Thomas Menke,
• Johannes Freudenreich and
• Claudio Pires

Beilstein J. Org. Chem. 2014, 10, 307–315, doi:10.3762/bjoc.10.28

• ; DMSO; nucleophilic vinylic substitution; steric hindrance; Introduction The 1,1,3,3-tetramethylindan-2-yl(idene) fragments shown in the hydrocarbon parts of formulae 4–8 (Scheme 1) are preferable to the corresponding acyclic di-tert-butylmethylidene moiety (t-Bu2C in 1–3) as the shielding substituent

The difluoromethylene (CF₂) group in aliphatic chains: Synthesis and conformational preference of palmitic acids and nonadecane containing CF₂ groups

• Yi Wang,
• Ricardo Callejo,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2014, 10, 18–25, doi:10.3762/bjoc.10.4

• aliphatic chain. Specifically 8,8,10,10- and 8,8,11,11-tetrafluorohexadecanoic acids (6b and 6c) are prepared as well as the singly modified analogue 8,8-difluorohexadecanoic acid (6a). Also 8,8,11,11-tetrafluorononadecane (27) is prepared as a pure hydrocarbon containing a 1,4-di-CF2 motif. The modified

• solid state. Thus it appeared appropriate to prepare a true hydrocarbon chain to further investigate the conformational preference of the 1,4-di-CF2 motif. Accordingly we selected to prepare tetrafluorononadecane 27. This is a long chain hydrocarbon with the 1,4-di-CF2 motif placed centrally. The

• that this is the preferred conformation of this motif in a hydrocarbon chain. Conclusion In conclusion, we have synthesised three palmitic acid analogues 6a–c carrying regiospecifically located CF2 groups. The tetrafluorononadecane 27 was also prepared as an example of a true hydrocarbon. Relatively