Intramolecular carbolithiation cascades as a route to a highly strained carbocyclic framework: competition between 5-exo-trig ring closure and proton transfer

• William F. Bailey and
• Justin D. Fair

Beilstein J. Org. Chem. 2013, 9, 537–543, doi:10.3762/bjoc.9.59

• significant that the penultimate olefinic alkyllithium 7 generated in the cascade appears to be resistant to rearrangement by proton transfer in the absence of a catalytic quantity of the hydrocarbon formed upon quenching of 7. In short, 5-exo-trig carbolithiations are robust processes that are much more

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

Caryolene-forming carbocation rearrangements

• Quynh Nhu N. Nguyen and
• Dean J. Tantillo

Beilstein J. Org. Chem. 2013, 9, 323–331, doi:10.3762/bjoc.9.37

• positioned on opposite sides of the hydrocarbon substrate due to the steric congestion at its core (note the position of NH3 throughout Figure 7), a scenario that could be probed by deuterium labeling of farnesyl diphosphate if a suitable caryolene synthase were isolated. The energetics for both pathways

Inter- and intramolecular enantioselective carbolithiation reactions

• Asier Gómez-SanJuan,
• Nuria Sotomayor and
• Esther Lete

Beilstein J. Org. Chem. 2013, 9, 313–322, doi:10.3762/bjoc.9.36

• enantioselectivity, favoring the coordination of the ligand with lithium. While solvent systems composed of hydrocarbon/diethyl ether are effective, the use of THF resulted in almost complete loss of enantioselectivity. The cyclization of amine 37b under identical conditions was less enantioselective than the

Towards a biocompatible artificial lung: Covalent functionalization of poly(4-methylpent-1-ene) (TPX) with cRGD pentapeptide

• Lena Möller,
• Christian Hess,
• Jiří Paleček,
• Yi Su,
• Axel Haverich,
• Andreas Kirschning and
• Gerald Dräger

Beilstein J. Org. Chem. 2013, 9, 270–277, doi:10.3762/bjoc.9.33

• peptides have successfully been used to generate biocompatible materials [10][11]. Conceptually, we planned to first functionalize the hydrocarbon TPX 2 via UV-mediated nitrene insertion to form polymer derivative 4 (Scheme 1) [12][13][14]. Therefore, nitrene precursor 3 was modified with an oligo(ethylene

• plasma treatment with nitrene insertion is a protocol of general importance for the functionalization of biomedical materials based on hydrocarbon-derived polymers. The importance of developing strategies for this kind of copper-free surface functionalization reported here was recently also demonstrated

A chemist and biologist talk to each other about caged neurotransmitters

• Graham C.R. Ellis-Davies

Beilstein J. Org. Chem. 2013, 9, 64–73, doi:10.3762/bjoc.9.8

• "? Chemist: It is well known in the pharmaceutical industry that water solubility is one of the true challenges for drug development. Often drugs are built up around rigid hydrocarbon scaffolds, such substances are inherently hydrophobic. The same issue applies to caged compounds, as in these we add aromatic

Polar reactions of acyclic conjugated bisallenes

• Reiner Stamm and
• Henning Hopf

Beilstein J. Org. Chem. 2013, 9, 36–48, doi:10.3762/bjoc.9.5

• reactions of the bisallenes would lead to functionalized derivatives that could be useful for other preparative investigations, just as in the pericyclic case [2][3][4][5][6]. The results of these initial studies are presented here. Since the parent hydrocarbon 1 (biallenyl) is rather unstable [7], we

• decided to use the tetramethyl derivative 2 (2,7-dimethylocta-2,3,5,6-tetraene) as a symmetric substrate and the tert-butyl derivative 3 (7,7-dimethylocta-1,2,4,5-tetraene) as an asymmetric starting material for our polar reactions (Scheme 1). Hydrocarbon 2, prepared by Skattebøl in the early 1960s [3][8

• ][9], is a crystalline solid at room temperature and stable for very long times. Bisallene 3, first prepared by Ruitenberg, Kleijn, Westmijze, Meijer and Vermeer [10] is decidedly more stable than the parent hydrocarbon 1: in solution the colorless oil can be kept for weeks at room temperature before

Chemical modification allows phallotoxins and amatoxins to be used as tools in cell biology

• Jan Anderl,
• Hartmut Echner and
• Heinz Faulstich

Beilstein J. Org. Chem. 2012, 8, 2072–2084, doi:10.3762/bjoc.8.233

• hydrocarbon chain instead of the disulfide group. DSP or DSS (248 µmol) were dissolved in 1.0 mL of N,N-dimethylformamide and added to 63 µmol dried aminophalloidin. The reaction was started with 2 µL triethylamine and allowed to proceed under magnetic stirring for 16 h at rt. The reaction was stopped with 10

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

• reported by Marvel and co-workers in the 1930s [7][8]; it is the highly substituted and hence stabilized hydrocarbon 3, a hexa-substituted derivative of 2 (Figure 2). Twenty-five years later, Kuhn and Fischer presented the preparation of 1,1,6,6-tetraphenyl-1,2,4,5-hexatetraene (4) as the first conjugated

• bisallene with unsubstituted allene carbon atoms [9]. And finally, also in the 1960s, Jacobs and Prempree reported on the synthesis of the first hexa-alkylated bisallene, hydrocarbon 5 [10][11]. We shall return to the preparation of these three compounds later. The upsurge in interest in allene chemistry is

• the tetramethylbutadiene 22 is first dibromocyclopropanated to the tetrabromide 23, which, on treatment with an organolithium reagent, is debrominated/rearranged to the target hydrocarbon 24. Hydrocarbon 24 is a stable colorless solid that can be worked with under normal laboratory conditions without

Laterally substituted symmetric and nonsymmetric salicylideneimine-based bent-core mesogens

• Sonja Findeisen-Tandel,
• Wolfgang Weissflog,
• Ute Baumeister,
• Gerhard Pelzl,
• H. N. Shreenivasa Murthy and
• Channabasaveshwar V. Yelamaggad

Beilstein J. Org. Chem. 2012, 8, 129–154, doi:10.3762/bjoc.8.15

• , corresponding compounds without hydroxy groups were additionally prepared. In order to focus the study on the effect of lateral substituents, the hydrocarbon chains at both terminal phenyl rings were fixed with dodecyloxy groups. Results and Discussion Monosalicylideneaniline compounds OH 1 bearing the

On the control of secondary carbanion structure utilising ligand effects during directed metallation

• Andrew E. H. Wheatley,
• Jonathan Clayden,
• Ian H. Hillier,
• Alison Campbell Smith,
• Mark A. Vincent,
• Laurence J. Taylor and
• Joanna Haywood

Beilstein J. Org. Chem. 2012, 8, 50–60, doi:10.3762/bjoc.8.5

• solvent or additives to influence the chemoselectivity of lithiation, 6-H was treated at −78 °C with t-BuLi in a hydrocarbon medium to which 1 equiv of PMDTA had been added. The resulting dark purple solution was transferred directly to a freezer (−30 °C) whereupon storage afforded a product that X-ray

• presence of different Lewis bases. In contrast to previous work on carbanion formation in the presence of an aromatic N+O directing group, 6-Lil·L dissolves in hydrocarbon media to reveal two structures in solution. Based on previous work and new DFT studies, we ascribe these as being cis (minor) and trans

Planar-bilayer activities of linear oligoester bolaamphiphiles

• Jonathan K. W. Chui,
• Thomas M. Fyles and
• Horace Luong

Beilstein J. Org. Chem. 2011, 7, 1562–1569, doi:10.3762/bjoc.7.184

• Information File 1, from which it is clear that we could have made similar representations as Figure 1 and Figure 2 with any other pair of compounds. Erratic behaviors may be aesthetically unappealing but should come as no surprise: The hydrocarbon chains that are present in every compound have significant

• -molecule structure–activity relationships for compounds 1–8. Grids are given in the following sequence in each case: Square-top (green); flicker (yellow); multiple-opening (blue); spike (red); erratic (purple). Yellow arrows indicate hydrocarbon homologs; green arrows indicate expansion of aromatic units

One-pot four-component synthesis of pyrimidyl and pyrazolyl substituted azulenes by glyoxylation–decarbonylative alkynylation–cyclocondensation sequences

• Charlotte F. Gers,
• Julia Rosellen,
• Eugen Merkul and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1173–1181, doi:10.3762/bjoc.7.136

• a long time [16][17]. This prominent appearance results from the electronic transition between the S0 and S1 state [18], as a consequence of low energy frontier molecular orbital transitions [19]. The bicyclic structure of this nonbenzoid hydrocarbon results from a five–seven ring annulation with a

• by our smooth glyoxylation–alkynylation sequences with a variety of unfunctionalized π-nucleophiles, such as pyrazoles, thiophenes, furans, and even the hydrocarbon azulene (1a) [53], we decided to perform optimization studies of the glyoxylation–decarbonylative alkynylation with guaiazulene (1b), a

Isotopic labelling studies for a gold-catalysed skeletal rearrangement of alkynyl aziridines

• Paul W. Davies,
• Nicolas Martin and
• Neil Spencer

Beilstein J. Org. Chem. 2011, 7, 839–846, doi:10.3762/bjoc.7.96

• generally mild reaction conditions using straightforward preparative procedures [1][2][3][4][5][6][7][8][9]. Many such processes also incorporate a rearrangement of the hydrocarbon skeleton present in the starting material, which can lead to unexpected and synthetically interesting outcomes [10][11]. One of

Intraannular photoreactions in pseudo-geminally substituted [2.2]paracyclophanes

• Henning Hopf,
• Vitaly Raev and
• Peter G. Jones

Beilstein J. Org. Chem. 2011, 7, 658–667, doi:10.3762/bjoc.7.78

• prepare the biscyclopropane analog of 11, the bisvinylcyclopropane 19 (or one of its cis-isomers) and subject this presumably strained hydrocarbon to our photocyclization conditions. Of course, this system also has various options to react, among them the photoisomerization to a mono- or all-cis

• (Figure 3), no reaction takes place from this orientation on irradiation in solution. Since we have already demonstrated that a comparable situation prevails for the simplest compound studied in this series, hydrocarbon 7 (Scheme 3), we conclude that reaction from this anti,anti-conformation is the

• ) gave 2.60 g (10 mmol, 100%) of pure hydrocarbon 7. 1H NMR (200 MHz, CDCl3) δ 6.81 (dd, 2H, J1 = 10.9, J2 = 17.4 Hz), 6.60–6.40 (m, 6H), 5.36 (dd, 2H, J1 = 1.5, J2 = 17.4 Hz), 5.08 (dd, 2H, J1 = 1.5 , J2 = 10.9 Hz), 3.60–3.40 (m, 2H), 3.05–2.86 (m, 6H) ppm; 13C NMR (50.3 MHz, CDCl3) δ 139.3, 138.0

Tribenzotriquinacenes bearing three peripheral or bridgehead urea groups stretched into the 3-D space

• Jörg Tellenbröker and
• Dietmar Kuck

Beilstein J. Org. Chem. 2011, 7, 329–337, doi:10.3762/bjoc.7.43

• derivatives; Introduction In the course of our extended research on polyfunctionalized derivatives of tribenzotriquinacene (TBTQ, 1) and some hydrocarbon congeners 2–4, which provide a great variety of convex–concave molecular building blocks [1][2][3][4][5][6][7], we focused our attention on the synthesis

Reciprocal polyhedra and the Euler relationship: cage hydrocarbons, C_nH_n and closo-boranes [B_xH_x]²⁻

• Michael J. McGlinchey and
• Henning Hopf

Beilstein J. Org. Chem. 2011, 7, 222–233, doi:10.3762/bjoc.7.30

• reciprocal polyhedra. The vertices in the closo-boranes correspond to faces in its polycyclic hydrocarbon counterpart and vice versa. The different bonding patterns in the two series are described. Several of these hydrocarbons (cubane, pentagonal dodecahedrane and the trigonal and pentagonal prismanes) are

• − 1–8, and CnHn hydrocarbons (n = 6, 8, 10 … 20; 9–16), the point groups and V, E, F values of the complementary CnHn molecules are collected in Table 1. Bonding comparisons The inverse geometric structures of the closo-boranes and their cage hydrocarbon complementary counterparts are the result of

• , or their corresponding anions [BxHx]2−, where x = 5 through 12, suggests that their complementary hydrocarbon cages CnHn, where n represents the even numbers 4 through 20, should also all be viable, as discussed herein. Synthetic routes to highly symmetrical polycyclic hydrocarbons As already noted

Ene–yne cross-metathesis with ruthenium carbene catalysts

• Cédric Fischmeister and
• Christian Bruneau

Beilstein J. Org. Chem. 2011, 7, 156–166, doi:10.3762/bjoc.7.22

• with acyclic internal olefins up to now. This would allow the introduction of a conjugated diene system into an aliphatic hydrocarbon chain. However, the production of terminal olefins upon ethenolysis of unsaturated fatty acid esters followed by cross-metathesis with an alkyne in one pot has recently

Syntheses and properties of thienyl-substituted dithienophenazines

• Annemarie Meyer,
• Eva Sigmund,
• Friedhelm Luppertz,
• Gregor Schnakenburg,
• Immanuel Gadaczek,
• Thomas Bredow,
• Stefan-S. Jester and
• Sigurd Höger

Beilstein J. Org. Chem. 2010, 6, 1180–1187, doi:10.3762/bjoc.6.135

• monolayers on HOPG (Figure 3a). Bright and dark colors originate from locally high and low tunneling currents, resulting from unsaturated (backbone) and saturated (alkyl side chain) hydrocarbon segments, respectively [37]. A unit cell with a = 2.5 ± 0.1 nm, b = 2.3 ± 0.1 nm, γ = 90 ± 2° could be determined

About the activity and selectivity of less well-known metathesis catalysts during ADMET polymerizations

• Hatice Mutlu,
• Lucas Montero de Espinosa,
• Oĝuz Türünç and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2010, 6, 1149–1158, doi:10.3762/bjoc.6.131

• C1 to challenging substrates, such as diethyl di(methallyl)malonate in fluorinated aromatic hydrocarbon solvents, resulted in a remarkable enhancement of catalytic activity. Moreover, this approach was successfully extended to the RCM of natural products and the cross-metathesis formation of

Expanding the gelation properties of valine-based 3,5-diaminobenzoate organogelators with N-alkylurea functionalities

• Hak-Fun Chow and
• Chin-Ho Cheng

Beilstein J. Org. Chem. 2010, 6, 1015–1021, doi:10.3762/bjoc.6.114

• alicyclic hydrocarbon, alcohols and even polar aprotic solvents such as DMSO and DMF by replacing the Cbz group with an N-alkylurea functionality (e.g., 2). In addition, the length of the alkyl chain –(CH2)nMe also exhibited some interesting effects on their gelation ability [15]. Results and Discussion

• target organogelators 2 in chloroform and acetone, their 1H and 13C NMR spectra were recorded in DMSO-d6. In addition, the 1H and 13C NMR spectra of analogues with thirteen or more carbon atoms in the aliphatic hydrocarbon chains were recorded at 100 °C to avoid gelation of the solvent. The 1H NMR

• spectra of compounds 2 showed the presence of the aliphatic hydrocarbon chains and the urea moieties. The methyl group of the aliphatic chains appeared as a triplet at ~ δ 0.86, while the methylenes of the aliphatic chains were located in close proximity to the signals of the valine side chain. On the

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

• Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

Functionalized copolyimide membranes for the separation of gaseous and liquid mixtures

• Nadine Schmeling,
• Roman Konietzny,
• Daniel Sieffert,
• Patrick Rölling and
• Claudia Staudt

Beilstein J. Org. Chem. 2010, 6, 789–800, doi:10.3762/bjoc.6.86

• plasticize polyimide membranes but propane, propylene and higher hydrocarbon do [25][45][48][49]. In order to avoid undesirable plasticization effects, cross-linkable copolyimides have been synthesized, and their separation properties characterized. In Figure 7 the experimenstal data for the separation of a

Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine)

• Katja Hofmann,
• Ingolf Kahle,
• Frank Simon and
• Stefan Spange

Beilstein J. Org. Chem. 2010, 6, No. 79, doi:10.3762/bjoc.6.79

•  2a shows a typical XPS wide-scan spectrum of the bare silica support which was unloaded. The spectrum contains the expected peaks from silicon (Si 2s and Si 2p) and oxygen (O 1s, O 2s and the O KLL Auger series). The small C 1s peak shows the presence of typical hydrocarbon surface contaminations

A novel and efficient method to prepare 2-aryltetrahydrofuran-2-ylphosphonic acids

• Vsevolod V. Komissarov,
• Anatoly M. Kritzyn and
• Jouko J. Vepsäläinen

Beilstein J. Org. Chem. 2010, 6, No. 63, doi:10.3762/bjoc.6.63

• [1][2][3][4]. As a part of our ongoing project, it seemed important to synthesize compounds with phosphonate and phenyl groups at one end of the hydrocarbon chain and a nucleic base residue at the other end. Previously, it was shown that compounds with similar structures inhibit purine nucleoside

• [18]. The length of hydrocarbon chain is also of major importance, since cyclic tetrahydropyran derivatives are not formed in the case of arylpentanones 9a,b under the same conditions as those used for the synthesis of furans 2 (Scheme 3). According to the NMR spectra, the only phosphorus containing