The preparation of several 1,2,3,4,5-functionalized cyclopentane derivatives

• André S. Kelch,
• Peter G. Jones,
• Ina Dix and
• Henning Hopf

Beilstein J. Org. Chem. 2013, 9, 1705–1712, doi:10.3762/bjoc.9.195

• Braunschweig, Germany Novartis Pharma AG, CH-4056 Basel, Switzerland 10.3762/bjoc.9.195 Abstract With the goal of eventually synthesizing [5]radialene (3), the still missing member of the parent radialene hydrocarbons, we have prepared the pentaacetates 21 and 31, the pentabromide 29 and the hexabromide 32

• . In principle these should be convertible by elimination reactions to the desired target molecule. Keywords: bromination; cyclopentanes; esterification; permethylcyclopentadiene; polyfunctional compounds; radialenes; Introduction Radialenes are cyclic cross-conjugated hydrocarbons that consist

• derivatives bearing alkyl and aryl and also functionalized substituents, beginning with 1 and ending with [6]radialene (4, Scheme 1) are known for the whole series [2][3][4][5], among the parent hydrocarbons one representative is still missing: [5]radialene (3). One reason for this absence is certainly the

Bromination of hydrocarbons with CBr₄, initiated by light-emitting diode irradiation

• Yuta Nishina,
• Bunsho Ohtani and
• Kotaro Kikushima

Beilstein J. Org. Chem. 2013, 9, 1663–1667, doi:10.3762/bjoc.9.190

• Yuta Nishina Bunsho Ohtani Kotaro Kikushima Research Core for Interdisciplinary Science, Okayama University, Tsushimanaka, Kita-ku, Okayama 700-8530, Japan Catalysis Research Center, Hokkaido University, Sapporo 001-0021, Japan 10.3762/bjoc.9.190 Abstract The bromination of hydrocarbons with CBr4

• hydrocarbons proceeds through radical abstraction of hydrogen atoms and trapping with bromide, whereas the bromination reactions of aromatic and unsaturated hydrocarbons are induced by electrophilic addition of bromine and/or a cationic bromide. Combinations of N-bromosuccinimide (NBS) with

• reported to serve as bromine sources for the bromination of saturated hydrocarbons, these reactions exhibit low selectivity or reactivity. Efficient bromination using Br2 as a bromine source combined with a stoichiometric base [24], an excess of MnO2 [25], or a catalytic amount of Li2MnO3 [26] has been

True and masked three-coordinate T-shaped platinum(II) intermediates

• Manuel A. Ortuño,
• Salvador Conejero and
• Agustí Lledós

Beilstein J. Org. Chem. 2013, 9, 1352–1382, doi:10.3762/bjoc.9.153

• (pyrazolyl)borate; n = 0, 1) produces a transient three-coordinate Pt(II) complex [Pt(R)(η2-N3)]n+ 10 (Scheme 10), which is able to activate C–H bonds of hydrocarbons or form solvent adducts [103][104][105]. Solution behavior In masked three-coordinate d8 complexes, the fourth coordination site is occupied

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• complexes. However, eco-friendly standards, including the demand for highly selective transformations, impose the development of metal-free processes, especially for large-scale productions, as in the case of the oxygenation of hydrocarbons. For this reason, many efforts have been devoted in the past decade

• processes, especially in the field of the selective oxygenation of hydrocarbons. Review Radical initiation by thermal decomposition Thermal decomposition of peroxides and azo-compounds is a well-known technique generally used to generate radicals in solution. Ishii and co-workers widely investigated the key

• zeolite, for the oxygenation of a wider range of hydrocarbons [34]. Moreover, the electronic effect of substituents on quinones and on the aromatic ring of NHPI was also investigated. Quinones bearing halogen groups were used in the selective oxidation of alkylarenes, alkenes and alkanes [35], revealing

3D-printed devices for continuous-flow organic chemistry

• Vincenza Dragone,
• Victor Sans,
• Mali H. Rosnes,
• Philip J. Kitson and
• Leroy Cronin

Beilstein J. Org. Chem. 2013, 9, 951–959, doi:10.3762/bjoc.9.109

• chemical properties; however their chemical compatibility is low. In fact they are not generally recommended for exposure to alcohol, glycols, alkalis, brake fluids, or to chlorinated or aromatic hydrocarbons [20]. Therefore, PP was the plastic of choice for the device fabrication. The shape of the 3D

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

• temperature. Keywords: carbolithiation cascade; carbometallation; intramolecular carbolithiation; intermolecular proton transfer; lithium–halogen exchange; strained hydrocarbons; Introduction The first publication describing an intramolecular carbolithiation appeared in 1968: Drozd and co-workers reported

A new intermediate in the Prins reaction

• Shinichi Yamabe,
• Takeshi Fukuda and
• Shoko Yamazaki

Beilstein J. Org. Chem. 2013, 9, 476–485, doi:10.3762/bjoc.9.51

• produced when pinene (a bicyclic monoterpene) was heated with paraformaldehyde. However, Prins performed the first rather comprehensive study of the reactions between formaldehyde and hydrocarbons with C=C double bonds [2][3]. These were styrene, pinene, camphene and anethole. As a catalyst, sulfuric acid

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

• the reaction products. Although this goal was accomplished, the overall process is considerably more complex (Scheme 3). Treatment of 2 or 4 in THF at −35 °C with 13 resulted in the formation of four hydrocarbons: two monoallylated products, 14 and 17, and two bisallylated ones, 19 and 20, with the

• pure form by preparative gas chromatography. All hydrocarbons are colorless oils that, even at −15 °C (deep freeze), are stable for a limited time only. A simple rationalization of the product formation, in which 14 and 17 are the primary products, is given in Scheme 3. Hydrocarbon 14 is the direct

• , and co-workers [21][22][23][24] are particular noteworthy in the present context. The French authors demonstrated that vinylallenes, hydrocarbons rather similar to the systems studied here, provide cyclopentenone derivatives in a process mimicking the Nazarov cyclization [25]. The first conjugated

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

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

• steps (high step economy). Keywords: alicyclic; bisallenes; cyclic; cycloadditions; cycloisomerization; isomerization; molecular complexity; step economy; Table of Contents Introduction Review Acyclic conjugated bisallenes 1.1 Synthesis of hydrocarbons 1.2 Synthesis of functionalized systems 1.3

• heteroaromatic moieties may take over the role of the aromatic core. Review 1 Acyclic conjugated bisallenes 1.1 Synthesis of hydrocarbons Bisallenes of type 2 or 6 have been prepared by many different routes and strategies from which, however, three stand out: i) The C6-carbon framework may be constructed by

• ’-reactions, but detailed mechanistic experiments have not been undertaken for this particular reaction so far [21]. The two C6H6-isomers 2 and 21 are produced in ca. 2:3 ratio and the total yield varies from 40–70%, depending primarily on the workup conditions. The separation of the two hydrocarbons by

Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10

• Teresa Weise,
• Marco Kai,
• Anja Gummesson,
• Armin Troeger,
• Stephan von Reuß,
• Silvia Piepenborn,
• Francine Kosterka,
• Martin Sklorz,
• Ralf Zimmermann,
• Wittko Francke and
• Birgit Piechulla

Beilstein J. Org. Chem. 2012, 8, 579–596, doi:10.3762/bjoc.8.65

• (38) (small amounts of which were found to be present among the natural volatiles), retention indices with methylketones as reference standards were calculated. Corresponding data published for methyl-branched hydrocarbons and increment calculations strongly suggested iso-branching for the main

Regio- and stereoselective oxidation of unactivated C–H bonds with Rhodococcus rhodochrous

• Elaine O’Reilly,
• Suzanne J. Aitken,
• Gideon Grogan,
• Paul P. Kelly,
• Nicholas J. Turner and
• Sabine L. Flitsch

Beilstein J. Org. Chem. 2012, 8, 496–500, doi:10.3762/bjoc.8.56

• hydrocarbons, including n-alkanes and isoalkanes, and has been reported to catalyse the terminal hydroxylation of chloroalkanes and long-chain alkenes [13]. It has been suggested that this strain contains an alkane-inducible NADH-dependent hydroxylase that catalyses the oxidation of n-octane to 1-octanol [13

Reduction of benzylic alcohols and α-hydroxycarbonyl compounds by hydriodic acid in a biphasic reaction medium

• Michael Dobmeier,
• Josef M. Herrmann,
• Dieter Lenoir and
• Burkhard König

Beilstein J. Org. Chem. 2012, 8, 330–336, doi:10.3762/bjoc.8.36

• protocol for the reduction of alcohols to hydrocarbons by using hydriodic acid, first described by Kiliani more than 140 years ago, was improved to be more applicable to organic synthesis. Instead of a strongly acidic, aqueous solution, a biphasic toluene–water reaction medium was used, which allowed the

• conversion of primary, secondary and tertiary benzylic alcohols, in good yields and short reaction times, into the corresponding hydrocarbons. Red phosphorous was used as the stoichiometric reducing agent. Keto, ester, amide or ether groups are tolerated, and catalytic amounts of hydriodic acid (0.2 equiv

Efficient and selective chemical transformations under flow conditions: The combination of supported catalysts and supercritical fluids

• M. Isabel Burguete,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2011, 7, 1347–1359, doi:10.3762/bjoc.7.159

• tuned by a proper selection of pressure and temperature parameters leading to a controlled variation of polarity, dissolution power, etc. All these factors offer good opportunities to perform hydrogenation reactions in scCO2 and supercritical hydrocarbons, leading to improved activity and, in some cases

Gold(I)-catalyzed synthesis of γ-vinylbutyrolactones by intramolecular oxaallylic alkylation with alcohols

• Michel Chiarucci,
• Mirko Locritani,
• Gianpiero Cera and
• Marco Bandini

Beilstein J. Org. Chem. 2011, 7, 1198–1204, doi:10.3762/bjoc.7.139

• synthesis and enables unprecedented manipulations of unfunctionalized hydrocarbons under mild reaction conditions [5][6][7][8][9]. In this context, electrophilic LTM activation of carbon–carbon unsaturations, adjacent to alcoholic moieties (i.e., allylic, benzylic, and propargylic alcohols, usually referred

Synthetic applications of gold-catalyzed ring expansions

• David Garayalde and
• Cristina Nevado

Beilstein J. Org. Chem. 2011, 7, 767–780, doi:10.3762/bjoc.7.87

• -2,4-hexadiene (7) in moderate yields when either AuI3 or AuCN were used as catalysts (Scheme 1, reaction 2). Only four years later, de Meijere reported a gold-catalyzed rearrangement of strained small ring hydrocarbons [12]. Although heterogeneous catalysis seemed to be operating in this case

Alkene selenenylation: A comprehensive analysis of relative reactivities, stereochemistry and asymmetric induction, and their comparisons with sulfenylation

• Vadim A. Soloshonok and
• Donna J. Nelson

Beilstein J. Org. Chem. 2011, 7, 744–758, doi:10.3762/bjoc.7.85

• selenenylation; asymmetric synthesis; calculations; electronic effects; regioselectivity; relative reactivities; steric effects; Introduction Electrophilic addition to alkenes is one of the most fundamental, generalized, and versatile methods for selective functionalization of hydrocarbons [1]. Despite recent

When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• gold complexes involve intramolecular Friedel–Crafts reactions and the addition of carbonyl groups. Intramolecular Friedel–Crafts reactions In the context of their studies on the Lewis acid-catalyzed rearrangement of strained three-membered ring hydrocarbons, such as methylenecyclopropanes and

• ]. Wang et al. also examined the behaviour of other cyclopropen-1,n-ynes. For substrates 89a and 89b possessing a 1,6-enyne moiety, the gold-catalyzed cycloisomerization led to the tricyclic hydrocarbons 90a (80%) and 90b (74%), respectively. The alkyne, chemoselectively activated by the gold complex

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

• same is true for the photoisomerization of 22 to 23 and 24. The structures of these new hydrocarbons were established by X-ray crystallography and spectroscopic analysis; among the noteworthy structural features of 13 and 15 are unusually long carbon–carbon single bonds (>1.64 Å). Keywords

• contribution we report on the results obtained with two hydrocarbons 11 (Scheme 4) and 16. Bis-ene-al 10 was obtained in excellent yield (97%) as a mixture of three isomers (Scheme 4) in a ratio of 70:15:1; the isomers were isolated by column chromatography and their structures were established from their

• of Z,Z-22 with a 1 kW halogen lamp in a Pyrex flask over 12 h (Scheme 8) gave only two [2 + 2] cycloaddition products: The hydrocarbons 23 and 24 in 3:5-ratio with a total yield of 70%. The isomers were separated by column chromatography and their structures established by NMR spectroscopy and single

Synthesis and self-assembly of 1-deoxyglucose derivatives as low molecular weight organogelators

• Guijun Wang,
• Hao Yang,
• Sherwin Cheuk and
• Sherman Coleman

Beilstein J. Org. Chem. 2011, 7, 234–242, doi:10.3762/bjoc.7.31

• synthesized the terminal acetylenes 9–11, saturated hydrocarbons 12–14, aryl derivatives 15,16, and two long chain diacetylene containing glycolipids 17,18. After we obtained these compounds, we then screened them for gelation in several solvents. These results are shown in Table 1. From the gelation test

• groups did show more promise than saturated hydrocarbons. Polydiacetylenes have interesting optical and electronic properties, and diacetylene containing gels may have useful applications as advanced sensing materials [35][40][41]. The morphologies of the self-assembled structures can be retained by

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

• described. Keywords: cage hydrocarbons; high symmetry; reciprocal polyhedra; Review Platonic polyhedra and the Euler relationship The Platonic solids have long fascinated geometers, artists and chemists alike. Molecular analogues of the tetrahedron (P4, B4Cl4, Si4t-Bu4), octahedron ([B6H6]2−), cube (C8H8

• , 12) are in accord with Euler's equation. Interestingly, the tetrahedron (4 vertices, 6 edges and 4 faces) is its own reciprocal. Boranes, hydrocarbons and inverse polyhedra Closo-borane anions and their carborane analogues adopt polyhedral structures in which each face is triangular [3]; Figure 3

Self-assembly and semiconductivity of an oligothiophene supergelator

• Pampa Pratihar,
• Suhrit Ghosh,
• Vladimir Stepanenko,
• Sameer Patwardhan,
• Ferdinand C. Grozema,
• Laurens D. A. Siebbeles and
• Frank Würthner

Beilstein J. Org. Chem. 2010, 6, 1070–1078, doi:10.3762/bjoc.6.122

• to room temperature, spontaneous gelation was observed (see Figure 1A, inset) in most cases within 5–10 minutes. For example, aromatic hydrocarbons (toluene, benzene), aliphatic hydrocarbons (methylcyclohexane, cyclohexane, n-heptane, n-hexane), chlorinated hydrocarbons (chlorobenzene

• aliphatic hydrocarbons (methylcyclohexane (MCH), cyclohexane, n-hexane, n-heptane) and in tetrachloroethylene the CGC values are even less than 0.1 wt %. Organogelators with such low CGC values are classified as supergelators [4], and thus the present quaterthiophene gelator T1 belongs to this category. The

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

• properties were extended from only aromatic solvents, to a wide range of other types of solvents such as alicyclic hydrocarbons, alcohols and polar solvents such as DMSO and DMF. It was also found that a longer N-alkylurea chain conferred improved gelation power and higher thermal stability as compared to

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

• hydrocarbons such as propylene, propane, aromatics or sulfur containing aromatics. Unfortunately, these components are present in mixtures of high commercial relevance and can be separated economically by single membrane units or hybrid processes where conventional separation units are combined with membrane

• [23][24], hydrocarbons, e.g., propylene and propane [25][26] or ethylene oxide [27]. Strong plasticization can even lead to a partial dissolution of the membrane as it has been found in aromatic/aliphatic separation [28]. These results indicate that if new markets for membrane systems are found, then

• separate the mixtures of saturated and unsaturated hydrocarbons to obtain, e.g., propylene of sufficient purity for polymerization reactions. As shown in Figure 6, a hybrid process combining a membrane unit and a distillation column could lead, depending on the separation characteristics of the membrane

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

• hydrocarbons from the methylene units of the polymer backbone and surface contaminations (component peak A). Component peak B shows C–N bonds of primary amino groups of the polymer and the amine-side carbon atoms (O=CH–NH–C) of residual amido groups. Formamido groups (O=CH–NH–C) contribute to the component

Synthesis and crystallographic analysis of meso-2,3-difluoro-1,4-butanediol and meso-1,4-dibenzyloxy-2,3-difluorobutane

• Bruno Linclau,
• Leo Leung,
• Jean Nonnenmacher and
• Graham Tizzard

Beilstein J. Org. Chem. 2010, 6, No. 62, doi:10.3762/bjoc.6.62

• ][33][34]. Herein we describe the first synthesis of meso-2,3-difluoro-1,4-butanediol 3 as a further simple vicinal difluoride building block as well as its successful monosilylation, and our attempts to employ 3 for the synthesis of fluorinated hydrocarbons. Results and Discussion Synthesis The