Dienes 2- propane

Methyl-2-cyclohexenyloxy)-EI5/3, 2971 (In -> 1,2-Dien) Propan 2-Methoxy-2-phenyl-XIII/I, 412... 

Benzene-1,3-dicarboxylic acid 2-Methylbuta-1,3-diene Propan-2-ol or 1-Methylethanol 2-Hydroxypropanoic acid Dodecanoic acid Di(dodecanoyl) peroxide Dodecanol... 

Abbreviations acac, acetylacetonate Aik, alkyl AN, acetonitrile bpy, 2,2 -bipyridine Bu, butyl cod, 1,5- or 1,4-cyclooctadiene coe, cyclooctene cot, cyclooctatetraene Cp, cyclopentadienyl Cp, pentamethylcyclopenladienyl Cy, cyclohexyl dme, 1,2-dimethoxyethane dpe, bis(diphenyl-phosphino)ethane dppen, cis-l,2-bis(di[Atenylphosphino)ethylene dppm, bis(diphenylphosphino) methane dppp, l,3-bis(diphenylphosphino)propane eda,ethylenediamine Et,ethyl Hal,halide Hpz, pyrazole HPz, variously substituted pyrazoles Hpz, 3,5-dimethylpyrazole Me, methyl Mes, mesityl nbd, notboma-2,5-diene OBor, (lS)-endo-(-)-bomoxy Ph, phenyl phen, LlO-phenanthroline Pr, f opyl py, pyridine pz, pyrazolate Pz, variously substituted pyrazolates pz, 3,5-dimethylpyrazolate solv, solvent tfb, tetrafluorobenzo(5,6]bicyclo(2.2.2]octa-2,5,7-triene (tetrafluorobenzobanelene) THE, tetrahydrofuran tht, tetrahydrothicphene Tol, tolyl. 

Apart from the carbene-1,2-addition route starting from 1,3-dienes, vinylcyclo-propanes may be obtained from 1,4-dienes through a di-n-methane rearrangement. 

The heat of hydrogenation for allene (Problem 6.37) to yield propane is -295 kj/mol, and the heat of hydrogenation for a typical monosubstituted alkene such as pcopene is - 126 kj/mol. Is allene more stable or less stable than you might expect for a diene Explain. 

Electron-deficient 1,3-dienes are known to react when heated with metho-xy(aryl)- or methoxy(alkyl)carbene complexes to afford vinylcyclopropane derivatives with high regioselectivity and diastereoselectivity [8a, 24]. Cyclo-propanation of the double bond not bearing the acceptor functional group and... 

Han S.J., Lohse D.J., Radosz M., and Sperling L.H. Thermoplastic vulcanizates from isotactic olypro-pylene and ethylene-propylene-diene terpolymer in supercritical propane Synthesis and morphology. Macromolecules, 31, 5407, 1998. 

A similar system based on rhodium has been studied (123) and was found to be less active than the equivalent iridium catalysts. Selective hydrogenation of acetylenes to olefins and dienes to monoolefins can be performed using the rhodium system, and the authors note that although propan-2-ol is an effective source of hydrogen (via oxidation to acetone), mild pressures of hydrogen gas can also be employed. 

Studies of di-ir-methane photochemical rearrangements have been one of the main areas of research in organic photochemistry for many years (for reviews, see Refs. 1-4). The first example of a reaction of this type was reported by Zimmerman in 1967 in the sensitized irradiation of barrelene 1 that yields semibullvalene 2 [5] (Scheme 1). The reaction has been extended to a large number of acyclic and cyclic 1,4-dienes that yield the corresponding vinylcyclo-propanes on irradiation, in the di-ir-methane (DPM) version of the rearrangement. This reaction also takes place when a vinyl unit is replaced by an aryl group. A few representative examples of DPM rearrangements are shown in Scheme 1 [6-9]. 

By rapid expansion of supercritical propane solution (RESS), and isobaric crystallisation (ICSS), isotactic polypropylene and ethylene-butylene copolymers were precipitated from the supercritical solution. The RESS process produced microfibres with a trace of microparticles, while the ICSS process produced microcellular products. Improvement in thermal stability was achieved by first synthesising a thermoplastic vulcanisate from polypropylene and ethylene-propylene-diene terpolymer from a supercritical propane solution, followed by RESS. 28 refs. 

The formal addition of hydrogen atom to the terminal double bond of vinylcyclo-propanes and of 1,5-diene systems under triplet oxygen provides another sequential... 

Thiadisilacyclopropanes result from the reaction of disilenes with sulphur and episul-phides. From the mechanistic standpoint, the reaction of RR,Si=SiRR/ is of great interest and the separation of the (E)- and (Z)-isomers (trans and cis) [R = 2,4,6-( -Pr)3C6H2, R = t-Bu] has led to the separate addition of sulphur to each. This occurs within a minute to give trans and ds-isomers, respectively, the latter with slightly different Si—S bond lengths60. Propylene sulphide reacted similarly, and the reaction of (i-Bu)2Si=Si(Bu-t)2 with thiophene leads to sulphur abstraction with the formation of the thiadisilacyclo-propane, with Si—S bonds of 217.1 pm, along with the l,2-disilacyclohexa-3,5-diene and 2,6-disilabicyclo[3.1.0]hex-3-ene (equation 29)61. 

A comparative study of nanocomposites (16% Nafion-silica and commercial SAC-13) has been performed by Hoelderich and co-workers169 in the alkylation of isobutane and Raffinate II. Raffinate II, the remaining C4 cut of a stream cracker effluent after removal of dienes, isobutane, propane, and propene, contains butane, isobutylene, and butenes as main components. High conversion with a selectivity of 62% to isooctane was found for Nafion SAC-13 (batch reactor, 80°C). Both the quality of the product and the activity of the catalysts, however, decrease rapidly due to isomerization and oligomerization. Treating under reflux, the deactivated catalysts in acetone followed by a further treatment with aqueous hydrogen peroxide (80°C, 2 h), however, restores the activity. 

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