Hydrocarbons, with Cyclo-olefins

The Naphthene Hydrocarbons. The naphthene hydrocarboiis are also called cycloparaffins and, as this name implies, they are saturated hydrocarbons in which the carbon chains form closed rings. The general formula for this aeries is C Ha and consequently they are isomeric with the olefins. They are named fay placing the prefix cyclo- before the name of the corresponding parato hydrocarbon. The first member of this series is cyclopropane and has the structure shown. The... 

It can be seen from the graph that the equilibrium products at temperatures below 500°C are mainly alkanes (also known as paraffins or saturated hydrocarbons), with the equilibrium giving roughly a 2 1 ratio of isopentane to normal pentane. As the temperature is increased from 500°C to 600°C, there is increased formation of alkene compounds (also known as olefins). At 700°C, we see increased formation of cyclo-pentene and of dienes, and above 800°C dienes are the favored product. 

Cycloaddition reactions of benzyne with cyclic olefins. Benzyne reacts with cyclo-hexadiene to give, as the main products, hydrocarbons (1)—(4).1 The first (1) arises by 2 + 4 cycloaddition, (2) and (3) arise by ene cycloadditions, and (4) is a result of 2 + 2 cycloaddition. Addition of catalytic amounts of silver fluoroborate exerts a marked effect in this case (1) becomes almost the exclusive product. Silver ion, however. 

This review deals with metal-hydrocarbon complexes under the following headings (1) the nature of the metal-olefin and -acetylene bond (2) olefin complexes (3) acetylene complexes (4) rr-allylic complexes and (5) complexes in which the ligand is not the original olefin or acetylene, but a molecule produced from it during complex formation. ir-Cyclopentadienyl complexes, formed by reaction of cyclopentadiene or its derivatives with metal salts or carbonyls (78, 217), are not discussed in this review, neither are complexes derived from aromatic systems, e.g., benzene, the cyclo-pentadienyl anion, and the cycloheptatrienyl cation (74, 78, 217), and from acetylides (169, 170), which have been reviewed elsewhere. 

The above type of bonding is assumed to occur in other metal-olefin and metal-acetylene complexes (172). Acetylenes have two mutually perpendicular sets of ir-orbitals and are therefore capable of being bonded to one or to two metal atoms both types of complexes are known. When the hydrocarbon is a nonconjugated polyolefin e.g., cyclo-octa-1,5-diene, each C C bond interacts independently with the metal atom. In complexes of conjugated polyolefins, e.g., cyclopentadiene, infrared and nuclear magnetic resonance studies (99) indicate that it is not yet possible to distinguish between structure (IV), in which each C C bond independently contributes two --electrons to the metal-olefin bonding, and structure (V), in which... 

Cyclo-hexane.—=The resulting compound CeHi2 corresponds to the olefine unsaturated hydrocarbons, CnH2n, and is isomeric with hexene. Hexene, however, readily adds two atoms of hydrogen and yields hexane, whereas hexa-hydro benzene is with difliculty converted into hexane. The compound, therefore, is not unsaturated. More important still is the fact that it proves to be identical with hexa-methy-lene or cyclo-hexane which, as we have recently shown, is a carbo-cyclic compound represented as follows ... 

Polyolefins and acetylenic hydrocarbons react with almost explorave violence with white fuming nitric acid, and olefins react vigorously. Saturated hydrocarbons, however, such as n-decane react slowly with concentrated nitric acid. Cyclo-monoolefins, e.g., cyclohexene, may be nitrated with nitrogen tetroxide to mixtures of 1,2-dinitrocyclohexane apd nitritonitrocyclohexane. ... 

Each test was perfonned with a mixture containing all reactants including 0.15 % C of one of the selected hydrocarbons found in real exhaust gases n-, iso-and cyclo-alkanes, n- and iso-olefins, diolefins, alkynes and aromatics. 

The 1 1 complex derived from phenyltungsten trichloride and aluminium trichloride is an effective catalyst for diene-cyclobutane metathetical interconversions. Thus, the tetracyclic compounds (291) and (292) were respectively isomerized to the dienes (293) and (294). Rather more surprising was the virtually quantitative formation of the cyclobutanoid compound (296) from (295). Reaction of norbomadiene with 2,2 -bipyridyl(cyclo-octa-l,5-diene)nickel at 25°C yielded the exo-trans,endo-metal o-carbocyclic (297) which, on treatment with an activated olefin (e.g. maleic anhydride), afforded the cyclo-dimer (298 predominantly exo-trans,endo) in good yield by displacement of the hydrocarbon moiety. Catalytic conversions can also be achieved. 

Cycloaddition.— Reactions of electrophilic olefins and acetylenes with tricarbonyl-iron complexes of cycloheptatriene and cyclo-octatetraene lead to 1,3-exo-products. Troponetricarbonyliron and tcne, however, have now been found to give complex (20) which results from previously unobserved 1,5-exo-cycloaddition. A dipolar intermediate (21) resulting from initial attack by the electrophile on the hydrocarbon... 

Epoxy alcohols are the normal products of the [VO(acac)2]+(Me2C(CN)N a -catalysed oxidation of cyclic olefins by dioxygen however, cyclo-octene is oxidized exclusively to cyclo-octene oxide. The oxidation of sulphides and alkenes by peroxides with a [V(0)(acac)2] catalyst have been compared and the nature of the monoperoxovanadium(v) intermediate investigated. Complexation of a Cr(CO)3 unit to aromatic hydrocarbons enhances the benzylic positions towards attack by superoxide ion, e.g., diphenylmethane is readily converted into benzophenone. Metal porphyrin complexes ML4 continue to attract attention both as reversible oxygen-carriers (M = Fe) and oxidation catalysts (M = Mn, Fe, or Co ). For example [Mn (=0 IPh)(TPP)Cl] is believed to be involved in the oxidation of cyclohexene to cyclohexanol by PhIO in the presence of [Mn(TPP)]+ and a ferryl intermediate [Fe (0)L4] has been proposed in the oxygenation of triphenylphosphine with iron(ii) porphyrin. [M(TPP)]X (M=Mn, X = OAc M=Fe, X=C1 M = Co, X=Br) catalyses the epoxidation of styrene and cyclohexene with NaOCl under phase-transfer conditions. ... 

Perfluoropropene oxide is a convenient, volatile, thermal source of difluoro-carbene, and its use in the preparation of fluorocyclopropanes has been further exemplified, perfluorinated, polyfluorinated, and hydrocarbon olefins being employed as substrates (see also p. 17) it has also been employed to convert perfluorobut-2-yne into 3,3-difluoro-l,2-bis(trifluoromethyl)cyclo-propene. Qose examination of the reaction between the epoxide and a mixture of cis- and rra .r-l-chloro-l,2-difluoroethylene at ca. 200°C has revealed that stereospecific addition of difluorocarbene takes place, but that loss of configuration can subsequently result from slow thermal isomerization of the cyclopropane product. Thermal decomposition of perfluoropropene oxide at 200 "C in the absence of a trap yields mainly perfiuorocyclo-propane and trifluoroacetyl fluoride together with tetrafluoroethylene, perfluoroisobutene oxide, perfluorobut-l-ene, and poly(difluoromethylene). 

In the first stage, ethylene is oligomerized to give a Schultz-Flory distribution of linear olefins in the range C4 to C20. The catalyst is a soluble nickel complex formed by the reaction of bis(cyclo-octadienyl) nickel with a phenyl or cyclohexyl-substituted phosphine derivative of the type R2PCH2COO , in bu-tanediol solution. When the ethylene is removed, the products separate as a hydrocarbon phase, and the catalyst solution can then be recycled. 

The year 1958 represents a pivotal moment for the cyclopropanation reaction of olefins. At that time, Simmons and Smith at DuPont reported the reaction of diiodomethane and Zn/Cu couple in the presence of olefins to afford cyclopropanes [56]. An important further advance in the Simmons-Smith cyclopropanation reaction resulted from Dauben s observation that cyclo-hex-2-enol underwent syn-selective methenylation [57, 58]. Additionally, the reaction was noted to be accelerated by the resident allylic hydroxyl group in the substrate. As a representative example, treatment of 87 with CH2I2 and Zn/Cu furnished 88 as a single diastereomer moreover, the parent hydrocarbon (4,4,10-trimethyl-A -octalin) failed to react under similar condi-... 

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