Alkene compounds

Compound A (C7Hi5Br) is not a primary alkyl bromide It yields a single alkene (compound B) on being heated with sodium ethoxide in ethanol Hydrogenation of compound B yields 2 4 dimethylpentane Identify compounds A and B... 

Nitrile oxides react with a wide variety of alkenic compounds and this reaction may be complicated by dimerization of the nitrile oxide to furoxan in the presence of unreactive double bonds (Scheme 98). 

The reaction of alkyl nitro compounds with acetyl chloride in the presence of an alkenic compound produced a 2-isoxazoline. The mechanism is believed to proceed via a nitrile oxide and is illustrated in Scheme 112 (B-79MI41613). 

Table 6.1 Common Names of Some Alkenes Compound Systematic name...

Figure 6.4 The requirement for cis-trans isomerism in alkenes. Compounds that have one of their carbons bonded to two identical groups can t exist as cis-trans isomers. Only when both carbons are bonded to two different groups are cis-trans isomers possible.

The cis-trans naming system used in the previous section works only with disub-stituted alkenes—compounds that have two substituents other than hydrogen on the double bond. With trisubstituted and tetrasubstituted double bonds, a more general method is needed for describing double-bond geometry. (Tiisub-stitnted means three substituents other than hydrogen on the double bond tetrasubstituted means four substituents other than hydrogen.)... 

Low oxidation states - An important characteristic of transition metal chemistry is the formation of compounds with low (often zero or negative) oxidation states. This has little parallel outside the transition elements. Such complexes are frequently associated with ligands like carbon monoxide or alkenes. Compounds analogous to Fe(CO)s, [Ni(cod)2] (cod = 1,4-cyclooctadiene) or [Pt(PPh3]3] are very rarely encountered outside the transition-metal block. The study of the low oxidation compounds is included within organometallic chemistry. We comment about the nature of the bonding in such compounds in Chapter 6. 

Treatment of (Et0)2P(0)H with Pt(PEt3)3 cleanly forms HPt [P(0)(0Et)2](PEt3)2 via oxidative addition of the H-P bond (Scheme 20), which we believe is the initiation process of the catalysis. Mechanistic detail of the hydrophosphorylation reaction will be described for the reaction with alkene compounds. 

Phomopsis sp. strain endophytes of the medicinal plant Erythrina crista-galli continue to yield novel compounds (Table 1). New phenyl-propane, pyronol, benzoic acid, phenylpyran, macrocyclic, and alkene compounds were discovered, as well as the known compounds clavatol, 4-hydroxymellein, mellein, mevalonolactone, mevinic acid, nectriapyrone, phomol, scytalone, and tyrosol. The new compounds were phomopy-ronol (101), 3-phenylpropane-l,2-diol (102), 4-(2,3-dihydroxypropoxy) benzoic acid (103), 2-(hydroxymethyl)-3-propylphenol (104), 2-... 

Beckmann fragmentation is frequently applied to cyclic oximes resulting in a ring-cleavage reaction. Normally, a nitrile-alkene compound is obtained from the oxime and further transformation is usual. 

For the application of alkenes as precursors in the synthesis of carbohydrates, knowledge of their stereochemistry is essential. Fortunately, several alkenic compounds having a defined configuration of the double bond and proper functional groups are readily available, making them convenient substrates in the synthesis of sugars. 

Ruthenium tetroxide is a four-electron oxidant which directly transforms alkenic compounds into oxidative cleavage products, i.e. carbonyl compounds and carboxylic acids.288 The reaction can be visualized as proceeding according to a [4 + 2] cycloaddition of the cis-dioxo moiety with the alkene, resulting in the formation of a RuVI cyclic diester which decomposes to ruthenium(IV) dioxide and oxidative cleavage products (equation 114).288 This reaction can be made catalytic... 

Compound A must therefore be 2-bromo-3-ethylpentane. Dehydrobromination of A will follow Zaitsev s rule, so that the major alkene (compound B) is 3-ethyl-2-pentene and the minor alkene (compound C) is 3-ethyl-l-pentene. 

There will be numerous facts to learn in the course of the year, however. For example, chemical reagents necessary to carry out specific reactions must be learned. You might find a study aid known as flash cards helpful. These take many forms, but one idea is to use 3X5 index cards. As an example of how the cards might be used, consider the reduction of alkenes (compounds with carbon-carbon double bonds) to alkanes (compounds containing only carbon-carbon single bonds). The front of the card might look like this ... 

Further evidence for the involvement of 116 in the amination reaction comes from the isolation of the related alkene complex 122 which by heating in dioxane solution gives allyl amine 117 (Eq. (28)). The latter results for the iron chlorides indicate an on-metal process with the ene reaction taking place in the sphere of the iron center, with both the nitroso and alkene compound coordinated to the sphere of the metal [64c,d]. 

The general formula for alkenes implies that at least two carbon atoms in any alkene compound have fewer than four bonded atoms. As a result, chemists refer to alkenes as unsaturated compounds. Unlike saturated compounds, unsaturated hydrocarbons contain carbon atoms that can potentially bond to additional atoms. 

Aqueous potassium permanganate was added to the two test tubes on the left. One test tube contains an alkane compound. The other test tube contains an alkene compound. Which is which ... 

Atkinson, Pitts, and coworkers at the University of California at Riverside are in the process of publishing a series of papers on NO3 chemistry. I will briefly describe a few of their results. Their method involves the use of a smog chamber experiment with long path infrared absorption measurements of reactant concentrations [26]. Their kinetic measurements are based on the competition between two different reactants for the NO3 radical. N2O5 is used as a source of NO3. Table 2 summarizes some of their data for reactions of NO3 with selected organic compounds. Most of these materials are present in significant concentrations only in polluted urban environments. For the alkene compounds the rate coefficients follow the general trend found few the addition reactions of O and OH. This supports the proposal that the mechanism involves addition to the double bond. A dramatic increase in reactivity is observed with the... 

F2C=CX2 (X = F or Cl), especially F2C=CF2, form cyclobutanes with many alkenes. Compounds of this type even react with conjugated dienes... 

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. 

We shall examine most closely the compounds made up of aromatic and alkane units, the alkylbenzenes. We shall look much more briefly at the aromatic-alkene compounds (alkenylbenzenes) and aromatic-alkyne compounds (aikynylbenzenes). 

The reactions are usually easier with methylseleno than with pheiwlseleno, P Chlorophenylsele no or (p-trifluoromethyl)phenylseleno derivatives, and allenes and alkylidenecyclopropanes are much more difficult to synthesize than other alkenic compounds. Thus, although allyl selenides resulting from selective elimination of the hydroxy and the methylseleno moiety are usually produced from P-(methylseleno)-p -(phenylseleno) alcohols, - - in the case of l-seleno-l-(r-hy[Pg.702]

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