1 - -1 -alkene 1,3-alkadiene

Bivalent radicals derived from unbranched alkenes, alkadienes, and alkynes by removing a hydrogen atom from each of the terminal carbon atoms are named by replacing the endings -ene, -diene, and -yne by -enylene, -dienylene, and -ynylene, respectively. Positions of double and triple bonds are indicated by numbers when necessary. The name vinylene instead of ethenylene is retained for —CH=CH—. 

Wilhoit, R.C., Marsh, K.N., Hong, X., Gadalla, N., Frenkel, M. Densities of Aliphatic Hydrocarbons Alkenes, Alkadienes, Alkynes and Miscellaneous Compounds. 

Polymerisa- diferent monomers add together on a large scale to form a polymer. The tion or monomers used are unsaturated compounds, e.g., alkenes, alkadienes... 

Tables Reduction of alkanes, alkenes, alkadienes and alkynes...

Depending on the reaction conditions, alkenes may undergo either of two types of catalytic polymerization. The products of the first type, which may be termed true polymerization, consist of alkenes having molecular weights which are integral multiples of the monomer alkene. The second type, conjunct polymerization, yields a complex mixture of alkanes, alkenes, alkadienes, cycloalkanes, cycloalkenes, cycloalkadienes, and, in some cases, aromatic hydrocarbons the products do not necessarily have a number of carbon atoms corresponding to an integral multiple of the monomer. 

The relevance of all this may seem tenuous, especially because no example of a simple cyclic polyene with a Mobius 7r system is known. However, the Mobius arrangement is relevant to cycloaddition because we can conceive of alkenes, alkadienes, and so on approaching each other to produce Mobius transition states when An electrons are involved. 

The same transition metal systems which activate alkenes, alkadienes and alkynes to undergo nucleophilic attack by heteroatom nucleophiles also promote the reaction of carbon nucleophiles with these unsaturated compounds, and most of the chemistry in Scheme 1 in Section 3.1.2 of this volume is also applicable in these systems. However two additional problems which seriously limit the synthetic utility of these reactions are encountered with carbon nucleophiles. Most carbanions arc strong reducing agents, while many electrophilic metals such as palladium(II) are readily reduced. Thus, oxidative coupling of the carbanion, with concomitant reduction of the metal, is often encountered when carbon nucleophiles arc studied. In addition, catalytic cycles invariably require reoxidation of the metal used to activate the alkene [usually palladium(II)]. Since carbanions are more readily oxidized than are the metals used, catalysis of alkene, diene and alkyne alkylation has rarely been achieved. Thus, virtually all of the reactions discussed below require stoichiometric quantities of the transition metal, and are practical only when the ease of the transformation or the value of the product overcomes the inherent cost of using large amounts of often expensive transition metals. 

Carlson, D. A., Roan, C.-S. and Yost, R.A. (1989). Dimethyl disulfide derivatives of long chain alkenes, alkadienes, and alkatrienes for gas chromatography/mass spectrometry. Anal. Chem., 61,1564-1571. 

Scolytidae Conophtorus n-alkanes, alkenes, alkadienes, 8 species heptacosene, two Page et al. (1990a)... 

Compounds are systematically named in the density tables as alky (alkenyl, alkynyl, etc.) derivatives of benzene in the style <side chains>benzene. Side chains consist of one or more alkyl (alkenyl, alkynyl, etc.) radicals attached to the benzene ring. Thus names such as butyl, pentyl, heptyl refer to saturated straight chain radicals. Unsaturated side chains are named as radicals from the corresponding alkene, alkadiene, alkyne, etc. Examples are ethenyl, (1-propenyl), (2-butenyl), (2,3-pentadienyl), and (4-pentynyl). The numbers indicate the postion of the double and triple bonds. 

Derivatives of benzene can also be named as phenyl derivatives of alkanes, alkenes, alkadienes, alkynes, etc. Examples of these two types of names are shown below. 

The most detailed smdies on the flavor of fish oil in recent years were probably those of Hsieh et al. (78, 79), Lin et al. (80), and Lin (81). In their studies, a series of alkanals, alkenals, alkadienals, and alkatrienals were determined by dynamic headspace gas chromatography-mass spectrometry in cmde menhaden oils (Table 11). Most of these aldehydes contributed to the characteristic oxidized oily odors, such as green grassy, waxy, and rancid in the crude oils. Alkatrienals, i.e., nonatrienal and decatrienals, were also found at ppb levels in the dynamic headspace of the crude oils. 2-fraM5,4-frflMi,7-cA-Decatrienal, 2-fra 5,4-d5,7-di-decatrienal,... 

Simple alkenes, alkadienes, and related compounds Alkanes Conclusions References... 

Table 2 Oxidation Potentials of Arylalkenes, Alkenes, Alkadienes, and Carotenes...

The dependence on Pd particle size of the hydrogenations of alkenes, alkadienes, and alkynes has been studied in the gas and liquid phases and for pure reactants or simulated real feedstocks. This is illustrated by some typical examples later. 

The whole chromatogram of PE pyrolysate is basically formed from a series of triplets (alkane, alkene, alkadiene). A narrow time window from 34 to 42 min. of the chromatogram from Figure 6.1.2 is shown in Figure 6.1.4. 

In addition to the arenes, enolates, and other nucleophiles depicted in Scheme 2.142, FITS reagents are also reactive in the perfluoroalkylation of unactivated alkenes, alkadienes [19], and acetylenes [20] (Scheme 2.146). In contrast with olefin perfluoroalkylation by means of perfluoroalkyl bromides or iodides (Section 2.2.1), this reaction does not follow a free radical mechanism but proceeds via cationic intermediates which can be either trapped by addition of nucleophiles or nucleophilic solvents or quenched by -deprotonation with a base (Scheme 2.147). 

Methylphenylacetylene (1-phenylpropyne), fert-butylphenylacetylene (1-phenyl-3,3-dimethyl-l-butyne), biphenylene, and diphenylacetylene (diphenyl-ethyne) were prepared by reliable methods. The other hydrocarbons were purchased and then purified until they met published criteria of purity (i.e., mp, thin layer chromatography, IR, and UV). The same procedure was followed for phenoxathiin, phenothiazine, and thianthrene. Finally, silicon derivatives of alkynes, alkenes, alkadienes, and arenes were made according to published procedures. 

The lower molecular weight acyclic unsaturated hydrocarbons (alkenes, alkadienes, alkynes, etc.) occur primarily, if not totally, in the vapor phase of mainstream smoke (MSS). Even though some of the vapor-phase components of cigarette MSS have been shown to be significant in vitro ciliastats, the low... 

The trialkyl or triaryl phosphite complexes are more accessible than those of tertiary phosphines. The phosphite ligands complex strongly to rhodium, and easily displace alkene, alkadiene and even carbonyF ligands from [RhCl(CO)2]2 (equations 41 and 42), a displacement that cannot be achieved by tertiary phosphines. Indeed, even tertiary phosphine ligands themselves can be displaced by the phosphite ligands (equation 43).The phosphite complexes can also be prepared by cleaving [RhX(P(OR)3 2]2 complexes with additional ligand (equation 26). 

To conclude this section, we should note what has not been discussed -and why. The emphasis has been on trying to understand how the nature of the surface metal atoms influences the type of hydrocarbon structure formed, and although there is a great deal of information available on the structures formed by higher and cyclic alkenes, alkadienes, alkynes and benzene, some of which will be touched on below, it is only with ethene that a sufficiently wide range of surfaces has been investigated to make comparisons between them possible. A further omission, to be remedied in Section 4.7, is any attempt to provide a theoretical basis for the observations any more profound than that outlined above. The reason for this delay is that further useful information comes from studying the detailed structures of certain adsorbed molecules (Section 4.5) and the manner of their thermal decomposition (Section 4.6). 

Aliphatic Hydrocarbons Alkenes, Alkadienes, Alkynes and Miscellaneous Compounds. 

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