Functional groups, organic with double bonds

The reaction of olefins with lead tetraacetate has not been a useful method in organic synthesis, because reactions such as addition of an oxygen functional group to the double bond, substitution of hydrogen at the allylic position, and C-C bond cleavage can occur to give complex mixtures of products. With some specific alkenes, however, reaction with lead tetraacetate can afford synthetically important compounds cleanly. For instance, reaction of the diacid with 6 equiv. lead tetraacetate in acetonitrile gave the dilactone in excellent yield (Scheme 13.36) [59]. 

The most important functional groups with double bonds are the C=C of alkenes and the C=0 of aldehydes and ketones. Both appear in many organic and biological molecules. Their most common reaction type is addition. 

The introduction of a reactive functionality into the polymer, such as unsaturation, offers the potential to use organic acids as coupling agents, but mixed results have been reported. A number of potentially suitable unsaturated products exist, notably, maleic acid and anhydride, acrylic and methacrylic adds, and unsaturated versions of fatty acids such as oleic acid. The acidities and double-bond reactivities of these compounds widely vary depending on their structures, and this probably accounts for the marked differences in their performance. Compounds such as acrylic acid have both high addity and high double-bond reactivity due to the proximity of the carbonyl group to the double bond. The only commercial products specifically developed for use with filled polymer systems are from Lubrizol Advanced Materials (SOLPLUS). 

Alkenes are hydrocarbons that contain a carbon-carbon double bond. A carbon-carbon double bond is both an important structural unit and an important functional group in organic chemistry. The shape of an organic molecule is influenced by the presence of this bond, and the double bond is the site of most of the chemical reactions that alkenes undergo. Some representative alkenes include isobutylene (an industrial chemical), a-pinene (a fragrant liquid obtained from pine trees), and famesene (a naturally occuning alkene with three double bonds). 

Various telomers and oligomers now available by the palladium-catalyzed reactions of butadiene with various nucleophiles are very useful compounds for organic synthesis, because these compounds have functional groups at one end and terminal double bonds at the other end. Several natural products have been synthesized from the telomers. 

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