Olefin conjugation

Represented by its abbreviation, MAV, the Maleic Anhydride Value Is based on the fact that olefinic conjugated double bonds can be added to maleic anhydride by the reaction below m]... 

Olefins conjugated with electron-withdrawing groups other than a carbonyl group undergo reactions with enamines in a manner similar to the carbonyl-conjugated electrophilic alkenes described above. Namely, they condense with an enamine to form a zwitterion intermediate from which either 1,2 cycloaddition to form a cyclobutane ring or simple alkylation can take place. 

Photodimerizations of other olefins conjugated with aromatic rings are shown below<51 53) ... 

Fuel components possessing conjugated olefins, conjugated carbonyl compounds, or any combination of chromophores or auxochromes can be the source of color bodies in fuel. Examples are provided in TABLE 4-9. ... 

The first metal-olefin complex was reported in 1827 by Zeise, but, until a few years ago, only palladium(II), platinum(Il), copper(I), silver(I), and mercury(II) were known to form such complexes (67, 188) and the nature of the bonding was not satisfactorily explained until 1951. However, recent work has shown that complexes of unsaturated hydrocarbons with metals of the vanadium, chromium, manganese, iron, and cobalt subgroups can be prepared when the metals are stabilized in a low-valent state by ligands such as carbon monoxide and the cyclopentadienyl anion. The wide variety of hydrocarbons which form complexes includes olefins, conjugated and nonconjugated polyolefins, cyclic polyolefins, and acetylenes. 

With a substituent such as a methyl group on the double bond of the olefin, conjugate addition products are isolated in satisfactory yields (equation 73). 

Some olefins conjugated with electron-withdrawing, unsaturated groups dimerize to cyclobutanes as photoproducts, apparently through their triplet states. For example, when acrylonitrile in acetone is irradiated under con-... 

At times, the carbonyl compound, obtained from the oxidation of an alcohol, suffers a further oxidation, causing the introduction of an olefin conjugated with the carbonyl. 

Anelli s protocol is not generally compatible with the presence of olefins,10 although the less reactive olefins conjugated with electron-with-drawing groups, like carbonyls, are not affected,45 and occasional examples in which normal olefins remain unchanged during the oxidation of alcohols are found in the literature.13... 

Inductive electron-withdrawal by the azido group, perhaps reinforced by the weak conjugative ( —K) effect, should activate nucleophilic addition (Ad ) reactions of olefins conjugated to the azido substituent. The only data available in this area concerns the addition in a dipolar aprotic medium of azide ion to picryl azide (18), in which the nucleophile is directed to the C(d position of the aromatic ring with the formation of the benzenide anion (19) . Although activation is predominantly due to the nitro groups, the inductive... 

Terminal olefins are easily hydrogenated. Their hydrogenation is much faster than the hydrogenation of double bonds in cyclic systems or internal double bonds. c/5-Olefms are hydrogenated faster than tran -olefins. Conjugated diole-... 

Addition of hydrogen cyanide to an olefin can be accomplished under catalysis with dicobalt octacarbonyl at 130° at a pressure of 25-200 atmospheres. Best results are obtained with terminal olefins, conjugated dienes, which give mainly 1,4-addition products, and with Diels-Alder adducts of cyclopentadiene, which give mixtures and/or position isomers. 

The influence of the mode of olefin substitution has been studied and it has been shown that /j,/j-dialkyl-subsiii utecl olefins conjugated with a sulfone are also very suitable for the cycloaddition. This is a rare example of such a substitution pattern in the acceptor substrate resulting in efficient cycloaddition. In the following examples, the palladium(O) catalyst was generated by reduction of palladium acetate (10 mol%) with butyllithium (20 mol%) in the presence of triisopropyl phosphite (60 mol %)58. 

Keywords Living polymerization, Living copolymerization, Rare earth metal complexes, Alkyl methacrylate, Alkyl acrylates, Lactones, Ethylene, 1-Olefins, Conjugated dienes, Acetylene... 

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