Abstract

In addition to the reactions with malic anhydride and related compounds, conjugated dienes react by 1,4-addition with olefinic and acetylenic compounds in which the unsaturated group is conjugated with one or more carbonyl or other unsaturated group. Even certain vinyls and allyl compounds have been found to function as dienophiles. Typical examples are the reactions of butadiene with acrolein beta-nitrostyrene, allyl chloride, and acetylene-dicarboxylic acid. The olefinic dienophiles yield cyclohexene derivatives and the acetylenic dienophiles lead to derivatives of 1,4-dihydrobenzene.