Diene

In organic chemistry, a diene (/ˈdaɪiːn/ DY-een); also diolefin, /daɪˈoʊləfɪn/ dy-OH-lə-fin) or alkadiene) is a covalent compound that contains two double bonds, usually among carbon atoms.

[1] They thus contain two alkene units, with the standard prefix di of systematic nomenclature.

Dienes can be divided into three classes, depending on the relative location of the double bonds:[1] According to the Gold Book definition, a "diene" could include one or more heteroatoms which replace unsaturated carbon atoms, giving structures that could more specifically be called heterodienes.

In the laboratory, more directed and more delicate processes are employed such as dehydrohalogenations and condensations.

Addition of polar reagents can generate complex architectures:[3] Nonconjugated dienes are substrates for ring-closing metathesis reactions.

These reactions require a metal catalyst:c The position adjacent to a double bond is acidic because the resulting allyl anion is stabilized by resonance.

In some cases, dienes are spectator ligands, remaining coordinated throughout a catalytic cycle and influencing the product distributions.