Diels-Alder reaction
Notice that the product retains the same basic cyclohexene structure. The substituents
simply extend from the ring.Alkynes can also react as dienophiles.
Diels-AlderreactionscansometimesreversethemselvesthroughRetro-Diels-Alderreactions.
For example, dicyclopentadiene can be cracked to form 1,3-cyclopentadiene by thermal
dissociation. Retro reactions occur under situations where the fragments are stable by
themselves.