While it is *possible* for another Diels-Alder to occur with another diene here, normal alkenes without electron withdrawing groups are not very good dienophiles. To get the reaction to work, you would likely have to heat it, and then you might run into problems with the retro-Diels-Alder occurring.

Cyclopentadiene *can* Diels-Alder with itself, but that’s as a concentrated liquid in the absence of solvent.

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This is usually beyond the scope of this course, but there are reactions known as “inverse electron diels alder” reactions, where *electron rich dienophiles* react with *electron poor * dienophiles. So if one were to treat that exo diels alder product with an electron-poor diene, another diels-alder reaction could occur.

Probably wouldn’t happen because the electronics are wrong. Need the diene plus a very electron withdrawing dienophile and linoleic doesn’t qualify in that regard. Diels Alder reactions in nature are well known, but usually intramolecular where there is higher effective concentration of reactants.

Cyclopentadiene is unusually reactive in Diels-Alder reactions because the diene is “locked” in an s-cis conformation. A quick Google search shows that DA reactions have been done with conjugated linoleic acids and reactive dienophiles like N-methyl maleimide: DOI: 10.1039/C2GC35792E

Thanks!

You’re right, Slim – things work slowly around here. On the fix list! EDIT: fixed. Thank you!