Cheudonic Acid

Whereas the 6-membered pyran ring usually occurs in natural products as a benzo derivative, some monocycMc structures are also known, most commonly as 4-keto derivatives called gamma-pyrones. Examples are maltol (3.46), which is found in the bark and needles of conifers such as pine cheUdonic acid (3.47), which is derived from poppy and other plants and kojic acid (3.48), which is formed in molds such as the Aspergilli. 

Dienes have been assembled to react in MOFs. In particular, Eddaoudi and coworkers employed Cu(II) ions to assemble the anion of the heterocyclic diolefin cheUdonic acid (cdo) for a donble [2-1-2] photodimerization (Fignre 17). The dicarboxylate reacted in a ID polymer via a SCSC transformation to give an unusual cagelike photodimer. 

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