Cyclopentenone

Cyclopentenones are found in a large number of natural products, including jasmone, the aflatoxins, and several prostaglandins.

One of the routes involves elimination of α-bromo-cyclopentanone using lithium carbonate[2] and Claisen condensation-decarboxylation-isomerization cascades of unsaturated diesters as shown below.

[4] As a functional group, the synthesis of 2-cyclopentenones is accomplished in a variety of other ways, including the Nazarov cyclization reaction from divinyl ketones, Saegusa–Ito oxidation from cyclopentanones, ring-closing metathesis from the corresponding dienes, oxidation of the corresponding cyclic allylic alcohols, and the Pauson–Khand reaction from alkenes, alkynes, and carbon monoxide.

In one example, a Danishefsky-type diene is reacted with a cyclopentenone to yield a fused tricyclic system en route to the synthesis of coriolin.

[6] It has been isolated from pressure-cooked pork liver by simultaneous steam distillation and continuous solvent extraction.

Industrial synthesis of cyclopentenone
Industrial synthesis of cyclopentenone
Cyclopentenone in the synthesis of coriolin
Cyclopentenone in the synthesis of coriolin