Methods for the Synthesis of 3-Oxocyclopentenes

The numerous methods for the preparation of the title compounds are surveyed. These compounds are major synthons for several important natural products including cis-jasmone, rethrolones, and prostaglandins. Basic approaches include cyclization of 1,4-diketones, modification of dioxocyclopentanes, molecular rearrangements, and direct introduction of oxygen. 1. Routes Based on 1,4-diketones 1.1. ß-Ketoester and Related Condensations 1.2. Approaches by way of Furans 1.3. Other 1,4-Diketone Preparations 2. Routes Based on Dioxocyclopentanes 2.1. 1,3-Dioxocyclopentanes 2.2. 1,2-Dioxocyclopentanes 3. Routes Based on Molecular Rearrangement 4. Direct Introduction of Oxygen 5. Miscellaneous Routes 6. Conclusions