Total synthesis of Δ12-PGJ2, 15-deoxy-Δ12,14-PGJ2, and related compounds

A key cyclopentenone possessing the α-chain was synthesized from TBS ether of 4-cyclopentene-1,3-diol monoacetate, and submitted to aldol reaction at the α′-position with the ω-chain aldehydes followed by dehydration to produce the title compounds. In a similar manner, 5-dehydro compounds (acetylene analogues) were synthesized successfully. In addition, palladium-catalyzed reaction of 4-cyclopentene-1,3-diol monoacetate with methyl malonate, the first step of the synthesis, was improved to afford the product in high yield by using t-BuOK or LDA in place of NaH.