Concise and Enantioselective Total Synthesis of 15-Deoxy-Δ12,14-Prostaglandin J2
摘要:
The concise and enantioselective synthesis of 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) has been accomplished in 11 steps from a known alcohol. The key step of the synthesis involves an asymmetric Rh-catalyzed cycloisomerization of ene-ynone, followed by an olefin isomerization.
The formal synthesis of (+)-15-deoxy-Δ12,14-prostaglandin J2 by utilizing SmI2-promoted intramolecular coupling of bromoalkynes and α,β-unsaturated esters
an SmI2-promoted radicalcyclization as a key reaction. It was conceived that 3 would be assembled from bromolactone 4 utilizing the radicalcyclization, however, 3 could not be obtained under the reaction conditions. On the other hand, the similar coupling reaction of bromoalkyne (R,E)-7a, the desired product syn-8 was given, via 3 for separation of diastereomers. The intermediate syn-8 was then transformed