Institute for Bio-Medical Research, Teijin Ltd., Asahigaoka, Hino, Tokyo 191, Japan
Abstract:
(5
)-Prostaglandin E2 (7) was synthesized fron (
)-4-
-butyldimethylsilyloxy-2-cyclopentenone (1) by
2-alkenyloxycarbonylatlon of the organocopper conjugate-addition adduct (3) followed by intramolecular palladium-catalyzed decarboxylative allylic alkylation. The (5
)-prostaglandin E2 skeleton was also obtained from the β-keto allylic ester (11) by a similar decarboxylative allylic alkylation. The decarboxylative allylic alkylation of another type of the three-component coupling product (12) gave new 6-methyleneprostaglandin E1 skeleton (15a), which was converted into new 6-methylprosta-glandin I methyl ester (20)
6-methyleneprostaglandin F1 derivative (16) by two different ways. The stereochemistry of this intramolecular decarboxylative allylic alkylation was discussed in the reaction of 2-(
)- or (
)-2-butenyloxy-carbonyl] cyclopentanone systems.