New Development in Syntheses of Prostaglandin Skeleton

Abstract

Four synthetic approaches to the primary PGs and its Stork's intermediate, and two approaches to the carbacyclin and its isocarbacyclin analogue are presented. In the first approach, PGE₂ was synthesized by the conjugate addition of vinylzincates to 2-cyclopentenones. In the second approach, the Stork's intermediate was synthesized by the [2, 3]-Wittig rearrangement. In the third approach, the 11-deoxy-Stork's intermediate was synthesized by the Pd(0)-catalyzed cyclization containing 1, 3-chirality transfer. In the fourth approach, PGE₂ was synthesized by the enone-switching reaction of the β-alkoxy-α-methylene cyclopentanone. The carbacyclin and its isocarbacyclin skeleton were synthesized by the Claisen rearrangement and Diels-Alder reaction, respectively, and those stereoselectivities were examined based on MM 2 transition model.