Abstract
rostaglandin E2 1 (PGE2) shows important biological activity because of ability to affect blood clotted and smooth muscle contraction. Moreover, prostaglandin E2 1 is used for cervical dilation during parturition or as an adjunct for cervical ripening and to induce uterine contractions in other obstetrical situations. In this synthesis, we focused our attention on constructing the cyclopentanone skeleton of PGE2 through cobalt-mediated Ferrier-type rearrangement. The synthetic routes includes: (1) starting from commercially available D-(-)-ribose 2, (2) carbon chain elongating with acetylenes via C-glycosidation 3, (3) manipulating to exo-vinyl ether 4, (4) converting the acetylenic moiety to its dicobalt complex 5, and (5) implementing Ferrier type rearrangement to afford the cyclopentanones 6a-d in 37-71% yields.