Synthesis of a Human Urinary Metabolite of Prostaglandin D2.

A chemical synthesis of the major human metabolite of prostaglandin D2, tricyclic-PGDM, is described. The synthetic route starts from iodocyclopentenone 1 (available from cyclopentadiene in 6 steps) and requires 13 synthetic transformations. The synthetic route takes advantage of a contrasteric allylation to establish the 1,2-cis relationship between the ring hydroxyl group and side chain. A second key sequence is the application of Fu's copper-catalyzed C-H insertion of a diazoacetate followed by an alkyne semihydrogenation to introduce the unsaturated side chain.