Synthesis of (±)-10,10-dimethylprostaglandin E1 methyl ester and its 15-epimer

Abstract

(±)-10,10-Dimethylprostaglandin E₁ methyl ester (28) and its 15-epimer (32) have been synthesised in 20 steps from the readily available 2,2-dimethylcyclopentane-1,3-dione (1). The key step in the synthesis, selective reduction of the C-2 carbonyl function of ethyl 5-(6-ethoxycarbonylhexyl)-3,3-dimethyl-2,4-dioxocyclopentanecarboxylate (9) to give the corresponding all-trans-hydroxycyclopentanone derivative (11), has been achieved by catalytic hydrogenation over Adams catalyst.