4-Methyl-4-(OTMS)oct-1-en-1-yl)-5-oxo-3-((TES)oxy)cyclopentyl)heptanoate (Mixture of cis/trans Isomers) is an intermediate in the synthesis of 8-iso Misoprostol (I821345), a very widely sold analog of prostaglandin E1, which is potent but acts as a non-selective agonist towards the prostanoid EP receptor subgroup.