[3aR,4R(1E,3S),5R,6aS]-5-Benzoyloxy-4-(3-hydroxy-4-phenoxy-1-buten-1-yl)-hexahydro-2H-cyclopenta[b]furan-2-one can be used as reagent/reactant in preparation of 15-Fluoro prostaglandin FP agonists as a new class of topical ocular hypotensives for the treatment of glaucoma. It can be obtained from (-)-Corey Lactone Benzoate (C694990) which a corey lactone derivative used in the preparation prostaglandin analogues for use as vasolidator as well as EP4 receptor agonists. Molecular Formula: C24H23ClO6 Molecular Weight: 442.89