New and facile syntheses of 7-fluoroprostaglandin F2α 1 and chemically stable 7-fluoro-17,20-dimethyl-2,4-methyleneprostacyclin 2 from commercially available methylenecyclopentanone are described. Construction of the key 7-hydroxyprostaglandin skeleton has been efficiently accomplished by the coupling of acetylenic acids with cyclopentanecarbaldehyde 4 under mild conditions.