isomeric hexanes skellysolve b containing increasing amounts of ethyl acetate those fractions containing the desired octadiene diol are combined and concentrated to yield the formula xvii intermediate following the steps of chart d the formula xvii compound wherein z is 1 pent 2 enyl and u02dc represents the u03b1 configuration is transformed to pge 3 using methods generally known in the art thus the formula xvii diol is converted to the formula xviii bis tetrahydropyranyl ether the oxo group of the lactone is reduced to form the formula xix lactol the formula xx compound is formed by a wittig reaction using u03c9 chloro or u03c9 bromopentanoic acid the formula xx 9 hydroxy group is oxidized to the 9 keto group of the formula xxi intermediate and finally the protective tetrahydropyranyl groups are removed by hydrolysis to yield the desired formula xxii dl pge 3 following the procedures of example 11 but substituting the exo formula i aldehyde for the endo aldehyde there are obtained the formula vi vii viii and ix exo compounds which are converted to the formula x lactone diol and thence to dl pge 3 following the procedures of example 11 for dl pge 3 but substituting the 15 u03b2 r configuration formula x octenyne diol for the s configuration compound there are formed any of the formula xvii to xxi intermediates wherein u02dc indicates the u03b2 configuration and thence dl 15 u03b2 pge 3 of formula xxii wherein u02dc indicates the u03b2 configuration although example 11 illustrates one embodiment of the process for preparing pge 3 wherein.