The present invention is directed to a processes for the synthesis of trans isomer of 4,6-disubstituted-tetrahydro-furo, thieno, pyrrolo and cyclopenta-[3,4][1,3]dioxoles (Formula I). The process comprises the steps of: (a) obtaining a compound of Formula II, which is a mixture of cis and trans-diastereomers, and (b) chemically decomposing the compound of Formula II in a solution comprising a solvent and an acid that is a hydrogen donor or an electron pair acceptor, whereby the cis diastereomer is decomposed and the compound of Formula I is obtained. The compounds prepared by the present invention are useful in treating diseases or conditions associated with platelet aggregation and/or platelet activation.