Disclosed is a process wherein a first olefin selected from certain .alpha.,.beta.-dihydroxyalkenes and 4-(alkenyl)ethylenecarbonates is reacted with a second olefin reactant to produce an olefin metathesis product. When the first olefin reactant is an optically enriched or enantiomerically pure .alpha.,.beta.-dihydroxyalkene, cross metathesis reactions produce products possessing the same optical purity. The .alpha.,.beta.-dihydroxyalkenes and the 4-(alkenyl)ethylene carbonates may be converted to hydrogenated products, and the 4-(alkenyl)ethylenecarbonates may be decarboxylated to provide the corresponding epoxides. The products of the disclosure may be used as monomers for the preparation of specialty polyesters and as intermediates in the manufacture pharmaceuticals and other chemicals.