To obtain information of structure–activity relationships (SARs) of 13-deoxytedanolide, its chemical transformation has been carried out, targeting on such functional groups as an epoxide, hydroxyls, ketones, and olefins. A total of 10 derivatives have been prepared and their cytotoxicity against P388 murine leukemia cells and inhibitory activity of polypeptide elongation in yeast cell lysate provided some important SARs; the southern hemisphere comprises the pharmacophore, while the epoxide-bearing side chain is essential for the activity.