Starting with 5-iodo-2′-deoxyuridine, a series of 5-alkynyl-2′-deoxyuridines (with n- propyl, cyclopropyl, 1-hydroxycyclohexyl, p-tolyl, p-tert-butylphenyl, p-pentylphenyl, and trimethylsilyl alkyne substituents) have been synthesized via the palladium-catalyzed (Sonogashira) coupling reaction followed by a simplified isolation protocol (76–94% yield). The cytotoxic activity of modified nucleosides against MCF-7 and MDA-MB-231 human ...