Coupling of 5-iodo-2'-deoxyuridine (I) with 1-decyne (II) in the presence of cuprous iodide and tetrakis(triphenylphosphine)palladium furnished the 5-decynyl uridine derivative (III). This was then cyclized to the title furopyrimidinone by treatment with cuprous iodide and triethylamine in refluxing methanol.