A simple and efficient method for synthesis of 5-substituted 2-deoxyuridine nucleosides using metal–halogen exchange reaction of 5-iodo-2-deoxyuridine sodium salt

Treatment of the sodium salt of 2-deoxy-3, 5-bis-O-(tert-butyldimethylsilyl)-5-iodouridine (3) with n-BuLi effected regioselective lithiation at the 5-position and the following reaction with various electrophiles afforded 5-substituted 2-deoxyuridines including 1b, the precursor of stable spinlabeled 1a, in good yields.