3‐Dcazacytosine (4‐amino‐2‐pyridone, 3), 3‐doazauracil (4‐hydroxy‐2‐pyridone, 5), 3‐deaza‐cytidine (4‐amino‐1‐β‐D‐ribofuranosyl‐2‐pyridonc, 9), and 3‐deazauridine (4‐hydroxy‐1‐β‐D‐ribo‐furanosyl‐2‐pyridone, 11) were prepared in high overall yields from 1‐methoxy‐1‐buten‐3‐yne (1). Ethyl 3,5,5‐triethoxy‐3‐pentenoate (2), obtained from acylatioti of 1 with diethyl carbonate and subsequent in situ conjugate addition of ethoxide, was cyelized with ammonia to provide 3. Diazotization of 3 and subsequent in situ hydroxydediazotization afforded 5. Nucleoside 9 was obtained from the stannic chloride‐catalyzed condensation of bis‐trimethylsilylated 3 and 1‐O‐acetyl‐2,3,5‐tri‐O‐benzoyl‐β‐D‐ribofuranose (7), followed by ammonolysis of the blocking groups. Diazotization of 9 and subsequent in situ hydroxydediazotization afforded nucleosidc 11.