5‐Vinylpyrimidines. Synthesis via organopalladium intermediates

Reactions of 1,3‐dimethyl‐5‐iodouracil or 2,4‐dimethoxy‐5‐iodopyrimidine with vinyl acetate in the presence of a catalytic amount of diacetato‐bis (triphenylphosphine) palladium (II) resulted in good yields of the corresponding 5‐vinylpyrimidines. The reactions are viewed as resulting from regioselective addition of an initially formed 5‐pyrimidinyl palladium species to the double bond of vinyl acetate followed by elimination of a palladium acetate with regeneration of the double bond and formation of the 5‐vinylpyrimidine product.