Pyridazines were allowed to react with allyltributyltin in the presenc
e of chloroformate to give 1-alkoxycarbonyl-6-allyl- and 1-alkoxycarbo
nyl-4-allyl-dihydro-pyridazines as major and minor products, respectiv
ely. The reaction was applied to other diazines, and tetrahydro-adduct
s were obtained in the case of pyrimidine and pyrazine. Benzo-fused di
azines also reacted in the same manner to afford the allyl-adducts in
good yields.