Abstract Addition of methanol or ethanol to perfluoro-1, 3-butadiene (I), catalysed with sodium alkoxide, afforded a mixture of the corresponding alkyl 4-alkoxy-3, 4, 4-trifluoro-2- butenoate VIb or VIa, dialkyl 2-fluorofumarate VIIb or VIIa, and dialkyl 2-alkoxy-2-butene- dioate IXb or IXa, in the overall yield 83% or 93%. The addition of propanol to the diene I in the presence of sodium propoxide gave dipropyl fluorofumarate (VIIc) as the sole product ...