Methyl 4-pentenoate is an unsaturated methyl ester that is prepared by the esterification of 1-pentenoic acid with methanol. It undergoes amidation with formamide via acetone-initiated photochemical reaction to form a 1:1 adduct. The metathesis of methyl 4-pentenoate with different Mo(VI)alkylidene complexes have been reported. It acts as a chain transfer agent during the polymerization of exo,exo-5,6-bis(methoxymethyl)-7-oxabicyclo[2. 2. 1]hept-2-ene using RuII(H20)6(tos)2 (tos =p-toluenesulfonate) as a catalyst.