2-氰基-3-羟基-2-丁烯酸乙酯

ethyl 4-acetamido-2,2-dimethyl-3-oxopentanoate

3-acetoxy-5-prop-2-enylcyclopent-2-en-1-one

(3-oxo-5-prop-2-enylcyclopenten-1-yl) acetate

[5-(2-methylprop-2-enyl)-3-oxocyclopenten-1-yl] acetate