ethyl 2-formyl-2-nitrile-4-pentynoate

2-cyano-2-ethoxycarbonyl-4-pentynal

2-ethoxycarbonyl-2-nitrile-4-pentynal

ethyl-2-cyano-2-formyl-4-pentynoate

ethyl 2-cyano-2-formyl-4-pentynoate