Methyl (2E)-4-(triphenylphosphoranylidene)-2-butenoate

methyl 4-diethoxyphosphorylbut-2-enoate

4-bromobut-2-en-1-ol

6-methoxy-6-oxohex-4-enoate

ethyl 2-[cyano(hydroxy)methyl]cyclopropane-1-carboxylate