methyl 1,3-butadiene-1-carboxylate

(2S)-2-(bromomethyl)-2H-furan-5-one

(E)-5-bromo-4-hydroxy-2-pentenoic acid

methyl (Z)-2,4-pentadienoate

2,3-O-ethoxymethylene-5-O-toluenesulfonyl-D-ribonolactone