2,2-diethoxy-4-methyl-5-methylidenefuran

5-hydroxy-4,5-dimethyl-5H-furan-2-one

(3aS,4S,6aR)-4-pivaloyloxymethyl-3a,4,6,6a-tetrahydro-3H-furo<3,4-c>pyrazol-6-one

(Z)-3-methyl-2,4-pentadienoic acid

3-methyl-4-oxopent-2-enoic acid