2-methyl-5-methylidene-1-prop-2-enylcyclopenta-1,3-diene;1-allyl-2-methyl-5-methylene-cyclopenta-1,3-diene;1-allyl-2-methyl-5-methylenecyclopenta-1,3-diene;2-methyl-5-methylidene-1-prop-2-enyl-cyclopenta-1,3-diene
2-methyl-5-methylidene-1-prop-2-enylcyclopenta-1,3-diene