2-methyl-5-methylidene-1-prop-1-en-2-ylcyclopenta-1,3-diene;1-isopropenyl-2-methyl-5-methylene-cyclopenta-1,3-diene;1-isopropenyl-2-methyl-5-methylenecyclopenta-1,3-diene;2-methyl-5-methylidene-1-prop-1-en-2-yl-cyclopenta-1,3-diene
2-methyl-5-methylidene-1-prop-1-en-2-ylcyclopenta-1,3-diene