5-pentan-3-ylidenecyclopenta-1,3-diene

5-prop-2-enylidenecyclopenta-1,3-diene

螺[1,3-二氧戊环-2,7'-双环[3.2.0]庚-3-烯]

5-(4-甲基-2-戊烷亚基)-1,3-环戊二烯

螺[2.4]庚-4,6-二烯