6-allyl-1,4-dioxaspiro<4,4>non-7-ene

6-pentyl-1,4-dioxaspiro<4.4>non-7-ene

2-phenylselenyl-5-(propene-3-yl)cyclopentanone

2-prop-2-enylcyclopentan-1-one

2-环戊烯酮