二螺[2.1.2.1]辛烷

1-buta-1,3-dien-2-yl-1-(2-methylidenebutyl)cyclopropane

1-but-1-en-2-yl-1-(2-methylidenebut-3-enyl)cyclopropane

8-methylidenedispiro[2.0.2⁴.5³]undecane

6-Methylene-spiro[2.6]nonane