3,3a,6,6a-tetrahydro-2H-spiro[pentalene-1,2'-[1,3]dioxolane]

methyl 6-ethenyl-2-oxobicyclo[3.1.0]hexane-1-carboxylate

4-Hydroxy-5,6-dihydro-pentalene-1,2-dicarboxylic acid

2,3-dicarbomethoxy-6-pyrrolidinobicyclo(3,3,0)octa-1,3,5-triene

6-(aminomethyl)bicyclo<3.2.0>-2-hepten-6-ol