(1R*,3S*,5S*)-7,7-dichloro-3-methyl-6-oxobicyclo<3.2.0>heptane-3-carboxylic acid

methyl (1R,3S,5R,6R)-3-methyl-6-hydroxybicyclo<3.2.0>heptane-3-carboxylate

methyl (1R,3S,5R)-3-methyl-6-oxobicyclo<3.2.0>heptane-3-carboxylate

methyl (2S,3aR,6aS)-1,2,3,3a,4,5,6,6a-octahydro-2-methyl-4-oxopentalene-2-carboxylate

tert-butyl 1-methyl-3-cyclopentencarboxylate