7,9-dihydroxy-2,3-dihydro-1H-cyclopenta[c]chromen-4-one

tert-butyl 2-oxocyclopentane-1-carboxylate

2-(ethoxycarbonyl)-2-(3,3,4,4,5,5,6,6-octafluoro-1-azacyclohex-1-en-2-yl)cyclopentanone

ethyl 2-amino-1-methylcyclopentane-1-carboxylate