ethyl (1R)-2-oxo-1-(3-oxobutyl)cyclohexane-1-carboxylate

2,5-bis[(4-nitrophenyl)methylidene]cyclopentan-1-one

2-异丁基环戊酮

tert-butyl 3-methylcyclopentene-1-carboxylate

2-环戊酮羧酸