5,5-dimethylcyclopent-2-en-1-one

N-butyl-2,2-dimethylpent-4-enamide

N-butyl-N-chloro-2,2-dimethylpent-4-enamide

2,2-dimethyl-N-phenylpent-4-enamide

N-tert-butyl-2,2-dimethylpent-4-enamide