ethyl 4-methylsulfanylbut-2-enoate

ethyl 2-(methylsulfanylmethyl)prop-2-enoate

6-methyl-6-tert-butyl-4,8-dioxa-5,7-dioxo-1,2-diazaspiro[2.5]oct-1-ene

2-tert-butyl-5-dimethylsulfonio-2-methyl-4,6-dioxo-1,3-dioxan-5-ide

2-tert-butyl-2-methyl-1,3-dioxane-4,6-dione