methyl 2,3-epoxy-2,6,6-trimethylcyclohexane-1-carboxylate

methyl 2,6,6-trimethyl-3-oxocyclohexene-1-carboxylate

2-(2-Methoxycarbonyl-ethyl)-7,7-dimethyl-1,4-dioxo-2,3,4,5,6,7-hexahydro-1H-indene-2-carboxylic acid methyl ester

2-(4,4-dimethyl-3,7-dioxo-1,2,5,6-tetrahydroinden-2-yl)acetic acid