dimethyl 2-phenacylidenepropanedioate

dimethyl 3-benzoyloxirane-2,2-dicarboxylate

3,4,8,9,10-pentaoxatricyclo<5.2.1.02,6>decane

methyl 5-(2-ethoxy-2-oxoethyl)-2-oxo-5-phenyl-2,5-dihydrofuran-3-carboxylate