Methyl 4,6-dimethyl-2-oxo-2H-pyran-5-carboxylate
Ethyl 2-(dihydro-2H-pyran-4(3H)-ylidene)acetate
Methyl 4-formyltetrahydro-2H-pyran-4-carboxylate
Methyl 2-(dihydro-2H-pyran-4(3H)-ylidene)acetate
