Studies on the Diels-Alder Reaction of 4-Carboxymethyl-5-ethoxyoxazole

The Diels-Alder reaction of 4-carboxymethyl-5-ethoxyoxazole (I) was investigated. First, the mechanism and the stereochemistry of the adducts in the course of the Diels-Alder reaction were discussed. Second, the reaction of I with asymmetrical dienophiles gave the substance that an electron attracting group was preferentially introduced at γ-position of pyridine nucleus. Finally, the reaction of I with maleic anhydride, fumaric acid, maleic acid and methacrylic acid afforded the decarboxylated compounds. The mechanism of these reaction was discussed.