The enantioselective hetero-Diels–Alder reaction of the cyclic azo compound 4-phenyl-1,2,4-triazole-3,5-dione
with 2,4-dienyl carboxylic acids was performed using tartaric acid ester as the chiral
auxiliary. The corresponding cycloadducts were obtained with enantioselectivities
of up to 76% ee. The cis-carboxylic acid produced could be converted into the corresponding cis- and trans-methyl esters by varying the reaction conditions.
Key words
hetero-Diels–Alder reaction - 4-phenyl-1,2,4-triazole-3,5-dione - 2,4-dienyl carboxylic
acid - tartaric acid ester - dehydropiperazine - methyl esterification