Synthesis of electron-deficient dienes bearing a chromonyl moiety via the reaction of 3-formylchromones with ylidenemalononitriles and ethyl α-cyano-β-methylcinnamate

3-Formylchromones react with ylidenemalononitriles in the presence of triethylamine in dichloromethane to produce the target electron-deficient dienes connected to the chromone system with excellent E-selectivity and in good yields. In a similar manner, their reaction with ethyl α-cyano-β-methylcinnamate gave a mixture of E,Z- and E,E-isomeric chromonyl dienes, from which the former could be isolated in a pure state by crystallization.