Aggregative activation and heterocyclic chemistry II nucleophilic condensations of ketone enolates on dehydrodihydropyran generated by complex bases

Article abstract of DOI:10.1016/0040-4020(94)01077-D

3,4-dehydrodihydropyran has been easily generated from 5-bromo-3,4-dihydropyran and nucleophilic or non nucleophilic complex bases. Under such conditions ketone enolates have been condensed for the first time on the short lived intermediate leading to heterocyclic derivatives under mild conditions and with good yields. The reactivity of dehydrodihydropyran is discussed.