SYNTHESIS OF SYMMETRICAL CHROMENO[2,3-<i>b</i>]CHROMENES ON THE BASIS OF О-QUINONE METHIDES AND 1,1-BIS(MORPHOLINO)ETHENE
DOI:
https://doi.org/10.1007/4228Keywords:
chromeno[2, 3-b]chromenes, ketenaminals, о-quinone methides, cascade reactions, Diels–Alder reaction.Abstract
The reaction of 1,1-bis(morpholino)ethene with precursors of о-quinone methides derived from Mannich bases of phenols and2-naphthols provided a series of chromeno[2,3-b]chromenes. The cascade process included a hetero-Diels–Alder reaction between
о-quinone methide and ketenaminal, elimination of secondary amine, and [4+2] cycloaddition between о-quinone methide and the
chromene intermediate.