Synthesis of 1,4-Dihydroquinolines and 4 H -Chromenes via Organocatalytic Domino Aza/Oxa-Michael/1,6-Addition Reactions of para -Quinone Methides and Ynals

An organocatalytic domino aza/oxa-Michael/1,6-addition reaction of -tosylaminophenyl or -hydroxyphenyl-substituted -quinone methides and ynals has been developed. In the presence of 20 mol % of morpholine, this unprecedented cascade reaction occurs readily in good yield (up to 99%), providing a highly efficient synthetic approach to synthetically valuable 1,4-dihydroquinolines and 4 -chromenes.