LITHIUM BROMIDE-PROMOTED THREE-COMPONENT SYNTHESIS OF OXA-BRIDGED TETRACYCLIC TETRAHYDROISOQUINOLINES

摘要

Heating a toluene solution of an alpha-isocyanoacetamide (1),an aldehyde (2) and an aniline (3) in the presence of lithium bromide at 60 °C provides the oxa-bridged tetracyclic tetrahydroquinoline (4) in good to excellent yield as a mixture of two separable diastereoisomers.In this one-pot multicomponent reaction,one C-N,one C-0 and three C-C bonds are formed with concomitant creation of five asymmetric centers and three heterocycles.Fragmentation of epoxy-tetrahydroquinoline (4) under mild acidic conditions affords 4,6-phenanthroline (5).