SYNTHETIC APPLICATION OF LITHIATION REACTIONS - XVI: SYNTHESES OF (+/-)TETRAHYDROPALMATINE, (+/-)CANADINE, (+/-)STYLOPINE AND (+/-)SINACTINE

Article abstract of DOI:10.1016/S0040-4020(01)91915-5

N,N-Dimethyl-3,4-dimethoxy- and methylenedioxybenzylamines were lithiated and the organolithium intermediates treated with paraformaldehyde to give the 2-hydroxymethyl derivatives.The latter were converted to 7,8-dimethoxy- and methylenedioxyisochroman-3-ones through successive reaction with ClCOOEt, KCN and KOH.The isochromanones on condensation with homoveratrylamine or homopiperonylamine, followed by cyclisation and reduction furnished the protoberberine alkaloids.