A three component "one-pot" condensation of 1,2- ethylenedioxybenzene and RCN nitriles with isobutylene oxide, isobutyraldehyde, or cyclohexanecarboxaldehyde in the presence of conc. H2SO 4 gives 1-R-3,3-dialkyl-6,7-ethylenedioxy-3,4-dihydroisoquinolines. © 2005 Springer Science+Business Media, Inc.